Motor learning in people with Parkinson's disease: Implications for fall prevention across the disease spectrum

Prevention of Falls in Parkinson's Disease: Guidelines and Gaps

Background

People living with Parkinson's disease (PD) have a high risk for falls.

Objective

To examine gaps in falls prevention targeting people with PD as part of the Task Force on Global Guidelines for Falls in Older Adults.

Methods

A Delphi consensus process was used to identify specific recommendations for falls in PD. The current narrative review was conducted as educational background with a view to identifying gaps in fall prevention.

Results

A recent Cochrane review recommended exercises and structured physical activities for PD; however, the types of exercises and activities to recommend and PD subgroups likely to benefit require further consideration. Freezing of gait, reduced gait speed, and a prior history of falls are risk factors for falls in PD and should be incorporated in assessments to identify fall risk and target interventions. Multimodal and multi-domain fall prevention interventions may be beneficial. With advanced or complex PD, balance and strength training should be administered under supervision. Medications, particularly cholinesterase inhibitors, show promise for falls prevention. Identifying how to engage people with PD, their families, and health professionals in falls education and implementation remains a challenge. Barriers to the prevention of falls occur at individual, environmental, policy, and health system levels.

Conclusion

Effective mitigation of fall risk requires specific targeting and strategies to reduce this debilitating and common problem in PD. While exercise is recommended, the types and modalities of exercise and how to combine them as interventions for different PD subgroups (cognitive impairment, freezing, advanced disease) need further study.

A Review of Artificial Intelligence-Based Gait Evaluation and Rehabilitation in Parkinson's Disease

Parkinson's disease (PD) is a long-term degenerative disease of the central nervous system that affects both motor and non-motor functions. In most cases, symptoms develop gradually, with non-motor symptoms increasing in frequency as the condition progresses. Tremors, stiffness, slow movements, and difficulty walking are some of the early symptoms. There may be problems with cognition, behavior, sleep, and thinking. Dementia caused by PD becomes more common as the disease progresses. The development of PD is linked to certain sequences of motion that eventually contribute to diminished function. Patients with Parkinson's disease (PWPD) have a sluggish, scattered gait that is accompanied by intermittent freezing of gait (FOG), in which efficient heading briefly pauses. In individuals with severe PD, FOG is a neurological deficit that is related to falls and has an unfavorable impact on the patient's standard of living. Artificial intelligence (AI) and ambient intelligence (AmI) are inextricably linked as intelligence is the ability to gain new information and employ it in novel contexts. The ambience is what accompanies us, while artificial represents something developed by humans. Wearable technologies are being designed to recognize FOG and support patients in the beginning to walk again via periodic cueing. The article proposes a unique automated approach for action description that utilizes AI to carry out a non-intrusive, markerless evaluation in real-time and with full robotics. This computerized method accelerates detection and safeguards from human error. Despite significant improvements brought about by the advent of novel technologies, the available assessment platforms still fail to strike the ideal equilibrium among expenditure, diagnostic precision, velocity, and simplicity. The value of the recommended approach can be seen through a comparison of the gait parameters collected by each of the motion-tracking gadgets.

Combination of Clinical and Gait Measures to Classify Fallers and Non-Fallers in Parkinson's Disease

Although the multifactorial nature of falls in Parkinson's disease (PD) is well described, optimal assessment for the identification of fallers remains unclear. Thus, we aimed to identify clinical and objective gait measures that best discriminate fallers from non-fallers in PD, with suggestions of optimal cutoff scores.

METHODS

Individuals with mild-to-moderate PD were classified as fallers (n = 31) or non-fallers (n = 96) based on the previous 12 months' falls. Clinical measures (demographic, motor, cognitive and patient-reported outcomes) were assessed with standard scales/tests, and gait parameters were derived from wearable inertial sensors (Mobility Lab v2); participants walked overground, at a self-selected speed, for 2 min under single and dual-task walking conditions (maximum forward digit span). Receiver operating characteristic curve analysis identified measures (separately and in combination) that best discriminate fallers from non-fallers; we calculated the area under the curve (AUC) and identified optimal cutoff scores (i.e., point closest-to-(0,1) corner).

RESULTS

Single gait and clinical measures that best classified fallers were foot strike angle (AUC = 0.728; cutoff = 14.07°) and the Falls Efficacy Scale International (FES-I; AUC = 0.716, cutoff = 25.5), respectively. Combinations of clinical + gait measures had higher AUCs than combinations of clinical-only or gait-only measures. The best performing combination included the FES-I score, New Freezing of Gait Questionnaire score, foot strike angle and trunk transverse range of motion (AUC = 0.85).

CONCLUSION

Multiple clinical and gait aspects must be considered for the classification of fallers and non-fallers in PD.

