Physiological aspects of neutral and phobic imagery: further observations.
This paper reports the physiological accompaniments of phobic and neutral imagery in 77 phobic patients before and after treatment. Before treatment, phobic was significantly discriminated from neutral imagery on heart rate in four of six studies, on skin conductance in two of six studies and on subjective anxiety in all six studies. When discrimination was present before treatment, subsequent clinical improvement was reflected on physiological measures, while subjective anxiety tended to persist longer. Heart rate, skin conductance and subjective anxiety correlated poorly with one another. In choosing autonomic measures of change in clinical trials, standard conditions of recording require careful planning. Tape-recorded instructions can be less effective in producing arousal than those delivered live.