Repeated Gait Perturbation Training in Parkinson's Disease and Healthy Older Adults: A Systematic Review and Meta-Analysis

Background: Gait impairments are common in healthy older adults (HOA) and people with Parkinson's disease (PwPD), especially when adaptations to the environment are required. Traditional rehabilitation programs do not typically address these adaptive gait demands in contrast to repeated gait perturbation training (RGPT). RGPT is a novel reactive form of gait training with potential for both short and long-term consolidation in HOA and PwPD. The aim of this systematic review with meta-analysis is to determine whether RGPT is more effective than non-RGPT gait training in improving gait and balance in HOA and PwPD in the short and longer term.Methods: This review was conducted according to the PRISMA-guidelines and pre-registered in the PROSPERO database (CRD42020183273). Included studies tested the effects of any form of repeated perturbations during gait in HOA and PwPD on gait speed, step or stride length. Studies using balance scales or sway measures as outcomes were included in a secondary analysis. Effects of randomized controlled trials (RCT) on RGPT were pooled using a meta-analysis of final measures.Results: Of the 4421 studies, eight studies were deemed eligible for review, of which six could be included in the meta-analysis, totaling 209 participants (159 PwPD and 50 HOA). The studies were all of moderate quality. The meta-analysis revealed no significant effects of RGPT over non-RGPT training on gait performance (SMD = 0.16; 95% CI = −0.18, 0.49; Z = 0.92; P = 0.36). Yet, in some individual studies, favorable effects on gait speed, step length and stride length were observed immediately after the intervention as well as after a retention period. Gait variability and asymmetry, signifying more direct outcomes of gait adaptation, also indicated favorable RGPT effects in some individual studies.Conclusion: Despite some promising results, the pooled effects of RGPT on gait and balance were not significantly greater as compared to non-RGPT gait training in PwPD and HOA. However, these findings could have been driven by low statistical power. Therefore, the present review points to the imperative to conduct sufficiently powered RCT's to verify the true effects of RGPT on gait and balance in HOA and PwPD.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php? Identifier: CRD42020183273.

Developing and Establishing Biomechanical Variables as Risk Biomarkers for Preventable Gait-Related Falls and Assessment of Intervention Effectiveness

The purpose of this review is to position the emerging clinical promise of validating and implementing biomechanical biomarkers of falls in fall prevention interventions. The review is framed in the desirability of blunting the effects of the rapidly growing population of older adults with regard to the number of falls, their related injuries, and health care costs. We propose that biomechanical risk biomarkers may be derived from systematic study of the responses to treadmill-delivered perturbations to both identify individuals with a risk of specific types of falls, such as trips and slips as well as quantifying the effectiveness of interventions designed to reduce that risk. The review follows the evidence derived using a specific public health approach and the published biomedical literature that supports trunk kinematics as a biomarker as having met many of the criteria for a biomarker for trip-specific falls. Whereas, the efficacy of perturbation training to reduce slip-related falls by older adults appears to have been confirmed, its effectiveness presently remains an open and important question. There is a dearth of data related to the efficacy and effectiveness of perturbation training to reduce falls to the side falls by older adults. At present, efforts to characterize the extent to which perturbation training can reduce falls and translate the approaches to the clinic represents an important research opportunity.

Perturbation Training for Fall-Risk Reduction in Healthy Older Adults: Interference and Generalization to Opposing Novel Perturbations Post Intervention

This study examined the effects of perturbation training on the contextual interference and generalization of encountering a novel opposing perturbation. One hundred and sixty-nine community-dwelling healthy older adults (69.6 ± 6.4 years) were randomly assigned to one of the three groups: slip-perturbation training (St, n = 67) group received 24 slips, trip-perturbation training (Tt, n = 67) group received 24 trips, and control (Ctrl: n = 31) group received only non-perturbed walking trials (ClinicalTrials.gov NCT03199729; https://clinicaltrials.gov/ct2/show/NCT03199729). After training, all groups had 30 min of rest and three post-training non-perturbed walking trials, followed by a reslip and a novel trip trial for St, a retrip and a novel slip trial for Tt, and randomized novel slip and trip trials for Ctrl. The margin of stability (MOS), step length, and toe clearance of post-training walking trials were compared among three groups to examine interferences in proactive adjustment. Falls, MOS at the instant of recovery foot touchdown, and hip height of post-training perturbation trials were investigated to detect interferences and generalization in reactive responses. Results indicated that prior adaptation to slip perturbation training, resulting in walking with a greater MOS (more anterior) and a shorter step length (p < 0.01) than that of the Ctrl group, would be associated with a greater likelihood to forward balance loss if encountered with a trip. The trip adaptation training mainly induced a higher toe clearance during walking (p < 0.01) than the Ctrl group, which could lead to reduced effectiveness of the reactive response when encountered with a novel slip. However, there was no difference in the reactive MOS, limb support, and falls between the control group and the slip and trip training groups on their respective opposing novel perturbation post-training (MOS, limb support, and falls for novel slip: Tt = Ctrl; for the novel trip: St = Ctrl, both p > 0.05). Current findings suggested that, although perturbation training results in proactive adjustments that could worsen the reactive response (interference) when exposed to an unexpected opposing perturbation, older adults demonstrated the ability to immediately generalize the training-induced adaptive reactive control to maintain MOS, to preserve limb support control, and to reduce fall risk.

