Auditory efferent function and cortical auditory responses in individuals with aphasia

Background Auditory-linguistic studies in individuals with aphasia have long been of interest to researchers.Aims The aim of this study is to investigate auditory cortical responses and efferent auditory system function in aphasia.Methods & Procedures Ten individuals with aphasia and 10 healthy control participants aged 50–65 years, were included. P1-N1 responses and DPOAEs with contralateral suppression were recorded using the Neurosoft system. Auditory stimuli were delivered ear-specifically through insert headphones. Surface electrodes were placed according to the international 10–20 system. The stimulus rate was presented as 1.1 and the stimulus intensity was 70 dB nHL. These tests were analyzed to assess auditory cortical and medial olivocochlear efferent function. Group comparisons were conducted using the Mann–Whitney U test.Outcomes & Results The median age of the participants was 60 years, and there were no significant differences between the groups in terms of age, sex, or socioeconomic-educational level (p > 0.05). Individuals with aphasia demonstrated significantly prolonged P1 and N1 latencies. An exploratory analysis also showed significantly reduced DPOAE suppression at 1 kHz in the right ear (p < 0.05); however, this isolated finding should be interpreted cautiously given the multiple comparisons performed without statistical correction. Additionally, significant correlations were found between cortical auditory potentials and language skills.Conclusions These exploratory findings suggest that aphasia may be associated with alterations in cortical auditory processing. The isolated DPOAE suppression finding also raises the possibility of altered auditory efferent function; however, this exploratory observation requires confirmation in larger samples.