Electrophysiological Study In Predicting Autonomic Disorders In Patients With Parkinson's Disease

Background and Objective:Parkinson's disease(PD)is an irreversible neurodegenerative disorder characterized by motor dysfunction and various nonmotor symptoms.Nonmotor symptoms are common in PD,especially autonomic symptoms,and almost all the functional autonomic symptoms can be involved in PD.Autonomic dysfunction can present in the early stages of PD,even before motor symptoms occur,and impact the quality of patients' life.However,it is still under-recognized in daily clinical practice.It is important to recognize autonomic impairment because symptomatic treatment is frequently effective.Most patients with PD describe autonomic symptoms detailed at the time of diagnosis and evalutated by the scales.Although the items in the questionnaire scale for assessing the disorder of autonomic nervous system(ANS)in PD patients are reliable and valid,they are more complicated and subjective.Objective measurements of autonomic function are needed.SSR and HRV tests are recommended since these tests are objective quantitative tests.SSR and HRV analyses are noninvasive and easily applicable electrophysiological tests are used in the measure of sympathetic and parasympathetic nervous system function,respectively.Therefore,to confirm the relationship between the non-invasive methods(SSR and HRV)and the autonomic dysfunction of PD,we evaluated the correlation between(1)PD patients and healthy controls;(2)SSR and HRV parameters and other clinical autonomic disorder parameters regularly occurring in PD and to find out whe ther SSR and HRV parameters may have the potential to serve as electrophysiological markers of dysautomomia of PD.Method:Data were obtained from the outpatient and inpatient clinic at the Neurology Department of the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University.Forty-eight PD patients with confirmed PD diagnosis and 30 healthy controls having no history of a neurological disease were recruited to participate in the study.SSR,HRV,Unified Parkinson's disease rating scale(UPDRS)-?,the Scales for outcomes in Parkinson's Disease-Autonomic(SCOPA-AUT),Hoehn and Yahr(H&Y)scale were evaluated.And Hamilton Depression Rating Scale for Depression(HAMD).Hamilton Anxiety Rating Scale for Anxiety(HAMA),Montreal Cognitive Assessment(MoCA).Pittsburgh Sleep Quality Index Scales were also evaluated.35 patients of PD with dizziness had orthostatic hypotension test.Result:The basic characteristics of the patients included the following:mean age(±SD)equal to 68.90(±9.09)years(range:38-81 years),duration of the disease was 5.4±4.2 years(range:0.3-14 years),the score of the H&Y 2.26±0.90(range:1-5).the score of the UPDRS-? 14.02±6.03(range:4-31).SCOPA-AUT 14±5.83(range:1-27).The mean age of the control group(63.33±6.94)years,range:48-76 years).Abnomal SSR was observed in 34 patients(70.83%),and 23 in 35(65.7%)of the early stage,11 in 13(84.6%)of the milddle and later stages.Absent lower limb SSR was determined unilaterally in 2.bilaterally in 1 of 3 advanced PD patients;there was significant difference between PD and control groups in terms of the of SSR(P<0.01).significant prolonged SSR latencies and decreased SSR amplitudes from both hands and feet.There was significant difference between H&Y>2.5 and H&Y?2.5 groups in terms of the SSR(except right lower side SSR latency)(P<0.01),significant prolonged SSR latencies and decreased SSR amplitudes.There was significant difference between H&Y>2.5 and H&Y<2.5 groups in terms of the SCOPA-AUT and UPDRS-?,significant higher scores of the SCOPA-AUT and UPDRS-III in H&Y>2.5 group.There was a significant dirrerent correlation between the parameters of SSR and H&Y and UPDRS-?.SSR latencies correlated positively with H&Y,SSR amplitudes correlated negatively with H&Y.SSR amplitudes correlated with the UPDRS-? and duration of disease.SSR amplitudes correlated negatively with UPDRS-?.The left hand SSR latency correlated positively with UPDRS-?.The right hand and right foot SSR latencies correlated negatively with duration of disease.There was no significant different correlation between the parameters(except right foot SSR latency)of SSR and MoCA score.There was no significant different correlation between the parameters of SSR and HAMD,HAMA,PSQI.The right foot SSR latency correlated positively with age,the right hand and right foot SSR amplitudes correlated negatively with age,but there was no significant different correlation between other parameters of SSR and age.There were significant differences between PD and control groups in HRV,with analysis of SDNN,SDANN,SDNN index,LF.LF/HF and total spectral power.The parameters of HRV were found decreased in patients with PD when compared with the control subjects except for rMSSD and HF power.The parameters of HRV(except HF power)correlated negatively with UPDRS-? and H&Y.There was a significant different correlation between the total spectral power,LF,VLF and duration of disease,MoCA score.There was a significant different correlation between SDNN-24h,SDNN and MoCA score.Total spectral power,LF,VLF correlated positively with MoCA score and negatively with duration of disease.SDNN-24h,SDNN correlated positively with MoCA score.pNN50 correlated negatively with HAMA.35 patients of PD with dizziness had orthostatic hypotension test.There were significant differences between OH(+)and OH(-)groups in HRV,with analysis of SDNN24h,SDANN,SDNN and VLF.The parameters of HRV were found decreased in H&Y>2.5 group when compared with H&Y?2.5 group except for HF power.Correlation between electrophysiological autonomic parameters and clinical PD scales demonstrated:The left hand SSR latency correlated positively with the SCOPA-AUT score,SSR amplitudes and HRV parameters correlated negatively with the SCOPA-AUT score;and the SCOPA-AUT score correlated positively with the UPDRS-?score and H&Y score.Some parameters of SSR were relevantly associated with HRV.The left hand SSR latency correlated negatively with LF/HF(r=-0.366,P=0.031).The right hand SSR amplitude correlated positively with SDNN(r=0.320,P=0.028),total spectral power(r=0.311,P=0.034),LF(r=0.355,P=0.014)and VLF(r=0.315,P=0.031).The left foot amplitude correlated positively with rMSSD(r=0.349,P=0.043),total spectral power(r=0.461,P=0.006),LF(r=0.472,P=0.005)and VLF(r=0.447,P=0.008).The right foot amplitude correlated positively with total spectral power(r=0.442,P=0.035).Conclusions:Quantitative changes in SSR and HRV analysis parameters were measured in PD patients.More severe of the PD,higher scores of the SCOPA-AUT and UPDRS-?,and more abnormal of the parameters of the SSR and HRV.These data demonstrated that SSR and HRV could provide complementary information about the presence of dysautomia in subjects with PD.Both SSR and HRV parameters are sensitive in determining ANS dysfunction not only in late but also in the early stage of PD,which can be used for early detection of autonomic dysfunction in patients with PD and have the potential to serve as electrophysiological markers of dysautomomia of PD.