A 72-year-old man presents to the ENT clinic with a 5-year history of progressive difficulty understanding speech, particularly in noisy environments. His wife reports he often asks people to repeat themselves, especially when they speak quickly. Audiometry shows bilateral symmetric sensorineural hearing loss with high-frequency predominance. Tympanometry is normal. The pattern shown as **A** in the diagram is most consistent with presbycusis. Which of the following is the MOST COMMON pathophysiologic mechanism underlying this patient's presentation?

Why outer hair cell degeneration at the basal cochlear turn is right

Sensory presbycusis, caused by outer hair cell degeneration at the basal cochlear turn, is the MOST COMMON pathophysiologic subtype of age-related hearing loss (Schuknecht classification). It produces the characteristic steeply sloping high-frequency audiometric pattern seen in A, with relatively preserved speech discrimination despite significant high-frequency loss. The patient's complaint of difficulty with consonants (s, sh, t, k) and muffled speech in noise is classic for this mechanism, as high-frequency sounds carry phonetic information critical for speech intelligibility. This subtype accounts for the majority of presbycusis cases and is consistent with the bilateral, symmetric, gradual progression described (Cummings Otolaryngology 7e; AAO-HNS 2022 Guidelines).

Why each distractor is wrong

Cummings Otolaryngology 7e; AAO-HNS Clinical Practice Guidelines 2022