The roles of blink reflex and sympathetic skin response in multiple sclerosis diagnosis

The neurological history and examination are important in multiple sclerosis (MS) diagnosis, but early and accurate diagnosis of MS often requires judicious use of paraclinical information. Electrophysiolgic techniques have an important role in demonstrating lesions that are clinically silent, but magnetic resonance imaging (MRI) is accepted as the most sensitive paraclinical test for detecting asymptomatic dissemination in space for MS patients. In order to test the sensitivity of electrophysiologic techniques in diagnosing asymptomatic MS lesions, we performed blink reflex (BR) and sympathetic skin response (SSR) studies on 13 female (mean age 39∓9 years) and 8 male (mean age 35∓14 years) patients with a diagnosis of definite MS who do not have any clinical symptoms nor signs referable to brainstem or autonomic system dysfunction. Forty three percent of patients on SSR testing and 40% of patients on BR testing demonstrated abnormal results. In countries with unfavorable economic conditions, diagnosis, especially the follow-up evaluation of MS patients, poses a major dilemma. The role of diagnostic techniques in MS diagnosis when MRI is available is an economic problem. Diagnostic evaluation adds to the cost of health expenses. We usually choose to perform MRI only at the initial diagnosis of MS and perform follow-up evaluations during remissions and exacerbations with the aid of electrophysiologic techniques. We stress the importance of electrophysiologic screenings in MS patients because they provide data that cannot be obtained through clinical evaluations, only with a little cost.