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In a human, if you were to avoid a tympanotomy (surgical examination of the middle ear), how could you distinguish between a blocked Eustachian tube, a ruptured eardrum, or a perilymph fistula?
For instance, take the situation where a young man (suffering from a common cold) blew his nose violently, became dizzy for 1 minute, and then reported loss of hearing in one ear of about 40%. What would your diagnosis be, possible treatments, and expected outcome?
I am not an ENT doctor, but I think the following diagnoses would suffice to determine each of the conditions:
- Blocked Eustachian tube: Complaints would be of sudden onset and likely associated with a common cold, or ear infection. Providing the patient with standard decongestant should provide quick relief.
- Ruptured eardrum: Patient should have subtle hearing loss apparent on audiogram and it would be relatively easily identified by routine otoscopic examination.
- Perilymph fistula: This condition is hard to diagnose and I quote from Vestibular Disorders Association:
A physician can arrive at a presumptive diagnosis [of a perilymph fistula] through a thorough probing for events close in time to the onset of symptoms, along with a variety of tests. These tests can include hearing tests (audiogram, ECOG), balance tests (VNG, VEMP) and some form of a “fistula test.”
The periplymph fistula is by far the most severe condition and the one with the most prominent effects on the vestibular system (balance). Multiple tests and rigorous medical exam is necessary.
With regard to your presented case study: Again, I am not an ENT doctor but a ruptured ear drum can result in dizziness due to the fact that one inner ear is exposed to cold air due to a rupture and the other ear is not. Unilateral inner ear cooling can result in dizziness. However, blowing your nose is unlikely to cause a ruptured eardrum as it is generally caused by more serious barotrauma (diving accidents and in-air plane cabin pressure malfunctions) (Web MD).
Similarly, the fistula is most often caused by more serious traumatic injuries (Vestibular Disorders Association).
A blocked Eustachian tube sounds the most plausible, as it is associated with the common cold (Web MD). Violently blowing your nose can cause fluid to travel up the middle ear, and possibly cause subsequent infections.
Rare Disease Database
NORD gratefully acknowledges Howard W. Francis, MD, Professor, Seth E. Pross, MD, Fellow and Yuri Agrawal, MD, Associate Professor, Division of Otology and Neurotology, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, for assistance in the preparation of this report.
Synonyms of Acoustic Neuroma
- acoustic neurilemoma
- acoustic neurinoma
- fibroblastoma, perineural
- neurinoma of the acoustic nerve
- neurofibroma of the acoustic nerve
- schwannoma of the acoustic nerve
- vestibular schwannoma
An acoustic neuroma, also known as a vestibular schwannoma, is a rare benign (non-cancerous) growth that develops on the eighth cranial nerve. This nerve runs from the inner ear to the brain and is responsible for hearing and balance (equilibrium). Although there is no standard or typical pattern of symptom development, hearing loss in one ear (unilateral) is the initial symptom in approximately 90 percent of affected individuals. Additional common findings include ringing in the ears (tinnitus) and dizziness or imbalance. The symptoms of an acoustic neuroma occur from the tumor pressing against the eighth cranial nerve and disrupting its ability to transmit nerve signals to the brain. An acoustic neuroma is not cancerous (malignant) it does not spread to other parts of the body. The reason an acoustic neuroma forms is unknown.
Signs & Symptoms
Some individuals, especially those with small tumors, may not have any associated symptoms (asymptomatic). However, even small tumors, depending upon their location, can cause significant symptoms or physical findings.
Acoustic neuromas are slow-growing tumors that can eventually cause a variety of symptoms by pressing against the eighth cranial nerve. Hearing loss in one ear (the ear affected by the tumor) is the initial symptom in approximately 90 percent of patients. Hearing loss is usually gradual, although in some rare cases it can be sudden. In some cases, hearing loss can also fluctuate (worsen and then improve). Hearing loss may be accompanied by ringing in the ears, a condition known as tinnitus, or by a feeling of fullness in the affected ear. In some cases, affected individuals may have difficulty understanding speech that is disproportional to the amount of hearing loss.
Acoustic neuromas can also cause dizziness and problems with balance such as unsteadiness. In rare cases, dizziness or balance problems may occur before noticeable hearing loss. Because these tumors usually grow very slowly, the body can often compensate for these balance problems.
Although slow-growing, acoustic neuromas can eventually become large enough to press against neighboring cranial nerves. While rare, symptoms resulting from the involvement of other cranial nerves include facial weakness or paralysis, facial numbness or tingling, and swallowing difficulties. Facial numbness or tingling can be constant or it may come and go (intermittent).
In some patients, acoustic neuromas may grow large enough to press against the brainstem, preventing the normal flow of cerebrospinal fluid between the brain and spinal cord. This fluid can accumulate in the skull, leading to a phenomenon called hydrocephalus, which causes pressure on the tissues of brain and results in a variety of symptoms including headaches, an impaired ability to coordinate voluntary movements (ataxia), and mental confusion. Headaches may also occur in the absence of hydrocephalus and in some rare cases may be the first sign of an acoustic neuroma. In very rare cases, an untreated acoustic neuroma that presses on the brain can cause life-threatening complications.
The exact cause of an acoustic neuroma is unknown. Most cases seem to arise for no apparent reason (spontaneously). No specific risk factors for the development of these tumors have been identified.
A variety of potential risk factors for acoustic neuroma have been studied including prior exposure to radiation to the head and neck area (as is done to treat certain cancers) or prolonged or sustained exposure to loud noises (as in an occupational setting). Research is under way to determine the specific cause and risk factors associated with an acoustic neuroma.
In a small subset of cases, acoustic neuromas occur as part of a rare disorder known as neurofibromatosis type II. This rare genetic disorder is usually associated with acoustic neuromas affecting both ears at once (bilateral). (For more information on this disorder, choose “neurofibromatosis” as your search term in NORD’s Rare Disease Database.)
An acoustic neuroma arises from a type of cell known as the Schwann cell. These cells form an insulating layer over all nerves of the peripheral nervous system (i.e., nerves outside of the central nervous system) including the eighth cranial nerve. The eighth cranial nerve is separated into two branches the cochlear branch, which transmits sound to the brain and the vestibular branch, which transmits balance information to the brain. Most acoustic neuromas occur on the vestibular portion of the eighth cranial nerve. Because these tumors are made up of Schwann cells and usually occur on the vestibular portion of the eighth cranial nerve, many physicians prefer the use of the term vestibular schwannoma. However, the term acoustic neuroma is still used more often in the medical literature.
Acoustic neuromas affect women more often than men. Most cases of acoustic neuroma develop in individuals between the ages of 30 and 60. Although quite rare, they can develop in children. Acoustic neuromas are estimated to affect about 1 in 100,000 people in the general population. Racial differences have been reported in which Black, Hispanic, and Asian Americans have relatively lower rates of acoustic neuroma diagnoses than White Americans.
Approximately 2,500 new patients are diagnosed each year. The incidence has risen in the last several years, which some researchers attribute to the greater frequency in which small tumors are recognized. However, many individuals with small acoustic neuromas may remain undiagnosed, making it difficult to determine its true frequency in the general population.
Symptoms of the following disorders can be similar to those of acoustic neuromas. Comparisons may be useful for a differential diagnosis.
Meniere’s disease is a rare disorder affecting the inner ear that is characterized by periodic episodes of rotary vertigo or dizziness progressive, fluctuating, low-frequency (low-pitch) hearing loss ringing in the ears (tinnitus) and a feeling of fullness or pressure in the ear. Symptoms may occur daily or only a couple times a year. Symptoms may develop suddenly. Over time hearing loss and tinnitus may become permanent. Vertigo can be severe and cause nausea, vomiting and sweating. The exact cause of Meniere’s disease is unknown (idiopathic). (For more information on this disorder, choose “Meniere” as your search term in the Rare Disease Database.)
