Tinnitusu olan bireylerde konuşma uyaranıyla frekans takip cevabının ve gürültüde konuşmayı algılama becerilerinin değerlendirilmesi

Abstract

Tinnitus is a common symptom in society which is characterized by the perception of sound in the auditory system without any external sound source. Although many theories have been proposed regarding the mechanism of tinnitus and the affected areas, there is still no consensus. The present study aimed to evaluate the auditory processing at the subcortical level of individuals with normal hearing tinnitus and investigate the effect of tinnitus on speech perception in noise. Sixteen individuals with normal hearing tinnitus at standard audiometric frequencies (0.25-8 kHz) and 20 normal individuals as the control group participated in the study. Hearing thresholds in the 0.25-16 kHz range were determined by pure tone audiometry evaluation of the participants. Afterwards, the subcortical auditory processing of the participants was evaluated with auditory brainstem response (ABR) and speech frequency following response (FFR) recordings. The Turkish Matrix Test was used in various listening conditions to evaluate speech perception in noise. Based on the participants' findings, there was no significant difference in pure tone hearing thresholds between the two groups (p>0.05). In terms of ABR findings, decreased I. wave amplitudes were found in individuals with tinnitus compared to normal individuals (p<0.05). In addition, individuals with tinnitus ABR I., III. and V. wave absolute latencies significantly delayed (p<0.05). When the FFR findings of the participants were examined, it was found that individuals with tinnitus did not differ significantly from normal individuals in terms of wave amplitudes (p>0.05). On the other hand, while there was no significant difference between the two groups in the Vₙ, A, D, E and F wave latencies (p>0.05), wave O latency was significantly delayed in individuals with tinnitus (p<0.05). In addition, FFR results showed that non-stimulus activity was greater in individuals with tinnitus compared to normal individuals (p<0.05). It was observed that individuals with tinnitus had poorer speech perception in noise performance compared to normal individuals (p<0.05). Depending on the present study's findings, the significant decrease in the amplitudes of ABR wave I suggests that tinnitus with normal hearing may be associated with cochlear synaptopathy. In addition, the O (offset) wave was significantly prolonged, and the increase in non-stimulus activity among the FFR findings was interpreted as decreased inhibition and impaired subcortical auditory processing in individuals with tinnitus. The fact that individuals with tinnitus have normal hearing but have poorer speech perception in noise performance supports the idea that these individuals may have cochlear synaptopathy and additionally suggests that cognitive skills may be affected.