Autonomic disturbances, predominantly sphincter impairment, are common in multiple sclerosis (MS). Our study performed spectral analysis of heart rate variability (SA HRV) in the supine-standing-supine test in 50 patients (12 males, 38 females, average age ± SD 33.5 ± 8.6 years) with a confirmed diagnosis of the remitting form of MS. SA HRV was also performed in a control group of 50 age – and sex-matched normal individuals. Results of SA HRV were correlated with the degree of clinical impairment (according to EDSS – Expanded Disability Status Scale), with the presence of sphincter dysfunction, with the presence of MRI-confirmed infratentorial lesions and with the type of therapy used. Patients with infratentorial lesions suffered sphincter dysfunction 4.5 times more often than patients in whom only supratentorial lesions were found. Compared to the control group, MS patients showed a significant decrease of the high-frequency (HF) component in SA HRV, increased ratio of low-frequency (LF) to HF component (LF/HF) when standing and decrease of the total power in SA HRV in supine position. Patients with sphincter dysfunction showed HF decrease when lying down as well. Patients treated with cytostatics had lower HF and total power in SA HRV compared to other patients. We did not find correlation between SA HRV parameters and the degree of clinical impairment or the presence of infratentorial lesions. SA HRV in the supine position test appears to be a sensitive method for detecting even subclinical changes in the autonomic nervous system.

        Key words: autonomic nervous system, cytostatics, multiple sclerosis, spectral analysis of heart rate variability.