Effectiveness of home-based rehabilitation using active video games on quality of life, cognitive and motor functions in people with Parkinson's disease: a systematic review

PURPOSE

We summarized the effectiveness of home-based active video game interventions on physical and cognitive functions, as well as quality of life in adults with Parkinson's disease. We also assessed the feasibility, safety, adherence, and retention of benefits of these interventions.

METHOD

We searched studies in eight databases from 1st March to 30th November 2020. Two authors independently performed the selection, data extraction and risk of bias evaluation (PROSPERO ID: CRD42020178138).

RESULTS

Nine studies were included in this systematic review (412 participants). All in all, home-based active video games were found effective in improving gait and balance functions in people with Parkinson's disease, equivalent to usual care and conventional therapy. No conclusion can be drawn on cognition and quality of life. Home-based active video games seemed feasible, safe, and were enjoyed by people with Parkinson's disease. The optimal dose, the need for supervision and the retention of benefits of these interventions are still to be determined. These results should be interpreted carefully, considering the limited number of included studies and their small sample sizes, the widespread heterogeneity of included studies and their medium average methodological quality.

CONCLUSION

Future research should focus on the effects of home-based active video games on impairments specific to Parkinson's disease, such as falls, freezing of gait and attention, as well as the dose, need for supervision and retention of the benefits of these interventions.IMPLICATIONS FOR REHABILITATIONHome-based active video games are effective in improving motor functions in people with PD.No conclusion can be drawn regarding cognition in people with PD.No conclusion can be drawn regarding quality of life in people with PD.Home-based active video games seem feasible and safe, and are enjoyed by people with PD.The dose, need for control and retention of the benefits still need to be determined.

Personalized practice dosages may improve motor learning in older adults compared to "standard of care" practice dosages: A randomized controlled trial

Standard dosages of motor practice in clinical physical rehabilitation are insufficient to optimize motor learning, particularly for older patients who often learn at a slower rate than younger patients. Personalized practice dosing (i.e., practicing a task to or beyond one's plateau in performance) may provide a clinically feasible method for determining a dose of practice that is both standardized and individualized, and may improve motor learning. The purpose of this study was to investigate whether personalized practice dosages [practice to plateau (PtP) and overpractice (OVP)] improve retention and transfer of a motor task, compared to low dose [LD] practice that mimics standard clinical dosages. In this pilot randomized controlled trial (NCT02898701, ClinicalTrials.gov), community-dwelling older adults (n = 41, 25 female, mean age 68.9 years) with a range of balance ability performed a standing serial reaction time task in which they stepped to specific targets. Presented stimuli included random sequences and a blinded repeating sequence. Participants were randomly assigned to one of three groups: LD (n = 15, 6 practice trials equaling 144 steps), PtP (n = 14, practice until reaching an estimated personal plateau in performance), or OVP (n = 12, practice 100% more trials after reaching an estimated plateau in performance). Measures of task-specific learning (i.e., faster speed on retention tests) and transfer of learning were performed after 2-4 days of no practice. Learning of the random sequence was greater for the OVP group compared to the LD group (p = 0.020). The OVP (p = 0.004) and PtP (p = 0.010) groups learned the repeated sequence more than the LD group, although the number of practice trials across groups more strongly predicted learning (p = 0.020) than did group assignment (OVP vs. PtP, p = 0.270). No group effect was observed for transfer, although significant transfer was observed in this study as a whole (p < 0.001). Overall, high and personalized dosages of postural training were well-tolerated by older adults, suggesting that this approach is clinically feasible. Practicing well-beyond standard dosages also improved motor learning. Further research should determine the clinical benefit of this personalized approach, and if one of the personalized approaches (PtP vs. OVP) is more beneficial than the other for older patients.

Adherence rate, barriers to attend, safety and overall experience of a physical exercise program via telemonitoring during COVID-19 pandemic for individuals with Parkinson's disease: A feasibility study

Background

Telemonitoring can maintain daily exercise routine during the COVID‐19 pandemic of individuals with Parkinson's disease (PD). However, there are barriers to adherence and attendance with remote physical rehabilitation. The main objective of this study was to evaluate adherence rate, barriers to attendance, and safety of a telemonitoring program for individuals with PD; and secondarily to evaluate the individual and their family members perceived overall experience when performing the telemonitoring physical exercise program.

Methods

This was a phase 1 of a clinical trial, engaging 19 individuals with idiopathic PD of an in‐person community rehabilitation program. For 24 weeks an asynchronous telemonitoring physical exercise program delivered two sessions per week by video including warm‐up, balance, aerobic and resistance exercises, and cool‐down. During the remote program were verified: adherence rate at entrance, attendance rate, barriers to attend, safety, and overall experience of the program.

