Time- and Intensity-Dependent Low-Pass Filtering of Auditory Brain Stem Responses

A new method of filtering auditory brain stem responses (ABR), which is time-and intensity-dependent, is proposed. The epoch containing the averaged response is divided up into 128 overlapping segments and each segment is differently filtered. The characteristics of a filter that is applied to a segment of the response are derived from the time-dependent spectral composition of normal ABRs at the appropriate stimulus intensity. After filtering, the segments are added together to yield a response with no significant amplitude and/or phase distortion, and with distinctly pronounced peaks that are excellently suitable for evaluation with an automated system.Une nouvelle methode de filtrage des potentiels evoques auditifs du tronc cerebral, fonction a la fois du temps et de l'intensite est proposee. L'epoque contenant la reponse moyenne est divisee en 128 segments qui se chevauchent et chaque segment est filtre differemment. Les caracteristiques du filtre utilise pour chaque segment de la reponse sont determinees a partir de la composition spectrale fonction du temps des PEATC normaux, a l'intensite de stimulation appropriee. Apres filtrage, les segments sont rajoutes pour fournir une reponse sans distorsion significative d'amplitude ou de phase, et avec des pics distincts prononces qui sont tout a fait adaptes a une evaluation automatique.