The severity of motor dysfunctions and urinary dysfunction is not correlated in multiple system atrophy

Although it is well known that patients with multiple system atrophy (MSA) cerebellar dominant type (MSA-C) show severe autonomic dysfunction, the relationship between autonomic and motor dysfunction remains uncertain. Previously we reported that severe urinary voiding dysfunction is useful in differential diagnosis of MSA and other diseases. Herein, we aimed to clarify the relationship between the severity of motor dysfunctions and urinary dysfunction.

This study is a retrospective review of 46 patients with MSA-C diagnosed according to Gilman's second consensus criteria. The severity of motor dysfunctions was evaluated using International Cooperative Ataxia Rating Scale (ICARS). Urinary voiding dysfunction was evaluated by measuring post-void residual (PVR). The mean duration of motor unit potentials in external anal sphincter muscles on electromyography, which represents the severity of neurodegeneration in Onuf's nucleus, was also examined.

The mean age of patients was 63.8 ± 8.2 years and mean disease duration was 3.0 ± 1.9 years. The mean ICARS score was 40.1 ± 14.7. The mean PVR was 119.1 ± 102 ml and the mean duration of motor unit potentials (MUPs) in anal sphincter electromyography was 9.2 ± 2.2 ms. The correlation coefficient between ICARS and PVR was 0.093 (p = .539), and between ICARS and mean duration of MUPs was 0.105 (p = .811). A significant positive correlation (r = 0.296, p = .005) was noted between PVR and the mean duration of MUP.

Motor and urinary dysfunctions were not correlated in MSA-C.