Diseases of the cochlea result in sensory hearing loss, a condition that is usually irreversible. Most cochlear diseases result in bilateral symmetric hearing loss. The presence of unilateral or asymmetric sensorineural hearing loss suggests a lesion proximal to the cochlea. Lesions affecting the eighth cranial nerve and central auditory system are discussed in the section on neural hearing loss. The primary goals in the management of sensory hearing loss are prevention of further losses and functional improvement with amplification and auditory rehabilitation.
Presbyacusis, or age-related hearing loss, is the most frequent cause of sensory hearing loss and is progressive, predominantly high-frequency, and symmetrical. Various etiologic factors (eg, prior noise trauma, drug exposure, genetic predisposition) may contribute to presbyacusis. Most patients notice a loss of speech discrimination that is especially pronounced in noisy environments. About 25% of people between the ages of 65 and 75 years and almost 50% of those over 75 experience hearing difficulties.
et al. Advances in understanding of presbycusis. J Neurosci Res. 2020;98:1685.
et al. Age-related hearing loss: unraveling the pieces. Laryngoscope Investig Otolaryngol. 2018;3:68.
et al. Age-related hearing loss: innovations in hearing augmentation. Otolaryngol Clin North Am. 2018;51:705.
Noise trauma is the second most common cause of sensory hearing loss. Sounds exceeding 85 dB are potentially injurious to the cochlea, especially with prolonged exposures. The loss typically begins in the high frequencies (especially 4000 Hz) and, with continuing exposure, progresses to involve the speech frequencies. Among the more common sources of injurious noise are industrial machinery, weapons, and excessively loud music. Personal music devices used at excessive loudness levels may also be injurious. Monitoring noise levels in the workplace by regulatory agencies has led to preventive programs that have reduced the frequency of occupational losses. Individuals of all ages, especially those with existing hearing losses, should wear earplugs when exposed to moderately loud noises and specially designed earmuffs when exposed to explosive noises.
et al. Noise-induced hearing loss and its prevention: current issues in mammalian hearing. Curr Opin Physiol. 2020;18:32.
et al. Risk of noise-induced hearing loss due to recreational sound: review and recommendations. J Acoust Soc Am. 2019;146:3911.
Head trauma (eg, deployment of air bags during an automobile accident) has effects on the inner ear similar to those of severe acoustic trauma. Some degree of sensory hearing loss may occur following simple concussion and is frequent after skull fracture.
K. Update on treatment options for blast-induced hearing loss. Curr Opin Otolaryngol Head Neck Surg. 2019;27:376.
Ototoxic substances may affect both the auditory and vestibular systems. The most commonly used ototoxic medications are aminoglycosides; loop diuretics; and several antineoplastic agents, notably cisplatin. These medications may cause irreversible hearing loss even when administered in therapeutic doses. When using these medications, it is important to identify high-risk patients, such as those with preexisting hearing losses or kidney disease. Patients simultaneously receiving multiple ototoxic agents are at particular risk owing to ototoxic synergy. Useful measures to reduce the risk of ototoxic injury include serial audiometry, monitoring of serum peak and trough levels, and substitution of equivalent nonototoxic drugs whenever possible. Efforts are underway to develop strategies, known as ototoxic chemoprotection, using drugs that shield the inner ear from damage during ototoxic exposure.
It is possible for topical agents that enter the middle ear to be absorbed into the inner ear via the round window. When the tympanic membrane is perforated, use of potentially ototoxic ear drops (eg, neomycin, gentamicin) is best avoided.
G. Pharmacological intervention in the field of ototoxicity. HNO. 2019;67:434.
et al. Local drug delivery for prevention of hearing loss. Front Cell Neurosci. 2019;13:300.
