Study of P300 in tinnitus patients

Abstract Background Tinnitus is a common auditory disorder often associated with sensorineural hearing loss (SNHL), affecting attention and cognitive processing. Comprehensive assessment of these deficits remains challenging. Objectives This study aims to evaluate auditory selective attention in tinnitus patients with normal peripheral hearing and with SNHL by using P300 auditory evoked potentials. Methods This cross-sectional study included 72 participants aged 20 to 60 years, divided into two groups. Study group I included 47 patients with bilateral tinnitus which were further subdivided into Subgroup Ia; 23 tinnitus patients with bilateral mild-to-moderate SNHL and Subgroup Ib; 24 tinnitus patients with normal peripheral hearing. Control group II consisted of 25 normal peripheral hearing individuals without tinnitus. All subjects underwent the Tinnitus Handicap Inventory (THI) questionnaire, full audiological evaluation, tinnitus psychoacoustic assessment, and P300 testing through both tone and speech stimuli. Results P300 amplitudes were significantly reduced and latencies were significantly prolonged in both tinnitus subgroups compared with the control group. Subgroup Ia showed the most pronounced reductions in P300 amplitudes and prolongations in latencies. In Subgroup Ia, P300 latency showed a significant positive correlation with THI score ( r = 0.295, p = 0.029) and pure-tone average (PTA) ( r = 0.374 for tone and r = 0.288 for speech; p < 0.05). In Subgroup Ib, tinnitus duration was negatively correlated with P300 amplitude for both tone and speech stimuli ( r = − 0.383 and − 0.382, p = 0.007). Conclusions Tinnitus is associated with central auditory processing impairments reflected in P300 alterations, more pronounced in SNHL patients. Findings support a central origin and emphasize the role of cortical neuroplasticity in tinnitus pathophysiology.