In 20 patients with remitting-relapsing type of multiple sclerosis (MS) the activity of the disease expressed as a degree of progression of disability according to the Expanded Disability Status Scale (EDSS) in oneyear follow-up was evaluated. The influence of activity of the disease on the degree of autonomic nervous system impairment was determined by the use of short-term spectral analysis of heart rate variability (HRV) in the supine-standing-supine test. Ten patients had an active form of the disease reflected by a progression in the EDSS (mean increase 0.9±0.51) and 10 patients showed no progression of the disease with the same or lower EDSS score after one-year follow-up. Compared to the patients without progression in the EDSS score there was reduction of the very low frequency (VLF) band in the group with an active form of the disease in the initial examination, but no significant difference between both groups in the other parameters was found. In comparison of both groups of the MS patients with the normal subjects in the initial examination, a reduction of the high frequency (HF) band and the total power in the supine position and a decrease of the VLF and the HF components with an increase of the LF/HF ratio in the standing position was found in the group of patients with an active form of the disease. Compared to the normal subjects, in the MS patients without progression a decrease of the LF component in the supine position was found and the reduction of the HF parameter was registered only in the standing position. Thus a more prominent impairment of the autonomic nervous system in the MS patients with an active form of the disease was found. The parameters of the HRV were not progressively deteriorated despite the progression in the EDSS score in one-year follow-up.

        Key words: autonomic nervous system, multiple sclerosis, spectral analysis of heart rate variability, sphincter impairment