E. Sudden Sensory Hearing Loss
Idiopathic sudden loss of hearing in one ear may occur at any age, but typically it occurs in persons over age 20 years. The cause is unknown; however, one hypothesis is that it results from a viral infection or a sudden vascular occlusion of the internal auditory artery. Prognosis is mixed, with many patients suffering permanent deafness in the involved ear, while others have complete recovery. Prompt treatment with corticosteroids has been shown to improve the odds of recovery. A common regimen is oral prednisone, 1 mg/kg/day, followed by a tapering dose over a 10-day period. Intratympanic administration of corticosteroids alone or in association with oral corticosteroids has been associated with an equal or more favorable prognosis. Because treatment appears to be most effective as close to the onset of the loss as possible, and appears not to be effective after 6 weeks, a prompt audiogram should be obtained in all patients who present with sudden hearing loss without obvious middle ear pathology.
et al. A systematic review and network meta-analysis of existing pharmacologic therapies in patients with idiopathic sudden sensorineural hearing loss. PLoS One. 2019;14:e0221713.
et al. Clinical practice guideline: sudden hearing loss (Update). Otolaryngol Head Neck Surg. 2019;161:S1.
F. Hereditary Hearing Loss
Sensory hearing loss with onset during adult life is often familial. The mode of inheritance may be either autosomal dominant or recessive. The age at onset, the rate of progression of hearing loss, and the audiometric pattern (high-frequency, low-frequency, or flat) can often be predicted by studying family members. Great strides have been made in identifying the molecular genetic errors associated with hereditary hearing loss. The connexin-26 mutation, the most common cause of genetic deafness, may be tested clinically, as can most other single gene mutations known to cause hearing loss. Hearing loss is also frequently found in hereditary mitochondrial disorders. Progress is being made toward the development of methods to restore lost hair cells in genetic and other forms of deafness via gene therapy or stem cell–mediated techniques.
F. Autoimmune Hearing Loss
Sensory hearing loss may be associated with a wide array of systemic autoimmune disorders, such as systemic lupus erythematosus, granulomatosis with polyangiitis, and Cogan syndrome (hearing loss, keratitis, aortitis). The loss is most often bilateral and progressive. The hearing level often fluctuates, with periods of deterioration alternating with partial or even complete remission. Usually, there is the gradual evolution of permanent hearing loss, which often stabilizes with some remaining auditory function but occasionally proceeds to complete deafness. Vestibular dysfunction, particularly dysequilibrium and postural instability, may accompany the auditory symptoms. A syndrome resembling Ménière disease may also occur with intermittent attacks of severe vertigo.
In many cases, the autoimmune pattern of audiovestibular dysfunction presents in the absence of recognized systemic autoimmune disease. Use of laboratory tests to screen for autoimmune disease (eg, antinuclear antibody, rheumatoid factor, erythrocyte sedimentation rate) may be informative. Specific tests of immune reactivity against inner ear antigens (anticochlear antibodies, lymphocyte transformation tests) are current research tools and have limited clinical value to date. Responsiveness to oral corticosteroid treatment is helpful in making the diagnosis and constitutes first-line therapy. If stabilization of hearing becomes dependent on long-term corticosteroid use, steroid-sparing immunosuppressive regimens may become necessary.
et al. Demystifying autoimmune inner ear disease. Eur Arch Otorhinolaryngol. 2019;276:3267.
et al. Hearing loss in autoimmune disorders: prevalence and therapeutic options. Autoimmun Rev. 2018;17:644.
ESSENTIALS OF DIAGNOSIS
Perception of abnormal ear or head noises.
Persistent tinnitus often, though not always, indicates the presence of sensory hearing loss.
Intermittent periods of mild, high-pitched tinnitus lasting seconds to minutes are common in normal-hearing persons.
Tinnitus is defined as the sensation of sound in the absence of an exogenous sound source. Tinnitus can accompany any form of hearing loss, and its presence provides no diagnostic value in determining the cause of a hearing loss. Approximately 15% of the general population experiences some type of tinnitus, with prevalence beyond 20% in aging populations.
Though tinnitus is commonly associated with hearing loss, tinnitus severity correlates poorly with the degree of hearing loss. About one in seven tinnitus sufferers experiences severe annoyance, and 4% are severely disabled. When severe and persistent, tinnitus may interfere with sleep and ability to concentrate, resulting in considerable psychological distress.
Pulsatile tinnitus—often described by the patient as listening to one’s own heartbeat—should be distinguished from tonal tinnitus. Although often ascribed to conductive hearing loss, pulsatile tinnitus may be far more serious and may indicate a vascular abnormality, such as glomus tumor, venous sinus stenosis, carotid vaso-occlusive disease, arteriovenous malformation, or aneurysm. In contrast, a staccato “clicking” tinnitus may result from middle ear muscle spasm, sometimes associated with palatal myoclonus. The patient typically perceives a rapid series of popping noises, lasting seconds to a few minutes, accompanied by a fluttering feeling in the ear.
