Quantitative evaluation protocol for upper limb motor coordination analysis in patients with ataxia.

Objective and quantitative measurement is crucial in the definition of functional impairment and in the tracking of disease progress over time of patients affected by progressive pathologies, such as ataxia. A new experimental procedure for the quantitative description of upper limb movement and coordination analysis was developed by the integration of an optoelectronic system and dedicated electronic board with four visual and pressure stimuli. 20 passive retroreflective markers were placed on the subject's body and two types pointing tests were defined: in the first one, the subjects were asked to reach with the index finger five consecutive times each of the three targets ("repetitive test"), and in the second one, the subjects were asked to randomly reach the targets with the index finger ("random test"). The preliminary results showed that patients affected by ataxia took more time with a less smooth finger tip movement to perform the reaching tests when compared to healthy subjects. The velocity was lower and its profile was more irregular in ataxic subjects. The new developed experimental procedure seems to be very promising in the quantitative description of upper limb movements of pathological and healthy subjects and it seems to be able to distinguish the impairments due to different levels of ataxia.