A Comparative Study Of Heart Rate Variability Of Multiple System Atrophy And Parkinson’s Disease

Objective: Symptoms of autonomic nervous were seen in patients either with MSAmultiple system atrophy (MSA) or with Parkinson’s diseases, leading to the difficulty indistinguishing these two diseases, especially in the early stage. More than20%of patientswere often misdiagnosed as PD. It is important to explore effective and noninvasive objectivemethods to differentiate MSA and PD as early as possible. Previous studies haverecommended various methods, including the eustachian tube filling experiment, tilted, sweatfunction experiment, quantitative sweat axon reflex experiment, sympathetic skin response,positron emission scanning, magnetic resonance spectrum analysis, anal sphincter andurethral sphincter electromyography, bladder function evaluation, blood pressure and test ofthe pupils, and so on. However, the diagnostic value of them in the identification of MSA andPD is still controversial. The aim of the present study was to compare the differences ofepidemiological, clinical data and the indicators of heart rate variability (HRV) amongpatients with MSA or PD, and to search for any characteristic parameters which can help indistinguishing the two diseases.Methods: A prospective studies of medical records of65consecutive patients (34patients with MSA and31patients with PD) admitted into our neurology ward in the FirstAffiliated Hospital of Dalian Medical University between October2012and January2014was performed. We collected data on the epidemiological characteristics including gender,age and duration, and the indicators of HRV including the time domain and frequency domain.The severity of disease of MSA and PD was assessed using Hoehn and Yahr stage, UnifedParkinson’s Disease Rating Scale (UPDRS)，and Mini Mental State Examination (MMSE) score. We used single factor analysis of variance and the receiver-operating characteristiccurve (ROC) to determine clinical index of the specificity of two diseases.Results:95cases of patients, including MSA group of34cases,18cases (52.9%) ofmen,16cases (47.1%) of women, were enrolled. In PD group of31cases,14cases (45.2%)were men, and17cases (54.8%) women. In control group of30cases,15cases (50.0%) weremen,15cases (50.0%) women. There was no significant difference with three groups ofgender composition (chi-square=0.011, P>0.011). There is no difference between the meanage [(60.26±6.46) VS.(62.74±5.96) VS.(59.37±6.02), P>0.05] among MSA、PD and thecontrol group. Two groups of patients with MMSE score and there is no significance (P>0.05). Two groups of patients UPDRS score comparison differences statistically significant (P<0.05). Patients with MSA and PD average Hoehn-Yahr stage respectively (2.44±0.44) and(1.29±0.62), two groups of patients Hoehn-Yahr stage compare differences significant (P <0.05). In the control group, patients with MSA and PD groups, HRV time domain indexSDNN, SDANN, rMSSD comparison differences had no significance (P>0.05), butPNN50%、CV comparative differences are significant (P <0.05), the two comparativeanalysis found that in the control and MSA group PNN50%, CV comparative differences aresignificant (P=0.005,0.005, respectively). In the control group, patients with MSA and PDgroups HRV in the frequency domain index ULF、total power、LF/HF comparison differenceshad no significance (P>0.05), but the VLF、LF、HF index comparison differences significant(P <0.05). Among them, the two comparative analysis found that in the control group andpatients with MSA group VLF, LF、 HF index comparative differences are statisticallysignificant (P=0.000,0.000,0.001). ROC curve analysis results indicated that thePNN50%、CV、VLF、 LF、HF、Hoehn-Yahr stage and UPDRS were significant (P <0.01).VLF、CV、LF、HF、PNN50%、UPDRS、Hoehn and Yahr staging area under the ROCcurve and its95%confidence interval,0.703(0.599-0.807),0.667(0.561-0.773) and0.561(0.553-0.767),0.650(0.542-0.758) and0.542(0.532-0.748),0.305(0.179-0.431) and0.179(0.010-0.126). Area under the ROC curve from big to small indexes respectively the VLF、CV、LF、HF、 PNN50%、 UPDRS、Hoehn and Yahr stage.Conclusions:(1) The severity of disease in patients with MSA seems to be higher than those with PD in the early disease stage;(2) In contrast to PD, both sympathetic and vagusnerve may be involved, resulting dysfunction of cardiovascular autonomic system;(3) HRVcan be used for the early identification between MSA and PD;(4) The VLF may have betterprediction effect and diagnostic value in distinguishing MSA and PD in the early stage.