Investigation of lower extremity reaction time and determination of its effect on gait in early multiple sclerosis patients

. In this study, which was planned to investigate the lower extremity reaction time and its effect on gait in early stage Multiple Sclerosis (MS) patients; 28 individuals with a definite diagnosis of MS between the ages of 20 and 50, with an Expanded Disability Status Scale (EDSS) score of 0-3, participated in the study. Individuals with MS were divided into two groups according to their EDSS score between 0-1,5 as Group I, and those between EDSS 2-3 as Group II. Individuals with MS were divided into two groups according to their EDSS score between 0-1,5 as Group I, and those between EDSS 2-3 as Group II. These individuals are similar in terms of age and gender; 20 healthy controls were included in the study as Group III. The reaction time was evaluated by surface electromyography (EMG) recordings in the setup we created using a programmable microcontroller. The data we examined about the reaction time; mean reaction time, reaction time variability, learning effect, minimum and maximum reaction time, minimum-maximum reaction time difference and number of wrong answers. The 6-Minute Walk Test (6MWT) and the Timed Up-Go Test (TUG) were used in clinical evaluations of gait. The GAITRite computerized gait analysis system was used to evaluate the spatio-temporal parameters of gait and gait initiation. The gait parameters examined for initiation of gait; first stride length, second stride length, step width, first stride time, second stride time, and first double support. In comparisons between groups, there was no difference between the three groups in terms of reaction time and gait (6MWT, TUG, spatio-temporal parameters) results (p>0.016), while a statistically significant difference was found in the variability of the first double support from the variability of the spatiotemporal parameters during initiation of the gait (p<0.016). When the origin of the difference was examined, it was seen that there was a difference between Group I and Group II, as well as between Group II and Group III, arising from Group II (p<0.05). Considering the correlation analyses, a moderate correlation was found between reaction time variability (RZD) and right swing phase and right stance phase (rho = 0.59 rho = -0.59 respectively), which are time characteristics of gait in Group I. In Group II, a relationship was found between RZD and the distance characteristics of gait, left step width and right step width (rho=0.62, rho=0.56 respectively). In gait initiation parameters, a correlation was found between first double support variability and RZD in Group II (rho=0.52). The fact that the reaction time was found to be similar in MS patients with no functional and minimal functional involvement and in healthy individuals suggests that the increase in reaction time that starts in the early period will only reach significance at higher disability levels. It is associated with temporal parameters of gait even in MS patients without functional loss; supports that applications that will improve reaction time can have positive effects on gait. Longer and more variable reaction time; spatio-temporal disturbances in gait and increased variability in gait initiation may be one of the underlying neurophysiological mechanisms