Sensorineural hearing loss involves pathology of which structures?

Sensorineural hearing loss involves pathology of which structures?

• A. Pathology of the outer ear only
• B. Pathology of the inner ear, CN VIII, or auditory cortex
• C. Pathology of the tympanic membrane only
• D. Damage to the middle ear bones

Answer: (B)

Sensorineural hearing loss occurs when the problem is in the parts that actually convert sound into neural signals or carry those signals to the brain, not in the structures that merely conduct sound. The inner ear’s cochlea houses hair cells that transduce mechanical vibrations into electrical impulses; damage here—from noise exposure, aging, or ototoxic drugs—reduces sensitivity and distorts the signal. The vestibulocochlear nerve (cranial nerve VIII) carries those impulses from the cochlea to the brain, so lesions along this pathway can cause hearing loss. The auditory cortex in the brain further processes sound, and disruptions there can impair perception even if peripheral parts are intact. In contrast, problems with the outer ear, tympanic membrane, or middle ear bones disrupt conduction of sound to the inner ear, yielding conductive hearing loss. So pathology in the inner ear, CN VIII, or the auditory cortex best characterizes sensorineural hearing loss.

Sensorineural hearing loss occurs when the problem is in the parts that actually convert sound into neural signals or carry those signals to the brain, not in the structures that merely conduct sound. The inner ear’s cochlea houses hair cells that transduce mechanical vibrations into electrical impulses; damage here—from noise exposure, aging, or ototoxic drugs—reduces sensitivity and distorts the signal. The vestibulocochlear nerve (cranial nerve VIII) carries those impulses from the cochlea to the brain, so lesions along this pathway can cause hearing loss. The auditory cortex in the brain further processes sound, and disruptions there can impair perception even if peripheral parts are intact. In contrast, problems with the outer ear, tympanic membrane, or middle ear bones disrupt conduction of sound to the inner ear, yielding conductive hearing loss. So pathology in the inner ear, CN VIII, or the auditory cortex best characterizes sensorineural hearing loss.