Short physical performance battery is not associated with falls and injurious falls in older persons: longitudinal data of the SCOPE project

INTRODUCTION

Falls and fall-related injuries in older persons are a major public health problem. Our objective was to study the predictive value of the Short Physical Performance Battery (SPPB) in the cohort of the SCOPE project on falls, injurious falls, and possible difference of prediction between indoors and outdoors falls.

METHODS

For this sub-study of the SCOPE project participants reporting no falls at baseline, and survey data on falls at the 12-month and 24-month follow-up were included. Participant´s characteristics were assessed during the baseline interview and medical examinations. Falls as well as injurious falls and fall circumstances were obtained self-reported. SPPB and its association with fallers vs. no fallers at 12 and at 24 months were studied with logistic regression models.

RESULTS

The 1198 participants had a median age of 79 years (77-82), and a median SPPB of 10 (8-11), with a 52.5% of female. A total of 227 and 277 falls (12- and 24- month visits, respectively) were reported. In the crude model, the SPPB sum scores (p < 0.001) as well as most single item scores were significant different between fallers and non-fallers over time. However, the association was attenuated in models adjusted for age, sex, marital status, number of medications, quality of life, handgrip strength, and muscle mass [e.g., 12 months; OR 0.94 (0.87-1.02)]. While SPPB fails to differentiate between injurious and non-injurious falls (p = 0.48), a lower SPPB score was associated with falls at home (p < 0.01) after 24 months.

CONCLUSION

SBPP was not able to significantly predict the risk of falling as well as experiencing an injurious fall.

TRIAL REGISTRATION

This study was registered prospectively on 25th February 2016 at clinicaltrials.gov (NCT02691546).

Kidney function and other associated factors of sarcopenia in community-dwelling older adults: The SCOPE study

AIM

Sarcopenia is associated with several factors and medical conditions among older adults, though previous research has shown limitations and inconsistencies, especially regarding chronic kidney disease (CKD). We investigated the clinical and laboratory variables associated with sarcopenia and severe sarcopenia in older adults, focusing on kidney function measures.

METHODS

Data from community-dwelling adults aged ≥75 years participating in the SCOPE multicenter prospective cohort study were assessed cross-sectionally. Comprehensive geriatric assessment was conducted; sociodemographic and lifestyle factors, clinical variables and comorbidities, anthropometric and bioelectrical impedance analysis, blood and urine laboratory variables were collected. EWGSOP2 revised criteria were used to define sarcopenia and its severity. Estimated glomerular filtration rate (eGFR) was calculated using creatinine and non-creatinine-based equations, and CKD stages were defined accordingly.

RESULTS

1420 participants were included, prevalence of sarcopenia was 10.6 %, and 6 % had severe sarcopenia. Multivariate logistic regression analysis showed that age [OR =1.14; 95 %CI (1.09-1.19)], body mass index (BMI) [0.83 (0.79-0.88)], disability performing instrumental activities of daily living (IADL) [2.61 (1.69-4.06)], Mini Mental State Examination (MMSE) score <24 [2.75 (1.62-4.67)], osteoporosis [2.39 (1.55-3.67)], and stage 4 CKD defined by CKD-EPIBTP-B2M, a non-creatinine-based eGFR equation [2.88 (1.11-7.49)], were independently associated with sarcopenia; as were specifically with severe sarcopenia, with more pronounced associations.

CONCLUSIONS

In community-dwelling older adults, sarcopenia is a relevant condition and is associated with severe CKD, older age, IADL, cognitive impairments, osteoporosis and low BMI. These factors should be assessed for proper identification and management of older patients with sarcopenia, and even more so with severe sarcopenia.

A survey of Israeli physical therapists regarding reactive balance training

BACKGROUND

'Reactive balance training' (RBT) was developed to improve balance reactions to unexpected losses of balance. Although this training method is effective, its practical usage in the field of physical-therapy in Israel and world-wide is still unclear.

AIMS

This study aimed to evaluate the extent of RBT use in physical-therapy clinics in Israel, to identify the significant barriers to/facilitators for implementing RBT in clinical practice among physical therapists, and to determine which aspects of RBT most interest physical therapists in Israel.

METHODS

Physical therapists in Israel completed a survey using a questionnaire regarding their knowledge and use of RBT in their clinical practices. We compared the specific use of RBT among users; non-users; and open-to-use physical therapists. The odds ratios of the facilitators and barriers were calculated using univariate and multivariate logistic regression models.

RESULTS

Four-hundred and two physical therapists responded to a yes/no question regarding their use of RBT. Three-quarters (75.4%) of physical therapists reported using RBT in their practices. The most prevalent barrier cited was insufficient space for setting up equipment and most prevalent facilitator was having a colleague who uses RBT. Most of the respondents wanted to learn more about RBT, and most of the non-users wanted to expand their knowledge and mastery of RBT principles.

CONCLUSIONS

There are misconceptions and insufficient knowledge about RBT among physical therapists in Israel, indicating that they may falsely believe that RBT requires large and expensive equipment, suggesting they categorize RBT as external perturbation training only. Reliable information may help to improve general knowledge regarding RBT, and to facilitate the more widespread implementation of RBT as an effective fall-prevention intervention method.

Development of an Elliptical Perturbation System that provides unexpected perturbations during elliptical walking (the EPES system)

BACKGROUND

'Perturbation-based balance training' (PBBT) is a training method that was developed to improve balance reactive responses to unexpected balance loss. This training method is more effective in reducing fall rates than traditional balance training methods. Many PBBTs are performed during standing or treadmill walking which targeted specifically step reactive responses, we however, aimed to develop and build a mechatronic system that can provide unexpected perturbation during elliptical walking the Elliptical Perturbation System (the EPES system), with the aim of improving specifically the trunk and upper limbs balance reactive control.

METHODS

This paper describes the development, and building of the EPES system, using a stationary Elliptical Exercise device, which allows training of trunk and upper limbs balance reactive responses in older adults.

RESULTS

The EPES system provides 3-dimensional small, controlled, and unpredictable sudden perturbations during stationary elliptical walking. We developed software that can identify a trainee's trunk and arms reactive balance responses using a stereo camera. After identifying an effective trunk and arms reactive balance response, the software controls the EPES system motors to return the system to its horizontal baseline position after the perturbation. The system thus provides closed-loop feedback for a person's counterbalancing trunk and arm responses, helping to implement implicit motor learning for the trainee. The pilot results show that the EPES software can successfully identify balance reactive responses among participants who are exposed to a sudden unexpected perturbation during elliptical walking on the EPES system.

CONCLUSIONS

EPES trigger reactive balance responses involving counter-rotation action of body segments and simultaneously evoke arms, and trunk reactive response, thus reactive training effects should be expected.

Quality of Life and Kidney Function in Older Adults: Prospective Data of the SCOPE Study

A longitudinal alteration in health-related quality of life (HRQoL) over a two-year period and its association with early-stage chronic kidney disease (CKD) progression was investigated among 1748 older adults (>75 years). HRQoL was measured by the Euro-Quality of Life Visual Analog Scale (EQ-VAS) at baseline and at one and two years after recruitment. A full comprehensive geriatric assessment was performed, including sociodemographic and clinical characteristics, the Geriatric Depression Scale-Short Form (GDS-SF), Short Physical Performance Battery (SPPB), and estimated glomerular filtration rate (eGFR). The association between EQ-VAS decline and covariates was investigated by multivariable analyses. A total of 41% of the participants showed EQ-VAS decline, and 16.3% showed kidney function decline over the two-year follow-up period. Participants with EQ-VAS decline showed an increase in GDS-SF scores and a greater decline in SPPB scores. The logistic regression analyses showed no contribution of a decrease in kidney function on EQ-VAS decline in the early stages of CKD. However, older adults with a greater GDS-SF score were more likely to present EQ-VAS decline over time, whereas an increase in the SPPB scores was associated with less EQ-VAS decline. This finding should be considered in clinical practice and when HRQoL is used to evaluate health interventions among older adults.

Unilaterally Applied Resistance to Swing Leg Shows a Different Adaptation Pattern Compared to Split-Belt Treadmill in Patients with Stroke

Persons with chronic stroke (PwCS) have a decreased ability to ambulate and walk independently. We aimed to investigate the differences between the motor adaptation process for two different perturbation methods: split-belt treadmill walking and unilaterally applied resistance to the swing leg during walking. Twenty-two PwCS undergo split-belt treadmill walking and unilaterally applied resistance to the swing leg during walking, each one week apart. The test included three phases: the baseline period, the early-adaptation period and the late-adaptation period, as well as the early-de-adaptation period and the late-de-adaptation period. The average step length, swing duration, double-limb support duration, and coefficient of variance (CV) of these parameters were measured. During the split-belt treadmill walking, PwCS showed an adaptation of double-limb support duration symmetry (p = 0.004), specifically a trend between baseline versus early-adaptation (p = 0.07) and an after-effect (late-adaptation compare to early-de-adaptation, p = 0.09). In unilaterally applied resistance to the swing leg during walking, PwCS showed lower swing phase duration CV, in the adaptation period (baseline compare to adaptation, p = 0.006), and a trend toward increased variability of gait in the de-adaptation period compare to the adaptation periods (p = 0.099). The rate of adaptation and de-adaptation were alike between the two perturbation methods. Our findings show that the learning process happening in the central nervous system of PwCS may be dependent on the nature of the perturbation (mechanical resistance vs. split-belt) and that PwCS are able to adapt to two types of errors.