Results and conclusion

Only one participant did not perform any session and 18 participants completed between 2 and 34 sessions. Participants with a caregiver showed higher attendance rates. The most frequently cited barriers to attend the program were: pain; lack of motor skills; and reduced physical fitness. In relation to safety of the program, the most frequently reported was fear of falling. Although participants reported the telemonitoring program induced health benefits and they had positive experiences for themselves and for their families, most of participants prefer an in‐person program. In this sense, the asynchronous telemonitoring physical exercise program was safe, showed moderate adherence, with attendance rate depending on the presence of a companion.

Virtual reality balance training to improve balance and mobility in Parkinson's disease: a systematic review and meta-analysis

BACKGROUND

In the last few years, virtual reality (VR) has been increasingly used to strengthen the effect of balance training (BT) in Parkinson's disease (PD).

OBJECTIVE

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to compare the effects of VR-BT relative to BT alone for improving balance and mobility PD subjects with balance/mobility difficulties.

METHODS

Four electronic databases were searched: two reviewers independently selected RCTs, extracted data, and applied the Cochrane risk-of-bias tool for randomized trials (version 2) and the GRADE framework for assessing the certainty of evidence. Primary outcomes were balanced (Berg Balance Scale-BBS), mobility (Timed Up and Go-TUG) and walking speed. Secondary outcomes were falls, walking distance and stability, spatial gait parameters, balance confidence, sensory integration ability, motor signs and quality of life.

RESULTS

We included 22 studies (901 patients). Meta-analysis on fourteen trials (430 patients) showed a mean difference (MD) of 2.09 points (95% confidence interval [CI] 0.86-3.33) on BBS favoring VR-BT compared to BT (low certainty evidence). Subgroup analyses showed higher balance improvement in most affected subjects (moderate certainty evidence) and using VR rehabilitation-specific systems vs. VR non-specific systems. Eight trials (236 patients) assessing mobility showed a MD of 1.55 s (95% CI 0.04-3.06) on TUG favoring VR-BT (very low certainty evidence). No differences were observed in walking speed. Estimated effects were not maintained for any outcome at follow-up.

CONCLUSIONS

This review suggests that VR-BT is more effective than BT to improve balance in PD subjects immediately after training, particularly in individuals with higher postural instability at baseline.

Feasibility and longitudinal effects of repeated participation in an annual, brief and intense exercise program in individuals with Parkinson's disease: A case report

BACKGROUND

Functional decline is expected over time in persons with Parkinson's disease (PD). Intense exercise (RPE ≥ 5-7/10), incorporating motor learning principles, may be beneficial. Purpose:The purpose of this case report is to describe the feasibility and longitudinal effects after individuals with PD participated in multiple, 3.5-day, intensive exercise programs called Movement Camp (Camp).

METHODS

Developed based on the principles of skill, capacity, and motivation, the Camp was offered four times (spring 2014-spring 2017) over the course of three years. Camp consisted of 3.5 days, with approximately 5.5 hours of exercise per day. The four participants on whom we are reporting were selected because they participated in three or more Camps, thus providing longitudinal data. Participants rotated through high-intensity, one-hour exercise stations targeting balance, endurance, gait, upper extremity function and three 30-minute group training sessions. Balance (Mini-BESTest), endurance (six-minute walk test), gait speed, and function (five times sit-to-stand) were examined.

RESULTS

Testing was completed prior to, post, and six weeks post intervention. Over three years, participants maintained or improved performance on most measures.

CONCLUSION

The outcomes of this case report suggest that brief, intensive exercise based on motor learning principles is feasible and may maintain or improve function in persons with PD over three years.

Video analysis of safety and reproducibility issues with the timed up-and-go test applied to patients with Parkinson's disease

PURPOSE

Falls are a major problem and cause poor quality of life and reduced life expectancy in people affected by Parkinson's disease (PD). The timed up-and-go (TUG) test is the most popular test of walking ability in patients with PD. However, it carries a risk of falls because patients are told to walk as quickly as possible. The purpose of this study was to characterise issues of safety and reproducibility arising in TUG tests.

METHODS

Our population was 7 hospitalised patients (4 men, 3 women) with PD and 1 healthy control. We used video capture, Motion Analyser software, and an innovative Yorisoi (snuggling nursing robot) robot.

RESULTS

We found the same movements when patients walked in time to a verbal rhythm provided by the physiotherapist and when they used the robot in walking. The TUG times were longest when the therapist provided no intervention. The typical PD patient experienced freezing of gait when rounding the reflective cone marker in the TUG test, and after turning, experienced gait festination. The patient thus encountered difficulty in using the reflective marker. Moreover, because of the characteristic PD shuffling gait, the patient's steps were difficult to count automatically. After the turn, the patient's body leaned heavily; however, if the physiotherapist or the robot applied a light force in the direction of the positive axis, it was possible to prevent a fall.

