VALIDATION OF THE ASSR TEST THROUGH COMPLEMENTARY AUDIOLOGYICAL METHODS

Introduction: Auditory Steady State Response (ASSR) is an objective method for determining the auditive threshold, applicable and necessary especially in children. The test is extremely important for recommending cochlear implant in children. The aim of the study was to compare pure tone audiometry responses and auditory steady-state thresholds. Materials and method: The study was performed on a group including both patients with normal hearing and with hearing loss. The main inclusion criteria accepted only patients with normal otomicroscopic aspect, normal tympanogram, capable to respond to pure tone audiometry, and with ear conduction thresholds between 0 and 80 dB NHL. The patients with suppurative otic processes or ear malformations were excluded. The research protocol was followed, the tests being performed in soundproofed rooms, starting with pure tone audiometry followed, after a pause, by ASSR determinations at frequencies of 0.5, 1.2 and 4 KHz. The audiological instruments were provided by a single manufacturer. ASSR was recorded at least two times for both borderline intensities, namely the one defining the auditory threshold and the first no-response intensity. The recorded responses were stored in a database and further processed in Excel. Discussion: The differences observed between pure tone audiometry and ASSR thresholds are important at 500 Hz and insignificant at the other frequencies. When approaching the PTA-ASSR relation, whatever the main characteristic between the PTA and ASSR thresholds in one ear, the profile of the lines gap maintains the same shape on the opposite ear. Conclusions: ASSR is a confident objective test, maintaining attention to low frequencies, where some differences might occur.