Can a subgroup of OCD patients with motor abnormalities and poor therapeutic response be identified?

In a subgroup of patients with obsessive-compulsive disorder (OCD), motor soft signs, tics and other movement disorders can be observed, indicating a special pathogenetic involvement of basal ganglia.

The main objective of this study was to verify the hypothesis that such motor dysfunction characterises a subgroup of OCD patients with poor treatment response. For assessing even subtle motor dysfunction, a new method for kinematical analysis of hand movements has been applied.

We examined the performance of 45 in-patients who met the DSM-IV criteria for OCD before and under therapy (sertraline and behaviour therapy) using a digitising tablet and kinematical analysis of simple handwriting and drawing movements. All subjects wrote a sentence, their signature and letter sequences. Moreover, they drew circles under different conditions. Three kinematical parameters (stroke duration, variation coefficient of peak velocity, stroke length) were calculated to quantify hand-motor performance.

Prior to therapy, non-responders wrote with significantly smaller amplitudes than responders. Additionally, non-responders drew significantly larger circles with the non-dominant hand at baseline, as compared to responders. Disturbances of handwriting were more frequent in non-responders than in responders.

Kinematical analysis of handwriting movements seems to be interesting for the prediction of poor response to treatments in OCD patients.