Bell’s palsy is a non-progressive neurological disorder of one of the facial nerves (7th cranial nerve). This disorder is characterized by the sudden onset of facial paralysis that may be preceded by a slight fever, pain behind the ear on the affected side, a stiff neck, and weakness and/or stiffness on one side of the face. Paralysis results from decreased blood supply (ischemia) and/or compression of the 7th cranial nerve. The exact cause of Bell’s palsy is not known. Viral (e.g., herpes zoster virus) and immune disorders are frequently implicated as a cause for this disorder. There may also be an inherited tendency toward developing Bell’s palsy. (For more information on this disorder, choose “Bell’s palsy” as your search term in the Rare Disease Database.)
Meningioma is a rare and typically benign (non-cancerous) tumor that can mimic an acoustic neuroma. While they can occur in any area of the lining of the brain and spinal cord (dura), meningiomas can form adjacent to the hearing and balance nerves and cause symptoms of unilateral (one-sided) hearing loss, dizziness or imbalance, facial numbness, and/or swallowing difficulty. Magnetic resonance imaging (MRI) can often distinguish between an acoustic neuroma and a meningioma but there are times when even a skilled radiologist is unable to definitively differentiate between the two. If surgery is performed, a pathologist will make the final diagnosis based on the microscopic appearance (histology).
A diagnosis of an acoustic neuroma is made based upon a thorough clinical evaluation, a detailed patient history, identification of characteristic findings and a variety of specialized tests. Such tests include hearing exams, x-ray scans such as magnetic resonance imaging (MRI) or computed tomography (CT), a specialized test that evaluates balance (electronystagmography), and a brainstem auditory evoked response (BAER).
An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures. MRIs are the most sensitive study to confirm the presence of an acoustic neuroma.
An electronystagmography test evaluates balance by detecting abnormal, involuntary eye movements, a condition known as nystagmus. Nystagmus may occur as a result of inner ear complications such as an acoustic neuroma.
A BAER exam checks hearing and neurological function and interaction by recording the brain’s response to certain sounds. Since an acoustic neuroma can disrupt the nerve pathway that relays sound from the ear to the brain, a positive result of a BAER exam could be caused by these tumors.
The treatment of an acoustic neuroma may involve observation (if the tumor is small and does not cause symptoms), surgical removal (microsurgery or excision) of the tumor, or the use of radiation to stop the tumor from growing (radiation therapy or radiosurgery).
This option may be preferred in affected individuals where no associated symptoms are present or where a small tumor is not growing or growing at a slow rate. This period of observation may be called “watch and wait”. In elderly individuals who do not have symptoms, watch and wait may be appropriate because an acoustic neuroma may not require treatment during an individual’s normal life expectancy and the inherent risks and complications of removal can be avoided.
Watchful waiting is also appropriate if an individual with hearing in only one ear is found with an acoustic neuroma in that ear. The patient may choose to live with the acoustic neuroma as long as it is not a life-threatening condition rather than risk further hearing loss that can potentially occur from therapy.
If an acoustic neuroma eventually causes symptoms, then radiation therapy or microsurgery may be necessary. There is not a single, “best” therapy for all affected individuals. The specific location and size of an acoustic neuroma as well as an affected individual’s overall level of hearing and general health are all considered when determining which treatment method is used.
Surgery performed with specialized instruments under a microscope (microsurgery) may be necessary in some individuals with an acoustic neuroma. Microsurgery allows physicians to perform surgery on very small body parts.
During microsurgery, a physician may remove all or part of an acoustic neuroma. Partial tumor removal is undertaken to reduce the risk of unwanted surgical complications. In other words, it may be easier and safer to take out part of the growth rather than the whole tumor. If the tumor is very large or if the person is older, partial removal may be more appropriate. Further surgery may be necessary in the future if partial tumor removal is performed.
When total tumor removal is indicated, the objective of the procedure is to protect the facial nerve and avoid facial paralysis. In addition the surgeon tries to preserve hearing as much as possible in the affected ear.
Three different surgical approaches are commonly used for individuals with an acoustic neuroma: retrosigmoid (suboccipital), middle fossa, and translabyrinthine. The size and location of the tumor as well as additional factors are all weighed when determining which approach is used.
Radiation Therapy (Radiosurgery or Radiotherapy)
Three dimensional focusing of radiation has become more accurate in recent years so that affected individuals may be treated at one session on an outpatient basis or, alternatively, smaller doses may be delivered over several sessions. The objective is to aim so accurately that the tumor cells are affected and damage to surrounding cells is minimized. Radiation therapy has the ability to stop growth of a tumor. Radiation therapy provides a noninvasive treatment option for individuals with an acoustic neuroma, but in some patients it may take weeks, months or even a couple years to see significant effects from this treatment. Tumors treated with radiation therapy can start to grow again at some point later on.
Post-treatment problems (from either surgery or radiation therapy) may include: cranial nerve deficits such facial weakness or numbness, hearing loss and dizziness. Headache, obstruction of fluid that surrounds the brain and spinal cord (cerebrospinal fluid), and/or decreased mental alertness due to blood clots or obstruction of flow of cerebrospinal fluid can also occur. Cerebrospinal fluid leakage or an infection that produces meningitis are rare complications of surgical therapy.
The facial nerve may be damaged by the acoustic neuroma or as a result of surgery. In some affected individuals, it may be necessary for the surgeon to remove portions of the facial nerve, resulting in temporary or permanent facial paralysis. The regrowth of the nerve (regeneration) and restoration of function to the muscles of the face may take up to a year. If the facial paralysis persists, a second surgery may be performed to connect the healthy portion of the facial nerve to another nerve such as the hypoglossal nerve (nerve that controls the tongue) in the neck or the nerve to masseter (nerve that helps with chewing) in the face. This may bring some improvement in function to the muscles of the face. There are a number of other surgical procedures that can aid in reanimating the face that can improve the function and appearance of the weakened side of the face.
Eye problems may develop in some individuals following surgical removal of an acoustic neuroma. Facial weakness can bring about incomplete eyelid closure on the affected side which may lead to irritation of the cornea. In rare instances, this has the potential to lead to blindness of the affected eye. The eye must be kept moist with frequent use of artificial tears, and a barrier applied during sleep, such as a moisture chamber, or taped closed. The use of an eye patch is discouraged as it may contribute to corneal damage.
Double vision (diplopia) may occur if there is pressure on the 6th cranial nerve, and there may be impairment of the muscles of the eyelids. Artificial tears or eye lubricants may be needed.
Additionally, if prolonged facial paralysis is not treated, then it is possible that food may “get lost” in the mouth on the affected side, which could contribute to dental problems.
There are many ongoing research investigations to better understand why acoustic neuromas form and continue to enlarge. For example, growth rates of acoustic neuroma tumors have been shown to be related to the expression levels of the common inflammatory chemical cyclooxygenase 2. Recent research has shown that the use of aspirin (a commonly used cyclooxygenase 2 inhibitor) among patients with acoustic neuroma is correlated with less tumor growth in a retrospective analysis. This was further supported with in vitro research showing that aspirin may lead to decreased rate of acoustic neuroma growth tumor culture.
Several investigations are underway looking into the potential use of other drugs for the treatment of acoustic neuromas primarily in patients with neurofibromatosis type II (NF2) with promising results. These include drugs that inhibit a number of cellular mechanisms including vascular endothelial growth factor (bevacizumab and PTC299), phosphoinositide-dependent kinase-1 (OSU-03012), ERBB2 receptor (Trastuzumab), epidermal growth factor (Erlotinib and Lapatinib), and p-21 activated kinases (IPA-3).
While continued work needs to be done, research into these and other drugs may lead to effective treatments for those with familial and sporadic acoustic neuromas in the future.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
For information about clinical trials sponsored by private sources, contact:
For information about clinical trials conducted in Europe, contact:
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- infections, such as rubella or herpes simplex virus
- premature birth
- low birth weight
- birth injuries
- drug and alcohol use while pregnant
- jaundice and Rh factor problems
- maternal diabetes
- high blood pressure while pregnant, called preeclampsia
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Berkow R., ed. The Merck Manual-Home Edition.2nd ed. Whitehouse Station, NJ: Merck Research Laboratories 2003:1260-1261.
Larson DE, ed. Mayo Clinic Family Health Book. New York, NY: William Morrow and Company, Inc 1996:584.
