Abstract
Freezing of gait (FOG) is a complicated gait disturbance in Parkinson's disease (PD) and a relevant subclinical predictor algorithm is lacking. The main purpose of this study is to explore the potential value of surface electromyograph (sEMG) and plasma α-synuclein levels as predictors of the FOG seen in PD. 21 PD patients and 15 normal controls were recruited. Motor function was evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS) and Freezing of gait questionnaire (FOG-Q). Simultaneously, gait analysis was also performed using VICON capture system in PD patients and sEMG data was recorded as well. Total plasma α-synuclein was quantitatively assessed by Luminex assay in all participants. Recruited PD patients were classified into two groups: PD patients with FOG (PD+FOG) and without FOG (PD-FOG), based on clinical manifestation, the results of the FOG-Q and VICON capture system. PD+FOG patients displayed higher FOG-Q scores, decreased walking speed, smaller step length, smaller stride length and prolonged double support time compared to the PD-FOG in the gait trial. sEMG data indicated that gastrocnemius activity in PD+FOG patients was significantly reduced compared to PD-FOG patients. In addition, plasma α-synuclein levels were significantly decreased in the PD+FOG group compared to control group; however, no significant difference was found between the PD+FOG and PD-FOG groups. Our study revealed that gastrocnemius sEMG could be used to evaluate freezing gait in PD patients, while plasma α-synuclein might discriminate freezing of gait in PD patients from normal control, though no difference was found between the PD+FOG and PD-FOG groups.
Highlights
Freezing of gait (FOG) is a paroxysmal locomotive gait disturbance observed in Parkinson’s disease (PD) and is regarded as a disability phenomenon [1,2]
Patients were identified as having PD by at least two movement disorder specialists, of which 13 PD+FOG patients were identified by at least two movement disorder specialists based on Freezing of Gait Questionnaire (FOGQ), identified by two criteria described as previous study [21]: (i)convincing subjective FOG reports, based on consistent and characteristic accounts of the phenomenon; (ii)a standardized and videotaped gait trajectory was performed containing specific elements known to provoke FOG [22]
We observed the following statistically significant parameters: slower walking speed (p = 0.006), smaller stride length (p = 0.004), smaller step length (p = 0.001) and prolonged double support time (p = 0.022) in the PD+FOG group compared to the PD-FOG
Summary
Freezing of gait (FOG) is a paroxysmal locomotive gait disturbance observed in Parkinson’s disease (PD) and is regarded as a disability phenomenon [1,2]. The freezing of gait questionnaire (FOG-Q) was developed to reliably identify and screen out ‘‘Freezers’’ among PD patients [4]. The identification of ‘‘Freezers’’ set the stage for application of kinematic analysis as an approach to unveiling the intrinsic characteristics of FOG [5,6,7]. A subclinical diagnostic test and prognosis marker for FOG in PD remains to be discovered. Accumulating evidence has been shown that an absence or extreme reduction in particular muscles, including triceps surae (TS), tibialis anterior (TIA) and gastrocnemius (GAS), were observed in PD patients, a finding contrary to patients with ataxic gait [8].
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