Decrease in speech pause times with treatment of endogenous depression.

Szabadi et al. claimed that speech pause time--the silent interval between phonations--was significantly elongated during episodes of unipolar depressions; thus representing an objective measure of psychomotor retardation. Phonation times were said to be unchanged. To replicate and possibly expand these findings, we measured pause and phonation times among four unipolar (UP) and three bipolar (BP) endogenously depressed inpatients. Speech was recorded while patients counted from one to ten at their desired rate, and then converted to paper prints with a voice-operated electrical relay. Among all patients, pause times were substantially longer during base-line medication-free periods than at discharge. Progressive decreases occurred in conjunction with clinical improvement. These data replicated Szabadi's observation on UP patients and extended it to BP depressed patients. Of potential clinical importance, in two cases we documented decreases in pause time of more than 50% within several days after starting treatment. Speech pause times may be pragmatically useful as objective pathophysiologic markers in depression. Significant decreases occur with recovery, and early decreases during treatment may, like changes in REM sleep, be predictive of ultimate clinical response.