Transient versus stable nature of fear of falling over 24 months in community-older persons with falls- data of the EU SCOPE project on Kidney function

BACKGROUND

Fear of falling (FoF) is an important risk factor for falls among older people. The objectives of our investigations were: a.) to present characteristics of older community-dwelling (CD) fallers with persistent or transient FoF (P-FoF or T-FoF) over 12 months, and b.) to investigate clinical predictors of P-FoF and T-FoF and c.) to explore differences between P-FoF and T-FoF.

METHODS

Our series consisted of 389 older people reporting a fall or injurious fall at baseline and during 24 months follow-up participating in a multicenter prospective study. T-FoF was defined as participants reported "not at all" at baseline and "somewhat/fairly/very concerned" at follow-up, or "not at all" at follow-up, and "somewhat/fairly/very concerned" at baseline, and P-FoF was defined as participants answered "somewhat/fairly/very concerned" in both assessments at baseline and at follow-up. The association between risk factors and T-FoF or P-FoF was investigated by logistic regression analysis.

RESULTS

The mean age of fallers in our sample was 79.0 years (SD 6.0), and 54.2% were females. Out of 389 older adults with a fall history at baseline, 83 participants (21.3%) did not report any FoF over time, P-FoF and T-FoF were observed in 42.7% and 35.9% of participants, respectively. After adjusting for potential confounders (e.g. age, gender), osteoporosis (OR = 2.04, 95%CI = 1.03-4.05) and impaired physical performance (OR = 2.38, 95%CI = 1.12-5.03) were significant predictors of T-FoF vs No-FoF. Osteoporosis (OR = 2.68, 95%CI = 1.31-5.48), depressive symptoms (OR = 3.54, 95%CI = 1.23-10.1) and living alone (OR = 2.44, 95%CI = 1.17-5.06) were significantly associated with P-FoF vs No-FoF. When comparing T-FoF and P-FoF, female gender (OR = 1.95, 95%CI = 1.16-3.27), BMI (OR = 1.08, 95%CI = 1.02-1.14), overall comorbidity (OR = 1.07, 95%CI = 1.02-1.13) and depression (OR = 2.55, 95%CI = 1.33-4.88) were significant predictors of P-FoF.

CONCLUSIONS

T-FoF and P-FoF may be predicted by different sets of risk factors among older fallers. Thus, fallers should be screened for FoF especially when carrying specific risk factors, including female gender, osteoporosis, depression, living alone, impaired physical performance, BMI, comorbidity. These findings may be helpful in designing tailored intervention to blunt the risks related to consequence of FoF among older people experiencing falls.

TRIAL REGISTRATION

The SCOPE study was registered prospectively at clinicaltrials.gov (NCT02691546; 25/02/2016).

The relevance of geriatric assessments on the association between chronic kidney disease stages and mortality among older people: a secondary analysis of a multicentre cohort study

Background

age-adapted definition of chronic kidney disease (CKD) does not take individual risk factors into account. We aimed at investigating whether functional impairments influence CKD stage at which mortality increases among older people.

Methods

our series consisted of 2,372 outpatients aged 75 years or more enrolled in a multicentre international prospective cohort study. The study outcome was 24-month mortality. Kidney function was assessed by estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR). Geriatric assessments included handgrip strength, short physical performance battery (SPPB), cognitive impairment, dependency in basic activities of daily living (BADL) and risk of malnutrition. Analysis was carried out by Cox regression, before and after stratification by individual functional impairments. Survival trees including kidney function and functional impairments were also investigated, and their predictivity assessed by C-index.

Results

overall, mortality was found to increase starting from eGFR = 30–44.9 ml/min/1.73 m² (hazard ratio [HR] = 3.28, 95% confidence interval [CI] = 1.81–5.95) to ACR = 30–300 mg/g (HR = 1.96, 95%CI = 1.23–3.10). However, in survival trees, an increased risk of mortality was observed among patients with impaired handgrip and eGFR = 45–59.9 ml/min/1.73 m², as well as patients with ACR < 30 mg/g and impaired handgrip and SPPB. Survival tree leaf node membership had greater predictive accuracy (C-index = 0.81, 95%CI = 0.78–0.84 for the eGFR survival tree and C-index = 0.77, 95%CI = 0.71–0.81 for the ACR survival tree) in comparison with that of individual measures of kidney function.

Conclusions

physical performance helps to identify a proportion of patients at an increased risk of mortality despite a mild–moderate impairment in kidney function and improves predictive accuracy of individual measures of kidney function.

Characteristics of step responses following varying magnitudes of unexpected lateral perturbations during standing among older people - a cross-sectional laboratory-based study

INTRODUCTION

The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falling.

AIM

We aimed to explore whether different kinematic patterns and strategies occur in the first recovery step in single-step trials in which a single step was required to recover from a fall, and in multiple-step trials in which more than one step was required to recover from a fall. In addition, in the multiple-step trials, we examined kinematic patterns of balance recovery where extra steps were needed to recover balance.

METHODS

Eighty-four older adults (79.3 ± 5.2 years) were exposed to unannounced right/left perturbations in standing that were gradually increased to trigger a recovery stepping response. We performed a kinematic analysis of the first recovery step of all single-step and multiple-step trials for each participant and of total balance recovery in the multiple-step trial.

RESULTS

Kinematic patterns and strategies of the first recovery step in the single-step trials were significantly dependent on the perturbation magnitude. It took a small, yet significantly longer time to initiate a recovery step and a significantly longer time to complete the recovery step as the magnitude increased. However, the first recovery step in the multiple-step trials showed no significant differences between different perturbation magnitudes; while, in total balance recovery of these trials, we observed a small, yet significant difference as the magnitude increased.

CONCLUSIONS

At relatively low perturbation magnitudes, i.e., single-step trials, older adults selected different first stepping strategies and kinematics as perturbation magnitudes increased, suggesting that this population activated pre-planned programs based on the perturbation magnitude. However, in the first recovery step of the multiple-step trials, i.e., high perturbation magnitudes, similar kinematic movement patterns were used at different magnitudes, suggesting a more rigid, automatic behavior, while the extra-steps were scaled to the perturbation magnitude. This suggest that older adults activate pre-planned programs based on the magnitude of the perturbation, even before the first step is completed..

Balance recovery stepping responses during walking were not affected by a concurrent cognitive task among older adults

Background

Most of older adults’ falls are related to inefficient balance recovery after an unexpected loss of balance, i.e., postural perturbation. Effective balance recovery responses are crucial to prevent falls. Due to the considerable consequences of lateral falls and the high incidence of falls when walking, this study aimed to examine the effect of a concurrent cognitive task on older adults’ balance recovery stepping abilities from unannounced lateral perturbations while walking. We also aimed to explore whether cognitive performance accuracy is affected by perturbed walking and between task trade-offs.

Methods

In a laboratory-based study, 20 older adults (> 70 years old) performed the following test conditions: (1) cognitive task while sitting; (2) perturbed walking; and (3) perturbed walking with a concurrent cognitive task. The cognitive task was serial numbers subtraction by seven. Single-step and multiple-step thresholds, highest perturbation achieved, 3D kinematic analysis of the first recovery step, and cognitive task performance accuracy were compared between single-task and dual-task conditions. Between task trade-offs were examined using dual-task cost (DTC).

Results

Single-step and multiple-step thresholds, number of recovery step trials, number of foot collision, multiple-step events and kinematic recovery step parameters were all similar in single-task and dual-task conditions. Cognitive performance was not significantly affected by dual-task conditions, however, different possible trade-offs between cognitive and postural performances were identified using DTC.

Conclusions

In situations where postural threat is substantial, such as unexpected balance loss during walking, balance recovery reactions were unaffected by concurrent cognitive load in older adults (i.e., posture first strategy).

The study was approved by the Helsinki Ethics Committee of Soroka University Medical Center in Beer-Sheva, Israel (ClinicalTrials.gov Registration number NCT04455607, ID Numbers: Sor 396–16 CTIL; 02/07/2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02969-w.

Diabetes, sarcopenia and chronic kidney disease; the Screening for CKD among Older People across Europe (SCOPE) study

Background

Sarcopenia may be more present in older adults with diabetes (DM). Accordingly, we evaluated the prevalence of sarcopenia and its associated risk factors among community-dwelling older adults with DM.

Methods

A cross-sectional analysis of older people living in the community was carried out. Participants (aged 75 years and more) came from an European multicenter prospective cohort (SCOPE study). Global geriatric assessment including short physical performance battery, handgrip strength test and bioelectrical impedance analysis was performed. Sarcopenia was defined by the updated criteria of the European Working Group on Sarcopenia in Older People (EWGSOP2). Estimated glomerular filtration rate (eGFR) was calculated using Berlin Initiative Study (BIS) to define the stages of chronic kidney disease (CKD). Previous known DM was defined as physician-diagnosed DM registered in the patient's medical record or the use of DM-related medications. Hemoglobin A1c levels and specific DM therapies administered were collected. Time elapsed from the first diagnosis of DM was not collected and, therefore, was not included in the analyses.

