T-wave amplitude utility revisited: some physiological and psychophysiological considerations

The last decade has seen some quite polemicized discussions concerning the utility of T-wave amplitude as a psychophysiological measure, but more recent reports indicate that we are now moving into a more empirically oriented and analytic examination of this topic. Such a report is one by Contrada et al. (1989), who manipulated sympathetic (beta-adrenergic) influences both pharmacologically and behaviorally, and whose main conclusion was that their results "support the hypothesis that T-wave is significantly affected by beta-sympathetic influence on the heart". However, we question their other conclusion that "a nonspecific effect of heart rate change on T-wave amplitude would also account for these results", and also suggest that their discussion of the "implications for the utility of T-wave amplitude in psychophysiological research" bears further consideration. In particular, for psychophysiologists, of fundamental importance is the distinction between T-wave amplitude's utility as a physiological index and its utility as a psychophysiological index. Concerning the former issue, we consider: (a) the alpha/beta adrenergic distinction, (b) inappropriate T-wave amplitude augmentation effects to sympathomimetic stimulation, (c) the nonspecific-response-to-tachycardia argument, and (d) the view of pulse transit time as a criterial standard, rather than as a candidate index. Regarding the issue of psychophysiological index utility, we consider: (a) dependent-variable sensitivity, drawing a further distinction between reactive and specific sensitivity, and (b) independent-variable-manipulation effectiveness.