title: Low-frequency sensorineural hearing loss. Brainstem response, speech and high-frequency audiometry.
abstract: Four cases of acquired, unilateral sensorineural hearing loss are presented. The low-frequency octave threshold changes are considered compatible with the low-frequency tails of neurons with characteristic frequencies of 2, 4 and 9 kHz. Zero speech discrimination was found in two patients with high-frequency threshold preservation at and above 4 kHz. Normal auditory brainstem responses were obtained in the two patients with low-frequency hearing loss confined to the frequency bands below 2 and 4 kHz respectively. Only wave I could be reliably identified in the two patients with single frequency threshold preservation at 2 and 9 kHz, while both presented a second, low amplitude wave with latency corresponding to our normative values for wave V. The latter may represent a delayed and pathological wave III.
mesh_terms: D000293:Adolescent; D000328:Adult; D001299:Audiometry; D001300:Audiometry, Evoked Response; D001301:Audiometry, Pure-Tone; D001302:Audiometry, Speech; D001309:Auditory Threshold / Q000502:physiology; D001933:Brain Stem / Q000503:physiopathology*; D002648:Child; D004200:Diseases in Twins; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000503:physiopathology; D003639:Hearing Loss, Sudden / Q000175:diagnosis; D006801:Humans; D008297:Male; D008583:Meningitis, Haemophilus / Q000150:complications; D008875:Middle Aged; D010898:Pitch Perception / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014012:Tinnitus / Q000175:diagnosis