Kinematic Analysis of Handwriting Movements in Individuals with Intellectual Disabilities with and without Obsessive Compulsive Symptoms

Theory/calculation: Movement disorders such as disturbances of coordination, clumsiness, and hand-related stereotypies are a frequent phenomenon in individuals with intellectual disabilities (ID). Obsessive-compulsive symptoms are also common in persons with ID. Our aim was to investigate hand motor dysfunction in persons with ID with and without OCD, using a digitizing tablet and the kinematic analysis of handwriting and drawing movements. Methods: We examinedthe hand motor performance of 23 individuals (12 males, 11 females, 42.6 ± 13.7 years old) with ID of heterogeneous aetiology. All subjects were required to write a sentence and draw circles under various conditions. Kinematic parameters were calculated to quantify hand motion. Results: Individuals with ID exhibit serious hand motor impairments suggestive of bradykinesia, irregularity, and micrographia. More than half of our ID patients (60.9%) displayed obsessive-compulsive symptoms of moderate severity (Y-BOCS total score: 16.6 ± 8.3). Interestingly, the ID patients with OCD displayed smaller amplitudes of hand motor movements than did patients with no obsessive-compulsive symptoms, while differences observed in the writing and drawing concentric circles trials were significant. Conclusions: The results of this pilot study support the use of kinematic analyses of handwriting movements to evaluate motor abnormalities in patients with ID and comorbid mental illnesses.