It is often possible to treat conductive hearing loss by removing the cause of the physical obstruction.īy far the most common cause of sensory neural hearing loss is damage to sensory hair cells in the cochlea. (image source: US Occupational Health Administration) A so called "bone conduction test", where sound is delivered as vibration to the skull rather than as airborne sound to the ear canal, can be used to confirm a suspected conductive hearing loss. Conductive hearing loss tends to a loss of sensitivity across the entire range of frequencies, most commonly in one ear only. Particular causes of hearing loss will be show up in the clinical audiogram in characteristic ways.Ĭonductive hearing loss comes about when the transmission of sound to the inner ear is impaired, perhaps due to impacted ear wax (cerum), an ear infection (otitis media with effusion or OME), or calcification of the middle ear ossicles (otosclerosis). Thresholds between -10 and +20 dB HL are considered in the normal range, while thresholds above 20 dB HL are considered diagnostic for mild, moderate, severe or profound hearing loss, as shown here: In a clinical audiogram test, pure tones between ca 2 Hz are presented at varying levels, to determine a patient's pure tone detection thresholds (the quietest audible sounds) in the left and right ear. dB relative to the quietest sounds that a young healthy individual ought to be able to hear. Clinicians measure sound intensity in dB HL (decibels Hearing Level), i.e.
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