Potenciais evocados auditivos do tronco encefálico com Tone Burst de 1000Hz em indivíduos sem ou com perda auditiva

Abstract

Brainstem Electric Response Audiometry (BERA) or Auditory Brainstem Response (ABR) is an evoked auditory potentials method of short latency, able to activate progressively the cochlear, the auditory nerve and the brainstem in responses to acoustic stimuli, characterized by waveforms from I to VII, which appear at the first mile seconds after the stimulus. Click-type sounds are the most used stimulus to produce those waves, although, ranging in a frequency between 2000 and 4000Hz which may underestimate ABR findings. The general objectives of this study was to characterize the 1000Hz Tone Burst, a brief tone stimulus of ABR, in normal, normal with fall, and hearing impairment subjects and to determine the level of minimum response of the 1000Hz Tone Burst in a sample composed of 60 subjects: 35 (58,3%) female sex, and 25 (41,7%) male sex. The specific purposes were to observe the association among the variables of the study such as: age, psychoacoustics thresholds, electrophysiological threshold and wave latency. It was measure the difference between the Psychoacoustics and the Electrophysiological threshold in normal and hearing-impaired subjects who differentiated according to type and the degree of the loss and determineted the hearing acuity and reproducibility of latency of wave V the 1000Hz. The variables of the study showed significant correlation between themselves. Age and Electrophysiological Auditory Threshold, Age and Latency; Psychoacoustics Threshold and electrophysiological and Electrophysiological and Latency as well as for both ears. The difference between Psychoacoustics Threshold / 1000Hz Pure Tone and Electrophysiological Auditory Threshold / 1000Hz Tone Burst was 38dB for the right ear and 37,5 for the left ear. In general, the Latency was under influence of the Age and the Electrophysiological Auditory threshold, but not whether normal, normal with fall or hearing loss ears. In conclusion, the use of 1000Hz Tone Burst provides important additional information, when there is not the audiometric configuration, that is, the psychoacoustics thresholds. The factor of correction is possible for correction for each type of hearing loss and in normal hearing ears, noraml with fall, to estimate the Psychoacoustics Threshold in relation to the Electrophysiological auditory Threshold.