(A)symmetry during gait initiation in people with Parkinson's disease: A motor and cortical activity exploratory study.

Background: Gait asymmetry and deficits in gait initiation (GI) are among the most disabling symptoms in people with Parkinson's disease (PwPD). Understanding if PwPD with reduced asymmetry during GI have higher asymmetry in cortical activity may provide support for an adaptive mechanism to improve GI, particularly in the presence of an obstacle. Objective: This study quantified the asymmetry of anticipatory postural adjustments (APAs), stepping parameters and cortical activity during GI, and tested if the presence of an obstacle regulates asymmetry in PwPD. Methods: Sixteen PwPD and 16 control group (CG) performed 20-trials in two conditions: unobstructed and obstructed GI with right and left limbs. We measured, through symmetry index, (i) motor parameters: APAs and stepping, and (ii) cortical activity: the PSD of the frontal, sensorimotor and occipital areas during APA, STEP-I (moment of heel-off of the leading foot in the GI until the heel contact of the same foot); and STEP-II (moment of the heel-off of the trailing foot in the GI until the heel contact of the same foot) phases. Results: Parkinson's disease showed higher asymmetry in cortical activity during APA, STEP-I and STEP-II phases and step velocity (STEP-II phase) during unobstructed GI than CG. However, unexpectedly, PwPD reduced the level of asymmetry of anterior-posterior displacement (p < 0.01) and medial-lateral velocity (p < 0.05) of the APAs. Also, when an obstacle was in place, PwPD showed higher APAs asymmetry (medial-lateral velocity: p < 0.002), with reduced and increased asymmetry of the cortical activity during APA and STEP-I phases, respectively. Conclusion: Parkinson's disease were not motor asymmetric during GI, indicating that higher cortical activity asymmetry can be interpreted as an adaptive behavior to reduce motor asymmetry. In addition, the presence of obstacle did not regulate motor asymmetry during GI in PwPD.

Correlation of the Handgrip Strength and Body Composition Parameters in Young Judokas.

Maximum isometric handgrip strength (MIHS) is a relevant parameter for judo performance and is related to health. Understanding the association between MIHS and MIHS relative (MIHSrel) and the absolute lean mass of the arm (LMarm) and the percentage of body fat (%BF) can provide important information for performance and health. The study aimed to investigate the correlation between MIHS and MIHSrel with the LMarm and the %BF of young judokas (sub-19, 15 males and 14 females). MIHS was measured using a multipurpose digital dynamometer with a load cell for computer. Body composition was measured by dual-energy X-ray absorptiometry (DXA). The correlation between MIHS, MIHSrel with LMarm and %BF was verified through Pearson's correlation, with a significance level of p < 0.05. Correlation between MIHSrel and %BF was very high only in female judokas for both arms (right, r = -0.76; left, r = -0.75). Correlations between LMarm and MIHS of the right and left arms ranged from very high to almost perfect for both sexes (r = 0.74 to 0.94). These results highlight the importance of strengthening the arms in young judokas, and controlling body fat for performance and health, especially in female judokas.

Perception of COVID-19 Pandemic by Brazilian People With Parkinson's Disease and Multiple Sclerosis.

COVID-19 in Brazil is threatening, and it has forced the government to adopt partial lockdown as a strategy to stop the spread of the virus in the first wave of pandemic (March 2020). These preventive measures during the COVID-19 pandemic may affect the motor and non-motor symptoms in people with Parkinson's disease (PD) and Multiple sclerosis (MS). Thus, the purpose of this study was to investigate the perception during the first wave of COVID-19 pandemic lockdown on motor and non-motor symptoms, and also measure physical activity level, quality of life, and sleep quality in Brazilian people with PD and MS. One hundred and fifty-three participants (PD-97 and MS-56) answered an online survey to identify the perception of motor and non-motor symptoms, and characterize the physical activity level, and quality of life and sleep in these neurological Brazillian population. During the beginning of pandemic lockdown in Brazil, our results indicated that 69% of people with PD and 55% of people with MS reported worse on motor aspects and lower amount of physical activity performed. Also, 75.2% (PD) and 92.9% (MS) of our cohort were considered inactive or sedentary. Based on the perception and behavior of the population studied, people with PD and MS should be encouraged to perform more physical activity in order to reduce the effects of isolation in motor and non-motor aspects of the diseases. Teleinterventions, such as home-based exercise, should be included in the new routine of people with PD and MS to reduce the impacts of lockdown and to maintain quality of life at a good level.