CONCLUSIONS

When applied to patients with PD, the TUG test requires modifications for safety and more accurate step counting to improve reproducibility.IMPLICATIONS FOR REHABILITATIONThe presence of a sense of security with the attendant or the robot is related to walking speed.The TUG test must be reproducible in patients with PD, regardless of whether there is a rhythm or an attendant, and must be able to count the steps in a shuffling gait.The TUG test must consider safety in patients with PD, because it is easier to fall after a turn and when sitting on a chair, and it is instructed to be in hurry walk.After making a turn, a patient's body may lean heavily; however, if a physiotherapist or a Yorisoi (snuggling nursing robot) robot applies a light force in the direction of the positive axis, it is possible to prevent a fall.Assertive technology, such as the Yorisoi robot, may be used to improve the safety TUG test in patients with PD.

The feasibility and efficacy of a serial reaction time task that measures motor learning of anticipatory stepping

BACKGROUND

Motor learning has been investigated using various paradigms, including serial reaction time tasks (SRTT) that examine upper extremity reaching and pointing while seated. Few studies have used a stepping SRTT, which could offer additional insights into motor learning involving postural demands. For a task to measure motor learning, naïve participants must demonstrate a) improved performance with task practice, and b) a dose-response relationship to learning the task.

RESEARCH QUESTION

Is a stepping SRTT feasible and efficacious for measuring motor learning?

METHODS

In this prospective study, 20 participants stood on an instrumented mat and were presented with stimuli on a computer screen. They stepped to the corresponding positions on the mat as quickly as possible. Presented stimuli included random sequences and a blinded imbedded repeating sequence. Three days after completing the randomly assigned practice dose [high dose group (n = 10) performed 4320 steps; low dose group (n = 10) performed 144 steps], a retention test of 72 steps was performed. Feasibility was measured as the proportion of participants who completed the assigned practice dose without adverse events. Efficacy was measured as within-group performance improvement on the random sequences and on the repeating sequence (paired t-tests), as well as a dose-response relationship to learning both types of sequences (independent t-tests).

RESULTS

All participants (mean age 26.8 years) completed all practice sessions without adverse events, indicating feasibility. High dose practice resulted in performance improvement while low dose did not; a dose-response relationship was found, with high dose practice resulting in greater learning of the task than low dose practice, indicating efficacy.

SIGNIFICANCE

This stepping SRTT is a feasible and efficacious way to measure motor learning, which could provide critical insights into anticipatory stepping, postural control, and fall risk. Future research is needed to determine feasibility, efficacy, and optimal practice dosages for older and impaired populations.

Is Aquatic Therapy Optimally Prescribed for Parkinson's Disease? A Systematic Review and Meta-Analysis

BACKGROUND

Aquatic therapy offers an alternative physiotherapy approach to managing the motor and non-motor symptoms associated with Parkinson's disease (PD).

OBJECTIVE

This review examined exercise prescription for aquatic therapy in PD and evaluated if aquatic therapy is as effective as land-based physiotherapy for improving movement, disability and wellbeing in people living with PD.

METHODS

A systematic search of eight databases was conducted to identify suitable randomized controlled trials from inception until August 2019. Aquatic therapy prescription data and outcomes of interest included gait, balance, motor disability, mobility, falls, mood, cognitive function and health related quality of life data was extracted and synthesised. A meta-analysis was performed where appropriate.

RESULTS

Fourteen studies involving 472 participants (Hoehn & Yahr scale I-IV) met the inclusion criteria. Eight were of modest quality, scoring 70-80% on the PEDro scale. Seven studies were included in the meta-analysis. Exercise prescription was highly variable and often insufficiently dosed. Similar gains were shown for aquatic therapy and land exercises for balance, motor disability or quality of life. A statistically significant difference was found for mobility as measured using the TUG (-1.5 s, 95 % CI -2.68 to -0.32; p = 0.01, I2 = 13%), in favor of aquatic therapy.

CONCLUSION

Aquatic therapy had positive outcomes for gait, balance and mobility that were comparable to land-based physiotherapy in the early stages of PD. The optimal dosage, content and duration of aquatic interventions for PD could not be confirmed in this meta-analysis. Many trials appeared to be under-dosed and therapy duration was low, ranging from 3-11 weeks.