Carlson ML, Martson AP, Glasgow AE, et al. Racial Differences in Vestibular Schwannoma. Laryngoscope. 2016 Feb 24. doi: 10.1002/lary.25892. [Epub ahead of print]
Boahene K. Facial Reanimation After Acoustic Neuroma Resection: Options and Timing of Intervention. Facial Plast Surg. 2015:103-9.
Dilwali S, Kao S, Fujita T, Landeggar LD, Stankovic KM. Nonsteroidal anti-inflammatory medications are cytostatic against human vestibular schwannomas. Translational Research 2015166:1.
Kandathil CK, Dilwali S, Wu CC, Ibrahimov M, McKenna MJ, Lee H, Stankovic KM. Aspirin Intake Correlates With Halted Growth of Sporadic Vestibular Schwannoma In Vivo. Otol Neurotol 201435: 353-357.
Fong B, Barkhoudarian G, Pezeshkian P, Parsa AT, Gopen Q, Yang I. The molecular biology and novel treatments of vestibular schwannomas. J Neurosurg 2011115:906–914.
Hong B, Krusche CA, Schwabe K, et al. Cyclooxygenase-2 supports tumor proliferation in vestibular schwannomas. Neurosurgery 201168:1112–7.
Theodosopoulos PV, Pensak ML. Contemporary Management of Acoustic Neuromas. Laryngoscope 2011121:1133-1137.
Agrawal Y, Clark HJ, Limb CJ, Niparko JK, Francis HW. Predictors of vestibular schwannoma growth and clinical implications. Otol Neurotol. 201031(5):807-812.
Tan M, Myrie OA, Lin FR, et al. Trends in the management of vestibular schwannomas at Johns Hopkins 1997-2007. Laryngoscope. 2010120:144-149.
Newton JR, Shakeel M, Flatman S, Beattie C, Ram B. Magnetic resonance imaging screening in acoustic neuroma. Am J Otolaryngol. 2010 Jul-Aug31(4):217-20. doi: 10.1016/j.amjoto.2009.02.005. Epub 2009 Jun 24
Roehm PC, Gantz BJ. Management of acoustic neuromas in patients 65 years or older. Otol Neurotol. 200728:708-14.
Regis J, Roche PH, Delsanti C, et al., Modern management of vestibular schwannomas. Prog Neurol Surg. 200720:129-41.
Edwards CG, Schwartzbaum JA, Lonn S, Ahlbom A, Feychting M. Exposure to loud noise and risk of acoustic neuroma. Am J Epidemiol. 2006163:327-333.
Lin D, Hegarty JL, Fischbein NJ, Jackler RK. The prevalence of “incidental” acoustic neuromas. Arch Otolaryngol Head Neck Surg. 2005131:241-44.
Bush DA, McAllister CJ, Loredo LN, et al. Fractionated proton beam radiotherapy for acoustic neuroma. Neurosurgery. 2002:50:270-75.
Magnan J, Barbieri M, Mora R, et al. Retrosigmoid approach for small and medium-sized acoustic neuromas. Otol Neurotol. 200223:141-45.
Maeta M, Saito R, Nameki H. False-positive magnetic resonance image in the diagnosis of small acoustic neuroma. J Laryngol Otol. 2001115:842-44.
Petit JH, Hudes RS, Chen TT, et al. Reduced-dose radiosurgery for vestibular schwannomas. Neurosurgery. 200149:1299-306, discussion 1306-07.
Pothula VB, Lesser T, Mallucci C, et al. Vestibular schwannomas in children. Otol Neurotol. 200122:903-07.
Brackman DE, Owens RM, Friedman RA, et al. Prognostic factors for hearing preservation in vestibular schwannoma surgery. Am J Otol. 200021:417-24.
Kutz JW, Jr., Roland PS. Skull Base, Acoustic Neuroma (Vestibular Schwannoma). Medscape. Last Update: Jan 26, 2015. Available at: http://www.emedicine.com/ent/topic239.htm Accessed March 24, 2016.
Mayo Clinic for Medical Education and Research. Acoustic Neuroma. Last Update: Dec 24, 2014. Available at: http://www.mayoclinic.com/health/acoustic-neuroma/DS00803 Accessed March 24, 2016.
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Hidden hearing loss is hitting people of all ages. Neuroscientists are still debating why.
Those affected can hear all right, but when it’s noisy, they can’t understand.
Recent work seems to underscore the importance of protecting your ears—even when you’re young. Some of the hearing loss we’ve blamed on age might be due to how many fire trucks we’ve stood next to. Anthony Gerace
Tucked inside the air traffic control tower in Portland, Maine, Samantha Bassett was busy making sure planes didn’t crash into each other. All systems seemed normal that day in May 2014. Aircraft pinged their positions on radar while a constant and chaotic barrage of updates and requests flowed through her headset.
Then, out of nowhere, a burst of interference screamed into Bassett’s right ear. Those in the business call this phenomenon “getting sidetoned.” It can happen when lightning strikes, equipment malfunctions, or radio signals cause feedback like you might hear at a rock concert.
Bassett simply took off the headset, switched on speaker mode, and kept working. The planes must go on, after all.
Within the hour, though, Bassett got a headache and grew nauseous. She ended up going to see her doctor.
She knew something was wrong, but the results from an audiogram—a test of how well the ear picks up sound across different frequencies—looked normal. She could detect soft high and low tones, and the ones in between. “You don’t have any hearing loss,” her doc told her. “You seem fine.”
But Bassett wasn’t fine. The nausea went away quickly, but loud environments continued to induce headaches. Her interactions started to change. In bars and restaurants, she couldn’t track the chatter. “I could see people talking, I saw their lips moving, and I knew sound was coming out,” she says. But she couldn’t decipher what that sound meant. She began to smile and nod a lot. At work, when plane traffic got heavy, she had to concentrate to interpret what she heard. “Before this happened, I could follow three to four conversations at once—because that’s what air traffic controllers are trained to do,” she says. Now, everything seemed to become harder.
For the next few years, Bassett continued to see specialists and search for answers, until she learned about a recently discovered phenomenon called hidden hearing loss. Usually, we expect that people’s sonic perception degrades because the receptors that detect sound get damaged and can’t pass the signals onward toward the brain. In a groundbreaking 2009 mouse study, though, Harvard auditory neuroscientists Charles Liberman and Sharon Kujawa found that sometimes the problem resides in another part of the ear: The receptors are fine, but some of the synapses that should transmit the messages have withered. As Liberman sees it, the microphone is good, but the stereo jack is damaged.
A person with this sort of damage can detect quiet sounds just fine, so audiograms don’t register any anomalies. But when surrounded by noise—where chitchat bounces off minimalist walls, machinery rumbles against a colleague’s instructions, or music blares from speakers—they can’t pick out the sounds they care about. Some individuals with these symptoms experienced a single blast, as Bassett did. Others were exposed to lower decibel levels over time, like listening to their orchestra practice, working in an engineering lab, or even mowing the lawn every Saturday. Some take prescription drugs that harm the delicate ear. Some have autoimmune disorders. Some are in their 20s. Some are in their 80s. The triggers vary, but the results appear the same: People can hear, but when it’s noisy, they can’t understand.
There are no statistics on how many might be affected, or exactly how much exposure would make you susceptible. Doctors can’t point to a single living person and definitively say they have hidden hearing loss. That’s because they can’t dissect your head, remove your inner ear, and see that your synapses are screwed up—which is currently the definitive biological test for the disorder. So the victims of this aural anomaly are, like Bassett, told repeatedly there’s nothing wrong. That’s why Kujawa, Liberman, and international groups are racing to understand the condition. Their research is leading the biotechnology industry toward treatments that could reverse the damage by coaxing synapses to regrow and give people back their normal, clamorous lives.
It’s a scientific path that matters to everyone in the modern world, unless they live under very quiet rocks. We’re exposed to more noise than ever. And it might be hurting us more than we realize.
