Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 8-01: Hearing Loss + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Two main types of hearing loss Conductive Sensorineural Most commonly caused by cerumen impaction or transient auditory tube dysfunction from upper respiratory tract infection +++ General Considerations +++ Conductive loss ++ Four mechanisms, each resulting in impairment of the passage of sound vibrations to the inner ear Obstruction (eg, cerumen impaction) Mass loading (eg, middle ear effusion) Stiffness effect (eg, otosclerosis) Discontinuity (eg, ossicular disruption) Generally more correctable than sensory and neural losses +++ Sensorineural loss ++ Sensory and neural causes of hearing loss are difficult to differentiate due to testing methodology, thus often referred to as "sensorineural" Sensory loss Most common form is a gradually progressive, predominantly high-frequency loss with advancing age (presbyacusis) Other common causes include Excessive noise exposure Head trauma Systemic diseases Sensory hearing loss is usually not correctable but may be prevented or stabilized However, sudden sensory hearing loss may respond to corticosteroids if delivered within several weeks of onset Neural loss Occurs with lesions involving the eighth nerve, auditory nuclei, ascending tracts, or auditory cortex It is the least common clinically recognized cause of hearing loss Causes include Acoustic neuroma Multiple sclerosis Cerebrovascular disease + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Reduction in hearing level Weber test Tuning fork is placed on the forehead or front teeth In conductive losses, the sound appears louder in the poorer hearing ear, whereas in sensorineural losses it radiates to the better side Rinne test Tuning fork is placed alternately on the mastoid bone and in front of the ear canal In conductive losses > 25dB, bone conduction exceeds air conduction, whereas in sensorineural losses, the opposite is true +++ Differential Diagnosis +++ Conductive (external or middle ear) ++ Cerumen (ear wax) impaction Transient auditory tube dysfunction Acute or chronic otitis media Mastoiditis Otosclerosis Disruption of ossicles Trauma or barotrauma Glomus tympanicum (middle ear tumor) Paget disease +++ Sensory ++ Presbycusis (age related) Excessive noise exposure Ménière disease (endolymphatic hydrops) Labyrinthitis Head trauma Ototoxicity Occlusion of ipsilateral auditory artery Hereditary hearing loss Autoimmune Systemic lupus erythematosus Granulomatosis with polyangiitis Cogan syndrome Other systemic causes Diabetes mellitus Hypothyroidism Hyperlipidemia Chronic kidney disease Infections +++ Neural ++ Acoustic neuroma Multiple sclerosis Cerebrovascular disease + Diagnosis Download Section PDF Listen +++ +++ Diagnostic Procedures ++ Formal audiometric studies are performed in a soundproofed room Pure-tone thresholds in decibels (dB) are obtained over the range of 250–8000 Hz for both air and bone conduction In conductive losses, there is a gap between the air and bone thresholds In sensorineural losses, both air and bone thresholds are equally diminished Speech discrimination measures the clarity of hearing, which is reported as percentage correct (90–100% is normal) Auditory brainstem-evoked responses may determine whether the lesion is sensory (cochlear) or neural (central) + Treatment Download Section PDF Listen +++ +++ Surgery ++ The cochlear implant—an electronic device that is surgically implanted to stimulate the auditory nerve—offers socially beneficial auditory rehabilitation to most adults with acquired deafness Many types of conductive hearing loss (eg, otosclerosis, tympanic membrane perforation, ossicular discontinuity) are surgically remediable Hearing aids An alternative strategy, the bone-anchored hearing aid, uses an oscillating post drilled into the mastoid, directly stimulating the ipsilateral cochlea (for conductive losses) or contralateral ear (profound unilateral sensorineural loss) +++ Therapeutic Procedures ++ Hearing aids Assistive devices are available to improve comprehension in individual and group settings, to help with hearing television and radio programs, and for telephone communication + Outcome Download Section PDF Listen +++ +++ Follow-Up ++ Routine audiologic screening is recommended for adults with prior exposure to potentially injurious levels of noise or in adults at age 65, and every few years thereafter +++ When to Refer ++ Every patient who complains of a hearing loss should be referred for audiologic evaluation unless the cause is easily remediable (eg, cerumen impaction, otitis media) Immediate audiometric referral is indicated for patients with idiopathic sudden sensorineural hearing loss because it requires treatment (corticosteroids) within a limited several-week time period + References Download Section PDF Listen +++ + +Almeyda R et al. Assessing and treating adult patients with hearing loss. Br J Hosp Med (Lond). 2018 Nov 2;79(11):628–33. [PubMed: 30418825] + +Cunningham LL et al. Hearing loss in adults. N Engl J Med. 2017 Dec 21;377(25):2465–73. [PubMed: 29262274] + +Johnson CE et al. Benefits from, satisfaction with, and self-efficacy for advanced digital hearing aids in users with mild sensorineural hearing loss. Semin Hear. 2018 May;39(2):158–71. [PubMed: 29915453] + +Jorgensen LE et al. Conventional amplification for children and adults with severe-to-profound hearing loss. Semin Hear. 2018 Nov;39(4):364–76. [PubMed: 30374208] + +Kaga K. Auditory nerve disease and auditory neuropathy spectrum disorders. Auris Nasus Larynx. 2016 Feb;43(1):10–20. [PubMed: 26209259] + +McRackan TR et al. Meta-analysis of quality-of-life improvement after cochlear implantation and associations with speech recognition abilities. Laryngoscope. 2018 Apr;128(4):982–90. [PubMed: 28731538] + +Michaud HN et al. Aural rehabilitation for older adults with hearing loss: impacts on quality of life—a systematic review of randomized controlled trials. J Am Acad Audiol. 2017 Jul/Aug;28(7):596–609. [PubMed: 28722643] + +Musiek FE et al. Perspectives on the pure-tone audiogram. J Am Acad Audiol. 2017 Jul/Aug;28(7):655–71. [PubMed: 28722648] + +Nieman CL et al. Otolaryngology for the internist: hearing loss. Med Clin North Am. 2018 Nov;102(6):977–92. [PubMed: 30342615] + +Vaden KI Jr et al. Longitudinal changes in audiometric phenotypes of age-related hearing loss. J Assoc Res Otolaryngol. 2017 Apr;18(2):371–5. [PubMed: 27830350]