Evaluation of Autonomic Dysfunction in Parkinson Disease by Cardiovascular Autonomic Indexes

ABSTRACT

BACKGROUND: Cardiovascular autonomic dysfunction is one of the most frequent non-motor symptoms in idiopathic Parkinson disease (IPD). Several cardiovascular autonomic indexes (CAIs) have been reported to represent the degree of autonomic dysfunction in various neurodegenerative diseases. However, quantitative assessment by autonomic function tests in IPD has not been fully evaluated yet. The aim of this study is to investigate the usefulness of the quantitative autonomic test for detecting subclinical cardiovascular autonomic dysfunction and their correlation to the clinical severity of motor symptoms in IPD. METHODS: Four parasympathetic and sympathetic indexes during cardiovascular autonomic tests were compared between patients with IPD (n=31, age=65.8+/-9.14, Hoen&Yahr (H&Y) stage=2.1+/-0.68) and age matched healthy controls (n=30, age=63.2+/-7.56). Parasympathetic indexes include expirationinspiration ratio (EI ratio), valsalva ratio, 3015 ratio, and vagal barosensitivity. Sympathetic indexes are pressure recovery time, sympathetic index 1, sympathetic index 3 and adrenergic baroseneitivity. To demonstrate the correlation between severity of clinical motor symptoms and the autonomic abnormality, we also compared the H&Y stage and the abnormalities of those CAIs. RESULTS: EI ratio (p=0.009) and Valsalva ratio (VR) (p<0.001) were significantly different between IPD and control groups. Among the parameters, EI ratio (r=-0.466, p=0.005) showed significant negative correlation with severity of clinical motor symptoms in IPD (H&Y< or =3). CONCLUSIONS: Among the CAIs, EI ratio, VR are useful in detecting subclinical autonomic cardiovascular dysfunction in IPD. EI ratio may be the possible evaluation method revealing the severity of clinical motor symptoms in IPD.