Habituation of the orientation reaction: Method study and comparison of measures among borderline hypertensitive and controls

The strength of the orienting reaction and the habituation of the OR to repeated stimulation have rarely been investigated in psychophysiological research on the etiology of hypertension. However, such biobehavioral measures may supplement conventional investigations that employ laboratory tasks, for example, mental arithmetic, in assessing individual differences in responsiveness. In a multi-parameter investigation, 56 male student subjects with normotensive blood pressure (122/73 mmHg), 31 subjects with mildly elevated BP (133/78 mmHg), and 48 moderately elevated BP (146/83 mmHg) were presented 10 medium intensity stimuli (85 dB, 1000 Hz). The response measures included a number of cardiovascular variables, electrodermal activity, and two EMG recordings. The investigation comprised two parts. First, a method study was conducted to select appropriate measures of habituation. A screening of response measures was made based on 80 of the subjects and the findings were cross-validated referring to the remaining 55 subjects. Thus eight measures of habituation were found whereby electrodermal responses were more sensitive than cardiovascular measures in depicting the course of habituation. Secondly, blood pressure groups were compared with regard to this set of measures. Neither the amplitude measures of the first OR nor the habituation of the OR differed between groups.