Multimodal Balance Training Supported by Rhythmical Auditory Stimuli in Parkinson's Disease: A Randomized Clinical Trial

Background:

Balance impairment in Parkinson’s disease (PD) improves only partially with dopaminergic medication. Therefore, non-pharmacological interventions such as physiotherapy are important elements in clinical management. External cues are often applied to improve gait, but their effects on balance control are unclear.

Objective/Methods:

We performed a prospective, single-blind, randomized clinical trial to study the effectiveness of balance training with and without rhythmical auditory cues. We screened 201 volunteers by telephone; 154 were assigned randomly into three groups: (1) multimodal balance training supported by rhythmical auditory stimuli (n = 56) (RAS-supported multimodal balance training); (2) regular multimodal balance training without rhythmical auditory stimuli (n = 50); and (3) control intervention involving a general education program (n = 48). Training was performed for 5 weeks, two times/week. Linear mixed models were used for all outcomes. Primary outcome was the Mini-BESTest (MBEST) score immediately after the training period. Assessments were performed by a single, blinded assessor at baseline, immediately post intervention, and after one and 6-months follow-up.

Results:

Immediately post intervention, RAS-supported multimodal balance training was more effective than regular multimodal balance training on MBEST (difference 3.5 (95% Confidence Interval (CI) 2.2; 4.8)), p < 0.001). Patients allocated to both active interventions improved compared to controls (MBEST estimated mean difference versus controls 6.6 (CI 5.2; 8.0), p < 0.001 for RAS-supported multimodal balance training; and 3.0 (CI 2.7; 5.3), p < 0.001 for regular multimodal balance training). Improvements were retained at one-month follow-up for both active interventions, but only the RAS-supported multimodal balance training group maintained its improvement at 6 months.

Conclusion:

Both RAS-supported multimodal balance training and regular multimodal balance training improve balance, but RAS-supported multimodal balance training–adding rhythmical auditory cues to regular multimodal balance training–has greater and more sustained effects.

Cortical thickness as predictor of response to exercise in people with Parkinson's disease

We previously showed that dual-task cost (DTC) on gait speed in people with Parkinson's disease (PD) improved after 6 weeks of the Agility Boot Camp with Cognitive Challenge (ABC-C) exercise program. Since deficits in dual-task gait speed are associated with freezing of gait and gray matter atrophy, here we performed preplanned secondary analyses to answer two questions: (a) Do people with PD who are freezers present similar improvements compared to nonfreezers in DTC on gait speed with ABC-C? (b) Can cortical thickness at baseline predict responsiveness to the ABC-C? The DTC from 39 freezers and 43 nonfreezers who completed 6 weeks of ABC-C were analyzed. A subset of 51 participants (21 freezers and 30 nonfreezers) with high quality imaging data were used to characterize relationships between baseline cortical thickness and delta (Δ) DTC on gait speed following ABC-C. Freezers showed larger ΔDTC on gait speed than nonfreezers with ABC-C program (p < .05). Cortical thickness in visual and fronto-parietal areas predicted ΔDTC on gait speed in freezers, whereas sensorimotor-lateral thickness predicted ΔDTC on gait speed in nonfreezers (p < .05). When matched for motor severity, visual cortical thickness was a common predictor of response to exercise in all individuals, presenting the largest effect size. In conclusion, freezers improved gait automaticity even more than nonfreezers from cognitively challenging exercise. DTC on gait speed improvement was associated with larger baseline cortical thickness from different brain areas, depending on freezing status, but visual cortex thickness showed the most robust relationship with exercise-induced improvements in DTC.

Dynamic posturography and posturographic training for Parkinson's disease in a routine clinical setting

BACKGROUND

Postural instability in Parkinson's disease (PD) often is ill-responsive to drugs and DBS. Physiotherapy is recommended but practicability and cost effectiveness are debatable.

RESEARCH QUESTION

Can a simple 'plug and play' posturography system produce clinically meaningful measures and elicit postural motor learning in PD patients?

METHODS

40 moderately affected PD patients in a general neurology outpatient clinic who complained of postural instability were included to practice shifts and stabilization of the center of pressure (COP) in a low intensity (once weekly 20-25 minutes over 6 weeks) dynamic posturographic training using the Biodex balance system^TM. Average deviations from mean COP position and from the center of the base of support (BOS) with different degrees of visual feedback in static and dynamic posturographic tasks other than the training tasks, the Berg-Balance-Scale (BBS) and patient self-ratings (FES-I, ABC scale) were assessed before and after training.

RESULTS

Posturographic performance was significantly better with eyes open than closed and more so with explicit visual feedback of COP position (p < 0.005). Only with this latter type of feedback and only the deviation form the BOS in dynamic and static posturography was significantly correlated with BBS and UPDRS III (p < 0.001). The deviation from the BOS under explicit visual feedback significantly improved after training (p < 0.005) whereas BBS, FES-I and ABC-scale did not.

