Esther Bekkers

Addition of a non-immersive virtual reality component to treadmill training to reduce fall risk in older adults (V-TIME): a randomised controlled trial.

BACKGROUND Age-associated motor and cognitive deficits increase the risk of falls, a major cause of morbidity and mortality. Because of the significant ramifications of falls, many interventions have been proposed, but few have aimed to prevent falls via an integrated approach targeting both motor and cognitive function. We aimed to test the hypothesis that an intervention combining treadmill training with non-immersive virtual reality (VR) to target both cognitive aspects of safe ambulation and mobility would lead to fewer falls than would treadmill training alone. METHODS We carried out this randomised controlled trial at five clinical centres across five countries (Belgium, Israel, Italy, the Netherlands, and the UK). Adults aged 60-90 years with a high risk of falls based on a history of two or more falls in the 6 months before the study and with varied motor and cognitive deficits were randomly assigned by use of computer-based allocation to receive 6 weeks of either treadmill training plus VR or treadmill training alone. Randomisation was stratified by subgroups of patients (those with a history of idiopathic falls, those with mild cognitive impairment, and those with Parkinsons disease) and sex, with stratification per clinical site. Group allocation was done by a third party not involved in onsite study procedures. Both groups aimed to train three times per week for 6 weeks, with each session lasting about 45 min and structured training progression individualised to the participants level of performance. The VR system consisted of a motion-capture camera and a computer-generated simulation projected on to a large screen, which was specifically designed to reduce fall risk in older adults by including real-life challenges such as obstacles, multiple pathways, and distracters that required continual adjustment of steps. The primary outcome was the incident rate of falls during the 6 months after the end of training, which was assessed in a modified intention-to-treat population. Safety was assessed in all patients who were assigned a treatment. This study is registered with ClinicalTrials.gov, NCT01732653. FINDINGS Between Jan 6, 2013, and April 3, 2015, 302 adults were randomly assigned to either the treadmill training plus VR group (n=154) or treadmill training alone group (n=148). Data from 282 (93%) participants were included in the prespecified, modified intention-to-treat analysis. Before training, the incident rate of falls was similar in both groups (10·7 [SD 35·6] falls per 6 months for treadmill training alone vs 11·9 [39·5] falls per 6 months for treadmill training plus VR). In the 6 months after training, the incident rate was significantly lower in the treadmill training plus VR group than it had been before training (6·00 [95% CI 4·36-8·25] falls per 6 months; p<0·0001 vs before training), whereas the incident rate did not decrease significantly in the treadmill training alone group (8·27 [5·55-12·31] falls per 6 months; p=0·49). 6 months after the end of training, the incident rate of falls was also significantly lower in the treadmill training plus VR group than in the treadmill training group (incident rate ratio 0·58, 95% CI 0·36-0·96; p=0·033). No serious training-related adverse events occurred. INTERPRETATION In a diverse group of older adults at high risk for falls, treadmill training plus VR led to reduced fall rates compared with treadmill training alone. FUNDING European Commission.

The Contribution of Proprioceptive Information to Postural Control in Elderly and Patients with Parkinson’s Disease with a History of Falls

