Autonomic dysfunction in multiple sclerosis and other updates on recent autonomic research

Excerpt

Multiple sclerosis (MS) is a demyelinating disorder of the central nervous system (CNS) that can result in varied neurological deficits, including motor dysfunction, sensory loss, and bladder abnormalities. Additionally, patients report significant fatigue. Although reports on the symptoms of autonomic dysfunction in patients with MS are increasing, the nature of the dysautonomia in MS remains unclear. Two recent publications have attempted to address this important topic. In an article published in Multiple Sclerosis & Related Disorders, Damla et al. [1] measured heart rate variability (HRV) in 51 patients recently diagnosed with relapsing–remitting multiple sclerosis (RRMS) and 44 matched healthy controls. All patients were evaluated before any immunomodulatory therapy was started. Participants had echocardiograms as well as 24-h HRV analysis. Those with an abnormal echocardiogram were excluded from the study. Additionally, all patients had brain and cervical MR imaging. The authors found that patients with RRMS had lower HRV values than controls, but there was no relationship between the location of the demyelinating lesions and the severity of the HRV abnormalities. There was also no relationship between HRV and MS-specific outcome measures, such as the Expanded Disability Status Scale (EDSS) or MS Functional Composite scores. Thus, patients with recently diagnosed MS appear to have a reduction in HRV without any clear relationship to the overall disease burden at the time of diagnosis. Therefore, the clinical relevance of these findings remains unclear. Moreover, since this was a cross-sectional study, it is unknown if these HRV abnormalities worsen as patients develop further demyelinating plaque burden or as they develop a progressive form of MS. …