Hair cell balding can cause profound hearing loss. That’s why audiologists, the specialists who treat such problems, have stuck with the traditional audiogram to diagnose aural issues. Anthony Gerace
On a too-hot summer day in July, Kujawa sits in her office at Massachusetts Eye and Ear, a Harvard teaching hospital housed in, as she describes it, “a building that’s kind of been pasted together,” with a third floor that connects to the others only in some places. A bookshelf displays, perhaps lower down than you’d imagine, the etched-glass cylinder of her 2017 Callier Prize in Communication Disorders. Out the window, the Charles River silently flows. “Patients tell us all the time that they don’t hear as well as they used to,” Kujawa says, “and then they go into the clinic, and audiologists do the usual things and say, ‘You’re good.’” The patients, she says, “know they’re not good.”
No one really knew why until Kujawa and Liberman discovered hidden hearing loss, causing what many in the field call a paradigm shift—changing how researchers think about the ear’s inner workings and the definition of hearing loss. In the traditional view, the organ simply grows less adept at detecting sound. When noise enters, it hits the eardrum and vibrates those tiny bones whose names you had to memorize in seventh grade. The action sends pressure waves through the liquid in the cochlea, the snail shell of the inner ear. Hair cells live there, and their tips bend in response, producing electricity that releases neurotransmitters at the other end. These drift across the synapses to nerve fibers, sparking more current. The brain speaks this electrical language and turns the juice into conversation, cuckoos, car horns.
Hair cell balding can cause profound hearing loss. That’s why audiologists, the specialists who treat such problems, have stuck with the traditional audiogram to diagnose aural issues. They play a series of sounds at a range of frequencies and volumes. If you can hear across the octaves, even when the tone is quiet, doctors say you’re normal. But that, Liberman says, is not a nuanced test. He draws an analogy: “It’s like going to an eye doctor and asking, ‘Is the chart on the wall?’ instead of ‘Can you read the bottom line?’” It tells the examiner that your eyes can pick up light, sure—but it doesn’t tell them whether your brain can transpose those photons into letters.
Liberman, who has the air of a concerned father, first worked with Kujawa when she was a postdoc. Today, his office—complete with commissioned illustrations of the inner ear and a joke jar labeled “the ashes of old bosses”—is a few doors down from hers.
Kujawa first detected clues of hidden hearing loss after she left her postdoc position for a faculty job at the University of Washington in the late ’90s. There, she was looking into data from an ongoing long-term research project called the Framingham Heart Study, which launched in 1948. As its name suggests, it deals primarily with cardiovascular data, but participating doctors also administered hearing tests, surveying more than 5,000 people from the Massachusetts factory town of the same name and continuing to do so over decades. Kujawa found something surprising: The ears of people who had been exposed to noise kept getting worse over time, faster than in those without noise damage. Scientists had thought that after, say, a truck backfired near your head, you would either immediately suffer the ill effects or quickly recover. You’d maybe feel like you had cotton in your ears for a day or two, and then bounce back. The data, though, seemed to show that problems could be delayed or ongoing.
Kujawa didn’t know why this happened, but she thought she could test it. In 2001, she joined the faculty at Mass Eye and Ear and continued collaborating with Liberman. It was there, in 2009, that the two conducted the definitive study that established hidden hearing loss as A Thing. The experiment was, at base, simple: They played 100-decibel noise—about the same level as using a lawn mower—at mice for two hours. They waited a few days or weeks, then they autopsied the subject’s wee ears. The pair saw something they didn’t expect. The rodents’ hair cells were intact, but 50 percent of the synapses were gone. “Literally half the connections … That was terrifying,” Liberman says.
The takeaway was this: You could be exposed to sound that wasn’t loud or sustained enough to fry hair cells but could still cut wires to the brain. The neural connections were more delicate, and they degraded earlier and easier than the hair cells. Two years later, other researchers named this neurological phenomenon hidden hearing loss. “Hidden” because in humans, there’s no simple way to see if those synapses snap, and the deficiency doesn’t directly reveal itself in any standard clinical tests. You can lose nearly 90 percent of the electrical connections before a doctor could tell something was wrong. “If the hair cells are still functioning normally,” Liberman says, “the audiogram can still be completely normal.”
If you’ve lost that high a percentage of your ear-brain hookups, you don’t have enough processing power to decipher all the sounds that the hair cells detect. Researchers have now seen evidence of hidden hearing loss in dead mice, guinea pigs, rats, chinchillas, and nonhuman primates. But people, though their ears curl and conduct current like those animals, are more difficult to study than their mammalian counterparts because you can’t simply dissect a live ear.
There’s a lot researchers don’t know about what hidden hearing loss means: how big a deal it is, how commonly it happens, how to identify the underlying biology without an autopsy. But Kujawa and Liberman are working on studies that aim to tease results from both animals and humans. They’ll work out the anatomy and physiology from dead body parts and living animals, and compare it to data from the real-life corporeality of folks like Bassett, who’s participating in one of Mass Eye and Ear’s projects.
It took Bassett, now in her early 40s, a long time to find these researchers and learn about the condition. About a year after her injury, perplexed doctors sent her to Mass Eye and Ear. At first, even her doctor there—who was outside Kujawa and Liberman’s group—agreed with the others. But when Bassett wouldn’t back down, they gave her a deeper kind of test. With electrodes stuck to Bassett’s head, they looked at her brain activity when she listened to sounds while sleeping. The assessment—called an auditory brainstem response exam—measures the spikes and dips from all the nerve fibers transmitting audio to gray matter specialists routinely use it for infants or young children, who lack the verbal skills for a normal audiogram. That’s when the doctors finally saw something wrong. Bassett’s injured ear could hear, sure, but she wasn’t getting the message. Scientists still can’t match that result with evidence of wasted-away synapses in breathing patients, but it’s progress in the right direction. Bassett felt like she wasn’t crazy, though she still didn’t have a name for the condition or know that others shared it.
Things started to change only in 2019, when her doctor helped connect her to audiologist Stéphane Maison, who works with Kujawa and Liberman. As Bassett ticked off her symptoms, Maison responded: “Yep. Yep. Yep. Yep.” The problem had a name, and lots of other people felt cut off from the world in the same way they ranged from middle-aged office workers to musicians with a lot of concert experience. “He’s the first one who said: ‘This is real. I believe you,’” Bassett recalls.
The electrode test Bassett underwent could potentially contribute to future diagnoses. But right now, the response it measures simply correlates with the condition’s symptoms, and noise in the data and other variables can influence the results.
To prove what underlies hidden hearing loss in humans, you have to study autopsied ears, which Liberman says “tell the truth.” A hard-bound folder, sitting on a counter in his lab, holds microscope slides of see-through slices of the organ, part of the clinic’s 2,500-ear archive, donated by former clinic patients and other individuals. Many samples come with an audiogram so scientists can see what sort of physical damage matches up to what types of aural decline happened when the subjects were alive.
Toward the back of the room, several shelves hold the kinds of amber-liquid jars you see in mad-scientist movies, each containing a temporal bone, where the cochlea resides. They dangle in plastic blocks, as if listening to the liquid.
With samples like these—impossible to get while their owners were alive—Liberman can stain specific types of cells with different proteins, hit them each with a frequency of light, and watch them gleam in a rainbow of colors. With the resulting images, he can count the person’s neural connections and hair cells. The latter line up like little violet teeth—or dark, blank spots where they’re missing. The ends of the auditory nerve look like green jellyfish the sheaths around the nerve fibers licorice red. It’s paint-by-number science. If only it were so uncomplicated in living humans.
Liberman and Kujawa hope they can combine the anatomy lessons from deceased humans and animals with the aural and brain tests in study participants to decide how to diagnose hidden hearing loss, understand enough about how it works to fix it, and lock down its causes precisely enough that, maybe someday, we can better prevent it.
Scientists are just beginning to delve into the ear-brain hookups that are at the root of hidden hearing loss. Anthony Gerace
Before her accident, Bassett had been ultraprotective of her ears. She began working at airports when she was just 17. Her first job was answering the phone, but before long she was out on the runway, chasing away animals, driving fuel trucks, parking planes. “I had a boss who kind of treated me like his own kid, so he was constantly like, ‘Wear your earplugs wear your headphones,’” she says. She even took the plugs to concerts.