SIGNIFICANCE

Our posturography procedures were well applicable as a routine clinical tool. They yielded clinically valid measures when COP position was visible and directional shifts from the BOS centre were quantified. Our training was effective for this posturographic measure only. Its significance as a predictor for clinical efficacy of higher intensity and longer term training schedules is hypothesized and warrants further studies.

Factors Associated With Responsiveness to Gait and Balance Training in People With Parkinson Disease

BACKGROUND AND PURPOSE

Although increasing evidence supports the benefit- of exercise among people with Parkinson disease (PwPD), it is unclear whether a given exercise modality suits all PwPD, given the heterogeneity of the disease. The purpose of this study was to explore factors associated with responsiveness to a highly challenging training intervention that incorporated dual-task exercises.

METHODS

Forty-seven PwPD (mean age: 73 years; 19 females, Hoehn and Yahr stages 2-3) who had participated in 10 weeks of highly challenging gait and balance training were included. Baseline demographics, disease-related factors, physical and cognitive ability, and perceived health were used for the prediction of percent change in balance performance (the Mini-BESTest) and comfortable gait speed between the pre- and postassessments, using multiple linear regression analyses.

RESULTS

Thirty-five percent of the variance of change in balance performance was explained by General Health Perceptions (β = -0.36), the Timed Up and Go test (β = -0.33), and the single-task performance of a cognitive task (β = -0.24). Forty-nine percent of change in gait speed was explained by gait speed while performing a dual task (β = -0.46), dual-task interference while walking (β = 0.43), time to complete the Timed Up and Go test (β = -0.29), and percent error on a cognitive task (β = -0.25).

DISCUSSION AND CONCLUSIONS

The results may suggest that the PwPD with overall lower perceived health, functional mobility, and cognitive functions are the ones most likely to benefit from highly challenging and attention-demanding gait and balance training.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A240).

Dynamic neural network approach to targeted balance assessment of individuals with and without neurological disease during non-steady-state locomotion

Background

Clinical balance assessments often rely on functional tasks as a proxy for balance (e.g., Timed Up and Go). In contrast, analyses of balance in research settings incorporate quantitative biomechanical measurements (e.g., whole-body angular momentum, H) using motion capture techniques. Fully instrumenting patients in the clinic is not feasible, and thus it is desirable to estimate biomechanical quantities related to balance from measurements taken from a subset of the body segments. Machine learning algorithms are well-suited for this type of low- to high-dimensional mapping. Thus, our goal was to develop and test an artificial neural network that to predict segment contributions to whole-body angular momentum from linear acceleration and angular velocity signals (i.e., those typically available to wearable inertial measurement units, IMUs) taken from a sparse set of body segments.

Methods

Optical motion capture data were collected from five able-bodied individuals and five individuals with Parkinson's disease (PD) walking on a non-steady-state locomotor circuit comprising stairs, ramps and changes of direction. Motion data were used to calculate angular momentum (i.e., “gold standard” output data) and body-segment linear acceleration and angular velocity data from local reference frames at the wrists, ankles and neck (i.e., network input). A dynamic nonlinear autoregressive neural network was trained using the able-bodied data (pooled across subjects). The neural network was tested on data from individuals with PD with noise added to simulate real-world IMU data.

Results

Correlation coefficients of the predicted segment contributions to whole-body angular momentum with the gold standard data were 0.989 for able-bodied individuals and 0.987 for individuals with PD. Mean RMS errors were between 2 and 7% peak signal magnitude for all body segments during completion of the locomotor circuits.

Conclusion

Our results suggest that estimating segment contributions to angular momentum from mechanical signals (linear acceleration, angular velocity) from a sparse set of body segments is a feasible method for assessing coordination of balance—even using a network trained on able-bodied data to assess individuals with neurological disease. These targeted estimates of segmental momenta could potentially be delivered to clinicians using a sparse sensor set (and likely in real-time) in order to enhance balance rehabilitation of people with PD.

Split-belt treadmill walking in patients with Parkinson's disease: A systematic review

BACKGROUND

Walking on a split-belt treadmill (SBT) can help to modulate an asymmetric gait, particularly for people with neurological conditions, such as Parkinson's disease (PD), where asymmetry plays a role due to the laterality of the disease.

RESEARCH QUESTION

This systematic review critically evaluates the literature on SBT in PD. First, different SBT paradigms and methodological approaches were evaluated. Second, the review explored how people with PD adapt their gait to different SBT conditions compared to healthy controls (HC).

METHODS

We conducted a systematic search of the PubMED, PsychINFO, and Web of Knowledge databases. Original research articles, published in English and investigating SBT walking in people with PD, were included.