Hemodynamic response to exercise is impaired in individuals with Parkinson's disease.

BACKGROUND: The aim of this study was to assess hemodynamic and cardiac autonomic response to high-intensity interval exercise (HIIE) versus moderate-intensity continuous exercise (MICE) in individuals with Parkinson's disease (PD). METHODS: Twelve individuals (six men) with PD were randomly assigned to perform HIIE (4 min of warm-up followed by 21 min alternating 1 min at levels 15-17 with 2 min at levels 9-11 of rating of perceived exertion [RPE] in a cycle ergometer), MICE (4 min of warm-up followed by 26 min at levels 11-14 of RPE in a cycle ergometer) and control (CON; 30 min of sitting rest) interventions in separate days. Heart rate (HR), blood pressure (BP), endothelial reactivity and heart rate variability (HRV) were assessed before, immediately after and 45 min after each intervention. HR and exercise workload were measured during each intervention. RESULTS: Despite the within (high- vs. low-intensity intervals of HIIE) and between (HIIE vs. MICE) differences in workload during exercise sessions, HR was not different between high- (average HR=98±18 bpm) and low-intensity (average HR 97±19 bpm) intervals of HIIE, as well as between HIIE (average HR=97±18 bpm) and MICE (average HR=93±19 bpm) throughout the exercise. There were significant, but small, increases (P<0.01) in HR and systolic BP at post HIIE and MICE, which returned to levels similar to preintervention during recovery. There were no within- and between-intervention differences in diastolic BP, endothelial reactivity and HRV. CONCLUSIONS: The present results suggest that hemodynamic response to exercise is impaired in individuals with PD.

Motor strategy during postural control is not muscle fatigue joint-dependent, but muscle fatigue increases postural asymmetry.

The aim of this study was to investigate the effects of ankle and hip muscle fatigue on motor adjustments (experiment 1) and symmetry (experiment 2) of postural control during a quiet standing task. Twenty-three young adults performed a bipedal postural task on separate force platforms, before and after a bilateral ankle and hip muscle fatigue protocol (randomized). Ankle and hip muscles were fatigued separately using a standing calf raise protocol (ankle fatigue) on a step and flexion and extension of the hip (hip fatigue) sitting on a chair, at a controlled movement frequency (0.5Hz), respectively. In both experiments, force, center of pressure, and electromyography parameters were measured. The symmetry index was used in experiment 2 to analyze the postural asymmetry in the parameters. Our main findings showed that muscle fatigue impaired postural stability, regardless of the fatigued muscle region (i.e., ankle or hip). In addition, young adults used an ankle motor strategy (experiment 1) before and after both the ankle and hip muscle fatigue protocols. Moreover, we found increased asymmetry between the lower limbs (experiment 2) during the quiet standing task after muscle fatigue. Thus, we can conclude that the postural motor strategy is not muscle fatigue joint-dependent and a fatigue task increases postural asymmetry, regardless of the fatigued region (hip or ankle). These findings could be applied in sports training and rehabilitation programs with the objective of reducing the fatigue effects on asymmetry and improving balance.

Prolonged Standing Task Affects Adaptability of Postural Control in People With Parkinson's Disease.

BACKGROUND: Studies on short-term upright quiet standing tasks have presented contradictory findings about postural control in people with Parkinson's disease (pwPD). Prolonged trial durations might better depict body sway and discriminate pwPD and controls. OBJECTIVE: The aim of this study was to investigate postural control in pwPD during a prolonged standing task. METHODS: A total of 26 pwPD and 25 neurologically healthy individuals performed 3 quiet standing trials (60 s) before completing a constrained prolonged standing task for 15 minutes. Motion capture was used to record body sway (Vicon, 100 Hz). To investigate the body sway behavior during the 15 minutes of standing, the analysis was divided into three 5-minute-long phases: early, middle, and late. The following body sway parameters were calculated for the anterior-posterior (AP) and medial-lateral (ML) directions: velocity, root-mean-square, and detrended fluctuations analysis (DFA). The body sway area was also calculated. Two-way ANOVAs (group and phases) and 1-way ANOVA (group) were used to compare these parameters for the prolonged standing and quiet standing, respectively. RESULTS: pwPD presented smaller sway area (P < .001), less complexity (DFA; AP: P < .009; ML: P < .01), and faster velocity (AP: P < .002; ML: P < .001) of body sway compared with the control group during the prolonged standing task. Although the groups swayed similarly (no difference for sway area) during quiet standing, they presented differences in sway area during the prolonged standing task (P < .001). CONCLUSIONS: Prolonged standing task reduced adaptability of the postural control system in pwPD. In addition, the prolonged standing task may better analyze the adaptability of the postural control system in pwPD.

