Objective: The study aimed to assess the kinematic characteristics of handwriting in patients with Spinocerebellar ataxia (SCA) and to compare it with patients with Parkinson’s disease (PD) and healthy controls (HC).

Background: Handwriting abnormalities are commonly observed in patients with Parkinson’s disease (PD) and Spinocerebellar ataxia (SCA). Digitizing tablet technology has revolutionized the study of kinematic variables of handwriting. Although several studies have explored the kinematic properties of handwriting in PD, similar studies in patients with SCA are few. As handwriting analysis may help in measuring the response to treatment, it is essential to identify the basic kinematic abnormalities of handwriting these disorders. 

Methods: Thirty patients each with SCA and PD, and 30 age-gender matched HC were studied. Severity of motor symptoms were measured by the Scale for the Assessment and Rating of Ataxia (SARA) for patients with SCA and by the Unified Parkinson’s Disease Rating Scale (UPDRSIII)for patients with PD. The subjects performed five standardized handwriting tasks on a digitizer (Wacom Intuos CTL-470). The data was collected and analysed using MovAlyzeR, a handwriting analysis software.

Results: Compared to the HC, handwriting of both PD and SCA groups were: (1) slower, as measured by absolute velocity (p < 0.01), (2) more dysfluent, as measured by number of peak acceleration points (p < 0.01), (3) smaller in size, as measured by the trace length of the writing (p < 0.01). The trace length of writing was significantly less in SCA (1.4 ± 0.5 cm) compared to PD (1.5 ± 0.6 cm) whereas the average velocity was significantly decreased in PD (2.0±1.5 cm/s) compared to SCA (2.5±1.3 cm/s).

Conclusions: Handwriting abnormalities in SCA and PD include disturbances in velocity, fluency and size. Our results suggest that micrographia, which is considered a clinical sign of parkinsonism, may also be present in SCA. Analysis of handwriting can be used as a simple and objective measure to determine disease severity in SCA and PD. These findings may also have relevance while designing rehabilitative interventions aimed at preserving the quality of life in patients with these debilitating diseases.

Presented at the 2nd Annual Conference of the Movement Disorders Society of India (MDSI) on 7th January 2017 at the NIMHANS Convention Centre, Bengaluru, India.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/assessment-of-graphomotor-impairment-in-patients-with-spinocerebellar-ataxia-and-parkinsons-disease/