Results

A total of 1,420 subjects were evaluated with a median age of 79.0 (6.0) years, of which 804 (56.6%) were women and 615 (43.3%) men; 315 (22.2%) participants had prior DM diagnosis, with a median age of 80.0 (6.0), 146 (46.3%) were women. Using EWGSOP2 definition, 150 (10.6%) participants in the SCOPE study met diagnostic criteria for sarcopenia. Participants without diabetes had more often normal results in the 3 sarcopenia components than participants with diabetes [887 (80.31%) vs. 227 (72.1%), p = 0.002], highlighting higher percentages of severe sarcopenia in participants with diabetes [27 (8.6%) vs. 58 (5.2%), p = 0.028]. Confirmed or severe sarcopenia was detected in 41 (13%) participants with diabetes and 109 (9.8%) participants without diabetes (p = 0.108). According to BIS equation, sarcopenia was not significantly more prevalent in the more advanced stages of CKD (p = 0.845). In multivariate analyses, older age (odds ratios [OR], 1.17; 95% confidence interval [CI], 1.08–1.27), and lower body mass index (OR, 0.79; 95% CI, 0.71–0.89 were associated with the presence of sarcopenia.

Conclusions

One tenth of all older community-dwelling subjects have sarcopenia. Older age and being thinner, but not worse renal function, were associated with higher prevalence of sarcopenia in older older adults with diabetes.

Muscle activation profile is modulated by unexpected balance loss in walking

BACKGROUND

During an unexpected loss of balance, avoiding a fall requires people to readjust their footing rapidly and effectively. A deeper understanding of muscle activation patterns in response to unexpected balance loss will provide insights into the mechanisms of balance recovery responses. This could have implications for treatment of people with balance deficits.

RESEARCH QUESTION

Explore the differences in balance recovery responses to perturbations in different phases of the gait cycle (single-support vs. double-support) in terms of biomechanical behavior (i.e., stepping and dynamic stability characteristics) and lower-limb muscle activation patterns.

METHODS

Muscle activation patterns of the ankle and knee muscles and muscle fiber type recruitment resulting from unannounced, mediolateral (i.e., right/left) horizontal-surface perturbations during walking was investigated in twenty healthy adults (27.00 ± 2.79 years, ten females). Surface electromyography (sEMG) total spectral power for specific frequency bands (40-60 Hz, 60-150 Hz, 150-250 Hz, 250-400 Hz and 400-1000 Hz), from tibialis anterior (TA) and vastus lateralis (VL) muscles were analyzed. Three mixed-effects models assessed behavioral and lower-limb muscle activation patterns resulting from perturbations in the gait cycle's single- and double-support phases. Statistical significance was set a priori at p < 0.05.

RESULTS

Compared to non-perturbed walking, we found a significant increase in the total spectral power of lower-extremity muscles during the first three seconds after perturbation. During the double-support phase of gait, we found a different muscle fiber type recruitment pattern between VL and TA muscles. However, there were no significant differences between VL and TA muscles for perturbations implemented in single-support phases.

SIGNIFICANCE

Our findings support the notion that muscle operating frequency is modulated in real-time to fit functional goal requirements, such as a rapid change of footing in response to unexpected loss of balance in single and double-support phases of gait.

Temporal But Not Spatial Gait Parameters Associated With Lower Balance Capacity in Moderate-High Functioning Persons With Stroke

BACKGROUND AND PURPOSE

Falls are a major health concern after stroke. Spatial and temporal gait asymmetry and variability can contribute to instability and increased fall risk in persons with stroke (PwS). We aimed to quantify gait spatiotemporal symmetry and variability parameters in PwS undergoing rehabilitation in the subacute stage of the disease, by comparison to healthy participants, and to examine the associations between these parameters and patients' reactive and proactive balance capacity.

METHODS

Twenty-two PwS and 12 healthy adults walked over a computerized treadmill system at their self-selected walking speed. Symmetry and variability of gait parameters (step length, swing time, and stance time) as well as upper extremity and lower extremity angular range of motion in the sagittal plane were extracted. In addition, the Berg Balance Scale (BBS) and the fall threshold in response to sudden surface translations at increasing intensities were assessed.

RESULTS

PwS demonstrated significantly higher asymmetry in all gait parameters in comparison to controls. Also, PwS demonstrated increased stance time variability in comparison to healthy controls and increased swing time variability in the paretic lower extremity. Significant negative associations were found between fall threshold and stance time asymmetry in PwS (r = -0.48, P = 0.022), between the BBS and swing time asymmetry (r = -0.50, P = 0.018), and between the BBS and stance time variability of the paretic lower extremity (r = -0.56, P = 0.006).

DISCUSSION AND CONCLUSIONS

Findings highlight the importance of gait temporal symmetry and variability measures for dynamic balance control after stroke. These parameters should be considered when assessing gait recovery and safety in PwS.Video Abstract available for more insight from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A355).

Examining Different Motor Learning Paradigms for Improving Balance Recovery Abilities Among Older Adults, Random vs. Block Training-Study Protocol of a Randomized Non-inferiority Controlled Trial

Introduction: Falls are the leading cause of fatal and nonfatal injuries among older adults. Studies showed that older adults can reduce the risk of falls after participation in an unexpected perturbation-based balance training (PBBT), a relatively novel approach that challenged reactive balance control. This study aims to investigate the effect of the practice schedule (i.e., contextual interference) on reactive balance function and its transfer to proactive balance function (i.e., voluntary step execution test and Berg balance test). Our primary hypothesis is that improvements in reactive balance control following block PBBT will be not inferior to the improvements following random PBBT.

Methods and Analysis: This is a double-blind randomized controlled trial. Fifty community-dwelling older adults (over 70 years) will be recruited and randomly allocated to a random PBBT group (n = 25) or a block PBBT group (n = 25). The random PBBT group will receive eight training sessions over 4 weeks that include unexpected machine-induced perturbations of balance during hands-free treadmill walking. The block PBBT group will be trained by the same perturbation treadmill system, but only one direction will be trained in each training session, and the direction of the external perturbations will be announced. Both PBBT groups (random PBBT and block PBBT) will receive a similar perturbation intensity during training (which will be customized to participant’s abilities), the same training period, and the same concurrent cognitive tasks during training. The generalization and transfer of learning effects will be measured by assessing the reactive and proactive balance control during standing and walking before and after 1 month of PBBT, for example, step and multiple steps and fall thresholds, Berg balance test, and fear of falls. The dependent variable will be rank transformed prior to conducting the analysis of covariance (ANCOVA) to allow for nonparametric analysis.

Discussion: This research will explore which of the balance retraining paradigms is more effective to improve reactive balance and proactive balance control in older adults (random PBBT vs. block PBBT) over 1 month. The research will address key issues concerning balance retraining: older adults’ neuromotor capacities to optimize training responses and their applicability to real-life challenges.

Clinical Trial Registration: Helsinki research ethics approval has been received (Soroka Medical Center approval #0396-16-SOR; MOH_2018-07-22_003536; www.ClinicalTrials.gov, NCT04455607).

Characteristics of upper-extremity reactions to sudden lateral loss of balance in persons with stroke

BACKGROUND

Upper-extremity reactions are part of a whole-body response to counterweight the falling center of mass after unexpected balance loss. Impairments in upper-extremity reactions due to unilateral hemiparesis may contribute to stroke survivors propensity for falling. We aimed to characterize upper-extremity (paretic and non-paretic sides) reactive movements in response to lateral balance perturbations in Persons with Stroke vs. healthy controls.

METHODS

Twenty-six subacute persons with stroke and 15 healthy controls were exposed to multidirectional sudden unannounced surface translations in stance. Spatiotemporal parameters of upper- and lower-extremity balance responses to lateral perturbations were analyzed.

FINDINGS

In both groups reactive upper-extremity movement initiation preceded reactive step initiation. In response to a loss of balance toward the paretic side, persons with stroke demonstrated delayed movement initiation of both upper- and lower-extremity compared with healthy controls (In persons with stroke: 234.7 ± 60.0 msec and 227.1 ± 39.6 msec for upper extremities vs. 272.1 ± 59.1 msec for lower-extremity; and in controls: 180.1 ± 39.9 msec and 197.8 ± 61.3 msec for upper-extremities vs. 219.3 ± 40.8 msec for lower-extremity; p = 0.001, Cohen's d's: 0.59-1.03) and a greater abduction excursion in the ipsilateral upper-extremity compared with the contralateral upper-extremity (In persons with stroke: 39.3 ± 23.6 cm vs. 24.9 ± 10.1 cm, respectively; In Controls: 42.6 ± 21.8 cm vs. 29.3 ± 17.3 cm, respectively).

INTERPRETATION

The faster upper-extremity reactive movement reactions compared to reactive step initiation in both persons with stroke and healthy controls suggests that balance recovery is an automatic "reflex-like" response. Delayed upper-extremity reactive reactions in conditions of surface translation toward the non-paretic side in persons with stroke may increase the risk of falls in the direction of the paretic side.

Development and piloting of a perturbation stationary bicycle robotic system that provides unexpected lateral perturbations during bicycling (the PerStBiRo system)

Background

Balance control, and specifically balance reactive responses that contribute to maintaining balance when balance is lost unexpectedly, is impaired in older people. This leads to an increased fall risk and injurious falls. Improving balance reactive responses is one of the goals in fall-prevention training programs. Perturbation training during standing or treadmill walking that specifically challenges the balance reactive responses has shown very promising results; however, only older people who are able to perform treadmill walking can participate in these training regimes. Thus, we aimed to develop, build, and pilot a mechatronic Perturbation Stationary Bicycle Robotic system (i.e., PerStBiRo) that can challenge balance while sitting on a stationary bicycle, with the aim of improving balance proactive and reactive control.

