The relationship between cognitive impairment and acoustic features in major depressive disorder: a longitudinal cohort study.

INTRODUCTION: Cognitive impairments, especially in executive function, attention, and working memory, are prevalent in major depressive disorder (MDD). While studies has identified brain areas involved in these deficits, the connection between cognitive function and acoustic features of speech remains underexplored. This study examines this relationship in MDD. METHODS: A longitudinal cohort study was conducted with 53 participants diagnosed with MDD (DSM-IV). Cognitive performance was assessed using the Trail Making Test (TMT), Digit Span (DS), Continuous Performance Test (CPT), and Symbol Coding (SC). Speech samples were analyzed for 6,373 vocal features across six domains: energy, pitch, prosody, spectral, voice quality, and others. Spearman's correlation and principal component analysis (PCA) assessed the link between cognitive scores and speech features. Regression analyses explored the predictive value of speech features for cognitive performance. RESULTS: Significant cognitive impairments in executive function and attention were observed. Strong correlations were found between spectral speech features, particularly high-frequency components, and sustained attention and executive function. PCA showed that depression severity independently predicted certain vocal feature components. Notably, speech features related to cognitive impairment remained consistent across different cognitive tasks, and treatment-induced changes were observed over 8 weeks. CONCLUSIONS: This study demonstrates that speech features, particularly spectral components, reflect cognitive impairment in MDD, offering promising non-invasive biomarkers for monitoring cognitive function in depression. Larger studies with extended follow-up are needed to explore their potential in predicting cognitive outcomes in MDD.