Spectro-temporal analysis of speech affected by depression and psychomotor retardation

To enhance current diagnostic methods used when assessing a depressed individual, an objective screening mechanism, ideally based on non-intrusive behavioral signals, is needed. Given the clinical description of depression speech as `dull, monotonous and flat' and promising previous results from spectral features, we hypothesize that the effects of depression on speech are embedded in spectro-temporal events. To test this hypothesis we explore different methodologies, based on the modulation spectrum, for extracting long-term spectro-temporal information from speech and assess their suitability as a clinical marker of depression. Results indicate that: depressive speech information is captured in the modulation spectrum, long-term spectro-temporal information is important in depressed speech identification and there are potential differences in the effects that depression and psychomotor retardation have on speech production mechanisms.