For routine, nonpulsatile tinnitus, audiometry should be ordered to rule out an associated hearing loss. For unilateral tinnitus, particularly associated with hearing loss in the absence of an obvious causative factor (ie, noise trauma), an MRI should be obtained to rule out a retrocochlear lesion, such as vestibular schwannoma. MRA and MRV and temporal bone computed tomography (CT) should be considered for patients who have pulsatile tinnitus to exclude a causative vascular lesion or sigmoid sinus abnormality.
The most important treatment of tinnitus is avoidance of exposure to excessive noise, ototoxic agents, and other factors that may cause cochlear damage. Masking the tinnitus with music or through amplification of normal sounds with a hearing aid may also bring some relief. Among the numerous drugs that have been tried, oral antidepressants (eg, nortriptyline at an initial dosage of 50 mg orally at bedtime) have proved to be the most effective. In addition to masking techniques, habituation techniques, such as tinnitus retraining therapy, may prove beneficial in those with refractory symptoms. Transcranial magnetic stimulation of the central auditory system has been shown to improve symptoms in some patients. Progress is also being made toward implantable brain stimulators to treat tinnitus.
et al. Approach to tinnitus management. Can Fam Physician. 2018;64:491.
Excessive sensitivity to sound may occur in normal-hearing individuals, either in association with ear disease, following noise trauma, in patients susceptible to migraines, or for psychological reasons. Patients with cochlear dysfunction commonly experience “recruitment,” an abnormal sensitivity to loud sounds despite a reduced sensitivity to softer ones. Fitting hearing aids and other amplification devices to patients with recruitment requires use of compression circuitry to avoid uncomfortable overamplification. For normal-hearing individuals with hyperacusis, use of an earplug in noisy environments may be beneficial, though attempts should be made at habituation.
et al. Insights from the third international conference on hyperacusis: causes, evaluation, diagnosis, and treatment. Noise Health. 2018;20:162.
et al. Association between hyperacusis and tinnitus. J Clin Med. 2020;9:2412.
ESSENTIALS OF DIAGNOSIS
Either a sensation of motion when there is no motion or an exaggerated sense of motion in response to movement.
Duration of vertigo episodes and association with hearing loss are the keys to diagnosis.
Must differentiate peripheral from central etiologies of vestibular dysfunction.
Peripheral: Onset is sudden; often associated with tinnitus and hearing loss; horizontal nystagmus may be present.
Central: Onset is gradual; no associated auditory symptoms.
Evaluation includes audiogram and electronystagmography (ENG) or videonystagmography (VNG) and head MRI.
Vertigo can be caused by either a peripheral or central etiology, or both (Table 8–2).
Table 8–2.Causes of vertigo. ||Download (.pdf) Table 8–2. Causes of vertigo.
|Peripheral causes |
| Vestibular neuritis/labyrinthitis |
| Ménière disease |
| Benign paroxysmal positioning vertigo |
| Ethanol intoxication |
| Inner ear barotraumas |
| Semicircular canal dehiscence |
|Central causes |
| Seizure |
| Multiple sclerosis |
| Wernicke encephalopathy |
| Chiari malformation |
| Cerebellar ataxia syndromes |
|Mixed central and peripheral causes |
| Migraine |
| Stroke and vascular insufficiency |
| Posterior inferior cerebellar artery stroke |
| Anterior inferior cerebellar artery stroke |
| Vertebral artery insufficiency |
| Vasculitides |
| Cogan syndrome |
| Susac syndrome |
| Granulomatosis with polyangiitis |
| Behçet disease |
| Cerebellopontine angle tumors |
| Vestibular schwannoma |
| Meningioma |
| Infections |
| Lyme disease |
| Syphilis |
| Vascular compression |
| Hyperviscosity syndromes |
| Waldenström macroglobulinemia |
| Endocrinopathies |
| Hypothyroidism |
| Pendred syndrome |
Vertigo is the cardinal symptom of vestibular disease. Vertigo is typically experienced as a distinct “spinning” sensation or a sense of tumbling or of falling forward or backward. It should be distinguished from imbalance, light-headedness, and syncope, all of which are nonvestibular in origin (Table 8–3).
