Analysis of secondary behavioral outcomes in patients undergoing tDCS and CBT for pain and opioid misuse

Abstract

Abstract One of the limitations of tDCS is the difficulty in localizing currents and subsequent difficulty of predicting behavioral outcomes of a particular electrode placement. This project attempts to address this limitation by analyzing behavioral outcomes on a study population undergoing tDCS over the dorsolateral prefrontal cortex (DLPFC) by analyzing longitudinal change in four other behavioral outcomes associated with the target brain region. A series of repeated measures factorial ANOVAs were run on data taken from 73 participants who were randomized to receive either real (N=44) or sham (N=29) tDCS paired with Cognitive Behavioral Therapy (CBT) weekly for 11 weeks. All analyses were conducted with group assignment as a between subjects factor and time as a within subjects factor, and yielded that the main effect of time was significant for anxiety (F=6.122, p=.016), depression (F=6.762, p=.011), pain catastrophizing (F=30.782, p<0.000), and sleep (F=17.820, p<0.000). However, no significant interaction was found between time and group assignment, suggesting that while the CBT treatment showed significant improvements in these non-target behavioral outcomes, those improvements were not significantly aided by the addition of tDCS. This is despite previous analyses of these data yielding significant improvement of the target variable in the group that received real tDCS over the group that received sham tDCS. Keywords: tDCS, target areas, CBT, pain