Effect of Agility and Perturbation Training on Pain, Balance and Functional Ability in Subjects with Patellofemoral Pain Syndrome

Background: Agility and Perturbation training have been advocated to improve pain, balance and functional abilities in subjects with osteoarthritis of knee but effect of same on Patellofemoral pain have not been explored in studies. The above techniques would be helpful along with standard rehabilitation programs in reducing dynamic knee instability or improving dynamic stability upon return to high level physical activity and have an additive effect of reducing pain in OA knee. Objective: The purpose of the study is to find the effect of Agility and Perturbation training on improvement of pain, balance and functional abilities in subject with Patellofemoral Pain Syndrome. Method: A randomized controlled study with 40 individuals has been taken with patellofemoral pain syndrome. 20 subjects have been selected for control group and 20 subjects for study group. Outcome measures includes Kujala function scale, Y balance test and Numeric pain rating scale were measured before and immediately after the treatment. Results: Analysis using Mann Whitney U Test and Independent t between the groups found that when pre intervention means of NPRS, Composite score YBT and Kujala Score were compared there is a statistically significant difference between the groups. When post intervention means of NPRS and Kujala score were compared between the groups there is no statistically significant difference between the groups. When post intervention means of Composite score YBT were compared there is a statically significant difference. Conclusion: The present study concludes that Agility and Perturbation training shown significant improvement of pain, function and balance in subject with Patellofemoral Pain Syndrome. Key words: Patellofemoral Pain Syndrome, Kujala function Scale, Y balance test.

The Effect of 4-weeks Perturbation Training on Balance, Movement Function, and Risk of Falling in Blind People

Background and Aims: Perturbation training is a type of exercise in which participants frequently experience loss of balance to practice and improve control of balance reactions. Due to postural control impairment in blind people, this study aimed to investigate the effect of 4-week perturbation-based balance training on risk of falling, movement function, and balance in people with visual impairment. Methods: In the current, 30 men with absolute visual impairment were randomly divided into control (n=15) and experimental (n=15) groups. The experimental group performed perturbation exercises for four weeks and three sessions per week for 60 minutes. To evaluate the static balance of the modified stork test, the dynamic balance of the Berg balance tests, the movement function of the Tinetti test, and the fall risk of the functional reach test before and after the training intervention were used. Data were analyzed using an independent t-test and repeated measures analysis of variance at the level of α=0.05. Results: The results showed that the experimental group had an increase in the mean scores of static balance (P=0.001), dynamic balance (P=0.001), movement function (P=0.001), and decreased risk of falling (P=0.001) and is significantly better than the control group. Also, in the post-test, the findings of intragroup changes showed that the experimental group had a more significant effect on increasing balance, increasing movement function, and decreasing the rate of falling than the control group (P<0.05). Conclusion: According to the results of the present study, the use of perturbation exercises improves balance, increases the level of movement function, and reduces the risk of falling in blind people. Due to the positive effects of exercises and the benefits of this type of rehabilitation, it is recommended that this rehabilitation program be performed on the blind and visually impaired. Sports instructors are advised to use the balance-based perturbation exercises in this study and other exercises for people with visual impairment to increase their fitness.

Changes in the Trend of Walking Motor Control in Athletes with Anterior Cruciate Ligament Deficiency in Response to Progressive Perturbation Trainings

Background and Purpose: The beliefs are that sudden and unpredictable balance disturbance by instruments that cause mechanical perturbations can affect individuals with Anterior Cruciate Ligament Deficiency (ACLD) to reach faster and more effective recovery of knee dynamic stabilization strategies to return successfully pre-injury levels. The aim of this study was to investigate the effect of mechanical perturbation training and standard training in the process of changes in motor control during walking task in coper ACLD individuals. Methods: Thirty athletes with a unilateral rupture of the Anterior Cruciate Ligament (ACL), classified as coper, were randomly assigned to perturbation and standard training groups. Intervention training results based on comparison of scores obtained from functional tests in 4 single-leg jump tests, scores of questioners, and surface Electromyography (sEMG) tests were determined between the two groups as well as between the two healthy and ACLD limbs in each group in the walking task. Results: The perturbation training group showed a significant increase in muscle activity in both healthy and ACLD limbs with an increase in similarity index (SI) (p=0.08, ES=0.81), while in the standard training group the results were not significant (p=0.39, ES=0.39). Conclusion: Individuals in the perturbation training group achieved higher scores on all tests compared to the standard training group. This means that the perturbation training group was more mentally and physically prepared in terms of strength, coordination and symmetry between the two limbs to participate in pre-injury sports levels.

Development of a Balance Recovery Performance Measure for Gait Perturbation Training Based on the Center of Pressure

Background: The availability of instrumented treadmills that can apply unexpected perturbations during walking has made gait perturbation training more popular in clinical practice. To quantify and monitor balance recovery while training, easy to use measures are needed and may be based on integrated force plate data. Therefore, we aimed to quantify and evaluate different implementations of the recovery performance measure based on center of pressure data.Methods: Recovery performance was calculated based on differences in center of pressure trajectories between unperturbed walking and balance recovery after a perturbation. Five methodological choices leading to 36 different implementations were evaluated. Test-retest reliability, effect sizes, and concurrent validity were evaluated against trunk velocity measures.Results: Differences in measures of (dis-)similarity, time normalization and reference data affected reliability, sensitivity and validity and none of the performance measure implementations based on center of pressure trajectories was superior on all criteria. Measures assessing perturbation effects on trunk velocities provided more reliable and sensitive recovery outcomes.Discussion: Different implementations of the recovery performance measure can be chosen dependent on constraints imposed in the clinical setting.Conclusion: Quantifying recovery performance based on center of pressure data is possible and may be suitable to monitor improvement in recovery performance after gait perturbations in specific clinical setups. Validity of performance measures in general requires further attention.