RESULTS

From the 925 studies originally identified, seven met the inclusion criteria and were selected for evaluation (n = 118 individuals with PD of whom 44 had freezing of gait (FOG)). The SBT paradigms varied across studies regarding the SBT settings, definitions of gait variables, and criteria for determining dominance of body side. Gait variability and bilateral coordination were found to adapt to the SBT condition similarly in people with PD and healthy controls (HC). Inconsistent results were found with respect to the adaptation of gait asymmetry, for the differences between PD and HC participants. The subgroup of people with PD and FOG showed reduced accuracy in detecting belt speed differences and slower adaptation to SBT conditions.

CONCLUSION

Individuals with mild to moderately severe PD adapted similarly to HCs to SBT walking for gait variability and bilateral gait coordination. However, those with FOG had impaired perception of belt speed differences and did not adapt their gait so readily. Although SBT can be useful for modulating gait asymmetry in some people with PD, it was not beneficial for all. We recommend standardization of SBT protocols for clinical practice in future studies.

The Effects of Dual-Task Cognitive Interference and Environmental Challenges on Balance in Huntington's Disease

BACKGROUND

Huntington's disease (HD) is characterized by chorea, balance and gait impairments, and cognitive deficits, which increase fall risk. Dual task (DT) and environmentally challenging paradigms reflect balance related to everyday life. Furthermore, the impact of cognitive deficits on balance dysfunction and falls in HD is unknown.

OBJECTIVE

To determine the impact of DT interference, sensory feedback, and cognitive performance on balance and falls in HD.

METHODS

Seventeen participants with HD (55 ± 9.7 years) and 17 age-matched controls (56.5 ± 9.3 years) underwent quantitative balance testing with APDM inertial sensors. Postural sway was assessed during conditions of manipulated stance, vision, proprioception, and cognitive demand. The DT was a concurrent verbal fluency task. Neuropsychological assessments testing multiple cognitive domains were also administered.

RESULTS

HD participants exhibited significantly greater total sway area, jerk, and variability under single-task (ST) and DT conditions compared to controls (P = 0.0002 - < 0.0001). They also demonstrated greater DT interference with vision removed for total sway area (P = 0.01) and variability (P = 0.02). Significantly worse postural control was observed in HD with vision removed and reduced proprioception (P = 0.001 - 0.01). Decreased visuospatial performance correlated with greater total sway and jerk (P = 0.01; 0.009). No balance parameters correlated with retrospective falls in HD.

CONCLUSIONS

HD participants have worse postural control under DT, limited proprioception/vision, and greater DT interference with a narrowed base and no visual input. These findings may have implications for designing motor and cognitive strategies to improve balance in HD.

Motor Learning Deficits in Parkinson's Disease (PD) and Their Effect on Training Response in Gait and Balance: A Narrative Review

Parkinson's disease (PD) is a neurological disorder traditionally associated with degeneration of the dopaminergic neurons within the substantia nigra, which results in bradykinesia, rigidity, tremor, and postural instability and gait disability (PIGD). The disorder has also been implicated in degradation of motor learning. While individuals with PD are able to learn, certain aspects of learning, especially automatic responses to feedback, are faulty, resulting in a reliance on feedforward systems of movement learning and control. Because of this, patients with PD may require more training to achieve and retain motor learning and may require additional sensory information or motor guidance in order to facilitate this learning. Furthermore, they may be unable to maintain these gains in environments and situations in which conscious effort is divided (such as dual-tasking). These shortcomings in motor learning could play a large part in degenerative gait and balance symptoms often seen in the disease, as patients are unable to adapt to gradual sensory and motor degradation. Research has shown that physical and exercise therapy can help patients with PD to adapt new feedforward strategies to partially counteract these symptoms. In particular, balance, treadmill, resistance, and repeated perturbation training therapies have been shown to improve motor patterns in PD. However, much research is still needed to determine which of these therapies best alleviates which symptoms of PIGD, the needed dose and intensity of these therapies, and long-term retention effects. The benefits of such technologies as augmented feedback, motorized perturbations, virtual reality, and weight-bearing assistance are also of interest. This narrative review will evaluate the effect of PD on motor learning and the effect of motor learning deficits on response to physical therapy and training programs, focusing specifically on features related to PIGD. Potential methods to strengthen therapeutic effects will be discussed.

The effect of functional-task training on activities of daily living for people with Parkinson`s disease, a systematic review with meta-analysis

OBJECTIVE

To evaluate the effect of functional-task training on activities of daily living (ADL) in people with Parkinson`s Disease.

