ABSTRACT
Background@#Differential diagnosis of idiopathic Parkinson disease (IPD) and multiple system atrophy-Parkinson type (MSA-P) is challenging since they share clinical features with parkinsonism and autonomic dysfunction. To distinguish MSA-P from IPD when the symptoms are relatively mild, we investigated the usefulness of the quantitative fractionalized autonomic indexes and evaluated the correlations of autonomic test indexes and functional status.@*Methods@#Thirty-six patients with parkinsonism (22 with IPD and 14 with MSA-P) in Soonchunhyang University Bucheon Hospital from February 2014 to June 2015 were prospectively enrolled in the study. We compared fractionalized autonomic indexes and composite autonomic scoring scale between patients with IPD and MSA-P with Hoehn and Yahr (H&Y) score ≤3. Parasympathetic indexes included expiratory/inspiratory ratio during deep breathing, Valsalva ratio (VR), and regression slope of systolic blood pressure (BP) in early phase II (vagal baroreflex sensitivity) during Valsalva maneuver. Sympathetic adrenergic indexes were pressure recovery time (PRT) and adrenergic baroreflex sensitivity (BRSa) (BP decrement associated with phase 3 divided by the PRT), sympathetic index 1, sympathetic index 3, early phase II mean BP drop, and pulse pressure reduction rate. Additionally, we compared the unified multiple system atrophy rating scale (UMSARS) and H&Y scores and the autonomic indexes in all patients.@*Results@#PRT was significantly different between the IPD and MSA-P groups (P = 0.004) despite the similar BP drop during tilt. Cutoff value of PRT was 5.5 s (sensitivity, 71.4%; specificity, 72.7%). VR (r = -0.455, P = 0.009) and BRSa (r = -0.356, P = 0.036) demonstrated a significant correlation with UMSARS and H&Y scores.@*Conclusions@#Among the cardiovascular autonomic indexes, PRT can be a useful parameter in differentiating the early stage of MSAP from that of IPD. Moreover, VR, and BRSa may be the optimal indexes in determining functional symptom severity.
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 expiration:inspiration ratio (E:I ratio), valsalva ratio, 30:15 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: E:I ratio (p=0.009) and Valsalva ratio (VR) (p<0.001) were significantly different between IPD and control groups. Among the parameters, E:I 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, E:I ratio, VR are useful in detecting subclinical autonomic cardiovascular dysfunction in IPD. E:I ratio may be the possible evaluation method revealing the severity of clinical motor symptoms in IPD.