Development of Assessment Methods for Humans with Impact on Reaching and Grasping

The basis for the research to follow is the evaluation of physiological and kinematic parameters of movement in hemiplegic individuals. The goal during last period was the development of an objective method for quantifying and analyzing the symmetry of Event-related Synchronization (ERS) that follows complex movement. The idea was evaluated in able-bodied subjects and then in individuals after cerebrovascular accident immediately after the accident and after six months. The motor task consisted of moving a magnetic mouse on a drawing board, while the physiological signal was the interpolated electroencephalographic (EEG) map (signed symmetry index (SI) of bipolar central-, fronto-central and centro-parietal channels). The conclusions from this study are that although the involved movements require a complex coordinated interaction between different limbs, the herein introduced method for studying symmetry measures using low-resolution bipolar EEG (20 bipolar channels) was sensitive enough to follow the recovery in the contralateral somatotopic organization of movement. The results suggest a normalization of somatotopic organization for the group of investigated subjects that was correlated to the functional recovery. The results of the pilot testing in eight hemiplegic individuals should be verified in larger clinical study. The results of this study will appear in Eder et al., 2006 in European Journal of Neurology.
The second study was related to the determination of the correlation between kinematic measures of movement and a clinical measure of spasticity and it was termed the Drawing Test (DT). The study was done in the Rehabilitation Center “Dr Miroslav Zotović” in Belgrade. 45 post-stroke hemiplegic individuals with various levels of spasticity and eight able-bodied subjects with no sensory-motor deficits of their upper extremities participated in the clinical trial. Subjects made self-paced radial point-to-point movements between the left, and the right corners of a square with a side of 200 mm at the surface of a drawing tablet. Hand coordinates were recorded by reading the coordinates from the mouse, which was attached to the hand. The DT scores were highly correlated with the AS scores in 49 out of 53 subjects based on the multiple linear regression analysis; thus, the DT can be used as a quantitative metrics of movement ability instead of the subjective clinical measure of spasticity. The test was developed to a tool that is now being used in the clinical studies in U.K. by our research colleagues. These studies were part of the Ph.D. project of Clemens Eder who received his degree in September 2005.
In the future work we will further evaluate the use of low density EEG and continue that analysis of the technique develop by Eder. In parallel, we will study in details the potentials of TMS in evaluating cortical plasticity with the special emphasis on the development of the protocol that guaranty the repetitive readings of MEP in selected muscles that are of interest for the study. Part of this research will be done in close collaboration with Dr Ina Tarkka from Finland in Neuron, Kuopio.