Methods

This paper describes the development, and building of the PerStBiRo using stationary bicycles. In addition, we conducted a pilot randomized control trial (RCT) with 13 older people who were allocated to PerStBiRo training (N = 7) versus a control group, riding stationary bicycles (N = 6). The Postural Sway Test, Berg Balance Test (BBS), and 6-min Walk Test were measured before and after 3 months i.e., 20 training sessions.

Results

The PerStBiRo System provides programmed controlled unannounced lateral balance perturbations during stationary bicycling. Its software is able to identify a trainee’s proactive and reactive balance responses using the Microsoft Kinect™ system. After a perturbation, when identifying a trainee’s trunk and arm reactive balance response, the software controls the motor of the PerStBiRo system to stop the perturbation. The pilot RCT shows that, older people who participated in the PerStBiRo training significantly improved the BBS (54 to 56, p = 0.026) and Postural Sway velocity (20.3 m/s to 18.3 m/s, p = 0.018), while control group subject did not (51.0 vs. 50.5, p = 0.581 and 15 m/s vs. 13.8 m/s, p = 0.893, respectively), 6MWT tended to improve in both groups.

Conclusions

Our participants were able to perform correct balance proactive and reactive responses, indicating that older people are able to learn balance trunk and arm reactive responses during stationary bicycling. The pilot study shows that these improvements in balance proactive and reactive responses are generalized to performance-based measures of balance (BBS and Postural Sway measures).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02015-1.

The Effects of Bicycle Simulator Training on Anticipatory and Compensatory Postural Control in Older Adults: Study Protocol for a Single-Blind Randomized Controlled Trial

Background: Falls are the leading cause of fatal and non-fatal injuries among older adults. Perturbation-Based-Balance Training (PBBT) is a promising approach to reduce fall rates by improving reactive balance responses. PBBT programs are designed for older adults who are able to stand and walk on a motorized treadmill independently. However, frail older adults, whose fall rates are higher, may not have this ability and they cannot participate. Thus, there is a critical need for innovative perturbation exercise programs to improve reactive balance and reduce the fall risks among older adults in a wider range of functioning. Trunk and arms are highly involved in reactive balance reactions. We aim to investigate whether an alternative PBBT program that provides perturbations during hands-free bicycling in a sitting position, geared to improve trunk and arm reactive responses, can be transferred to reduce fall risks and improve balance function among pre-frail older adults.

Methods: In a single-blinded randomized-controlled trial, 68 community-dwelling pre-frail older adults are randomly allocated into two intervention groups. The experimental group receives 24-PBBT sessions over 12-weeks that include self-induced internal and machine-induced external unannounced perturbations of balance during hands-free pedaling on a bicycle-simulator system, in combination with cognitive dual-tasks. The control group receives 24 pedaling sessions over 12-weeks by the same bicycle-simulator system under the same cognitive dual-tasks, but without balance perturbations. Participants' reactive and proactive balance functions and gait function are assessed before and after the 12-week intervention period (e.g., balance reactive responses and strategies, voluntary step execution test, postural stability in upright standing, Berg Balance Test, Six-meter walk test, as well as late life function and fear of falling questionnaires).

Discussion: This research addresses two key issues in relation to balance re-training: (1) generalization of balance skills acquired through exposure to postural perturbations in a sitting position investigating the ability of pre-frail older adults to improve reactive and proactive balance responses in standing and walking, and (2) the individualization of perturbation training to older adults' neuromotor capacities in order to optimize training responses and their applicability to real-life challenges.

Clinical Trial Registration:www.clinicaltrials.gov, NCT03636672 / BARZI0104; Registered: July 22, 2018; Enrolment of the first participant March: 1, 2019. See Supplementary File.

Impaired kidney function is associated with lower quality of life among community-dwelling older adults : The screening for CKD among older people across Europe (SCOPE) study

Background

Quality of life (QoL) refers to the physical, psychological, social and medical aspects of life that are influenced by health status and function. The purpose of this study was to measure the self-perceived health status among the elderly population across Europe in different stages of Chronic Kidney Disease (CKD).

Methods

Our series consisted of 2255 community-dwelling older adults enrolled in the Screening for Chronic Kidney Disease (CKD) among Older People across Europe (SCOPE) study. All patients underwent a comprehensive geriatric assessment (CGA), including included demographics, clinical and physical assessment, number of medications taken, family arrangement, Geriatric Depression Scale (GDS), Cumulative Illness Rating Scale, History of falls, Lower urinary tract symptoms, and Short Physical Performance Battery (SPPB). Estimated glomerular filtration rate (eGFR) was calculated by Berlin Initiative Study (BIS) equation. Quality of life was assessed by Euro Qol questionnaire (Euro-Qol 5D) and EQ-Visual Analogue Scale (EQ-VAS). The association between CKD (eGFR < 60, < 45 ml or < 30 ml/min/1.73m²) and low EQoL-VAS was investigated by multivariable logistic regression models.

Results

CKD was found to be significantly associated with low EQoL-VAS in crude analysis (OR = 1.47, 95%CI = 1.16–1.85 for eGFR< 60; OR = 1.38, 95%CI = 1.08–1.77 for eGFR< 45; OR = 1.57, 95%CI = 1.01–2.44). Such association was no longer significant only when adjusting for SPPB (OR = 1.20, 95%CI = 0.93–1.56 for eGFR< 60; OR = 0.87, 95%CI = 0.64–1.18 for eGFR< 45; OR = 0.84, 95%CI = 0.50–1.42), CIRS and polypharmacy (OR = 1.16, 95%CI = 0.90–1.50 for eGFR< 60; OR = 0.86, 95%CI = 0.64–1.16 for eGFR< 45; OR = 1.11, 95%CI = 0.69–1.80) or diabetes, hypertension and chronic obstructive pulmonary disease (OR = 1.28, 95%CI = 0.99–1.64 for eGFR< 60; OR = 1.16, 95%CI = 0.88–1.52 for eGFR< 45; OR = 1.47, 95%CI = 0.92–2.34). The association between CKD and low EQoL-VAS was confirmed in all remaining multivariable models.

Conclusions

CKD may significantly affect QoL in community-dwelling older adults. Physical performance, polypharmacy, diabetes, hypertension and COPD may affect such association, which suggests that the impact of CKD on QoL is likely multifactorial and partly mediated by co-occurrent conditions/risk factors.

Chronic kidney disease in the context of multimorbidity patterns: the role of physical performance : The screening for CKD among older people across Europe (SCOPE) study

Background

Chronic kidney disease (CKD) is known to be associated with several co-occurring conditions. We aimed at exploring multimorbidity patterns associated with CKD, as well as the impact of physical performance and CKD severity on them in a population of older outpatients.

Methods

Our series consisted of 2252 patients enrolled in the Screening of CKD among Older People across Europe multicenter observational study. Hypertension, stroke, transient ischemic attack, cancer, hip fracture, osteoporosis, Parkinson’s disease, asthma, chronic obstructive pulmonary disease, congestive heart failure, angina, myocardial infarction, atrial fibrillation, anemia, CKD (defined as GFR < 60, < 45 or < 30 ml/min/1.73 m²), cognitive impairment, depression, hearing impairment and vision impairment were included in the analyses. Physical performance was assessed by the Short Physical Performance Battery (SPPB) and used as stratification variable. Pairs of co-occurring diseases were analyzed by logistic regression. Patterns of multimorbidity were investigated by hierarchical cluster analysis.

Results

CKD was among the most frequently observed conditions and it was rarely observed without any other co-occurring disease. CKD was significantly associated with hypertension, anemia, heart failure, atrial fibrillation, myocardial infarction and hip fracture. When stratifying by SPPB, CKD was also significantly associated with vision impairment in SPPB = 5–8 group, and hearing impairment in SPPB = 0–4 group. Cluster analysis individuated two main clusters, one including CKD, hypertension and sensory impairments, and the second including all other conditions. Stratifying by SPPB, CKD contribute to a cluster including diabetes, anemia, osteoporosis, hypertension and sensory impairments in the SPPB = 0–4 group. When defining CKD as eGFR< 45 or 30 ml/min/1.73 m², the strength of the association of CKD with hypertension, sensory impairments, osteoporosis, anemia and CHF increased together with CKD severity in pairs analysis. Severe CKD (eGFR< 30 ml/min/1.73 m²) contributed to a wide cluster including cardiovascular, respiratory and neurologic diseases, as well as osteoporosis, hip fracture and cancer.

Conclusions

CKD and its severity may contribute significantly to specific multimorbidity patterns, at least based on the cluster analysis. Physical performance as assessed by SPPB may be associated with not negligible changes in both co-occurring pairs and multimorbidity clusters.

Trial registration

The SCOPE study is registered at clinicaltrials.gov (NCT02691546).

Prevalence of sarcopenia in community-dwelling older adults using the updated EWGSOP2 definition according to kidney function and albuminuria : The Screening for CKD among Older People across Europe (SCOPE) study

Background

Loss of muscle mass and function may be more pronounced in older adults with chronic kidney disease (CKD) and with albuminuria. Thus, we investigated the prevalence of sarcopenia among community-dwelling older adults according to kidney function and grade of albuminuria. We also explored differences in the prevalence of sarcopenia according to three different equations for the estimation of glomerular filtration rate (eGFR).

