Koklear İmplant Kullanan Bireylerde Spektral ve Temporal Çözünürlük Becerilerinin Araştırılması

Abstract

Auditory performance, which affects the communication skills of individuals with cochlear implants in daily life, is associated with the ability to encode temporal and spectral information. While hearing loss which occurs as per language acquisition process shapes speech perception at cochlear implant users, there is no consensus on which cues are more likely to be benefitted. In the current study, tests evaluating the spectral and temporal resolution skills of cochlear implant users with hearing loss according to language acquisition time and the relationship between speech perception in silence and noise conditions were evaluated. For this purpose, 15 individuals with postlingual hearing loss using unilateral cochlear implants in the 18-55 age range, 15 individuals with prelingual hearing loss, and 30 individuals in the same age range with normal hearing thresholds were included in the study. Turkish Matrix Test (TMT) was applied to all participants who met the inclusion criteria under silence and noise conditions. Spectral-Temporally Modulated Test (SMRT) and Spectral Modulation Detection Test (EasyQSMD) were applied to evaluate spectral resolution. Random Gap Detection Test (RGDT) and Gaps In Noise Test (GIN) from gap detection paradigms for evaluation of the temporal resolution; Temporal Modulation Detection Threshold Test (EasyMDT) for evaluation of the temporal modulation threshold were applied. Findings of the study showed that there was a statistically significant difference between research groups in all speech tests and spectral resolution tests (p<0,05). While GIN test, MDTs at 100Hz and 200Hz modulation frequency showed a statistically significant difference between research groups (p<0,05); RGDT and MDTs at 10 Hz modulation frequency did not show a statistically significant difference between research groups (p>0,05). The prelingual hearing loss group performed poorer than both groups in the overall psychophysical assessment. In the postlingual hearing loss group, spectral resolution test findings showed a statistically significant correlation with the speech discrimination scores in silence (p<0.05), whereas the GIN results showed a statistically significant correlation with the speech discrimination scores in noise (p<0.05). In the prelingual hearing loss group, only GIN results showed a statistically significant correlation with speech discrimination in silence and noise (p<0.05). The findings did not show the high correlation coefficient between spectral resolution and speech tests observed in previous studies. However, hearing loss in cochlear implant users according to the time of language acquisition can be considered to benefit from different cues during speech coding. When the independent individual variables were examined, it was seen that the effect of the duration of cochlear implant use on the tests was higher. This study evaluated the spectral and temporal resolution evaluations of prelingual and postlingual cochlear implant users with many psychophysical subtests and examined the associated conditions together.