Virtual reality head-mounted goggles increase the body sway of young adults during standing posture.

The aim of this study was to investigate the effects of wearing virtual reality head-mounted goggles (VR) on body sway in young adults. We run two experiments, in which we compared the body sway while standing during the conditions of 1) wearing and non-wearing VR with eyes-opened (experiment #1), 2) wearing and no-wearing VR with eyes-closed (experiment #2), and 3) wearing VR with eyes-opened when the scene was turned on and off (experiment #2). Forty-four (experiment #1) and fifteen (experiment #2) young adults were instructed to remain as still as possible on a force plate for 60-s and performed three trials in each quiet standing condition. The center of pressure (CoP) displacement, mean velocity, root mean square (RMS), area and median frequency of sway were calculated in both experiments. In the experiment #1, wearing VR condition with eyes-opened largely increased the AP and ML CoP displacement, AP mean velocity, AP and ML RMS, and area (p < 0.05) compared to non-wearing VR with eyes-opened. In the experiment #2, no differences were found for any conditions (eyes-closed and eyes-opened with turned on and off VR scene). In conclusion, wearing VR head-mounted goggles increased body sway of young adults during standing postural task, when the individuals were with eyes-opened. However, the effects of wearing VR head-mounted goggles on body sway disappeared when the individuals were with eyes-closed or the google scene was turned off the scene compared to not wearing VR head-mounted goggles with eyes-closed or turned on scene, respectively.

Parkinson's patients delay fixations when circumventing an obstacle and performing a dual cognitive task.

BACKGROUND: People with Parkinson's disease (PD) do not differ from neurologically healthy individuals in obstacle circumvention during walking, therefore they are able to use visual feedback adequately to control motor behavior in this task. However, individuals are often distracted by the secondary task when circumventing an obstacle. An increased cognitive load can require prolonged gaze fixation time on a location of interest to compensate for longer information processing duration. RESEARCH QUESTION: To investigate the effects of cognitive dual tasking (DT) on gaze behavior during waking with obstacle circumvention in people with PD and control group, and to determine the impact of gaze behavior on motor strategy. METHODS: Fifteen individuals with PD (PD-group) and 15 neurologically healthy individuals walked at a self-selected speed over a walkway and circumvented an obstacle centered in the walkway. The experimental conditions (5 trials each one) included obstacle circumvention without DT (OC) and obstacle circumvention with DT (OCDT). In the cognitive task, the participant mentally counted the number of times a target number appeared in an audio recording. We analyzed gaze behavior (i.e. number of gaze fixations and duration on the ground and obstacle), standard gait measures and DT cost. Two-way ANOVAs were completed for gait parameters and moment of fixation. RESULTS: There was no significant difference in DT cost between groups and no obstacle contacts. The participants performed a longer mean duration of fixations on the ground during OCDT compared to OC. Group x condition interactions indicated that the PD-group delayed the obstacle fixation relative to the NHI for OCDT (p < 0.001) and presented greater medial-lateral body clearance (p < 0.001) and longer double support time (p < 0.001) during OCDT compared to OC. SIGNIFICANCE: The results of this study suggest that deficits in locomotion during DT in PD-group may be caused, at least in part, by a reduced ability to fixate gaze at appropriate times during walking.

Effects of Ankle Muscle Fatigue and Visual Behavior on Postural Sway in Young Adults.