Proprioceptive deficits negatively affect postural control but their precise contribution to postural instability in Parkinson’s disease (PD) is unclear. We investigated if proprioceptive manipulations differentially affect balance, measured by force plates, during quiet standing in 13 PD patients and 13 age-matched controls with a history of falls. Perceived limits of stability (LoS) were derived from the differences between maximal center of pressure (CoP) displacement in anterior–posterior (AP) and medio-lateral (ML) direction during a maximal leaning task. Task conditions comprised standing with eyes open (EO) and eyes closed (EC): (1) on a stable surface; (2) an unstable surface; and (3) with Achilles tendon vibration. CoP displacements were calculated as a percentage of their respective LoS. Perceived LoS did not differ between groups. PD patients showed greater ML CoP displacement than elderly fallers (EF) across all conditions (p = 0.043) and tended to have higher postural sway in relation to the LoS (p = 0.050). Both groups performed worse on an unstable surface and during tendon vibration compared to standing on a stable surface with EO and even more so with EC. Both PD and EF had more AP sway in all conditions with EC compared to EO (p < 0.001) and showed increased CoP displacements when relying on proprioception only compared to standing with normal sensory input. This implies a similar role of the proprioceptive system in postural control in fallers with and without PD. PD fallers showed higher ML sway after sensory manipulations, as a result of which these values approached their perceived LoS more closely than in EF. We conclude that despite a similar fall history, PD patients showed more ML instability than EF, irrespective of sensory manipulation, but had a similar reliance on ankle proprioception. Hence, we recommend that rehabilitation and fall prevention for PD should focus on motor rather than on sensory aspects.

Clinical balance scales indicate worse postural control in people with Parkinson’s disease who exhibit freezing of gait compared to those who do not: A meta-analysis

Postural instability and freezing of gait (FOG) are key features of Parkinsons disease (PD) that are closely related to falls. Uncovering the postural control differences between individuals with and without FOG contributes to our understanding of the relationship between these phenomena. The objective of this meta-analysis was to investigate whether postural control deficits, as detected by clinical balance scales, were more apparent in FOG+ compared to FOG-. Furthermore, we aimed to identify whether different scales were equally sensitive to detect postural control deficits and whether medication affected postural control differentially in each subgroup. Relevant articles were identified via five electronic databases. We performed a meta-analysis on nine studies which reported clinical balance scale scores in 249 freezers and 321 non-freezers. Methodological analysis showed that in 5/9 studies disease duration differed between subgroups. Despite this drawback, postural control was found to be significantly worse in FOG+ compared to FOG-. All included clinical balance scales were found to be sufficiently sensitive to detect the postural control differences. Levodopa did not differentially affect postural control (p=0.21), as in both medication states FOG+ had worse postural stability than FOG-. However, this finding warrants a cautious interpretation given the limitations of the studies included. From subscore analysis, we found that reactive and dynamic postural control were the most affected postural control systems in FOG+. We conclude that our findings provide important evidence for pronounced postural instability in individuals with FOG, which can be easily picked up with clinical evaluation tools. Posturographic measures in well-matched subgroups are needed to highlight the exact nature of these deficits.

Analysis of free-living gait in older adults with and without Parkinson's disease and with and without a history of falls: identifying generic and disease specific characteristics.

BACKGROUND Falls are associated with gait impairments in older adults (OA) and Parkinsons disease (PD). Current approaches for evaluating falls risk are based on self-report or one-time assessment and may be suboptimal. Wearable technology allows gait to be measured continuously in free-living conditions. The aim of this study was to explore generic and specific associations in free-living gait in fallers and nonfallers with and without PD. METHODS Two hundred and seventy-seven fallers (155 PD, 122 OA) who fell twice or more in the previous 6 months and 65 nonfallers (15 PD, 50 OA) were tested. Free-living gait was characterized as the volume, pattern, and variability of ambulatory bouts (Macro), and 14 discrete gait characteristics (Micro). Macro and Micro variables were quantified from free-living data collected using an accelerometer positioned on the low back for one week. RESULTS Macro variables showed that fallers walked with shorter and less variable ambulatory bouts than nonfallers, independent of pathology. Micro variables within ambulatory bouts showed fallers walked with slower, shorter and less variable steps than nonfallers. Significant interactions showed disease specific differences in variability with PD fallers demonstrating greater variability (step length) and OA fallers less variability (step velocity) than their nonfaller counterparts (p < 0.004). CONCLUSIONS Common and disease-specific changes in free-living Macro and Micro gait highlight generic and selective targets for intervention depending on type of faller (OA-PD). Our findings support free-living monitoring to enhance assessment. Future work is needed to confirm the optimal battery of measures, sensitivity to change and value for fall prediction.