Research seems to underscore the importance of protecting your ears from quotidian sounds that you wouldn’t have given a second thought—even when you’re young and feel untouchable. Liberman and Maison recently did a study of college kids: About 35 percent of their subjects, mostly audiology students, had used safeguards, while the other 65 percent—mostly pop music students at several Boston schools—had been less careful. “A lot of them are really abusing their ears,” Liberman says.
Both groups had normal standard audiograms. But when the scientists looked at the kids’ brains, using a test similar to Bassett’s, the music students showed more signal from the hair cells compared with their cochlear neurons. In other words, some of the message was getting lost. These subjects also couldn’t recognize words as well when there was background noise or an echo, or when the sound was sped up.
This was a small pilot study, but Liberman and Maison plan to gather a larger population of people and track them to see how their hearing changes over time. Aging, Liberman suspects, isn’t the only thing causing the decline we experience long-term. Some of it is the result of exposure. “If we lived on a deserted island and were not constantly barraged by environmental noises created by human machines that our bodies did not evolve to protect ourselves against,” he muses, “would our hearing deteriorate as much as it does?” Old studies of tribespeople in Sudan in the early 1960s—their ability pristine compared with city dwellers of the same era—suggest it would not. Unlike the eyes’ tendency to grow farsighted no matter what, some of the decline we’ve blamed on age might be due to how many fire trucks we’ve stood next to.
Other researchers come at hidden hearing loss from different perspectives. Gabriel Corfas—a neuroscientist at the University of Michigan’s Kresge Hearing Research Institute who has collaborated with Liberman—thinks there’s more to the condition than shrinking synaptic power: In his view, it’s a symptom that can be caused by more than one problem. His research shows that when a mouse’s ears lose the myelin that insulates the neurons, the critter experiences the symptoms of hidden hearing loss, even though its synapses are fine. He theorizes that autoimmune disorders like Guillain-Barré syndrome—which is associated with food poisoning, the flu, hepatitis, and the Zika virus—strip the body of this myelin, and so might produce that result.
Colleen Le Prell of the Callier Center for Communication Disorders in Dallas (the place that gave Kujawa her award) harbors a deeper doubt about this new condition. Le Prell, whose work focuses on preventing human hearing loss, has found no evidence that recreational noise affects the ear. She asked adults in their 20s to keep track of the time and volume when they went to a loud place, and she measured their hearing and speech-recognition abilities before and after. In participants who opted for a lot of high-decibel fun, Le Prell found no indication that they experienced any permanent changes. She considered the sounds produced by wiggling hair cells, the subjects’ ability to comprehend words in both quiet and boisterous environments, and the electrical impulses within the ear. The kids seemed all right, at least if they quantified their activities accurately—not a guarantee.
Meanwhile, another group, at University College London, is trying alongside Mass Eye and Ear to develop a diagnostic test—and to see if those are worth doing in the first place. According to speech and hearing scientist Tim Schoof, the group is using the electrode-based exam, as well as tests of how well participants can decipher specific sounds against background noise, to compare clamor-averse young people with adults over 45 who have been exposed to loud environments. They’ve recruited through musicians’ groups, as well as shooting- and motor-sports clubs.
Back at Harvard, Kujawa continues to find motivation in the many emails she gets from distressed people who come across her research. “They recognize their problems in it,” she says. “They are looking for answers because the answers we’ve given them haven’t been very satisfactory.”
Things are starting to look up. Already, a few companies—some staffed by people who used to work with Kujawa and Liberman—are working on therapeutics, like chemicals called neurotrophins that could help neurons regrow their synapses. If the connections to the brain could blossom again, and the hair cells were fine, hearing could return to baseline.
Even without treatments, awareness has made life better for Bassett, in that she now understands what might be happening inside her head. “It was just such a huge relief to hear that there’s something wrong,” she says.
“We would be hard-pressed in our society to find somebody who has never had a noise exposure that was maybe too loud,” Kujawa says. The Occupational Safety and Health Administration sets limits—based on length, loudness, and frequency—on what sound levels are allowed and the situations in which protection is required. But those guidelines are based on what causes hair-cell loss. Kujawa and Liberman say we don’t know enough yet to determine exactly which levels are safe for synapses. There’s no public-awareness campaign urging people to wear earplugs when they cut the grass, which Liberman does, or stick their fingers in their ears when an ambulance drives by, as Schoof does. But maybe there should be, even though there aren’t yet hard-and-fast delineations for what “too loud” means. As researchers learn more about the ear’s hidden frailties, everyone else should too, so we stop thinking that hearing loss is a thing that just happens when you’re old, and no matter what.
Sidetone-type accidents are going to occur, sure, but much of hidden hearing loss might be within our control. We can decide to wear earplugs to the runway, the factory floor, or jam-band practice, and then maybe, at the dinner parties of the future, we’ll do more than just nod and smile.
This story originally published in the Noise, Winter 2019 issue of Popular Science.
The causes of migraine disease are generally not well understood, and causes of vestibular migraine are even less so. The belief is that abnormal brainstem activity changes how we normally interpret our senses, including pain, and alters blood flow through the arteries in the head as well.
There are mechanisms thought to be activated that link the trigeminal system (a part of the brain activated during migraines) to the vestibular system.
The association between hemiplegic migraine and episodic ataxia type 2 with mutations in the CACNA1A gene have raised the question of a possible connection between vestibular migraines and abnormalities in this gene. Other mutations in the ATP1A2 and SCN1A genes have also been studied in patients with vestibular migraines, but without a conclusive relationship so far.
All of these genes are related to ion channels that control how electricity travels in the brain.
Vestibular migraines usually occur in people with an established history of common migraines—also called migraine without aura—yet it's important to note that vestibular migraines are underdiagnosed.
Like other forms of a migraine, vestibular migraine is more common in women than men. These migraines often make their appearance between the ages of 20 and 40 but can begin in childhood. For women, a worsening of symptoms is often noted in the pre-menstrual period. Vestibular migraines are known to run in families.
Other Vestibular Disorders
Acoustic neuroma: This tumor in your inner ear isn’t cancerous and grows slowly, but it can squeeze the nerves that control your hearing and balance. That leads to hearing loss, ringing in your ear, and dizziness. In some cases, a neuroma can press against your facial nerve and cause that side of your face to feel numb.
An acoustic neuroma can be taken out with surgery, or your doctor might treat it with radiation to stop it from growing.
Ototoxicity: Some drugs and chemicals can damage your inner ear. Others attack the nerve that connects your inner ear to your brain. Either can cause hearing loss. Sometimes, this gets better when you stop taking the drug or stay away from the chemical. In other cases, the damage can be permanent.
Enlarged vestibular aqueducts (EVA): The narrow, bony canals that go from your inner ear to the inside of your skull are called vestibular aqueducts. If these get larger than they should be, you can lose your hearing. The causes of EVA aren’t clear, but they seem to be linked to certain genes you can get from your parents.
There’s no proven treatment for EVA. The best ways to safeguard your hearing is to avoid contact sports or anything that can lead to a head injury, and stay away from fast changes in pressure, like the kind that happens with scuba diving.
Vestibular migraine: If your brain sends the wrong signals to your balance system, that can lead to a severe headache, dizziness, sensitivity to light or sound, hearing loss, and ringing in your ears. Some people also say they get blurred vision.
If you have vestibular migraines often, your doctor may give you a drug to prevent them. Many medications, including some antidepressants, and calcium channel blockers (which relax your blood vessels), can help.
Mal de debarquement: When you move in a way you never have before, like on a boat, your brain adapts to the feeling. But sometimes, it can get “stuck” in the new motion, and you may feel off balance, like you’re rocking or swaying, even after you've stopped moving. This usually gets better in a few hours but sometimes symptoms can persist for weeks or even years.
You may experience other symptoms including a staggering walk, trouble focusing or feeling fatigue. There’s no cure, but you may be able to manage symptoms with medications and vestibular rehabilitation.
