CARDIOVASCULAR AUTONOMIC DYSFUNCTION IN MULTIPLE-SCLEROSIS IS LIKELY RELATED TO BRAIN-STEM LESIONS

Impairment of cardiovascular autonomic reflexes has been described in multiple sclerosis (MS), and believed reflecting dysfunction of reflex pathways located within the central nervous system. A battery of card iovascular autonomic tests were performed in 40 patients with definite MS: R-R interval variation test, deep breathing, Valsalva manoeuvre, blood pressure and heart rate responses to standing, sustained handgri p. The results were evaluated by Bayesian analysis, a pattern recognit ion technique. The patients had also magnetic resonance imaging (MRI) of brain and in 19 subjects of cervical spinal cord. Deep breathing te st and sustained handgrip test produced most frequently abnormal resul ts (17.5% and 40%, respectively). However. only 4 patients (10%) had t wo or more tests abnormal with a very variable pattern. Evaluation by Bayesian analysis revealed 7 patients (17.5%) with definite autonomic dysfunction. A correlation was found between the confidence level obta ined by Bayesian analysis, as index of autonomic function, and the Kur tzke brainstem FS score (r = 0.43, P < 0.01). There was a significant association between presence of autonomic dysfunction and clinical (P < 0.02) and MRI (P < 0.005) evidence of brainstem lesions.