Research:
Measures of Arousal
Psychophysiological Measures of Arousal: Documentation of
Treatment Effects &
Impact of Disability

Principal Investigators: Don Bailey & Maria Boccia
Post-Doctoral Fellow: Jane Roberts

Funded by the FRAXA Research Foundation, 1998-2000

Many of the behavior problems associated with fragile X syndrome (FXS) are theoretically linked to high levels of physiological arousal, called hyperarousal. While there are few studies that support this finding (Miller, et al., 1999; Roberts et al., 2001), no one has looked at the relationship of physiological arousal to challenging behaviors or treatment effects. This FRAXA funded research project was aimed at increasing our understanding of the relationship of specific behaviors to physiological arousal and the treatment effects of medication on physiological arousal and specific behaviors.

Research Questions

In this research project, we had three primary questions. First, what is the relationship of physiological arousal to attention, motor activity, academic test performance, IQ level, and FMRP in boys who do not take medication? Second, does stimulant medication affect physiological arousal, attention, motor activity, and academic test performance? Third, do boys who are prescribed stimulant medication display different behaviors or different levels of physiological arousal than boys who are not prescribed medication?

Method

We examined these questions by completing three studies. In the first study, we assessed 19 boys who have not been prescribed medication. These boys were tested annually for three years, and we had IQ and FMRP data from a related study. In the second study, we assessed 12 boys who took stimulant medication. First, we compared the behavior of the 12 boys on a day when they were medicated and on a day when they were unmedicated. Second, we compared these 12 boys when they were unmedicated to the 19 boys for whom medication was not prescribed. In the third study, we looked at the behavior and physiological arousal of four boys before they were prescribed stimulants compared to four boys who were not prescribed medication within our study period. In all assessments, we videotaped the boys completing an academic test and gathered heart activity throughout the assessment. Then, we reviewed the videotapes and scored the amount of time the boys were on task and in their seat.

Results

  • Study 1 Results: The findings suggest that levels of physiological arousal generally decrease over time, which is the pattern expected for typically developing individuals. We found that physiological arousal was not related to FMRP; however, it was related to IQ level such that boys with lower IQs had higher levels of physiological arousal. In addition, lower levels of physiological arousal were related to increased attention and appear to be related to decreased activity (i.e., sitting in one's seat) but are not related to academic test scores.
  • Study 2 Results: These results suggest that levels of physiological arousal did not change from the day the boys were unmedicated compared to the day that they were medicated. However, there were differences in behavior and academic test performance. Specifically, the boys had better attention, were less active, and had higher academic test performance when they were medicated than when they were not medicated. In addition, these 12 boys had poorer attention and more active behaviors when unmedicated compared to the 19 boys who were not prescribed medication. However, the physiological arousal levels were not different between these two groups.
  • Study 3 Results: We found that the four boys who eventually were treated with stimulant medication were more active before they began taking stimulants than boys who never were treated with stimulants. However, their levels of physiological arousal were not different

In summary, it appears that physiological arousal is related to attention, motor activity, and IQ level in boys who are not prescribed medication; however, it is not related to FMRP. In addition, specific behaviors (e.g., high activity and poor attention) are associated with and may be predictive of stimulant medication use. While these findings may make intuitive sense in that we might expect boys who are more active and less attentive to be prescribed stimulant medication and boys who are medicated to have better behavior regulation, this is the first study to use direct observation and measures of physiological arousal to examine treatment efficacy of stimulant medication in boys with FXS.