Vestibular Disorders Association: “The Human Balance System,” About Vestibular Disorders,” “Benign Paroxysmal Positional vertigo (BPPV),” “Ototoxicity,” “Acoustic Neuroma,” Vestibular Rehabilitation Therapy (VRT),” “Medication: Can Medication Help Me Feel Better?” “Dietary Considerations: Does Diet Really Matter?”
NHS Choices: “Labyrinthitis.”
Cleveland Clinic: “Vestibular Neuritis.”
American Academy of Otolaryngology-Head and Neck Surgery: “Meniere's Disease.”
National Institute on Deafness and Other Communication Disorders: “Meniere's Disease.”
American Hearing Research Foundation: “Perilymph Fistula,” “Top Ten Facts You Should Know about Vestibular Disorders.”
Royal Victorian Eye and Ear Hospital: “Vestibular Migraine.”
Onset of symptoms: acute, chronic, fluctuating, or recurrent?
What impact is there on day to day communication (for example, hearing in groups or one to one)?
Associated ear, nose, and throat (ENT) symptoms
Vertigo: described as a sensation of dizziness likened to “room spin” associated with or without nausea
Otorrhoea: is it purulent or clear?
Otalgia: otitis media or externa (is there any associated itching or discharge?)
Head and neck: localised pain, swelling, lump
Risk factors for otological disease
Infection (adult or childhood), trauma, or previous surgery
History of exposure to noise (including occupational)
Use of ototoxic drugs: permanent damage from aminoglycosides (such as gentamicin) or chemotherapy drugs (particularly platinum based treatments such as cisplatin) reversible damage from salicylates (most common in older people) quinine toxicity and very high dose loop diuretics.
Medical history: diabetes (doubles the risk of hearing loss) vasculitis autoimmune inner ear disease stroke (can lead to central loss of hearing).
Family history: common for otosclerosis, owing to autosomal dominant inheritance.
Be aware of the red flag symptoms and signs (box 1)
Box 1 Red flags
Sudden onset or rapidly progressive hearing loss
A rapid onset (over a 72 hour period) of a sensation of hearing impairment in …
Hearing Loss at Birth (Congenital Hearing Loss)
Congenital hearing loss means hearing loss that is present at birth. Causes of hearing loss in newborns include:
Genetics is the cause of hearing loss in many babies. Genetic hearing loss can be present at birth or develop later in life. The genes that cause hearing loss can come from one or both parents. You both may hear fine but carry a gene that causes hearing loss in your baby. Or, one of you may have a hearing loss that you pass on to your baby.
Some babies have a genetic syndrome. Hearing loss may be a part of the syndrome. Examples include:
Your baby will have his or her hearing tested at the hospital. This newborn hearing screening can help you know how your baby hears.
Hear and now
As far as Amy Yotopoulos could tell, her father, Edwin Lutz, was changing with age, the way most people do. He had become more introverted and quiet, less engaged. But he was still the same. He was simply finding everything harder to hear.
Illustration by Gérard DeBois
As his six grandchildren were born and learned to talk, he had difficulty picking up what they were saying. Trying to keep up in any conversation wasn’t just difficult, it was sometimes impossible. “If I didn’t hear something right at the beginning, I just gave up. So I just kind of gave up on listening,” Lutz said.
Lutz, who is now 76, was frustrated with his first pair of hearing aids, which he received about 12 years ago. He would only put them in if his wife, Peggy, suggested it, and then they would squeal or he’d still struggle to hear, only to give up and toss them back in the drawer. Yotopoulos watched as her father grew tired of saying “I can’t hear you” to her and his grandkids. “And it was hard for the kids to take turns, speak clearly and slowly, face Grandpa, et cetera,” she says. “So we all just figured this was the new normal.”
For Yotopoulos, director of the Mind Division of the Stanford Center on Longevity, this new normal was unacceptable. How could a man whose daughter was an expert on healthy aging be unable to address his hearing loss? Yotopoulos was well aware how common it is for aging adults to be afflicted with hearing loss how rarely they get adequate treatment and how vast the impact of untreated hearing loss can be on their health, mobility, finances and relationships.
With access to the Stanford Medicine physician-scientists who are making advances in the diagnosis and treatment of hearing loss, Yotopoulos also knew that new solutions were within reach — not just for her dad, but for the millions of people who have hearing loss today or are projected to have it in the future.
According to the National Institutes of Health, “Approximately one in three people between the ages of 65 and 74 has hearing loss, and nearly half of those older than 75 have difficulty hearing.” A review of literature in the October 2017 JAMA Otolaryngology raised that estimate, stating that hearing impairment affects nearly two-thirds of Americans who are 70 and older. Simply put, adults older than 70 are more likely to have hearing loss than to have normal, healthy hearing.
Despite these statistics, fewer than 20 percent of people with hearing loss obtain treatment. The small percentage of people who address the issue, such as by getting hearing aids, don’t usually do so until eight to 10 years after their initial diagnosis — enough time for some of the conditions related to hearing loss to take hold.
Understanding hearing loss
The way we live with hearing loss, however, is in the midst of a revolution, with enormous changes ahead. New approaches to testing and more affordable and effective treatments are clearing the way for healthier hearing in aging adults. Those changes can’t come soon enough. Aging adults are less willing than ever to let hearing loss slow them down and are more open to wearing advanced, in-ear devices.
Yotopoulos says people might be more motivated to take action if they were fully aware of the health consequences of not being treated.
“We can’t say hearing loss causes these issues at this point, but it’s correlated with decreased mental health, such as depression, and increased risk of cognitive decline, dementia and death,” Yotopoulos says. “It’s correlated with your balance, risk of falls and sense of social engagement. And we now know that social isolation has the same mortality and risk factors as smoking a pack of cigarettes a day, or as being obese.”
Because her dad had surmounted other serious health issues, his hearing loss seemed a relatively manageable problem. Still, it was a continual source of frustration. The simple joy of watching British television mysteries with his wife became a complicated activity full of missed moments and him asking questions. Lutz could no longer hear the sounds of the outdoors that he loved. And there was no joy in going to restaurants, where background noise made it impossible to follow conversations.
“I thought he was just kind of calmer or just wanted to watch things,” says Yotopoulos. “And it was a little sad because he wasn’t this ‘Hey let’s play a card game together’ kind of grandpa anymore.”
“Hearing loss is a potent isolator,” says Robert Jackler, MD, the Edward C. and Amy S. Sewall Professor in Otorhinolaryngology, professor of neurosurgery and of surgery at Stanford. “Human communication is nourishing not only to the soul, but also to the mind and, ultimately, the body. People who become isolated and unable to interact with others withdraw into an ever-closing circle that leads to unhappiness and depression for many.”
Edwin Lutz and his wife, Peggy, don’t let his hearing problems slow them down. They hike, kayak, backpack, sail, golf and enjoy time with friends and family. ‘At our age, one can never stop because if you do, you will never get back,’ he says. (Photo courtesy of Edwin Lutz)
For older adults, that isolation has far-reaching consequences. “When you lose your hearing, you don’t just lose your ability to hear,” says Matthew Fitzgerald, PhD, assistant professor of otolaryngology-head and neck surgery at Stanford. “There’s evidence to suggest that the brain may reorganize, that the brain will change, when you have hearing loss and are deprived of sound.”
Losing our sense of sound as we age is, for most people, caused by the deterioration of cells deep in the inner ear known as hair cells. “It’s a popular misconception that hearing loss, when you grow older, is ‘nerve deafness.’ In fact, we know that the hearing part of the brain and the hearing nerve remain intact,” explains Jackler, who is chair of the Department of Otolaryngology-Head & Neck Surgery. Instead, most adults experience a gradual breakdown of “a relatively small population of hair cells that take vibrations in the air and turn them into nerve impulses the brain understands as sound.” Repeated exposure to loud noise — at work sites or concerts, for example — can expedite that breakdown.
