72. Characterization of the occlusion effect through auditory steady-state response in normal-hearing adults

• Published in: Clinical neurophysiology 2016-09, Vol.127 (9), p.e319-e320
• Main Authors: Guerrero-Aranda, Alioth, Torres-Fortuny, Alejandro, Mijares-Nodarse, Eleina
• Format: Article
• Language: English
• Subjects: Neurology
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2016.05.347

Objective This paper aims to characterize the behavior of the occlusion effect using Auditory Steady State Responses (ASSR) in order to estimate a compensating electrophysiological correction factor. Methods The stimulus consisted of a combination of four sinusoidal carrier tones of 500, 1000, 2000 y 4000 Hz, modulated in amplitude (95% depth) at the following rates: 104.2, 107.8, 111.4 and 115 Hz; respectively. It was presented via bone conduction for each participant (32 in total) under two different conditions (occluded vs. un-occluded ear). Results Occlusion caused a significant decrease of bone-conducted ASSR thresholds at low frequencies but a significant increase at 4000 Hz. Some subjects, however, showed no occlusion effect. The electrophysiological correction factors were 12 and 8 dB HL for 500 and 1000 Hz, respectively. Conclusions Our findings indicate that threshold variations at high frequencies need to be considered when conducting bone-conduction testing with ear canal occlusion. The fact that the occlusion effect is not present in every individual may have some clinical implications. Our findings also suggest that correction factors recommended for behavioral testing can be applicable when using ASSRs. Significance This research estimates correction factors based on electrophysiological measures (eCF) to compensate for an expected OE.