Ankle muscle fatigue has been shown to increase body sway. In addition, body sway in quiet upright standing is reduced when saccadic eye movements are performed. The purpose of this study was to investigate the effects of visual information manipulation on postural control during ankle muscle fatigue in young adults. Twenty young adults performed: (1) two 60-s trials in quiet bipedal standing with eyes open, eyes closed, and while performing saccadic eye movements; (2) maximum voluntary isometric contractions in a leg press device, custom-made to test ankle plantar flexion force; (3) a calf raise exercise on top of a step to induce ankle muscle fatigue; and (4) a repetition of items 1 and 2. Postural sway parameters were compared with two-way ANOVAs (vision condition × fatigue; p < 0.05). Ankle muscle fatigue increased anterior-posterior and medial-lateral displacement and RMS of sway, as well as sway area. Saccadic eye movements reduced anterior-posterior displacement and RMS of sway and area of sway compared to eyes open and eyes closed conditions. Both saccadic eye movements and eyes closed increased the frequency of AP sway compared to the eyes open condition. Finally, anterior-posterior displacement, anterior-posterior RMS, and both anterior-posterior and medial-lateral sway frequency were affected by an interaction of fatigue and vision condition. Without muscle fatigue, closing the eyes increased anterior-posterior displacement and RMS of sway, compared to eyes open, while during muscle fatigue closing the eyes closed reduced anterior-posterior displacement and had no significant effect on anterior-posterior RMS. In conclusion, body sway was increased after induction of ankle muscle fatigue. Saccadic eye movements consistently reduced postural sway in fatigued and unfatigued conditions. Surprisingly, closing the eyes increased sway in the unfatigued condition but reduced sway in the fatigued condition.

Influence of obstacle color on locomotor and gaze behaviors during obstacle avoidance in people with Parkinson's disease.

The color of an obstacle may enable a more detailed view of the environment to facilitate obstacle avoidance. However, people with Parkinson's disease (PD) present visual contrast and color detection dysfunction, which could affect obstacle avoidance according to obstacle color. Thus, the aim of this study was to investigate the influence of obstacle color on locomotor and gaze behavior during obstacle avoidance in people with PD and neurologically healthy older individuals. Thirteen people with PD and eleven matched-control group individuals, with normal visual acuity (20/20 on the Snellen chart), performed 20 trials (5 trials for each obstacle color condition) of the obstacle avoidance task with the following obstacle colors: white, black, red, and blue. Participants were positioned at the beginning of a walkway with their eyes closed and, after the start command, opened their eyes, started walking at their preferred velocity, and crossed the obstacle. Spatial-temporal parameters and fixations on the obstacle (gaze behavior) were measured using a three-dimensional camera system and mobile eye-tracker, respectively. Our main findings were the absence of significant color interaction on locomotor and gaze behaviors, the absence of significant main effect of color on gaze behavior, and an effect of obstacle color on locomotor behavior, specifically in the placement of the heel from the obstacle after crossing and toe-clearance for both trailing and leading limbs, which indicates that obstacle color can play a role in obstacle avoidance during walking. However, there was no consistent obstacle color that influenced the locomotor behavior. Therefore, the conclusion of this study is that obstacle color seems to affect locomotor behavior, but not gaze behavior, during walking with obstacle avoidance in people with PD and neurologically healthy individuals. However, no particular obstacle color causes a consistent effect on locomotor behavior.

Gaze and motor behavior of people with PD during obstacle circumvention.

The aim of this study was to analyze the motor and visual strategies used when walking around (circumvention) an obstacle in patients with Parkinson's disease (PD), in addition to the effects of dopaminergic medication on these strategies. To answer the study question, people with PD (15) and neurologically healthy individuals (15 - CG) performed the task of obstacle circumvention during walking (5 trials of unobstructed walking and obstacle circumvention). The following parameters were analyzed: body clearance (longer mediolateral distance during obstacle circumvention of the center of mass -CoM- to the obstacle), horizontal distance (distance of the CoM at the beginning of obstacle circumvention to the obstacle), circumvention strategy ("lead-out" or "lead-in" strategy), spatial-temporal of each step, and number of fixations, the mean duration of the fixations and time of fixations according to areas of interest. In addition, the variability of each parameter was calculated. The results indicated that people with PD and the CG presented similar obstacle circumvention strategies (no differences between groups for body clearance, horizontal distance to obstacle, or obstacle circumvention strategy), but the groups used different adjustments to perform these strategies (people with PD performed adjustments during both the approach and circumvention steps and presented greater visual dependence on the obstacle; the CG adjusted only the final step before obstacle circumvention). Moreover, without dopaminergic medication, people with PD reduced body clearance and increased the use of a "lead-out" strategy, variability in spatial-temporal parameters, and dependency on obstacle information, increasing the risk of contact with the obstacle during circumvention.