Is the dopaminergic loss associated with gait and postural impairments in subjects with Parkinson's disease at different motor stages?

Gait and postural control deficiencies in Parkinson's disease (PD) involve several specific motor aspects. The aim of this study was to identify and compare the main changes in gait kinematics and postural control with dopaminergic loss in the striatum region. This is a cross-sectional study that included 42 individuals with PD at different motor stages, according to the Hoehn & Yahr scale (H&Y). Motor subsection of the Movement Disorder Society-Unified Parkinson Disease Rating Scale-part III (MDS-UPDRS III) was used to evaluate general motor aspects. Gait kinematics was assessed using a three-dimensional motion capture system. Postural control was assessed by stabilometry using force platforms. Dopamine depletion was verified through 99mTc-TRODAT-1 (SPECT-CT) examination. We included 12, 15 and 15 individuals classified as H&Y I, II and III, respectively. We identified worse values of dopamine transporter uptake, MDS-UPDRS III, gait parameters (velocity, step length and stride length) and center of pressure displacement as the disease progressed. Our results indicate that higher dopaminergic loss and gait and postural control deficits occur between the H&Y levels II and III.

Impairments in gait kinematics and postural control may not correlate with dopamine transporter depletion in individuals with mild to moderate Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by the loss of dopamine, an important neurotransmitter involved in regulating movement. Nuclear medicine imaging methods such as single-photon emission computed tomography (SPECT) combined with radiotracers can obtain the density of this neurotransmitter. This reduced density leads to classic PD symptoms, such as bradykinesia, tremor and stiffness, consequently affecting walking and postural control. The aim of this study was to verify the correlation between disorders of gait kinematics and postural instability with dopamine depletion in individuals with mild to moderate PD. This is a descriptive, observational cross-sectional study. Subjects were assessed for spatiotemporal gait parameters by a three-dimensional motion capture system, for postural control by stabilometry on a force plate. Dopamine depletion was verified through 99mTc-TRODAT-1 (SPECT-CT) examination. The subjects were in the off-stage of levodopa in all analysis. We evaluated 71 individuals, 32 with mild to moderate PD (HY 2 and 2.5) and 39 healthy individuals matched for gender, age, and height. There was a significant difference between the groups regarding the spatiotemporal variables of gait, as well as in the stabilometric variables. However, there was no correlation between these disturbances and the uptake values of 99mTc-TRODAT-1. The results indicate that there is no correlation between gait impairments and postural instability of individuals with mild to moderate PD and the dopaminergic depletion measured through the 99mTc-TRODAT-1 (SPECT-CT).

Bicephalic Transcranial Direct-Current Stimulation Does Not Add Benefits to a Footdrop Stimulator for Improving Functional Mobility in People With Chronic Hemiparesis After Stroke: A Double-Blind, Randomized Controlled Trial.

OBJECTIVE: The aim of this study was to assess the effects of applying transcranial direct-current stimulation (tDCS), a footdrop stimulator (FDS), and gait training simultaneously on functional mobility in people with chronic hemiparesis after stroke. METHODS: In this double-blind controlled trial, 32 individuals with mild, moderate, and severe chronic hemiparesis after stroke were randomized to tDCS plus FDS or sham tDCS plus FDS groups. Both groups underwent 10 concurrent tDCS and FDS gait training sessions 5 times per week for 2 weeks. Functional mobility was evaluated by the Timed "Up & Go" test (TUG). Secondary outcomes included spasticity of plantarflexors, knee extensors, and hip adductors; quality of life; and walking endurance (distance covered during each treadmill gait training session). Clinical assessments were performed before treatment, after treatment, and at a 1-month follow-up. A generalized estimating equation was used to compare the effects of time, group, and time × group interaction. RESULTS: No difference between groups was observed during performance of the TUG or other outcomes. TUG performance was improved in both the tDCS plus FDS group (before treatment = 24.29 [95% CI = 17.72-33.28]; after treatment = 21.75 [95% CI = 15.75-30.08]) and the sham tDCS plus FDS group (before treatment = 19.63 [95% CI = 16.06-23.0]; after treatment = 18.45 [95% CI = 15.26-22.3]). This improvement remained at the follow-up evaluation. Both groups also showed reduced spasticity of plantarflexors and knee extensors, increased quality of life, and increased total distance walked. CONCLUSION: This study provided no evidence that bicephalic tDCS improves functional mobility, spasticity, quality of life, or walking endurance in people with chronic hemiparesis after stroke. IMPACT: Bicephalic tDCS does not add relevant benefits to FDS and gait training in people who have chronic hemiparesis after stroke. Given that tDCS has few additional effects and given its costs for clinical practice, tDCS for rehabilitation in people with chronic hemiparesis after stroke is discouraged. FDS and gait training improve functional mobility, walking resistance, and quality of life in people with chronic hemiparesis after stroke.

Movement smoothness in chronic post-stroke individuals walking in an outdoor environment-A cross-sectional study using IMU sensors.

