Marina Brozgol

Executive Function and Falls in Older Adults: New Findings from a Five-Year Prospective Study Link Fall Risk to Cognition

Background Recent findings suggest that executive function (EF) plays a critical role in the regulation of gait in older adults, especially under complex and challenging conditions, and that EF deficits may, therefore, contribute to fall risk. The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up. Secondary objectives were to assess whether single and dual task walking abilities, an alternative window into EF, were associated with fall risk. Methodology/Main Results We longitudinally followed 256 community-living older adults (age: 76.4±4.5 yrs; 61% women) who were dementia free and had good mobility upon entrance into the study. At baseline, a computerized cognitive battery generated an index of EF, attention, a closely related construct, and other cognitive domains. Gait was assessed during single and dual task conditions. Falls data were collected prospectively using monthly calendars. Negative binomial regression quantified risk ratios (RR). After adjusting for age, gender and the number of falls in the year prior to the study, only the EF index (RR: .85; CI: .74–.98, p = .021), the attention index (RR: .84; CI: .75–.94, p = .002) and dual tasking gait variability (RR: 1.11; CI: 1.01–1.23; p = .027) were associated with future fall risk. Other cognitive function measures were not related to falls. Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up (p<0.02). Conclusions/Significance These findings demonstrate that among community-living older adults, the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier. The present results link falls among older adults to cognition, indicating that screening EF will likely enhance fall risk assessment, and that treatment of EF may reduce fall risk.

Can an accelerometer enhance the utility of the Timed Up & Go Test when evaluating patients with Parkinson's disease?

INTRODUCTION The Timed Up and Go (TUG) test is a widely used measure of mobility and fall risk in older adults and in Parkinsons disease (PD). We tested the hypothesis that body-fixed accelerometers can provide insight into TUG performance in PD patients. METHODS We examined 17 patients with PD (Hoehn and Yahr score: 2.7+/-0.7; ON state) and 15 age-matched healthy controls; mean ages were 66.8+/-5.9 years, 67.6+/-9.6 years, respectively. Subjects wore a 3D-accelerometer (ADXL330, Analog Devices) on the lower back while performing the TUG test. Sit-to-Stand and Stand-to-Sit times were extracted from the anterior-posterior (AP) signal. Parameters included Sit-to-Stand, Stand-to-Sit durations, amplitude range (Range) and slopes (Jerk). Acceleration median and standard deviation (SD) were also calculated. RESULTS Stopwatch-based TUG duration tended to be higher for the PD patients compared to the control group, although not significantly (p=0.08). In contrast, the TUG duration that was extracted from the acceleration signal was significantly (p<0.02) higher in the PD group compared to the control group. Many acceleration-parameters were also significantly different (p<0.05) between groups; most were not correlated with TUG duration. CONCLUSIONS Accelerometer-derived parameters are sensitive to group differences, indicating that PD patients have poorer mobility during specific aspects of the TUG. In addition to test duration, these measures may serve as complementary and objective bio-markers of PD to augment the evaluation of disease progression and the response to therapeutic interventions.

Does the Evaluation of Gait Quality During Daily Life Provide Insight Into Fall Risk? A Novel Approach Using 3-Day Accelerometer Recordings

Background. Many approaches are used to evaluate fall risk. While their properties and performance vary, most reflect performance at a specific moment or are based on subjective self-report. Objective. To quantify fall risk in the home setting using an accelerometer. Methods. Seventy-one community-living older adults were studied. In the laboratory, fall risk was assessed using performance-based tests of mobility (eg, Timed Up and Go) and usual walking abilities were quantified. Subsequently, subjects wore a triaxial accelerometer on their lower back for 3 consecutive days. Acceleration-derived measures were extracted from segments that reflected ambulation. These included total activity duration, number of steps taken, and the amplitude and width at the dominant frequency in the power spectral density, that is, parameters reflecting step-to-step variability. Afterwards, self-report of falls was collected for 6 months to explore the predictive value. Results. Based on a history of 2 or more falls, subjects were classified as fallers or nonfallers. The number of steps during the 3 days was similar (P = .42) in the fallers (7842.1 ± 6135.6) and nonfallers (9055.3 ± 6444.7). Compared with the nonfallers, step-to-step consistency was lower in the fallers in the vertical axis (amplitude fallers, 0.58 ± 0.22 psd; nonfallers, 0.71 ± 0.18 psd; P = .008); in the mediolateral axis, step-to-step consistency was higher in the fallers (P = .014). The 3-day measures improved the identification of past and future falls status (P < .005), compared to performance-based tests. Conclusions. Accelerometer-derived measures based on 3-day recordings are useful for evaluating fall risk as older adults perform daily living activities in their everyday home environment.

The Dynamic Gait Index in healthy older adults: the role of stair climbing, fear of falling and gender.