Methods

A cross-sectional analysis of 1420 community-dwelling older adults (≥75 years old) included in the SCOPE study, a multicenter prospective cohort study, was conducted. Comprehensive geriatric assessment including short physical performance battery (SPPB), handgrip strength test and bioelectrical impedance analysis (BIA) was performed. Sarcopenia was defined using the updated criteria of the European Working Group on Sarcopenia in Older People (EWGSOP2). eGFR was calculated using Berlin Initiative Study (BIS), Chronic Kidney Disease Epidemiological Collaboration (CKD-EPI) and Full Age Spectrum (FAS) equations, and urinary albumin-to-creatinine ratio (ACR) was collected to categorize CKD according to Kidney Disease Improving Global Outcomes guidelines.

Results

Median age was 79.5 years (77.0–83.0), 804 (56.6%) were women. Using EWGSOP2 definition, 150 (10.6%) participants met diagnostic criteria for sarcopenia. Moreover, 85 (6%) participants had severe sarcopenia. Sarcopenia was more prevalent in participants with more advanced stages of CKD according to BIS eq. (9.6% in stages 1 and 2 and 13.9% in stages 3a, 3b and 4, p = 0.042), and also according to CKD-EPI (9.8% vs. 14.2%, p = 0.042) and FAS although not reaching statistical signification (9.8% vs. 12.7%, p = 0.119). Thus, differences in prevalence are observed among CKD categories as estimated by different equations. Prevalence of sarcopenia was also higher with increasing albuminuria categories: 9.3% in normoalbuminuric, 13.2% in microalbuminuric and 16.8% in macroalbuminuric participants, (p = 0.019).

Conclusions

Sarcopenia is common among community-dwelling older adults, especially among those with more advanced CKD categories, with prevalence estimates differing slightly depending on the equation used for the estimation of eGFR; as well as among those with higher albuminuria categories.

Kidney function and other factors and their association with falls : The screening for CKD among older people across Europe (SCOPE) study

Background

Reduced kidney function has become a major public health concern, especially among older people, as Chronic Kidney Disease (CKD) is associated with increased risk of end stage renal disease and mortality. Falls are a serious negative health outcome in older persons with one third of people aged 65 years experiencing a fall per year and increasing fall rates with increasing age. The impact of CKD on falls in older community-dwelling persons is not well investigated. Additionally, lower urinary tract symptoms (LUTS) may also increase the risk of falls. Therefore, our aim was to investigate the impact of CKD and LUTS on falls as well as on injurious falls.

Methods

The SCOPE study is an observational, multinational, multicenter, prospective cohort study involving community-dwelling older persons aged 75 years and more recruited from August 2016 to March 2018 in seven European countries. The main outcomes of the present study were any falls and any injurious falls during the 12 months before enrolment. The cross-sectional association of estimated glomerular filtration rate (eGFR) and LUTS with study outcomes was investigated by logistic regression analysis adjusted for baseline characteristics of enrolled subjects.

Results

Our series consisted of 2256 SCOPE participants (median age = 79.5 years, 55.7% female). Of them, 746 participants experienced a fall and 484 reported an injurious fall in the 12 months prior to baseline assessment. CKD was not significantly associated with falls (OR = 0.95, 95%CI = 0.79–1.14 for eGFR< 60; OR = 1.02, 95%CI = 0.81–1.28 for eGFR< 45; OR = 1.08, 95%CI = 0.74–1.57 for eGFR< 30) or injurious falls (OR = 0.91, 95%CI = 0.67–1.24 for eGFR< 60; OR = 0.93, 95%CI = 0.63–1.37 for eGFR< 45; OR = 1.19, 95%CI = 0.62–2.29 for eGFR< 30). LUTS were found significantly associated with both falls (OR = 1.56, 95%CI = 1.29–1.89) and injurious falls (OR = 1.58, 95%CI = 1.14–2.19), and such associations were confirmed in all multivariable models.

Conclusions

Cross-sectional data suggest that CKD may not be associated with history of falls or injurious falls, whereas LUTS is significantly associated with the outcomes.

Trial registration

This study was registered on 25th February 2016 at clinicaltrials.gov (NCT02691546).

The kinematics and strategies of recovery steps during lateral losses of balance in standing at different perturbation magnitudes in older adults with varying history of falls

BACKGROUND

Step-recovery responses are critical in preventing falls when balance is lost unexpectedly. We investigated the kinematics and strategies of balance recovery in older adults with a varying history of falls.

METHODS

In a laboratory study, 51 non-fallers (NFs), 20 one-time fallers (OFs), and 12 recurrent-fallers (RFs) were exposed to random right/left unannounced underfoot perturbations in standing of increasing magnitude. The stepping strategies and kinematics across an increasing magnitude of perturbations and the single- and multiple-step threshold trials, i.e., the lowest perturbation magnitude to evoke single step and multiple steps, respectively, were analyzed. Fall efficacy (FES) and self-reported lower-extremity function were also assessed.

RESULTS

OFs had significantly lower single- and multiple-step threshold levels than NFs; the recovery-step kinematics were similar. Surprisingly, RFs did not differ from NFs in either threshold. The kinematics in the single-step threshold trial in RFs, however, showed a significant delay in step initiation duration, longer step duration, and larger center of mass (CoM) displacement compared with NFs and OFs. In the multiple-step threshold trial, the RFs exhibited larger CoM displacements and longer time to fully recover from balance loss. Interestingly, in the single-stepping trials, 45% of the step-recovery strategies used by RFs were the loaded-leg strategy, about two times more than OFs and NFs (22.5 and 24.2%, respectively). During the multiple-stepping trials, 27.3% of the first-step recovery strategies used by RFs were the loaded-leg strategy about two times more than OFs and NFs (11.9 and 16.4%, respectively), the crossover stepping strategy was the dominated response in all 3 groups (about 50%). In addition, RFs reported a lower low-extremity function compared with NFs, and higher FES in the OFs.

CONCLUSIONS

RFs had impaired kinematics during both single-step and multiple-step recovery responses which was associated with greater leg dysfunction. OFs and NFs had similar recovery-step kinematics, but OFs were more likely to step at lower perturbation magnitudes suggesting a more "responsive" over-reactive step response related from their higher fear of falling and not due to impaired balance abilities. These data provide insight into how a varying history of falls might affect balance recovery to a lateral postural perturbation.

TRIAL REGISTRATION

This study was registered prospectively on November 9th, 2011 at clinicaltrials.gov ( NCT01439451 ).

Characteristics of proactive balance and gait performance in subacute stroke patients demonstrating varying reactive balance capacity: A research study

BACKGROUND

Persons with stroke (PwS) demonstrate impaired reactive balance control placing them at increased risk of falls. Yet, tests used in clinical practice to assess this risk usually rely on proactive balance control.

OBJECTIVE

To investigate differences in proactive balance in PwS with varying reactive balance capacity.

METHODS

Reactive balance control was assessed in 48 first-event subacute PwS by measuring multiple-step threshold and fall threshold in response to unannounced surface perturbations. They were classified as low-, medium- high- threshold fallers and non-fallers in accordance with the perturbation magnitude at which they were unable to maintain balance (fall threshold). Proactive balance control and gait performance were tested using the Berg Balance test, 10-meter walk test, 6-minute walk test and the Activities-specific Balance Confidence Scale (ABC).

RESULTS

PwS who demonstrated poor reactive balance capacity were also more impaired in their proactive balance and gait. Proactive balance and gait performance were significantly different between the 4 groups while ABC was not. The associations between reactive and proactive measures of balance were moderate (r = 0.53-0.67).

CONCLUSIONS

The moderate correlations between reactive and proactive balance control suggest the recruitment of different neural mechanisms for these two operations, highlighting the importance of assessing and treating reactive balance in clinics.

Novel methodology for assessing total recovery time in response to unexpected perturbations while walking

Walking stability is achieved by adjusting the medio-lateral and anterior-posterior dimensions of the base of support (step length and step width, respectively) to contain an extrapolated center of mass. We aimed to calculate total recovery time after different types of perturbations during walking, and use it to compare young and older adults following different types of perturbations. Walking trials were performed in 12 young (age 26.92 ± 3.40 years) and 12 older (age 66.83 ± 1.60 years) adults. Perturbations were introduced at different phases of the gait cycle, on both legs and in anterior-posterior or medio-lateral directions, in random order. A novel algorithm was developed to determine total recovery time values for regaining stable step length and step width parameters following the different perturbations, and compared between the two participant groups under low and high cognitive load conditions, using principal component analysis (PCA). We analyzed 829 perturbations each for step length and step width. The algorithm successfully estimated total recovery time in 91.07% of the runs. PCA and statistical comparisons showed significant differences in step length and step width recovery times between anterior-posterior and medio-lateral perturbations, but no age-related differences. Initial analyses demonstrated the feasibility of comparisons based on total recovery time calculated using our algorithm.

