Compromised Dynamic Cerebral Autoregulation In Patients With Parkinson’s Disease

Objective: To aim of this study is to analyze dynamic cerebral autoregulation(d CA)and its correlation with autonomic symptomsin patients with different subtypes of Parkinson’s Disease(PD).Methods: Patients diagnosed as Parkinson’s Disease according to the latest clinical diagnostic criteria for Parkinson’s disease of the International Movement Disorders Society in 2015 were enrolled in this study.All patients were admitted to the third Hospital of Hebei Medical University from January2021 to December 2021.Age-and sex-matched healthy controls from the same region were recruited simultaneously.All the enrolled PD patients received Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale to evaluate their motor symptoms;modified Hoenh-Yahr staging scale to assess disease level;Parkinson’s Disease Non-Motor Symptom Scale to evaluate non-motor symptoms;Scales for Outcomes in Parkinson’s Disease-Autonomic questionnaire to evaluate autonomic symptoms.The d CA function of all the study populations was measured by transcranial doppler ultrasound system(9d-PRO,Delikai Shenzhen,China),which uses the transfer function analysis(TFA)modle developed by Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences and Matlab software to analyze noninvasive continuous cerebral blood fow velocity(CBFV)of the bilateral middle cerebral artery and arterial blood pressure(ABP)recorded by transcranial doppler ultrasound system.The d CA parameters in each frequency band of bilateral 0.02～0.5 Hz were obtained,including gain,phase and coherence between the output and input signals.Among them,the coherence of very low frequency(0.02～0.07HZ)≥0.51 is used as the quality control parameter,the phase difference(phase)≥ 52,and the gain(gain)< 1 as the threshold value for normal d CA.Phase difference(phase)< 52,gain(gain)≥ 1 indicates that d CA is the abnormal.When the results of phase and gain are inconsistent,phase is used as the main evaluation parameter.First,the d CA parameters,middle cerebral artery velocity systolic(MCA-Vs)of PD patients and healthy controls were compared and analyzed.Second,patients with PD were divided into two groups according to the clinical manifestations:tremor dominant(TD)PD and non-tremor dominant(n TD)PD(including postural instability and gait difficulty subtype and intermediate sutype)PD patients.The differences in d CA parameters,and motor symptoms,non-motor symptoms,and autonomic nerve impairment symptom scores were compared between the two groups of PD patients.Finally,Spearman correlation analysis and partial correlation analysis were used to analyze the correlation between d CA impairment and clinical characteristics.Results:100 PD patients and 100 healthy controls completed the d CA function test effectively and were included in the statistical analysis.The bilateral phase of patients with PD were signifcantly lower than that of the healthy control group(P < 0.01)and the bilateral gain of patients with PD were signifcantly higher than that of the healthy control group(P <0.01),documenting that d CA is impaired in patients with PD.There are different degrees of correlation between abnormal d CA parameters and subtype,MDS-UPDRSIII scores,PD-NMSS scores,and SCOPA-AUT scores.After controlling for SCOPA-AUT scores,There was no correlation between abnormal d CA parameter and subtype,MDS-UPDRSIII scores,SCOPA-AUT scores and PD-NMSS scores.Furthermore,The comparison between groups of PD patients with different subtypes showed that:The bilateral phase in the n TD group was significantly lower than that in the TD group(P < 0.01),and the scores of motor function,non-motor function and autonomic nerve function in the n TD group were significantly higher than those in the TD group,suggesting that non-tremor PD patients are more likely to have impaired d CA,and the symptoms of motor,non-motor and autonomic impairment are also more severe.Conclusions:Our study documented that d CA is impaired in patients with PD,MDS-UPDRSI and MAP are independent factors to predict impaired d CA in patients with PD.There are differences in the degree of d CA impairment in different subtypes of PD patients.The d CA function impairment in n TD PD patients is more severe,and the motor,non-motor and autonomic symptoms are also more severe.Our study suggested that the cerebral blood flow autoregulation detection technology used in this study can evaluate the d CA function of PD patients,and is helpful for the classification and prognosis of PD patients.Further evaluation of the d CA of PD patients with symptoms of impaired autonomic function is required to clarify whether d CA is involved in the mechanism of impaired autonomic function.