The Dynamic Gait Index (DGI) was developed as a clinical tool to assess gait, balance and fall risk. Because the DGI evaluates not only usual steady-state walking, but also walking during more challenging tasks, it may be an especially sensitive test. The present investigation evaluated the DGI and its association with falls, fear of falling, depression, anxiety and other measures of balance and mobility in 278 healthy elderly individuals. Measures included the DGI, the Berg Balance Test (BBT), the Timed Up and Go (TUAG), the Mini-Mental State Exam (MMSE), the Unified Parkinsons Disease Rating Scale (UPDRS) motor part, the Activities-specific Balance Confidence (ABC) scale and the number of annual falls. The DGI was moderately correlated with the BBT (r=0.53; p<0.001), the TUAG (r=-0.42; p<0.001) and the ABC (r=0.49; p<0.001). Fallers performed worse on the DGI compared to non-fallers (p=0.029). Scores on the DGI were near perfect in men (23.3+/-1.2), but among women, there was a small, but significant (p<0.001) decrease (22.5+/-1.6). The reduction in the DGI score in women was due to stair climbing performance, with many women (65%) choosing to walk while holding a handrail, compared to only 39% of men. Scores on the BBT, the TUAG, the UPDRS and the MMSE were similar in men and women. Conversely, ABC scores and fall history were different. These findings suggest that the DGI, although susceptible to ceiling effects, appears to be an appropriate tool for assessing function in healthy older adults.

An instrumented timed up and go: the added value of an accelerometer for identifying fall risk in idiopathic fallers

The Timed Up and Go (TUG) test is a widely used measure of mobility and fall risk among older adults that is typically scored using a stopwatch. We tested the hypothesis that a body-fixed accelerometer can enhance the ability of the TUG to identify community-living older adults with a relatively high fall risk of unknown origin. Twenty-three community-living elderly fallers (76.0 ± 3.9 years) and 18 healthy controls (68.3 ± 9.1 years) performed the TUG while wearing a 3D-accelerometer on the lower back. Acceleration-derived parameters included Sit-to-Stand and Stand-to-Sit times, amplitude range (Range), and slopes (Jerk). Average step duration, number of steps, average step length, gait speed, acceleration-median, and standard-deviation were also calculated. While the stopwatch-based TUG duration was not significantly different between the groups, acceleration-derived TUG duration was significantly higher (p = 0.007) among the fallers. Fallers generally exhibited lower Range and Jerk (p < 0.01). While TUG stopwatch duration successfully identified 63% of the subjects, an accelerometer-derived three-measure-combination correctly classified 87% of the subjects. Accelerometer-derived measures were generally not correlated with TUG duration. These findings demonstrate that fallers have difficulty with specific TUG aspects that can be quantified using an accelerometer. Without compromising simplicity of testing, an accelerometer can apparently be combined with TUG duration to provide complementary, objective measures that allow for a more complete, sensitive TUG-based fall risk assessment.

A Training Program to Improve Gait While Dual Tasking in Patients With Parkinson's Disease: A Pilot Study

Impairments in the ability to perform another task while walking (ie, dual tasking [DT]) are associated with an increased risk of falling. Here we describe a program we developed specifically to improve DT performance while walking based on motor learning principles and task-specific training. We examined feasibility, potential efficacy, retention, and transfer to the performance of untrained tasks in a pilot study among 7 patients with Parkinsons disease (PD). Seven patients (Hoehn and Yahr stage, 2.1±0.2) were evaluated before, after, and 1 month after 4 weeks of DT training. Gait speed and gait variability were measured during usual walking and during 4 DT conditions. The 4-week program of one-on-one training included walking while performing several distinct cognitive tasks. Gait speed and gait variability during DT significantly improved. Improvements were also seen in the DT conditions that were not specifically trained and were retained 1 month after training. These initial findings support the feasibility of applying a task-specific DT gait training program for patients with PD and suggest that it positively affects DT gait, even in untrained tasks. The present results are also consistent with the possibility that DT gait training enhances divided attention abilities during walking.

Dual-Task Training on a Treadmill to Improve Gait and Cognitive Function in Elderly Idiopathic Fallers

Background and Purpose: Daily activities require the ability to dual task (DT), utilizing cognitive resources while walking to negotiate complex environmental conditions. For older adults, these additional cognitive demands often lead to reduced gait quality that increases the risk of falls. The aim of this study was to assess whether a combined intervention, consisting of treadmill training (TT) while performing DT, improves cognitive and motor performance in older adults with a history of multiple falls. Methods: A repeated measures design was used to evaluate the effects of training in 10 elderly fallers (mean age, 78.1 ± 5.81 y, 7 women). The progressive intensive training sessions included walking on a treadmill while practicing a variety of dual tasks 3 times a week for more than 6 weeks. Cognitive and motor measures were used to assess the effects of the intervention immediately after training and 1 month posttraining. Results: Improvements were observed in Berg Balance Scale (P = 0.02), Dynamic Gait Index (P = 0.03), gait speed during usual walking and while DT (P < 0.05), and cognitive performance as measured by the Trails Making Test B (P = 0.02). Furthermore, quality of life improved (SF-36: P = 0.01) as did physical activity (Physical Activity Scale for Elderly: P = 0.02). At 1 month postintervention, changes were not significant. Discussion and Conclusions: After 6 weeks of TT + DT program, elderly fallers demonstrated improved scores on tests of mobility, functional performance tasks, and cognition. Dual task training can be readily implemented by therapists as a component of a fall-risk reduction training program. Video Abstract available. See Video (Supplemental Digital Content 1, http://links.lww.com/JNPT/A81) for more insights from the authors.