BACKGROUND: Walking speed is often used in the clinic to assess the level of gait impairment following stroke. Nonetheless, post-stroke individuals may employ the same walking speed but at a distinct movement quality. The main objective of this study was to explore a novel movement quality metric, the estimation of gait smoothness by the spectral arc length (SPARC), in individuals with a chronic stroke displaying mild/moderate or severe motor impairment while walking in an outdoor environment. Also, to quantify the correlation between SPARC, gait speed, motor impairment, and lower limb spasticity focused on understanding the relationship between the movement smoothness metric and common clinical assessments. METHODS: Thirty-two individuals with a chronic stroke and 32 control subjects participated in this study. The 10 meters walking test (10 MWT) was performed at the self-selected speed in an outdoor environment. The 10 MWT was instrumented with an inertial measurement unit system (IMU), which afforded the extraction of trunk angular velocities (yaw, roll, and pitch) and subsequent SPARC calculation. RESULTS: Movement smoothness was not influenced by gait speed in the control group, indicating that SPARC may constitute an additional and independent metric in the gait assessment. Individuals with a chronic stroke displayed reduced smoothness in the yaw and roll angular velocities (lower SPARC) compared with the control group. Also, severely impaired participants presented greater variability in smoothness along the 10 MWT. In the stroke group, a smoother gait in the pitch angular velocity was correlated with lower limb spasticity, likely indicating adaptive use of spasticity to maintain the pendular walking mechanics. Conversely, reduced smoothness in the roll angular velocity was related to pronounced spasticity. CONCLUSIONS: Individuals with a chronic stroke displayed reduced smoothness in the yaw and roll angular velocities while walking in an outdoor environment. The quantification of gait smoothness using the SPARC metric may represent an additional outcome in clinical assessments of gait in individuals with a chronic stroke.

Bi-cephalic transcranial direct current stimulation combined with functional electrical stimulation for upper-limb stroke rehabilitation: A double-blind randomized controlled trial.

BACKGROUND: Stroke survivors often present poor upper-limb (UL) motor performance and reduced movement quality during reaching tasks. Transcranial direct current stimulation (tDCS) and functional electrical stimulation (FES) are widely used strategies for stroke rehabilitation. However, the effects of combining these two therapies to rehabilitate individuals with moderate and severe impairment after stroke are still unknown. OBJECTIVE: Our primary aim was to evaluate the effects of concurrent bi-cephalic tDCS and FES on UL kinematic motor performance and movement quality of chronic post-stroke subjects with moderate and severe compromise. Our secondary aim was to verify the effects of combining these therapies on handgrip force and UL motor impairment. METHODS: We randomized 30 individuals with moderate and severe chronic hemiparesis after stroke into tDCS plus FES (n=15) and sham tDCS plus FES (n=15) groups. Participants were treated 5 times a week for 2 weeks. Kinematic motor performance (movement cycle time, velocity profile) and movement quality (smoothness, trunk contribution, joint angles) were assessed during an UL reach-to-target task.Handgrip force and motor impairment were also recorded before and after the intervention. RESULTS: Participants allocated to the tDCS plus FES group improved movement cycle time (P=0.039), mean reaching velocity (P=0.022) and handgrip force (P=0.034). Both groups improved the mean returning phase velocity (P=0.018), trunk contribution (P=0.022), movement smoothness (P=0.001) and UL motor impairment (P=0.002). CONCLUSIONS: Concurrent bi-cephalic tDCS and FES slightly improved reaching motor performance and handgrip force of chronic post-stroke individuals with moderate and severe UL impairment. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02818608).

Upper-limb movement smoothness after stroke and its relationship with measures of body function/structure and activity - A cross-sectional study.

INTRODUCTION: After a stroke, upper limb (UL) motor impairments interfere with functional activities and quality of life. Even though a range of assessment tools has been developed to assess UL, few studies explore the interfaces between different levels of functioning after stroke. OBJECTIVES: (a) verify the correlation between movement smoothness and other measures of body function/structure [UL - Fugl-Meyer Assessment (FMA), and handgrip strength]; (b) verify which body function/structure [UL-FMA and/or handgrip strength] could predict UL movement smoothness; and (c) verify if movement smoothness could predict levels of activity, as assessed by the Box and Block Test (BBT). MATERIALS AND METHODS: Cross-sectional study. Thirty-four individuals with chronic hemiparesis after stroke were enrolled. Measurements of body function/structure included FMA, handgrip strength and kinematic measure of movement smoothness. Levels of activity were measured using the Box and Block Test (BBT). RESULTS: Movement smoothness showed strong correlation with FMA (r = 0.70, p < .001) and moderate correlation with handgrip strength (r = 0.63, p < .001). FMA explained 46.4% of the variation in movement smoothness. Movement smoothness was moderately correlated with BBT (r = -0.560, p < .005) and predicted 31% of the variation in BBT. CONCLUSION: We recommend the use of UL-FMA to predict movement smoothness in chronic post-stroke subjects. This study also showed that movement smoothness influences the level of activity. Then, movement smoothness may be emphasized during stroke rehabilitation to enhance the UL level of activity in chronic post-stroke subjects.