Effect of forward masking on auditory brainstem response in individuals with tinnitus

To examine the impact of forward masking (FM), both on-frequency and off-frequency, on low (0.5 kHz), mid (1 & 2 kHz), and high-frequency (4 kHz) probe stimuli in Auditory brainstem response (ABR) test for individuals with tinnitus. The experimental design followed a standard group comparison research, where ABR was acquired across three experimental conditions: unmasked, off-frequency FM, and on-frequency FM. Thirty participants with tinnitus and 30 without tinnitus were recruited. The between-group comparison showed that the tinnitus group exhibited a longer wave V peak absolute latency and smaller response amplitude than controls for unmasked conditions. However, when the masker was introduced in both FM conditions, the tinnitus group tended to have an unidentifiable wave V peak response, which was significant at higher masker intensities. The altered ABR in the tinnitus group under FM conditions could suggest altered neural synchrony and reduce nerve fiber firing at the subcor tical level in individuals with tinnitus.