Reflections of depression in acoustic measures of the patient's speech

Background: The literature on acoustic measures of voice in depression is r eviewed. Authors have separated results derived from studies of automatic s peech, such as counting or reading, from free speech. Free speech requires cognitive activity Such as word finding and discourse planning in addition to the motor activity of automatic speech. Also, results have been less amb iguous if homogeneous groups of agitated or retarded depressed patients wer e examined. Methods: These distinctions are applied to the results of a 12- week double-blind treatment trial that compared response to nortriptyline. (25-100 mg/day) with sertraline (50-150 mg/day). Twelve male and ten female elderly depressed patients and an age-matched normal control group (n = 19 ) were studied. Patients were divided into retarded or agitated groups on t he basis of ratings. Results from measures of fluency (speech productivity and pausing) and prosody (emphasis and inflection) are described. Results: Depressed patients showed less prosody than the normal subjects. Improvemen t in the retarded group was reflected in briefer pauses but not longer utte rances. There was a trend in the agitated group for improvement to be refle cted in the utterance but not the pause measure. Conclusions: Clinical impr essions are substantially related to acoustic parameters. Temporal changes associated with depression appear to reflect the depressed state whereas pr osodic features seem to reflect a depressed trait. Acoustic measures of the patient's speech may provide objective procedures to aid in the evaluation of depression. Limitations of the study are discussed. (C) 2001 Elsevier S cience BY All rights reserved.