Effects of mechanical perturbation gait training on gait and balance function in patients with stroke: A pre-post research study

Patients with stroke (PwS) demonstrate impaired gait and balance, and asymmetric gait, placing them at high risk of falls. We aimed to investigate the effects of a single training session that included mechanical external perturbation which resists forward movement of the paretic leg during its swing phase of walking on gait and balance in PwS. In a pre-post pilot study, gait asymmetry and balance function were assessed in 22 first-event chronic PwS (i.e., unilateral hemiparesis). PwS underwent tests during baseline and one week later, after participating in a single training session that resisted forward stepping during the swing phase of walking with a device secured around the patient's waist and connected diagonally to the patient's foot by a tension cord. Ground reaction forces and center of pressure were sampled during treadmill gait to assess step length asymmetry. Performance-oriented mobility assessment (POMA), a two-minute walk test (2MWT), and the voluntary step execution test were also measured. We found no significant improvement in step length asymmetry. However, POMA scores, as well as voluntary step execution tests improved with a moderate effect size. It seems that applying diagonal resistance force to the swinging leg resulted in insufficient horizontal force. However, the improvement in the preparation phase, i.e., better weight-bearing abilities during the voluntary stepping, may be due to the compression force applied to the lower limb joints thus providing proprioceptive training. This suggests that proprioceptive training may improve gait performance in stroke patients in a very short training period.

Open-loop and closed-loop control of posture: Stabilogram-diffusion analysis of center-of-pressure trajectories among people with stroke

Many people with stroke (PwS) demonstrate reduced balance and increased postural sway afterwards, which may ultimately lead to falls and injury. In this study, we aimed to better understand postural sway behavior and the mechanisms of balance control by examining balance in upright standing among PwS using methods from statistical mechanics i.e., the Stabilogram diffusion analysis (SDA). Center-of-pressure displacements while standing still were measured in 25 PwS and 11 healthy subjects. The traditional postural sway parameters were measured, and the SDA was used to characterize balance control in eyes-open and eyes-closed conditions. We found that PwS demonstrated significantly greater postural sway in the mediolateral and anterior-posterior directions and significantly higher SDA short-term diffusion coefficients and critical displacement in both eyes-open and eyes-closed conditions. There was also a significant group-by-condition interaction, whereas PwS demonstrated more sway in the eyes-closed condition. The SDA analysis revealed unstable behavior during short-term intervals, interpreted as larger distance of sway until closed-loop control took place. This significant group-by-condition interaction suggests that PwS have a significantly greater reliance on visual input compared with healthy subjects.

Characteristics of First Recovery Step Response following Unexpected Loss of Balance during Walking: A Dynamic Approach

INTRODUCTION

Many falls in older adults occur during walking and result in lateral falls. The ability to perform a recovery step after balance perturbation determines whether a fall will occur.

AIM

To investigate age-related changes in first recovery step kinematics and kinematic adaptations over a wide range of lateral perturbation magnitudes while walking.

METHODS

Thirty-five old (78.5 ± 5 years) and 19 young adults (26.0 ± 0.8 years) walked at their preferred walking speed on a treadmill. While walking, the subjects were exposed to announced right/left perturbations in different phases of the gait cycle that were gradually increased in order to trigger a recovery stepping response. The subjects were instructed to react naturally and try to avoid falling. Kinematic analysis was performed to analyze the first recovery step parameters (e.g., step initiation, swing duration, step length, and the estimated distance of the center of mass from the base of support [dBoS]).

RESULTS

Compared with younger adults, older adults displayed a significantly lower step threshold and at lower perturbation magnitudes during the experiment. Also, they showed slower compensatory step initiation, shorter step length, and dBoS with similar step recovery times. As the perturbation magnitudes increased, older adults showed very small, yet significant, decreases in the timing of the step response, and increased their step length. Younger adults did not show changes in the timing of stepping, with a tendency toward a significant increase in step length.

CONCLUSIONS

First compensatory step performance is impaired in older adults. In terms of the dynamic approach, older adults were more flexible, i.e., less automatic, while younger adults displayed more automatic behavior.

Inter-observer Reliability and Concurrent Validity of Reactive Balance Strategies after Stroke

BACKGROUND

Falls are a common complication in persons with stroke (PwS). Reliable assessment of balance responses to unexpected loss of balance has the potential to identify risk for falls.

OBJECTIVES

To examine inter-observer reliability of balance responses to unannounced surface perturbations in PwS and to explore the concurrent validity of a balance recovery assessment protocol.

METHODS

Two observers evaluated balance recovery strategies and fall threshold (a fall into a harness system) in 15 PwS and 15 healthy adults who were exposed to forward, backward, right, and left unannounced surface translations in six increasing intensities while standing.

RESULTS

Observer agreement was 100% for the fall threshold. Kappa coefficients for step strategies were 0.960-0.988 in PwS and 0.886-0.938 in healthy adults, 0.905-0.988 for arm reactions in PwS and 0.754-0.926 in healthy adults. Significant correlations were found between fall threshold and Berg Balance Scale (r = 0.691), 6-minute walk test (r = 0.599), and fall efficacy scale-international (r= -0.581).

CONCLUSIONS

A trained examiner can reliably classify reactive balance responses to surface perturbations. The high frequency of falls observed in PwS highlights the importance of assessing reactive balance responses to different directions and intensities of surface translations.

Insufficient Balance Recovery Following Unannounced External Perturbations in Persons With Stroke

Background. Persons with stroke (PwS) are at increased risk of falls, especially toward the paretic side, increasing the probability of a hip fracture. The ability to recover from unexpected loss of balance is a critical factor in fall prevention. Objectives. We aimed to compare reactive balance capacity and step kinematics between PwS and healthy controls. Methods. Thirty subacute PwS and 15 healthy controls were exposed to forward, backward, right, and left unannounced surface translations in 6 increasing intensities while standing. Single step threshold, multiple step threshold, and fall threshold (ie, perturbation intensity leading to a fall into harness system) were recorded as well as reactive step initiation time, step length, and step velocity. Results. Twenty-five PwS fell into harness system during the experiment while healthy controls did not fall. Fourteen out of 31 falls occurred in response to surface translations toward the nonparetic side, that is, falling toward the paretic side. Compared with healthy controls, PwS demonstrated significantly lower fall threshold and multiple step threshold in response to forward, backward, and lateral surface translations. Impairments were more pronounced in response to forward surface translation and toward the nonparetic side (ie, loss of balance toward the paretic side). A trend toward significant shorter step length in response to lateral surface translations was found in PwS compared with healthy controls. Conclusions. Findings highlight the importance of assessing reactive balance capacity in response to perturbations in different directions and intensities in addition to the routine assessment in PwS.

Analysis of Brain Lesion Impact on Balance and Gait Following Stroke

Falls are a leading cause of serious injury and restricted participation among persons with stroke (PwS). Reactive balance control is essential for fall prevention, however, only a few studies have explored the effects of lesion characteristics (location and extent) on balance control in PwS. We aimed to assess the impact of lesion characteristics on reactive and anticipatory balance capacity, gait, and hemiparetic lower limb function, in PwS. Forty-six subacute PwS were exposed to forward, backward, right and left unannounced horizontal surface translations in six increasing intensities while standing. Fall threshold (i.e., perturbation intensity that results in a fall into the harness system) was measured. In addition, the Berg Balance Scale (BBS), 6 Minute Walk Test (6MWT) and Lower Extremity Fugl-Meyer (LEFM) were measured. Lesion effects were analyzed separately for left and right hemisphere damaged (LHD, RHD) patients, using voxel-based lesion-symptom mapping (VLSM). Our results show that voxel clusters where damage exerted a significant impact on balance, gait and lower-limb function were found in the corticospinal tract (CST), in its passage in the corona radiata and in the posterior limb of the internal capsule. An additional significant impact was found to lesions affecting the putamen and the external capsule (EC). Balance, gait, and hemiparetic lower limb function showed much overlap of the corresponding “significant” voxel clusters. Test scores of RHD and LHD patients were affected largely by damage to homologous regions, with the LHD group showing a wider distribution of “significant” voxels. The study corroborates and extends previous findings by demonstrating that balance control, gait, and lower limb function are all affected mainly by damage to essentially the same brain structures, namely—the CST and adjacent structures in the capsular-putaminal region.

Validity and Inter-observer Reliability of the TURN 180 Test to Identify Older Adults Who Reported Falls

BACKGROUND

Falls while turning are associated with increased risk of hip fracture in older adults. Reliable and clinically valid methods for turn ability assessments are needed.

OBJECTIVES

To explore the inter-observer reliability and known group validity of the TURN 180 test.

METHODS

We divided 78 independent older adults (mean age 76.6 ± 6.5 years) into three groups: non-fallers, infrequent fallers (1-2 falls per year), and recurrent fallers (> 2 falls per year). Participants underwent performance-based tests: Timed Up and Go (TUG), Performance Oriented Mobility Assessment (POMA), and Berg Balance Scale (BBS). TUG was videotaped for later analysis of the TURN 180 test by two blinded observers.

RESULTS

A significant difference was found in the TURN 180 test parameters among the groups (P < 0.04). TURN 180 was highly correlated with TUG (r = 0.81-0.89, P < 0.001) and BBS (r = -0.704-0.754, P < 0.0001) and moderately with POMA (r = -0.641-0.698, P < 0.0001). The number of steps was found to be the strongest parameter to determine fallers among older adults (specificity 96.3%, sensitivity 40%). Inter-rater reliability (intraclass correlation coefficient 0.91-0.96, P < 0.0001) was found to be excellent for the number of steps, time taken to accomplish a turn, and total test score categories.

