שאלה משלב א׳ בא.א.ג וכירורגיה של ראש וצוואר · מועד 2024 (ספטמבר), שאלה 94

Acoustic reflex testing helps distinguish COCHLEAR from RETROCOCHLEAR pathology: reflex DECAY (a fall of more than 50% within 10 seconds at 500 and 1000 Hz) and elevated or absent reflexes disproportionate to the hearing level suggest a retrocochlear lesion, while in cochlear loss the reflex is present at a reduced sensation level. The reflex is BILATERAL (ipsilateral and contralateral, since the pathway crosses in the brainstem), the normal threshold is about 70-100 dB (not 40-60), and in SUPERIOR CANAL DEHISCENCE the reflex is PRESENT despite an apparent air-bone gap - a useful discriminator from otosclerosis.