Everyday Stepping Quantity and Quality Among Older Adult Fallers With and Without Mild Cognitive Impairment: Initial Evidence for New Motor Markers of Cognitive Deficits?

Background Recent work demonstrated that the gait of people with mild cognitive impairment (MCI) differs from that of age-matched controls and, in general, that walking ability, as measured in the clinic, does not necessarily reflect actual, daily performance. We evaluated if the quantity and quality of everyday walking (ie, community ambulation) differs in older adults with MCI, compared to age-matched controls. Methods Inclusion criteria included: age 65-90 years, able to walk at least 5 minutes unassisted, and ≥2 falls in the past 6 months. Subjects with MCI were included if they scored 0.5 on the Clinical Dementia Rating Scale. To assess stepping quantity and quality, subjects wore a tri-axial accelerometer on the lower-back for 7 days. Results Age and gender were similar (p > .10) in MCI (n = 36, 77.8 ± 6.4 years; 27.8% men) and controls (n = 100, 76.0 ± 6.2 years; 22.0% men). As expected, Montreal Cognitive Assessment scores were lower (p < .001) in MCI (21.31 ± 4.05), compared to controls (25.81 ± 2.64). Walking time was lower (p = .016) in MCI (0.74 ± 0.48 hours/d), compared to controls (1.05 ± 0.66 hours/d). Within-bout walking (eg, stride regularity) was less consistent (p = .024) in MCI (0.51 ± 0.14), compared to controls (0.58 ± 0.14). Changes in stride regularity across bouts were lower (p < .001) in MCI (0.13 ± 0.04), compared to controls (0.17 ± 0.01). Conclusions Older adults with MCI walk less and with a more variable within-bout and less variable across-bout walking pattern, as compared to cognitively-intact subjects matched with respect to age and gender. These findings extend previous clinical work and suggest that MCI affects both the quantity and quality of community ambulation.

Freezing-related perception deficits of asymmetrical walking in Parkinson’s disease

Patients with Parkinsons disease (PD), and especially those with freezing of gait (FOG), are known to experience impairments in gait rhythmicity, symmetry, and bilateral coordination between both legs. In the current study, we investigated whether deficits in perception of gait speed between limbs were more pronounced in freezers than in non-freezers and could explain some of these gait impairments. We also assessed cognitive ability and proprioception. Twenty-five PD patients (13 freezers, 12 non-freezers) and 12 healthy controls walked on a split-belt treadmill, while the speed of one of the belts was gradually increased. Participants had to indicate the moment at which they perceived belt speeds to be different. The main outcome variables were the number of correct responses (perception accuracy) and the difference in belt speeds at the moment the participants perceived belt speeds to be different (perception threshold). In addition, gait characteristics during both split- and tied-belt walking were determined. Results showed significantly lower perception accuracy in freezers, whereas the perception threshold did not differ between groups. During tied-belt walking, freezers exhibited more asymmetrical step lengths and limb excursions than non-freezers and healthy controls. Greater step length and limb excursions were associated with better perception, whereas more variable gait was associated with more impaired perception. The results confirm the hypothesis that freezers have impaired perception of locomotor asymmetry. While proprioceptive and cognitive ability did not explain these findings, the possible causal link with the occurrence of FOG needs further corroboration.

Fall-prone older people's attitudes towards the use of virtual reality technology for fall prevention