CONCLUSIONS

The TURN 180 test is highly reliable and can identify the older adults who fall. Our results show that the TURN 180 test can serve as a good performance-based examination for research or clinical setting.

Effects of Perturbation-Based Balance Training in Subacute Persons With Stroke: A Randomized Controlled Trial

BACKGROUND

Reactive balance responses are critical for fall prevention. Perturbation-based balance training (PBBT) has shown a positive effect in reducing the risk of falls among older adults and persons with Parkinson's disease.

OBJECTIVE

To explore the effect of a short-term PBBT on reactive balance responses, performance-based measures of balance and gait and balance confidence.

METHODS

Thirty-four moderate-high functioning, subacute persons with stroke (PwS) (lower extremity Fugl-Meyer score 29.2 ± 4.3; Berg Balance Scale [BBS] score 43.8 ± 9.5, 42.0 ± 18.7 days after stroke onset) hospitalized in a rehabilitation setting were randomly allocated to PBBT (n = 18) and weight shifting and gait training (WS&GT) (n = 16). Both groups received 12 training sessions, 30 minutes each, for a period of 2.5 weeks. PBBT included unexpected balance perturbations during standing and treadmill walking, WS&GT included weight shifting in standing and treadmill walking without perturbations. The main outcome measures, that is, multiple step-threshold and fall-threshold were examined at baseline, immediately postintervention, and about 5 weeks postintervention. The secondary outcome measures, that is, BBS, 6-minute walk test (6MWT), 10-meter walk test (10MWT), and Activity-specific Balance Confidence (ABC) scale were examined at baseline and immediately postintervention.

RESULTS

Compared with the WS&GT group, immediately postintervention participants in the PBBT group showed higher multiple-step thresholds in response to forward and backward surface translations (effect size [ES] = 1.07 and ES = 1.10, respectively) and moderate ES in the ABC scale (ES = 0.74). No significant differences were found in fall-threshold, BBS, 6MWT, and 10MWT between the groups.

CONCLUSIONS

Inclusion of perturbation training during rehabilitation of PwS improved reactive balance and balance confidence.

The effects of unexpected mechanical perturbations during treadmill walking on spatiotemporal gait parameters, and the dynamic stability measures by which to quantify postural response

Most falls occur after a loss of balance following an unexpected perturbation such as a slip or a trip. Greater understanding of how humans control and maintain stability during perturbed walking may help to develop appropriate fall prevention programs. The aim of this study was to examine changes in spatiotemporal gait and stability parameters in response to sudden mechanical perturbations in medio-lateral (ML) and anterior-posterior (AP) direction during treadmill walking. Moreover, we aimed to evaluate which parameters are most representative to quantify postural recovery responses. Ten healthy adults (mean = 26.4, SD = 4.1 years) walked on a treadmill that provided unexpected discrete ML and AP surface horizontal perturbations. Participants walked under no perturbation (normal walking), and under left, right, forward, and backward sudden mechanical perturbation conditions. Gait parameters were computed including stride length (SL), step width (SW), and cadence, as well as dynamic stability in AP- (MoS-AP) and ML- (MoS-ML) directions. Gait and stability parameters were quantified by means, variability, and extreme values. Overall, participants walked with a shorter stride length, a wider step width, and a higher cadence during perturbed walking, but despite this, the effect of perturbations on means of SW and MoS-ML was not statistically significant. These effects were found to be significantly greater when the perturbations were applied toward the ML-direction. Variabilities, as well as extremes of gait-related parameters, showed strong responses to the perturbations. The higher variability as a response to perturbations might be an indicator of instability and fall risk, on the same note, an adaptation strategy and beneficial to recover balance. Parameters identified in this study may represent useful indicators of locomotor adaptation to successfully compensate sudden mechanical perturbation during walking. The potential association of the extracted parameters with fall risk needs to be determined in fall-prone populations.

The inter-observer reliability and agreement of lateral balance recovery responses in older and younger adults

The purpose of this study was to evaluate the inter-observer reliability and agreement of balance recovery responses, step and multiple-steps thresholds, and kinematic parameters of stepping responses. Older and younger adults were exposed to 36 progressively challenging right and left unannounced surface translations during quiet standing. Subjects were instructed to "react naturally". Step threshold and multiple-step threshold were defined as the minimum disturbance magnitude that consistently elicited one and more than one recovery step, respectively. Fall threshold is defined as the minimum disturbance magnitude from which a fall resulted (i.e., fall into harness system or grasped one of the anchor straps of the harness, or grasped the research assistant to maintain balance). The inter-observer reliability of balance recovery responses for older adults were excellent, especially for step and multiple-step thresholds (ICC2,1 = 0.978 and ICC2,1 = 0.971, respectively; p < 0.001). Also kinematic parameters of stepping responses such as step recovery duration and step length were excellent (ICC2,1 > 0.975 and ICC2,1 = 0.978, respectively; p < 0.001), substantial reliability was found for swing phase duration (ICC2,1 = 0.693, p < 0.001). Younger adults showed similar ICCs. The Bland-Altman plots demonstrated excellent limits of agreement (LOA > 90%) for most kinematic step parameters and stepping thresholds. These results suggest that balance recovery responses and kinematic parameters of stepping including step threshold and multiple-step threshold are extremely reliable parameters. The measure of balance recovery responses from unexpected loss of balance is feasible and can be used in clinical setting and research-related assessments of fall risk.

Perturbation exercises during treadmill walking improve pelvic and trunk motion in older adults-A randomized control trial

BACKGROUND

Most falls among older adults occur while walking. Pelvic and trunk motions are required to maintain stability during walking. We aimed to explore whether training that incorporates unexpected loss of balance during walking that evokes balance recovery reactions will improve pelvic, thorax, and trunk kinematics at different walking speeds.

METHODS

Fifty-three community-dwelling older adults (age 80.1 ± 5.6 years) were randomly allocated to an intervention group (n = 27) or a control group (n = 26). Both groups received 24 training sessions over 3 months. The intervention group received unexpected perturbation of balance exercises during treadmill walking, while the control group performed treadmill walking only. The primary outcome measures were the pelvic, thorax, and trunk motion. The secondary outcome measures were stride times, length, and width.

RESULTS

Compared to control, participation in the intervention program led to improvement in pelvic and trunk transverse rotations especially at participants' preferred walking speed. No improvement where found in pelvic list while thorax transverse rotation improved in both groups.

CONCLUSIONS

Pelvic and trunk transverse motion, parameters previously reported to deteriorate during aging, associated with gait stability and a risk factor for falls, can be improved by gait training that includes unexpected loss of balance.

Validity of the microsoft kinect system in assessment of compensatory stepping behavior during standing and treadmill walking

Background

Rapid compensatory stepping plays an important role in preventing falls when balance is lost; however, these responses cannot be accurately quantified in the clinic. The Microsoft Kinect™ system provides real-time anatomical landmark position data in three dimensions (3D), which may bridge this gap.

Methods

Compensatory stepping reactions were evoked in 8 young adults by a sudden platform horizontal motion on which the subject stood or walked on a treadmill. The movements were recorded with both a 3D-APAS motion capture and Microsoft Kinect™ systems. The outcome measures consisted of compensatory step times (milliseconds) and length (centimeters). The average values of two standing and walking trials for Microsoft Kinect™ and the 3D-APAS systems were compared using t-test, Pearson’s correlation, Altman-bland plots, and the average difference of root mean square error (RMSE) of joint position.

Results

The Microsoft Kinect™ had high correlations for the compensatory step times (r = 0.75–0.78, p = 0.04) during standing and moderate correlations for walking (r = 0.53–0.63, p = 0.05). The step length, however had a very high correlations for both standing and walking (r > 0.97, p = 0.01). The RMSE showed acceptable differences during the perturbation trials with smallest relative error in anterior-posterior direction (2-3%) and the highest in the vertical direction (11–13%). No systematic bias were evident in the Bland and Altman graphs.

Conclusions

The Microsoft Kinect™ system provides comparable data to a video-based 3D motion analysis system when assessing step length and less accurate but still clinically acceptable for step times during balance recovery when balance is lost and fall is initiated.

Parameters and Measures in Assessment of Motor Learning in Neurorehabilitation; A Systematic Review of the Literature

Upper limb function, essential for daily life, is often impaired in individuals after stroke and cerebral palsy (CP). For an improved upper limb function, learning should occur, and therefore training with motor learning principles is included in many rehabilitation interventions. Despite accurate measurement being an important aspect for examination and optimization of treatment outcomes, there are no standard algorithms for outcome measures selection. Moreover, the ability of the chosen measures to identify learning is not well established. We aimed to review and categorize the parameters and measures utilized for identification of motor learning in stroke and CP populations. PubMed, Pedro, and Web of Science databases were systematically searched between January 2000 and March 2016 for studies assessing a form of motor learning following upper extremity training using motor control measures. Thirty-two studies in persons after stroke and 10 studies in CP of any methodological quality were included. Identified outcome measures were sorted into two categories, “parameters,” defined as identifying a form of learning, and “measures,” as tools measuring the parameter. Review's results were organized as a narrative synthesis focusing on the outcome measures. The included studies were heterogeneous in their study designs, parameters and measures. Parameters included adaptation (n = 6), anticipatory control (n = 2), after-effects (n = 3), de-adaptation (n = 4), performance (n = 24), acquisition (n = 8), retention (n = 8), and transfer (n = 14). Despite motor learning theory's emphasis on long-lasting changes and generalization, the majority of studies did not assess the retention and transfer parameters. Underlying measures included kinematic analyses in terms of speed, geometry or both (n = 39), dynamic metrics, measures of accuracy, consistency, and coordination. There is no exclusivity of measures to a specific parameter. Many factors affect task performance and the ability to measure it—necessitating the use of several metrics to examine different features of movement and learning. Motor learning measures' applicability to clinical setting can benefit from a treatment-focused approach, currently lacking. The complexity of motor learning results in various metrics, utilized to assess its occurrence, making it difficult to synthesize findings across studies. Further research is desirable for development of an outcome measures selection algorithm, while considering the quality of such measurements.