As a boy growing up on a farm in South Dakota, Lutz was a hunter. “We shot rifles and shotguns,” he says. “And we didn’t wear any hearing protection.” In 1965, when Lutz was 23, he began his service as a helicopter pilot for the Army, serving in the Vietnam War. “Even though we had flight helmets and earplugs, the high frequency of the turbines caused complete high-frequency hearing loss,” says Lutz. In 1987, his military retirement physical showed that Lutz still had hearing in the lower ranges, but over time he began to lose that as well.
“It wasn’t a single event that caused my hearing loss,” says Lutz. “It was a gradual progression, part of it age, and part of it the environment I was in.”
The onset of hearing loss as we age may be gradual, but the accumulated effect on our population is developing into an epidemic of drastic proportions. This is especially true in the United States as the baby boom generation — the 75 million babies born from 1946 to 1964 — has reached or is about to reach senior citizenship. The number of individuals of all ages with mild to complete hearing loss will balloon from just under 44 million today to nearly 55 million in 2030.
With such vast demand for audiological health care services, coupled with recent advances in technology and treatments, the hearing care industry is ripe for transformation. Even as the industry is changing, so are the aging individuals it serves. “It used to be that grandmother sat upstairs and knitted and came down for dinners and was with the grandchildren,” says Jackler. “Now seniors want to live active, full and socially engaged lives. They want to go to seminars, enjoy restaurants and be out with friends until a much later age.”
That’s certainly true for Ed and Peggy Lutz. While most of their friends near their home in the state of Washington travel south for the winter, the Lutzes go north. Ed Lutz is the youngest male member of his ski club at Big White in Kelowna, British Columbia. The oldest member is 90. “I’ve had two strokes and lost a third of my peripheral vision on the left side, so I follow my wife down the slopes now,” he says.
Lutz has also had two heart attacks, remedied by a pacemaker and defibrillator. Yet he and his wife still enjoy hiking and backpacking, sea kayaking, sailing on the lake, playing bridge, golfing, and volunteering at the local community civic center and the annual chamber music festival. “At our age, one can never stop because if you do, you will never get back.”
That desire to stay active and engaged as an aging adult can accentuate the stigma of hearing loss and of using hearing aids. For many adults, losing hearing is a signal of increasing and inevitable physical fragility that can be profoundly difficult to accept. Wearing a hearing aid can feel like having that fragility openly on display. Many would rather live without it.
Couple this with the outrageous prices of hearing aids and the barriers to care feel insurmountable.
High demand for cutting costs of care
Hearing aids cost anywhere from $1,000 to $6,000, which includes the device — or devices, as two are often needed — and the professional services to fit and program them. Few insurance companies provide coverage for hearing aids, though the full coverage the Veterans Health Administration provides is a welcome exception.
Hearing aids are the third most expensive tangible investment most families make, after a house and car. Yet the investment is still a good choice because the use of hearing aids has been shown to mitigate income loss up to $22,000 annually for people with extreme hearing loss. Annual excess medical expenditures for U.S. adults with hearing loss who are 65 and older are estimated at $3.1 billion, according to a study in the Journal of the American Geriatrics Society published in June 2014.
“It’s horrendous how expensive hearing aids are. They are enormously overpriced,” says Jackler. “The profit margin for hearing aids approximates that for popcorn at the movie theater.”
That movie-popcornlike profit margin may soon be a thing of the past, as the new wave of hearing health takes hold. On Aug. 18, 2017, the Over-the-Counter Hearing Aid Act, designed to provide greater public accessibility and affordability for over-the-counter hearing aids, was signed into law. The law will make it easier for people with mild to moderate hearing loss to access hearing aids. “The challenge,” explains Fitzgerald, “is getting people the right type of care they need for their level of hearing loss. Individuals who have more difficulty communicating will likely be best served by seeing an audiologist, while individuals who have less difficulty communicating should benefit from an over-the-counter device. What’s missing is a way to help triage or help guide patients as to what level of care they should be seeking.”
For family members like Yotopoulos and Peggy Lutz, having a way to help guide Ed Lutz to the right level of care would have simplified things. Recognizing that need — for people with hearing loss and their family members who notice it — Yona Vaisbuch, MD, clinical instructor of otolaryngology at Stanford, is developing an online tool for front-line assessment “to help bring people over the age of 55 to try solutions like hearing aids.” First conceived in a six-month project with the Stanford Byers Center for Biodesign, the nonprofit website WeHearYou will offer a short video on awareness, a basic hearing screening, an explanation of treatments and an option to input your location to find a provider.
“Today we know that age-related hearing loss doesn’t start when you’re 60 or 70. That’s when it becomes really symptomatic,” says Vaisbuch. “We now know that people in their 30s are already beginning to experience subtle decline.” His hope is that the website will be a way to screen and inform as many people as possible.
“When you have hearing loss, you spend a lot of time just trying to compensate for that,” says Vaisbuch. “We call it the cognitive load. You’re putting all your cognitive effort into hearing, instead of into the other things you’re doing. With time, those brain changes will not be reversible. That’s why we need to treat hearing loss as soon as possible.”
But to adequately treat hearing loss, patients must first have an accurate diagnosis — a key to revolutionized hearing care. Jackler and Fitzgerald are challenging the routine hearing tests of the past and are developing a new approach.
“The way hearing testing has been done for the past 60 years is threshold testing in a quiet room,” says Jackler. “Well, for most people, their problem is not how well they hear really soft whispers in a quiet room.”
“The reality is that when patients walk in the door, the No. 1 complaint they have is the difficulty of understanding speech in the presence of background noise,” says Fitzgerald, who is the chief of audiology at Stanford Health Care and Lucile Packard Children’s Hospital Stanford. “At Stanford, we’re taking the lead in trying to make speech in noise the default test of speech perception in the audiology test battery. This small, but fundamental shift would be one of the most significant changes in how hearing testing is done in this country in decades.”
The change would be particularly beneficial for older people with hearing loss, Fitzgerald says, because “when you get older, the ability to extract speech from background noise gets a little worse than when you’re younger, and the existing test battery doesn’t account for that possibility at all.” Testing a patient’s ability to communicate and understand speech may allow audiologists and physicians to parse the effects of aging from the effects of hearing loss.
While these new measures are part of the standard audiometric testing at Stanford, only some clinics nationally have incorporated them. “They are more often seen as something extra,” says Fitzgerald.
Changing decades of clinical practice doesn’t happen overnight, Fitzgerald says, and some audiologists question what it adds to their practice. His research aims to show how these measures can be readily integrated and to emphasize the additional information that can be gained from their use. The next, ideal step after that research is published, he says, would be for the governing bodies for both audiology and otolaryngology to recommend guidelines for speech in noise testing as part of the baseline audiological evaluation. “I’m optimistic that high-quality published research, in conjunction with maintaining a presence at national meetings, will facilitate this transition that is long overdue,” Fitzgerald says.
The more accurate the measure of a patient’s hearing difficulty, the more accurate and personalized treatment can be. Because hearing difficulty is highly individualized, from the degree and type of hearing loss right down to the shape of the ear, there’s no one-size-fits-all solution. With a broad selection of fittings, features and styles, a variety of hearing aids can drastically improve hearing for people with mild to severe hearing loss right now.
“There’s been more development in hearing aids in the past seven years than in the past 70,” says Gerald Popelka, PhD, adjunct professor of neurosurgery, head of the Stanford Ear Institute Neuromodulation Research Lab and one of the inventors of the first digital hearing aid.
High-tech advancements in devices
Those advances include everything from digital Bluetooth-connected hearing aids that work with devices like televisions and other sound systems to stream audio to designs that fit invisibly in the ear canal or with a low-profile shape around the ear. Each can be programmed to the individual frequency needs of the listener.
Even as today’s technology can readily solve the hearing difficulties of many people, the pace of innovation is still gaining momentum. Solutions to hearing loss are being developed both within the ear and beyond the ear. By the time that Generation Y — the only generation to outnumber baby boomers, and one that’s already accustomed to the regular use of in-ear devices — begins to reach age 60 in 2041, these innovations, along with others we cannot yet imagine, will be available.
“Increasingly,” says Jackler, “wearing something on your ear will be a badge of technological prowess rather than a marker of age and infirmity.” Jackler and his associates in Stanford’s audiology division and the Byers Center for Biodesign envision devices that are capable of doing much more than enhancing hearing for users of any age.