Table 8–3.Common vestibular disorders: differential diagnosis based on classic presentations. ||Download (.pdf) Table 8–3. Common vestibular disorders: differential diagnosis based on classic presentations.
|Duration of Typical Vertiginous Episodes ||Auditory Symptoms Present ||Auditory Symptoms Absent |
|Seconds ||Perilymphatic fistula ||Benign paroxysmal positioning vertigo (cupulolithiasis), vertebrobasilar insufficiency, migraine-associated vertigo |
|Hours ||Endolymphatic hydrops (Ménière syndrome, syphilis) ||Migraine-associated vertigo |
|Days ||Labyrinthitis, labyrinthine concussion, autoimmune inner ear disease ||Vestibular neuronitis, migraine-associated vertigo |
|Months ||Acoustic neuroma, ototoxicity ||Multiple sclerosis, cerebellar degeneration |
1. Peripheral vestibular disease
Peripheral vestibulopathy usually causes vertigo of sudden onset, may be so severe that the patient is unable to walk or stand, and is frequently accompanied by nausea and vomiting. Tinnitus and hearing loss may be associated and provide strong support for a peripheral (ie, otologic) origin.
A thorough history will often narrow down, if not confirm the diagnosis. Critical elements of the history include the duration of the discrete vertiginous episodes (seconds, minutes to hours, or days), and associated symptoms (hearing loss). Triggers should be sought, including diet (eg, high salt in the case of Ménière disease), stress, fatigue, and bright lights (eg, migraine-associated dizziness).
The physical examination of the patient with vertigo includes evaluation of the ears, observation of eye motion and nystagmus in response to head turning, cranial nerve examination, and Romberg testing. In acute peripheral lesions, nystagmus is usually horizontal with a rotatory component; the fast phase usually beats away from the diseased side. Visual fixation tends to inhibit nystagmus except in very acute peripheral lesions or with CNS disease. In benign paroxysmal positioning vertigo, Dix-Hallpike testing (quickly lowering the patient to the supine position with the head extending over the edge and placed 30 degrees lower than the body, turned either to the left or right) will elicit a delayed-onset (~10 sec) fatigable nystagmus. Nonfatigable nystagmus in this position indicates CNS disease.
Since visual fixation often suppresses observed nystagmus, many of these maneuvers are performed with Frenzel goggles, which prevent visual fixation, and often bring out subtle forms of nystagmus. The Fukuda test can demonstrate vestibular asymmetry when the patient steps in place with eyes closed and consistently rotates in one direction.
In contrast, vertigo arising from CNS disease (Table 8–2) tends to develop gradually and then becomes progressively more severe and debilitating. Nystagmus is not always present but can occur in any direction, may be dissociated in the two eyes, and is often nonfatigable, vertical rather than horizontal in orientation, without latency, and unsuppressed by visual fixation. ENG is useful in documenting these characteristics. Evaluation of central audiovestibular dysfunction requires MRI of the brain.
Episodic vertigo can occur in patients with diplopia from external ophthalmoplegia and is maximal when the patient looks in the direction where the separation of images is greatest. Cerebral lesions involving the temporal cortex may also produce vertigo; it is sometimes the initial symptom of a seizure. Finally, vertigo may be a feature of a number of systemic disorders and can occur as a side effect of certain anticonvulsant, antibiotic, hypnotic, analgesic, and tranquilizer medications or of alcohol.
Laboratory investigations, such as audiologic evaluation, caloric stimulation, ENG, VNG, vestibular-evoked myogenic potentials (VEMPs), and MRI, are indicated in patients with persistent vertigo or when CNS disease is suspected. These studies help distinguish between central and peripheral lesions and identify causes requiring specific therapy. ENG consists of objective recording of the nystagmus induced by head and body movements, gaze, and caloric stimulation. It is helpful in quantifying the degree of vestibular hypofunction. Computer-driven rotatory chairs and posturography platforms offer additional diagnostic modalities from specialized centers.
et al. Vestibular lab testing: interpreting the results in the headache patient with dizziness. Curr Neurol Neurosci Rep. 2020;20:16.
et al. Dizziness and the otolaryngology point of view. Med Clin North Am. 2018;102:1001.
