The Correlation Between Freezing Of Gait And Brain Iron Deposition In Parkinson’s Disease

Objective:Parkinson’s disease(PD)is a common neurological degenerative disease.The loss of nigrostriatal dopaminergic neurons is the main pathological feature,and the increase in brain iron content can induce free radicals to participate in the degeneration of dopaminergic neurons.At the same time,the increased brain iron deposition is also one of the factors causing cognitive impairment in PD patients.Freezing of gait(FOG)is a common gait disorder in PD.Current studies have shown that FOG is closely related to cognitive impairment.Patients with FOG often have cognitive impairment in PD,and cognitive dysfunction can also promote the occurrence of freezing of gait,they are related.Therefore,we considered that the occurrence of FOG in PD patients may be related to the increased brain iron deposition.We used quantitative magnetic susceptibility mapping(QSM)imaging technology to investigate whether patients with and without FOG in PD have differences in iron deposition in specific brain regions,then explored the correlation between iron deposition and FOG in patients with PD.Methods:We collected the clinical and related scale data of 26 clinically confirmed PD patients who were treated in the Department of Neurology in our hospital from November 2017 to December 2018.According to the score of the Movement Disorder Society-Unified Parkinson Disease Rating Scale(MDS-UPDRS)item 13 “Freezing while walking” or item 3 of the FOG Questionnaire(FOGQ),26 PD patients were divided into two groups witn PD-FOG(+)(n=10)and PD-FOG(-)(n=16).Then measured the iron deposition of the severe and contralateral side of Substantia nigra(SN),Red nucleus(RN),Caudate nucleus(CN),Putamen(PUT),Globus pallidus(GP),and Supplementary motor area(SMA)of the patients,then explored its correlation with clinical characteristics.Results:There were no significant differences between the PD-FOG(+)group and PD-FOG(-)group in gender,age,age of onset,severely diseased side,type of onset,course of disease,Hoehn-Yahr(H-Y)stage,Mini-Mental State Examination(MMSE),Montreal cognitive assessment scale(MoCA),UPDRS-I and IV scores(P> 0.05).In the PD-FOG(+)group,the scores of UPDRS-II,III,Parkinson’s Disease Questionnaire-39(PDQ-39)and Freezing of gait Questionnaire(FOGQ)were higher than that of PD-FOG(-)group,and the differences were statistically significant(P <0.05).In the whole PD group,the susceptibility values of SN,RN of the severe side were higher than that of the contralateral side,and the differences were statistically significant(P < 0.05).In the PD subgroup,compared with the PD-FOG(-)group,the susceptibility values of SN,CN,PUT,and SMA of the PD-FOG(+)group were higher,and the differences were statistically significant(P < 0.05),but there were no statistically significant differences in the susceptibility values of the RN and GP between the two groups of patients(P> 0.05).In the whole PD group,there was a positive correlation between the susceptibility value of SN in the severe side and the UPDRS-III score during the off-state(r = 0.542,P <0.05).In the PD-FOG(+)group,the susceptibility value of the SN was positively correlated with the FOGQ score(r =0.801,P <0.05).Conclusion:The PD-FOG group had more severe motor symptoms and worse quality of life.The PD-FOG group had higher levels of iron in the SN,CN,PUT and SMA,and the severity of FOG was related to the iron deposition in the SN.