A clinico-statistical analysis of writer’s cramp signals: Study with indigenously developed multi-channel intramuscular EMG

Abstract

We investigated the hand muscles of Dystonia Writer’s cramp (WC) subjects affected due to DYT1 gene mutations in the brain. In clinical environments WC is done subjectively and lacking the objective. Therefore, the aim of the study is to determine if there is a quantifiable EMG difference in Writer’s Cramp (WC) patients with concordant mirror movements (MMs) from those with discordant MMs. For this, the five innocuous intramuscular microelectrodes (100 µ) are passed through five-muscles of intrinsic right-hand (RH). The EMG signals are acquired parallelly from five-muscles using indigenously built multi-channel EMG while subject writing with right-hand (RH), and with intrinsic left-hand. A canonical correlation-analysis between right-hand writing signal (RHWS) and left hand writing signals (LHWS) for each subject was carried out; giving squared canonical correlations. Correlations, for each subject between the signals when inscribing firstly with RH and then with LH are specified. Though, correlations are mostly negligible, albeit, some correlations are quite significant and distinctly high. These are presented as a Table of significant-correlations, i.e., correlations which are greater than 0.50 in absolute-value. It is found that often, the same muscle pairs will have significant correlation with same sign, in both ‘hand signals’ (i.e., RHWS, LHWS). In our computation, the scatter plot showed first two principal component (PC) scores explaining about 80% of variation. However, these findings are to be cross—validated with clinical findings on the same subjects.