METHODS

We searched five databases (Cinahl, Embase, Medline, Pedro and CENTRAL). The included studies were assessed on therapeutic validity and risk of bias. We classified the quality of evidence according to the principles of the GRADE approach. All assessments were executed independently by two researchers. The results of included studies were pooled in a meta-analyses and heterogeneity was explored by meta-regression analysis.

RESULTS

Out of 2546 identified studies, 69 full texts articles were checked for eligibility, of which ten were included in the systematic review. Moderate quality of evidence indicated that exercise interventions containing functional-task training had a positive effect on ADL performance scores on the Unified Parkinson's Disease Rating Scale (UPDRS) in people with Parkinson (pwp) directly after intervention (UPDRS=-2.62(-5.34;0.10)). This effect improved, in favor of functional-task interventions, at the first follow-up (UPDRS=-4.0(-7.56;-0.4)). A post-hoc meta-regression analysis yielded a significant relationship between intensity rate (minutes/week) and the size of the (average) effect on ADL score.

CONCLUSION

Exercise interventions containing functional-task training have a clinically important positive effect on ADL performance in pwp directly after intervention and at first follow-up, compared to no intervention or placebo. The intensity rate of the functional-task training should be as intense as possible, within the capabilities of the person with PD. Future research is necessary to determine the exact amount of effect that can be contributed to functional-task training.

A machine learning approach to targeted balance rehabilitation in people with Parkinson's disease using a sparse sensor set

Clinical Balance Assessments Often Rely On Functional Tasks As A Proxy For Balance (E.G., Timed Up And Go). In Contrast, Analyses Of Balance In Research Settings Incorporate Quantitative Biomechanical Measurements (E.G., Whole-Body Angular Momentum, H) Using Motion Capture Techniques. Fully Instrumenting Patients In The Clinic Is Not Feasible, And Thus It Is Desirable To Estimate Biomechanical Quantities Related To Balance From Measurements Taken From A Subset Of The Body Segments. Machine Learning Algorithms Are Well-Suited For This Type Of Low- To High-Dimensional Mapping. Thus, Our Objective Was To Develop And Validate An Artificial Neural Network For Estimating Contributions To H From 12 Body Segments Using Only Five Inertial Measurement Units. The Network Was Trained, Tested And Validated On Data From Five Able-Bodied Individuals Performing Forty Trials Each Of A Circuit Involving Complex Walking Tasks, Including Stairs, Ramp, And Direction Changes. The Network Was Also Separately Tested On Four Trials Of An Individual With Parkinson'S Disease Walking On The Circuit. The Output Of The Network Was Strongly Correlated With The Segment Contributions To H In Both Able-Bodied (R= 0.997) And Parkinson'S Disease (R= (0.998) Subjects. The Estimated Values Also Had Low Error Relative To The Signal Magnitude, With The Largest Mean ± SD Rootmean-Squared Errors Of 8.04 ± 1.76% Peak Signal Magnitude In Able-Bodied Individuals And 7.96 ± 0.91% In The Individual With Parkinson'S Disease. These Promising Results Establish The Feasibility Of Using A Sparse Set Of Inertial Measurement Units To Provide Quantitative Data To Clinicians For Targeted Balance Rehabilitation Across Different Patients.

Dopamine Replacement Medication Does Not Influence Implicit Learning of a Stepping Task in People With Parkinson's Disease

INTRODUCTION

Treatment of Parkinson's disease (PD) with exogenous dopamine (ie, levodopa) may positively affect motor symptoms, but may negatively affect other functions such as the learning of motor skills necessary for rehabilitation. This study aimed to determine whether levodopa medication affects general and sequence-specific learning of a stepping task and the transfer of movement skill to untrained balance tasks in people with PD.

METHODS

Participants with PD were randomized to practice "on" (n = 14) or "off" (n = 13) levodopa medication. Participants practiced 6 blocks of 6 trials of 24 steps of a stepping task over an acquisition period of 3 consecutive days, followed by single retention blocks of 6 trials 2 and 9 days later. Participants were also assessed on untrained balance (ie, transfer) tasks "on" levodopa before practice and following late retention.

RESULTS

There were no between-group differences in general learning, sequence-specific learning, or transfer of skill to untrained balance tasks ( P > .05). Both groups demonstrated general and sequence-specific learning ( P < .001) and trends for improvement in untrained tasks ( P < .001 to P = .26) following practice. Detailed analysis of early acquisition revealed no difference between medication groups.

CONCLUSION

People with PD improved performance on the stepping task with practice. The between-group effect sizes were small, suggesting that levodopa medication status ("on" versus "off") during practice did not significantly affect general or sequence-specific learning of the task or components of early acquisition. The practice dose required to optimally result in functional improvements in untrained balance tasks, including reductions in falls, remains to be determined.