Old adult fallers display reduced flexibility of arm and trunk movements when challenged with different walking speeds

Specific patterns of pelvic and thorax motions are required to maintain stability during walking. This cross-sectional study explored older-adults' gait kinematics and their kinematic adaptations to different walking speeds, with the purpose of identifying mechanisms that might be related to increased risk for falls. Fifty-eight older adults from self-care residential facilities walked on a treadmill, whose velocity was systematically increased with increments of 0.1meters/second (m/s) from 0.5 to 0.9m/s, and then similarly decreased. Thorax, pelvis, trunk, arms, and legs angular total range of motion (tROM), stride time, stride length, and step width were measured. Twenty-one of the subjects reported falling, and 37 didn't fall. No significant effect of a fall history was found for any of the dependent variables. A marginally significant interaction effect of fall history and walking speed was found for arms' tROM (p=0.098). Speed had an effect on many of the measures for both groups. As the treadmill's velocity increased, the non-fallers increased their arm (15.9±8.6° to 26.6±12.7°) and trunk rotations (4.7±1.9° to 7.2±2.8°) tROM, whereas for the fallers the change of arm (14.7±14.8° to 20.8±13°) and trunk (5.5±2.9° to 7.3±2.3°) rotations tROM were moderate between the different walking speeds. We conclude that walking speed manipulation exposed different flexibility trends. Only non-fallers demonstrated the ability to adapt trunk and arm ROM to treadmill speed i.e., had a more flexible pattern of behavior for arm and trunk motions, supporting the upper-body's importance for stability while walking.

Unexpected perturbations training improves balance control and voluntary stepping times in older adults - a double blind randomized control trial

BACKGROUND

Falls are common among elderly, most of them occur while slipping or tripping during walking. We aimed to explore whether a training program that incorporates unexpected loss of balance during walking able to improve risk factors for falls.

METHODS

In a double-blind randomized controlled trial 53 community dwelling older adults (age 80.1±5.6 years), were recruited and randomly allocated to an intervention group (n = 27) or a control group (n = 26). The intervention group received 24 training sessions over 3 months that included unexpected perturbation of balance exercises during treadmill walking. The control group performed treadmill walking with no perturbations. The primary outcome measures were the voluntary step execution times, traditional postural sway parameters and Stabilogram-Diffusion Analysis. The secondary outcome measures were the fall efficacy Scale (FES), self-reported late life function (LLFDI), and Performance-Oriented Mobility Assessment (POMA).

RESULTS

Compared to control, participation in intervention program that includes unexpected loss of balance during walking led to faster Voluntary Step Execution Times under single (p = 0.002; effect size [ES] =0.75) and dual task (p = 0.003; [ES] = 0.89) conditions; intervention group subjects showed improvement in Short-term Effective diffusion coefficients in the mediolateral direction of the Stabilogram-Diffusion Analysis under eyes closed conditions (p = 0.012, [ES] = 0.92). Compared to control there were no significant changes in FES, LLFDI, and POMA.

CONCLUSIONS

An intervention program that includes unexpected loss of balance during walking can improve voluntary stepping times and balance control, both previously reported as risk factors for falls. This however, did not transferred to a change self-reported function and FES.

TRIAL REGISTRATION

ClinicalTrials.gov

REGISTRATION NUMBER

NCT01439451 .

Application of the clinical version of the narrow path walking test to identify elderly fallers

INTRODUCTION

Falling during walking is a common problem among the older population. Hence, the challenge facing clinicians is identifying who is at risk of falling during walking, for providing an effective intervention to reduce that risk. We aimed to assess whether the clinical version of the narrow path walking test (NPWT) could identify older adults who are reported falls.

MATERIALS AND METHODS

A total of 160 older adults were recruited and asked to recall fall events during the past year. Subjects were instructed to walk in the laboratory at a comfortable pace within a 6 meter long narrow path, 3 trials under single task (ST) and 3 trials dual task (DT) conditions without stepping outside the path (i.e., step errors). The average trial time, number of steps, trial velocity, number of step errors, and number of cognitive task errors were calculated for ST and DT. Fear of falling, performance oriented mobility assessment (POMA) and mini-metal state examination (MMSE) were measured as well.

RESULTS

Sixty-one subjects reported that they had fallen during the past year and 99 did not. Fallers performed more steps, and were slower than non-fallers. There were no significant differences, however, in the number of steps errors, the cognitive task errors in ST and DT in POMA and MMSE.

CONCLUSION

Our data demonstrates slower gait speed and more steps during the NPWT in ST and DT in fallers. There is no added value of DT over the ST for identification of faller's older adults.

Altered characteristics of balance control in obese older adults

BACKGROUND

Obesity is one of the most significant epidemiological trends of the last decades. Recently it was found that obese individuals show postural instability. Balance control mechanisms in obese older adults were less studied. Therefore we aimed to investigate the effect of obesity on balance control mechanisms in older adults.

METHODS

Parameters from Stabilogram-Diffusion Analysis (SDA) and measures from summary statistics of foot centre-of-pressure (COP) displacements along the anterior-posterior (AP) and mediolateral (ML) directions in eyes open and eyes closed conditions were used to characterize postural control in 22 obese (30-<35kg/m(2)), 26 overweight (25-<30kg/m(2)), and 18 normal weight subjects (18.5-<25kg/m(2)).

RESULTS

Obese group subjects demonstrated significantly greater transition displacement, transition time interval, and short-term scaling exponent in the ML-direction compared with the normal weight group (eyes open and closed). In the AP-direction the obese group showed greater transition displacement (eyes open) and short-term scaling exponent (eyes open and closed). Average AP-COP and ML-COP ranges of COP sway were higher in the obese group compared with the normal weight group (eyes open and closed).

CONCLUSIONS

This work indicates an altered postural control process in obese older adults. A greater sway displacement before closed-loop feedback mechanisms are called into play was seen in the ML direction that may lead to a higher risk of instability and fall events.

Postural control: differences between youth judokas and swimmers

AIM

Specific physical training may improve balance control. This study aims to explore the underlying mechanisms of balance control in young Judokas compared with the type of training that does not require balance skills (swimming).

METHODS

Nine young judokas and nine age-gender matched swimmers (10.5-17-year-old) participated in the cross-sectional study. Postural Stability was collected using force platform during 10 upright standing trials in each of the three conditions: eyes open, eyes closed, and standing on foam. The force platform data were sampled at a frequency of 100 Hz, than analyzed using summary statistics and Stabilogram-Diffusion Analysis (SDA) for mediolateral (ML) and anteroposterior (AP) directions.

RESULTS

The results show that Judokas have better stability than swimmers in eyes closed condition but lower stability while standing on foam, with no significant differences in eyes open condition. The long-term effective diffusion coefficient of the SDA was significantly lower in judokas in all three postural task conditions.

CONCLUSIONS

The results show that Judokas are able to cope with momentary loss of vision better than swimmers, and less able to compensate reduction in somatosensory cutaneous sensation (e.g. standing on foam). These results suggest that judokas are less visually dependent relying on their sensorimotor system compare with swimmers. judokas have a more effective closed-loop balance control thus able to minimize their sway. It seems that training includes unexpected perturbations of the postural control system, emphasizing sensorimotor adaptabilities.

Vestibulo-ocular response and balance control in children and young adults with mild-to-moderate intellectual and developmental disability: a pilot study

The vestibulo-ocular response (VOR) may not be fully developed in children with an intellectual and developmental disability (IDD). This study aimed to identify the presence of VOR deficit in children and young adults with unspecified mild-to-moderate intellectual and developmental disability and its effect on balance control. Twenty-one children and young adults with IDD ranging in age from 8 to 22 years (mean 17.5 ± 3.9 years) were included in the study. The VOR was evaluated with the Head Impulse Test and the Static and Dynamic Visual Acuity Test (S&D-VAT). Postural stability was measured in an upright standing position by the Clinical Test for Sensory Interaction in Balance (CTSIB), single leg stance (SLS) during eyes open and eyes closed, and Romberg stance under eyes open and eyes closed conditions using a force platform. Reduced vestibulo-ocular responses were found in 13 of 21 (62%) participants who were able to complete testing. In the fifth condition of the CTSIB (standing on foam with eyes closed), those without VOR deficit were able to maintain balance longer than those with VOR deficit (29 s [median 30] vs. 12s [median 7.3], respectively; p=0.03). The study demonstrates potential effects of VOR deficit in children and young adults with IDD and some significant differences in balance control between those with and without a VOR deficit. VOR function in children and young adults with IDD should be routinely tested to enable early detection of deficits.