Psychoacoustic Characteristics of Tinnitus in Individuals with Auditory Neuropathy Spectrum Disorder

The study aimed at understanding the psychoacoustic characteristics of tinnitus in individuals with auditory neuropathy spectrum disorder (ANSD). It attempts to assess the pitch and intensity of loudness of tinnitus matched by individuals with ANSD. Fifty individuals who were diagnosed as having auditory neuropathy spectrum disorder were included in the study. Tinnitus evaluation was carried out where the individuals matched the frequency and intensity of loudness of the tinnitus. The results of the study shows that pitch matched by majority of patients with ANSD is predominantly low pitched (<1000 Hz). The frequency of tinnitus matched by the patients with ANSD also correlated with the degree of maximal hearing loss. The intensity of loudness of the tinnitus was around 10-15 dB higher than their threshold in majority of the patients considered in the study. There was a weak negative correlation for the matched frequency and intensity of loudness. The results of the study suggest that majority of individuals with low frequency hearing loss had low pitched tinnitus. Thus, there could be discordant damage between outer and inner hair cells, abnormal firing of auditory nerve in individuals with ANSD which can lead to tinnitus. Thus, it can help to understand the physiology of tinnitus in individuals with ANSD.