Cardiovascular autonomic dysregulation and fatigue in multiple sclerosis

Both cardiovascular disturbances and fatigue are frequent in multiple sclerosis (MS). We investigated their relationship in 84 MS patients (mean age 39.9 +/- 8.9 years) using five established autonomic tests and three different fatigue questionnaires. 64.2% of the patients were categorised as being fatigued. Fatigue perception was weakly related to EDSS. Moderate cardiovascular disturbances were found in 16.6% of the patients, and 10.7% had severe cardiovascular autonomic abnormalities. Cardiovascular dysfunction was slightly related to age and to EDSS. In 19.4% of all patients signs of autonomic failure and fatigue were co-existent. Using correlation analysis, we found only weakly significant correlation coefficients between some single autonomic test parameters and fatigue scores, which were confounded by age effects. The analysis of dichotomised data revealed slightly significant differences in fatigue experience between patients with and without abnormalities regarding the handgrip test and the Valsalva reaction. Thus, autonomic disturbances might contribute to fatigue symptoms in a MS subgroup, but the overall influence of the autonomic cardiovascular regulation towards fatigue experience seems to be of minor relevance.