Test-retest reliability of psychophysiological assessment

Thirty subjects participated in a study of the test-retest reliability of five psychophysiological assessment procedures: habituation. Quiz Electrocardiogram, anger imagery, aversive slides and startle. The procedures were presented in identical fashion, 2 weeks apart. Skin conductance level and response, heart rate, vasomotor response, skin temperature, frontalis and forearm electromyogram, respiration rate. and systolic and diastolic blood pressure were recorded continuously. The following analyses were performed on Test-Retest data: correlations, baseline changes, profile similarity, and stability of ranked standardized physiological scores. Significant but modest Test-Retest correlations were found for skin conductance level and response, skin temperature, respiration rate, heart rate and systolic blood pressure. Absolute scores were more often stable than change scores. All baselines were stable from Test to Retest. Four baselines and four test procedures had Test-Retest Profile Similarity Index scores indicating reliability. Chi-square analyses of Retest ranks of standardized physiological scores showed that the two most and least responsive measures accounted for Test-Retest stability. Conclusions were: (a) Psychophysiological response patterns are reliable for baselines and procedures, and single psychophysiological measures (especially absolute scores) are moderately stable; (b) Traditional (correlational) estimates of the reliability of single psychophysiological responses are limited by individual-response stereotypy, but multivariate analysis of response pattern provides a better index of reliability.