[Instantaneous measurement of acoustic reflex latency in daily practice. The apparatus. Results].
Increase in acoustic reflex latency (time between stimulus onset and response) provides a highly specific and sensitive sign for early detection of lesions of the first or second auditory neurones. The performance of a new apparatus, including an Amplaid 702 impedance meter with a specially designed numeric oscilloscope, employed systématically for all audiometric examinations (87 subjects) was compared with that of a reference apparatus (Madsen ZO 73 + Elema Schoenander-jet ink recorder). The new apparatus provided a very simple, precise, and rapid method for measuring acoustic reflex latency. The technique has its limits, however, of critical importance being the determination of the acoustic reflex threshold at close to 1 dB (modification of the apparatus), the means for measuring latency, and the use of three criteria for distinguishing retrocochlear lesions from others. The effect of age on latency, variations in the test-retest results according to the type of deafness, and the influence of averaging techniques are discussed. Typical retrocochlear lesions were rare in this series, and the 5 cases observed are described in detail, followed by a discussion of the advantages and inconveniences of systematic as against selective screening.
D000158:Acoustic Impedance Tests / Q000295:instrumentation*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D006311:Hearing Disorders / Q000175:diagnosis; D006313:Hearing Loss, Central / Q000175:diagnosis; D006801:Humans; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000175:diagnosis; D011930:Reaction Time / Q000502:physiology*; D012022:Reflex, Acoustic
Mesure instantanée de la latence du réflexe acoustique en pratique quotidienne. Appareillage. Résultats.