Vertigo Syndromes Due to Peripheral Lesions
A. Endolymphatic Hydrops (Ménière Syndrome)
The cause of Ménière syndrome is unknown. Distention of the endolymphatic compartment of the inner ear is thought to be part of the pathogenesis of the disorder. Although a precise cause of hydrops cannot be established in most cases, two known causes are syphilis and head trauma. The classic syndrome consists of episodic vertigo, with discrete vertigo spells lasting 20 minutes to several hours in association with fluctuating low-frequency sensorineural hearing loss, tinnitus (usually low-tone and “blowing” in quality), and a sensation of unilateral aural pressure (Table 8–3). These symptoms in the absence of hearing fluctuations suggest migraine-associated dizziness. Symptoms wax and wane as the endolymphatic pressure rises and falls. Caloric testing commonly reveals loss or impairment of thermally induced nystagmus on the involved side. Primary treatment involves a low-salt diet and diuretics (eg, acetazolamide). For symptomatic relief of acute vertigo attacks, oral meclizine (25 mg) or diazepam (2–5 mg) can be used. In refractory cases, patients may undergo intratympanic corticosteroid injections, endolymphatic sac decompression, or vestibular ablation, either through transtympanic gentamicin, vestibular nerve section, or surgical labyrinthectomy.
Patients with labyrinthitis suffer from acute onset of continuous, usually severe vertigo lasting several days to a week, accompanied by hearing loss and tinnitus. During a recovery period that lasts for several weeks, the vertigo gradually improves. Hearing may return to normal or remain permanently impaired in the involved ear. The cause of labyrinthitis is unknown. Treatment consists of antibiotics, if the patient is febrile or has symptoms of a bacterial infection, and supportive care. Vestibular suppressants are useful during the acute phase of the attack (eg, diazepam or meclizine) but should be discontinued as soon as feasible to avoid long-term dysequilibrium from inadequate compensation.
C. Benign Paroxysmal Positioning Vertigo
Patients suffering from recurrent spells of vertigo, lasting a few minutes per spell, associated with changes in head position (often provoked by rolling over in bed), usually have benign paroxysmal positioning vertigo (BPPV). The term “positioning vertigo” is more accurate than “positional vertigo” because it is provoked by changes in head position rather than by the maintenance of a particular posture.
The typical symptoms of BPPV occur in clusters that persist for several days. There is a brief (10–15 sec) latency period following a head movement before symptoms develop, and the acute vertigo subsides within 10–60 seconds, though the patient may remain imbalanced for several hours. Constant repetition of the positional change leads to habituation. Since some CNS disorders can mimic BPPV (eg, vertebrobasilar insufficiency), recurrent cases warrant head MRI/MRA. In central lesions, there is no latent period, fatigability, or habituation of the symptoms and signs. Treatment of BPPV involves physical therapy protocols (eg, the Epley maneuver or Brandt-Daroff exercises), based on the theory that it results from cupulolithiasis (free-floating statoconia, also known as otoconia) within a semicircular canal.
et al. Benign positional vertigo, its diagnosis, treatment and mimics. Clin Neurophysiol Pract. 2019;4:97.
et al. Benign paroxysmal positional vertigo. Adv Otorhinolaryngol. 2019;82:67.
In vestibular neuronitis, a paroxysmal, usually single attack of vertigo occurs without accompanying impairment of auditory function and will persist for several days to a week before gradually abating. During the acute phase, examination reveals nystagmus and absent responses to caloric stimulation on one or both sides. The cause of the disorder is unclear though presumed to be viral. Treatment consists of supportive care, including oral diazepam, 2–5 mg every 6–12 hours, or meclizine, 25–100 mg divided two to three times daily, during the acute phases of the vertigo only, followed by vestibular therapy if the patient does not completely compensate.
et al. Long-term clinical outcome in vestibular neuritis. Curr Opin Neurol. 2019;32:174.
et al. Clinical characteristics of acute vestibular neuritis according to involvement site. Otol Neurotol. 2020;41:143.
