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Objective: According to the DSM-5, trichotillomania (TTM) is now considered as an obsessive-compulsive spectrum disorder (OCD). Nevertheless, this change did not suffice the biological overlaps and distinctions between OCD and TTM. Quantitative EEG is a widely available and noninvasive method for diagnostic screening and thus may serve as a unique tool for investigating brain electrical activity differences between OCD and TTM. Taken together, the ultimate goal of this study was to study the quantitative EEG differences between TTM, OCD patients and health participants.
Method: Thirty-nine TTM patients, forty OCD patients and twenty-three healthy controls were enrolled for this study. We calculated theta and beta cordance values for each electrode and frequency band that provide an index of regional cortical activity.
Results: Post-hoc t-tests for theta cordance values did not show any significant results. Regarding beta cordance values, we found a significant right frontal activity differences between TTM and OCD cases (p=0.013) but not with healthy controls (p=0.19). Significant differences were also observed in the prefrontal beta cordance values between TTM and OCD cases (p=0.001) but not healthy controls (p=0.15). Lastly, there was a difference between healthy controls and OCD cases in regards to left temporal beta cordance values (p=0.010).
Conclusion: One main finding of this study was the greater discordance in the right frontal and prefrontal beta activity for OCD patients compared to TTM. In addition to this, we found a significantly higher concordance for left temporal beta activity compared to healthy subjects only for OCD patients. These findings replicated the previously well-defined left frontotemporal dysfunction in OCD patients. In addition to this, our demonstrated activity differences in the right and prefrontal areas between OCD and TTM may help us to understand the underlying physiopathology between OCD and TTM.