Auditory Temporal Processing in Tinnitus Patients with Normal Hearing

Abstract

Tinnitus is a chief complaint among clients attending audio-vestibular clinics. Although tinnitus is associated with hearing loss in the majority of the patients, approximately 20% to 30% of tinnitus patients have normal hearing sensitivity (Stouffer, 1990). Identification of the underlying mechanisms involved in tinnitus generation in such patients is crucial for the development of novel and effective therapies. Recently, researchers evaluated the auditory temporal processing abilities in tinnitus patients subjectively by the means of the psychophysical tests mainly. c-ABR as an objective electrophysiological measure reflects the quality of temporal encoding in the central auditory pathways (Tahaei et al., 2014). Hence, c-ABR could serve as an objective tool to assess auditory temporal processing abilities. In the current work, psychophysical and electrophysiological assessment of auditory temporal processing in both tinnitus and normal subjects was done using psychophysical tests of temporal processing and c-ABR respectively. The study group comprised 20 tinnitus subjects with normal hearing sensitivity while, the control group comprised 20 normal hearing subjects with no tinnitus. All the subjects in the current study were submitted to full history taking, Otological examination, basic audiological evaluation using 2 channel AC40 audiometer, Immittancemetry using Maico model MI 34, temporal processing tests using two channel Welch Allyn GSI 61 audiometer and speech evoked auditory brainstem responses using Auditory Evoked Potentials System: Biologic Navigator Pro. Moreover, the subjects of the study group were subjected to the following: tinnitus distress scale and tinnitus matching tests.