Labyrinthine concussion is the most common cause of vertigo following head injury. Symptoms generally diminish within several days but may linger for a month or more. Basilar skull fractures that traverse the inner ear usually result in severe vertigo lasting several days to a week and deafness in the involved ear. Chronic posttraumatic vertigo may result from cupulolithiasis. This occurs when traumatically detached statoconia (otoconia) settle on the ampulla of the posterior semicircular canal and cause an excessive degree of cupular deflection in response to head motion. Clinically, this presents as episodic positioning vertigo. Treatment consists of supportive care and vestibular suppressant medication (diazepam or meclizine) during the acute phase of the attack, and vestibular therapy.
et al. Vestibular dysfunction in acute traumatic brain injury. J Neurol. 2019;266:2430.
Leakage of perilymphatic fluid from the inner ear into the tympanic cavity via the round or oval window is a rare cause of vertigo and sensory hearing loss. Most cases result from either physical injury (eg, blunt head trauma, hand slap to ear); extreme barotrauma during airflight, scuba diving, etc; or vigorous Valsalva maneuvers (eg, during weight lifting). Treatment may require middle ear exploration and window sealing with a tissue graft; however, this is seldom indicated without a clear-cut history of a precipitating traumatic event.
et al. Diagnosis and treatment of perilymphatic fistula. Adv Otorhinolaryngol. 2018;81:133.
Position receptors located in the facets of the cervical spine are important physiologically in the coordination of head and eye movements. Cervical proprioceptive dysfunction is a common cause of vertigo triggered by neck movements. This disturbance often commences after neck injury, particularly hyperextension; it is also associated with degenerative cervical spine disease. Although symptoms vary, vertigo may be triggered by assuming a particular head position as opposed to moving to a new head position (the latter typical of labyrinthine dysfunction). Cervical vertigo may often be confused with migraine-associated vertigo, which is also associated with head movement. Management consists of neck movement exercises to the extent permitted by orthopedic considerations.
K. Approach to cervicogenic dizziness: a comprehensive review of its aetiopathology and management. Eur Arch Otorhinolaryngol. 2018;275:2421.
P. An overview of central vertigo disorders. Adv Otorhinolaryngol. 2019;82:127.
Episodic vertigo is frequently associated with migraine headache. Head trauma may also be a precipitating feature. The vertigo may be temporally related to the headache and last up to several hours, or it may also occur in the absence of any headache. Migrainous vertigo may resemble Ménière disease but without associated hearing loss or tinnitus. Accompanying symptoms may include head pressure; visual, motion, or auditory sensitivity; and photosensitivity. Symptoms typically worsen with lack of sleep and anxiety or stress. Food triggers include caffeine, chocolate, and alcohol, among others. There is often a history of motion intolerance (easily carsick as a child). Migrainous vertigo may be familial. Treatment includes dietary and lifestyle changes (improved sleep pattern, avoidance of stress) and antimigraine prophylactic medication.
et al. Migraine associated vertigo. Adv Otorhinolaryngol. 2019;82:119.
I. Superior Semicircular Canal Dehiscence
Deficiency in the bony covering of the superior semicircular canal may be associated with vertigo triggered by loud noise exposure, straining, and an apparent conductive hearing loss. Autophony is also a common feature. Diagnosis is with coronal high-resolution CT scan and VEMPs. Surgically resurfacing or plugging the dehiscent canal can improve symptoms.
et al. Systematic review of round window operations for the treatment of superior semicircular canal dehiscence. J Int Adv Otol. 2019;15:209.
et al. Aggregating the symptoms of superior semicircular canal dehiscence syndrome. Laryngoscope. 2018;128:1932.
Vertigo Syndromes Due to Central Lesions
CNS causes of vertigo include brainstem vascular disease, arteriovenous malformations, tumors of the brainstem and cerebellum, multiple sclerosis, and vertebrobasilar migraine (Table 8–2). Vertigo of central origin often becomes unremitting and disabling. The associated nystagmus is often nonfatigable, vertical rather than horizontal in orientation, without latency, and unsuppressed by visual fixation. ENG is useful in documenting these characteristics. There are commonly other signs of brainstem dysfunction (eg, cranial nerve palsies; motor, sensory, or cerebellar deficits in the limbs) or of increased intracranial pressure. Auditory function is generally spared. The underlying cause should be treated.
P. An overview of central vertigo disorders. Adv Otorhinolaryngol. 2019;82:127.