Potentials of Enhanced Context Awareness in Wearable Assistants for Parkinson's Disease Patients with the Freezing of Gait Syndrome

Freezing of gait (FOG) is a common gait deficit in advanced Parkinson’s disease (PD). It is often a cause of falls, interferes with daily activities and significantly impairs quality of life. Gait deficits in PD patients are often resistant to pharmacologic treatment; therefore effective nonpharmacologic assistance is needed.In this paper we show the potential of context aware assistance for PD patients with FOG and present our first results on start and turn FOG assistance using our modular wearable research platform. We developed a real-time FOG detection system which provides external acoustic cues when FOG is detected from on-body motion sensors, until the subject resumes walking. In an evaluation study, ten PD patients tested our device. We recorded over 8h of data. Eight patients experienced FOG during the study, and 237 FOG events have been identified by physiotherapists in a post video analysis. For the first time PD patients with the FOG syndrome were assisted by a context-aware wearable system. We report a high accuracy of freeze detection (73.1% sensitivity, 81.6% specificity, user independent). Based on subjective reports, the majority of patients indicated a benefit from the automatic cueing.We discuss how additional sensor modalities can paint a more complete view of the user’s context and may increase the system’s accuracy, decrease its latency, and eventually allow going from freeze detection to freeze preemption.

Clinical Experience Using a 5-Week Treadmill Training Program With Virtual Reality to Enhance Gait in an Ambulatory Physical Therapy Service

Background Current literature views safe gait as a complex task, relying on motor and cognitive resources. The use of virtual reality (VR) in gait training offers a multifactorial approach, showing positive effects on mobility, balance, and fall risk in elderly people and individuals with neurological disorders. This form of training has been described as a viable research tool; however, it has not been applied routinely in clinical practice. Recently, VR was used to develop an adjunct training method for use by physical therapists in an ambulatory clinical setting. Objective The aim of this article is to describe the initial clinical experience of applying a 5-week VR clinical service to improve gait and mobility in people with a history of falls, poor mobility, or postural instability. Design A retrospective data analysis was conducted. Methods The clinical records of the first 60 patients who completed the VR gait training program were examined. Training was provided 3 times per week for 5 weeks, with each session lasting approximately 1 hour and consisting of walking on a treadmill while negotiating virtual obstacles. Main outcome measures were compared across time and included the Timed “Up & Go” Test (TUG), the Two-Minute Walk Test (2MWT), and the Four Square Step Test (FSST). Results After 5 weeks of training, time to complete the TUG decreased by 10.3%, the distance walked during the 2MWT increased by 9.5%, and performance on the FSST improved by 13%. Limitations Limitations of the study include the use of a retrospective analysis with no control group and the lack of objective cognitive assessment. Conclusions Treadmill training with VR appears to be an effective and practical tool that can be applied in an outpatient physical therapy clinic. This training apparently leads to improvements in gait, mobility, and postural control. It, perhaps, also may augment cognitive and functional aspects.

Can a single lower trunk body-fixed sensor differentiate between level-walking and stair descent and ascent in older adults? Preliminary findings

Stair ascent and descent are common forms of ambulation that may be challenging to detect. Here, we propose the first step towards differentiating between stair negotiation and level-walking using a single body-fixed sensor. Seventeen healthy older adults (age: 79.3±4.2 years, 47% women) wore a body-fixed sensor on the lower-back while performing level-walking and stair negotiation. Measures derived from the 3D acceleration and angular-velocity signals included medians, ranges, step duration, step and stride regularity, filtered vertical to horizontal acceleration ratio (VAF/HAF), and wavelet-based features. Friedmans and Wilcoxon tests compared between conditions. Stepwise-binary logistic-regression evaluated classification accuracy. During level-walking, yaw range was lowest and anterior-posterior and vertical step and stride regularity were highest (p≤0.007). Anterior-posterior step regularity (p=0.003), VAF/HAF (p=0.094), and yaw range (p=0.105) identified level-walking (92.2% accuracy). During stair ascent, roll range, median anterior-posterior acceleration and anterior-posterior wavelet-coefficient were lowest (p≤0.006), while VAF/HAF was highest (p=0.0029). Anterior posterior wavelet coefficient (p=0.038) and VAF/HAF (p=0.018) identified stair ascent (94.3% accuracy). During stair descent, vertical and medio-lateral ranges were highest and medio-lateral stride regularity and VAF/HAF were lowest (p≤0.006). VAF/HAF (p=0.01), medio-lateral acceleration range (p=0.069), and medio-lateral stride regularity (p=0.072) identified stair descent (90.2% accuracy). These findings suggest that a single worn body-fixed sensor can be used to differentiate between level-walking and stair negotiation.