Background: Virtual reality (VR) technology is a relatively new rehabilitation tool that can deliver a combination of cognitive and motor training for fall prevention. The attitudes of older people to such training are currently unclear. Objective: This study aimed to investigate: (1) the attitudes of fall-prone older people towards fall prevention exercise with and without VR; (2) attitudinal changes after intervention with and without VR; and (3) user satisfaction following fall prevention exercise with and without VR. Methods: A total of 281 fall-prone older people were randomly assigned to an experimental group receiving treadmill training augmented by VR (TT+VR, n = 144) or a control group receiving treadmill training alone (TT, n = 137). Two questionnaires were used to measure (1) attitudes towards fall prevention exercise with and without VR (AQ); and (2) user satisfaction (USQ). AQ was evaluated at baseline and after intervention. USQ was measured after intervention only. Results: The AQ revealed that most participants had positive attitudes towards fall prevention exercise at baseline (82.2%) and after intervention (80.6%; p = 0.144). In contrast, only 53.6% were enthusiastic about fall prevention exercise with VR at baseline. These attitudes positively changed after intervention (83.1%; p < 0.001), and 99.2% indicated that they enjoyed TT+VR. Correlation analyses showed that postintervention attitudes were strongly related to user satisfaction (USQ: r = 0.503; p < 0.001). Conclusions: Older peoples attitudes towards fall prevention exercise with VR were positively influenced by their experience. From the perspective of the user, VR is an attractive training mode, and thus improving service provision for older people is important.

Balancing between the two: Are freezing of gait and postural instability in Parkinson’s disease connected?

HighlightsPostural instability in people with FoG is mostly present during dynamic situations.Weight‐shifts, scaling and timing elicit the largest FoG‐related postural deficits.Postural instability likely reinforce and exacerbate FoG episodes and vice versa.Accumulation of several deficits explains postural breakdown in people with FoG.People with FoG may generate small and slow movements to lower postural demand. Abstract Postural instability and freezing of gait (FoG) are key features of Parkinson’s disease (PD) closely related to falls. Growing evidence suggests that co‐existing postural deficits could influence the occurrence and severity of FoG. To date, the exact nature of this interrelationship remains largely unknown. We analyzed the complex interaction between postural instability and gait disturbance by comparing the findings available in the posturographic literature between patients with and without FoG. Results showed that FoG and postural instability are intertwined, can influence each other behaviorally and may coincide neurologically. The most common FoG‐related postural deficits included weight‐shifting impairments, and inadequate scaling and timing of postural responses most apparent at forthcoming postural changes under time constraints. Most likely, a negative cycle of combined and more severe postural deficits in people with FoG will enhance postural stability breakdown. As such, the wide brain network deficiencies involved in FoG may also concurrently influence postural stability. Future work needs to examine whether training interventions targeting both symptoms will have extra clinical benefits on fall frequency.

The Impact of Dual-Tasking on Postural Stability in People With Parkinson's Disease With and Without Freezing of Gait

Background. Postural instability and freezing of gait (FOG) are major problems in patients with Parkinson’s disease (PD), and both contribute to falls. However, the interrelationship between these 2 deficits is still unclear. Objective. This study investigated whether dual-tasking influenced postural control differently in freezers (FOG+) and nonfreezers (FOG−). Methods. Thirty-three patients with PD (19 FOG+, 14 FOG−, well-matched) and 28 healthy controls underwent 4 postural control tasks, consisting of standing on either stable or unstable surfaces with eyes open or closed. Each condition was performed with and without a cognitive dual-task (DT). Center of pressure and center of mass variables and cognitive DT performance outcomes were investigated. Results. Postural stability decreased to a larger extent in FOG+ under DT conditions compared with the other groups, although overall most differences were found between FOG+ and controls. FOG+ exhibited worse postural control compared with FOG− under stable surface DT conditions, shown by higher medial-lateral sway measures (group × surface × task, P < .05). Also, postural DT cost (%) was higher in FOG+ than in FOG− in unstable surface conditions without vision. Controls performed better on the cognitive DT when balancing compared with sitting, whereas this improvement was absent in both PD subgroups and more so in FOG+. Conclusions. Postural stability in FOG+ deteriorated more than in FOG− and controls upon cognitive load. Our results extend earlier findings on gait that the compensatory mechanisms to cope with DT stance are insufficient in FOG+. The findings highlight the need for adapted rehabilitation programs for this subgroup, comprising motor-cognitive balance training.