“It turns out that having a telemetry system attached to the human body has very important implications, not the least of which are for hearing,” says Jackler. “If you have something clipped on your ear that communicates out to a computer system, you have the ability to monitor oxygen, glucose, blood pressure and, through little EKG-like sensors on your chest, the electrical activity of your heart.”
All of this health monitoring could be available in the same device — Vaisbuch calls such devices “earables” — that stores and plays your music or audiobooks and connects to your phone or to audio text messaging. Such a device could, for example, alert you if you’re starting to cross the street when a car is coming or discreetly remind you of the name of the host’s spouse when you arrive at a party. As voice-to-text technology improves, it could eliminate the need for a keyboard, reducing carpal tunnel syndrome. It could be programmed to lower background noise and amplify voices in spaces that are often especially challenging for people with hearing loss, such as restaurants or theaters. It could also use noise-cancelling technology to silence the environment when desired.
“The ear becomes an important part of this enriched linkage between the human body and machines,” says Jackler. “You’re looking at a coupling of man and electronic device that really changes our understanding of how diseases function.”
Another intervention that Jackler hopes will become a reality in the near future is a biological cure for hearing loss. Through the Stanford Initiative to Cure Hearing Loss, more than a hundred scientists and technicians are working to cure inner-ear hearing loss — the type that results from hair cell degeneration — which remains incurable today.
Stefan Heller, PhD, the Edward C. and Amy H. Sewall Professor and professor and vice chair of research in otolaryngology, was the first to discover the stem cells within the inner ear of mammals that can be converted to hair cells. “We know that hair cells regenerate in birds, reptiles and amphibians,” says Jackler, “but not particularly in mammals such as humans.”
Under Heller’s leadership, the hearing loss initiative is exploring the manipulation of pluripotent stem cells — foundational stem cells that exist in the patient’s own body, in this case in the ear itself — to restore hair cells and allow patients to hear again. So far, the team has seen success only in mice.
“We’re very hopeful that this will come to humans in the next decades and that what was heretofore incurable will become curable,” says Jackler, “and that we’ll be able to rejuvenate hearing in the elderly, in the child born deaf and in someone who’s lost hearing from a variety of medical conditions.”
Until that cure is available, Jackler is still enthusiastic about the increasing options available to patients. “I have a huge optimism about the future of our ability to help people with hearing loss,” he says.
For two days in March 2017, the Stanford Center on Longevity gathered international experts in a broad range of fields including audiology, psychology, engineering, architecture and health advocacy to focus on improving communication for people with hearing loss. Yotopoulos and her colleagues had organized the conference to increase awareness of the prevalence and risks of untreated hearing loss, and of the need to think about hearing in the context of accessibility for all ages and in all settings. “It’s such an important piece of what Stanford University is doing with education and with creating community,” Yotopoulos says. “If we aren’t able to hear and listen to each other, we don’t have anything.”
Participants at the conference looked at many aspects of hearing, such as how acoustics in public spaces could be enhanced how hearing tests could be improved how hearing aid device technology, service, and cost could be transformed for the better and how close scientists are to a cure. Even as they underscored the coming crisis of hearing loss in a ballooning population of aging adults, they envisioned a world designed to enhance listening and communication.
Yotopoulos had already seen, personally, the impact of some of these changes. In 2015, her father was fitted with two Bluetooth-enabled hearing aids at a Veterans Affairs clinic in Washington. “The audiologist was great,” says Lutz. “He said, ‘Now you’ve got hearing aids, Ed, but you know you’ve still got to learn how to listen.’ And my wife thought that was really great advice.”
Lutz has his own advice for people with hearing loss: “Don’t give up if the first pair of hearing aids doesn’t feel right. Let your mind get accustomed to the new sounds.”
He’s happy to hear the birds easily again. And he’s able to keep up with the clues when he and his wife watch their favorite mysteries.
“My wife can set the TV volume to what’s comfortable for her, and with the device I can set it for what’s comfortable for me,” says Lutz. “And I’m not afraid to go to a restaurant or a crowded place because I can adjust the ambient noise. I feel more comfortable around people in conversations, and I understand the kids better.”
Being able to communicate easily with his wife has been the most meaningful improvement. “Just being able to hear what she said, rather than having to have her repeat herself three times,” says Lutz. “Now I can hear her more often and I can answer her, so it’s clear, yeah, I’m paying attention to you. We have a pretty good life, but the hearing aids have enhanced it.”
Though they live far apart, Yotopoulos loves talking with her dad on the phone about everything from the activities of her now-teenage kids to the Lutzes’ latest adventures — such as learning to play the guitar and speak Spanish. It’s not only easier for her to communicate with him, but it’s also good to see him as the active, involved person he really is. “Having the hearing aids that actually work for him changed so much,” she says.
How to prevent hearing damage from gunfire
Most noise-induced hearing loss is preventable. Terry urges parents to stress the importance of wearing hearing protection in noisy environments with their children and act as a role model by wearing it themselves.
&ldquoWe live in a really noisy world and good hygiene is important,&rdquo Terry said. &ldquoJust like you would wear vision protection (when shooting), you should wear hearing protection, too. It makes a difference and prevents hearing loss so it&rsquos a good idea to get it started off right in the first place. If you can prevent hearing loss, it&rsquos much better than having to deal with hearing loss later on.&rdquo
The bad news: Even with hearing protection, gunfire is so loud that people who are exposed to it regularly will likely develop hearing loss later in life. The (somewhat) good news? Hearing protection will at least reduce the severity of your hearing loss, possibly keeping it to a level that's still treatable with hearing aids.
Evidence supports COVID hearing loss link, say scientists
Credit: Unsplash/CC0 Public Domain
Hearing loss and other auditory problems are strongly associated with COVID-19 according to a systematic review of research evidence led by University of Manchester and NIHR Manchester Biomedical Research Centre (BRC) scientists.
Professor Kevin Munro and Ph.D. researcher Ibrahim Almufarrij found 56 studies that identified an association between COVID-19 and auditory and vestibular problems.
They pooled data from 24 of the studies to estimate that the prevalence of hearing loss was 7.6%, tinnitus was 14.8% and vertigo was 7.2%.
They publish their findings in the International Journal of Audiology.
However, the team—who followed up their review carried out a year ago—described the quality of the studies as fair.
Their data primarily used self-reported questionnaires or medical records to obtain COVID-19-related symptoms, rather than the more scientifically reliable hearing tests.
Kevin Munro, Professor of Audiology at The University of Manchester and Manchester BRC Hearing Health Lead said: "There is an urgent need for a carefully conducted clinical and diagnostic study to understand the long-term effects of COVID-19 on the auditory system.
"It is also well-known that viruses such as measles, mumps and meningitis can cause hearing loss little is understood about the auditory effects of the SARS-CoV-2 virus."
"Though this review provides further evidence for an association, the studies we looked at were of varying quality so more work needs to be done."
Professor Munro, is currently leading a year-long UK study to investigate the possible long-term impact of COVID-19 on hearing among people who have been previously treated in hospital for the virus.
His team hope to accurately estimate the number and severity of COVID-19 related hearing disorders in the UK, and discover what parts of the auditory system might be affected
They will also explore the association between these and other factors such as lifestyle, the presence of one or more additional conditions and critical care interventions.
A recent study led by Professor Munro, suggested that more than 13 percent of patients who were discharged from a hospital reported a change in their hearing.
Ibrahim Almufarrij said: "Though the evidence is of varying quality, more and more studies are being carried out so the evidence base is growing. What we really need are studies that compare COVID-19 cases with controls, such as patients admitted to hospital with other health conditions.
"Though caution needs to be taken, we hope this study will add to the weight of scientific evidence that there is a strong association between COVID-19 and hearing problems."
Professor Munro added: "Over the last few months I have received numerous emails from people who reported a change in their hearing, or tinnitus after having COVID-19.
"While this is alarming, caution is required as it is unclear if changes to hearing are directly attributed to COVID-19 or to other factors, such as treatments to deliver urgent care."