[Computerized method for arm movement assessment in Parkinson's disease and cerebellar syndrome patients]

In clinical setting, the symptoms of the impaired motor behavior in patients with different neurological diseases are identified by classical tests incorporated in clinical neurological examination. New computerized methods for objective motor assessment have been recently suggested in the literature. We developed computerized method for assessment and evaluation of arm movement in patients with Parkinson's disease (PD) in early phase and in patients with cerebellar syndrome. Method is based on automatic acquisition of hand coordinates during drawing of line and circle, and off-line analysis of kinematic parameters (time duration, path length, mean and maximal velocity, velocity profile, and precision). Clinical application is in recognition and follow-up of the impaired kinematic parameters, specific for these two groups of patients.

We propose computerized method that consists of two motor tasks: Task 1- drawing a line defined with end points; and Task 2 - drawing a circle defined by referential model. The first task was rather simple with defined direction, and the second included continuous change of the direction that required permanent adjustment. The aim was to detect which kinematic parameters were particularly different in PD and in patients with cerebellar syndrome in relation to healthy controls, and then to apply this method as an additional instrument in clinical evaluation.

Hand trajectories were assessed during simple self-paced 1) point-to-point movement-Task 1; and 2) circle-Task 2, by cordless magnetic mouse in a hand on digitizing board (Drawing board 111, 305 x 457 mm, GTCO Cal Comp Inc). The subjects were seated in a relaxed manner on the chair adjusted to the table height, and instructed not to correct drawn line during performance of a task. The first session was for practicing the tests only, and in the next session, the subjects repeated 5 times each task. All sessions were videotaped with CCD camera. Testing included three groups: 10 Parkinsonian patients, 8 patients with cerebellar syndrome and 10 healthy controls, age matched, with not known neurologic motor or sensory disorders. Data were obtained using custom-made software written in C++, and stored in computer for further analysis. Data were analyzed using the Excel (ver. 9.0) and MatLab (ver. 6.0). The following kinematic parameters were calculated: time duration, path length, mean and maximal velocity, velocity profile and precision, and then statistically processed. Generalized linear model was formed in SPSS 10.0.

The data from all subjects and from all trials for two tasks were first visually inspected. In the first task, PD patients significantly differed in relation to controls in the following parameters: mean and maximal velocity, while in the second task, time duration and mean velocity were significantly different. For patients with cerebellar syndrome in relation to controls, mean and maximal velocity, and path length were significantly different for the first task, while in the second task, path length. For the task to draw a line, both groups of patients had statistically smaller mean and maximal velocities in respect to controls, and for the drawing of a circle, none parameter was at the same time statistically different for both groups in regard to controls. Between the two groups of patients, the only statistically different kinematic parameter was the length of drawn line. The velocity profile for the same task was shown as characteristic for the three groups.

Identifying the abnormal kinetic parameters of hand movement as well as their correlation with classical clinical signs could be highly important in the process of patient's motor control status evaluation, and could enable better understanding of the course and prognosis of specific pathological entity.