Correlation between neuromuscular assessment and evoked potential in the prediction of the multiple sclerosis evolution

Background: Multiple sclerosis (MS) is characterized by a great heterogeneity of both its clinical course and the aspect of the lesions. The main purpose of this study is to evaluate the neuromuscular disorders in MS using electrophysiological parameters, in order to enable the rehabilitation physician to set the goals of a prophylactic intervention. The major research question addressed here is to identify the correlations between the electrophysiological parameters obtained by tensiomyographic (TMG) and visual evoked potential (VEP) testing in patients with MS, and to clinically apply these results in prevention and rehabilitation of motor disorders. The alteration of muscular structure and function affects the postural control. Research method: The group of subjects consisted of 40 MS patients, aged 38.15±11.19 years, without clinically detectable gait disorders. The neurophysiological assessment methods used were the visual evoked potentials (VEP) and tensiomyography (TMG). In addition, the clinical and functional assessments were performed by clinical examination and evaluation of the Expanded Disability Status Scale (EDSS) score and spasticity. Results: We found that there is a strong correlation between the values of the neuro-muscular parameters, which reflect the intramuscular conduction, and the characteristics of the P100 wave. At the level of the tibialis anterior muscle (TA), the P100 has an increased latency, which is pathognomonic for MS, and this is directly correlated with an increased levels of displacement (Dm) and a decreased contraction time (Tc). We also investigated some of the muscles belonging to the posterior compartment of the lower leg, namely the medial grastrocnemius (mGM) and the lateral gastrocnemius (mGL). We observed, both in the mGM and mTA, the same significant correlation between the Tc and Dm on the one hand and the P100 wave on the other hand, this correlation being stronger for Dm. These analyses determined the most significant parameters having a diagnostic value, which may reveal changes in a preclinical stage. Conclusions: Exploring MS patients by these two methods of evaluation and correlating the results of these investigations created the basis of a new algorithm for diagnosing and predicting possible motor disorders in these subjects and also set the goals for a rehabilitation program. By identifying the correlations between the TMG and the VEP early on, we can implement precocious rehabilitation program with the purpose of preventing or limiting the gait and balance disorders that may occur in time in patients with MS.