Predicting Falls in Parkinson Disease: What Is the Value of Instrumented Testing in OFF Medication State?

BackgroundFalls are a common complication of advancing Parkinson''s disease (PD). Although numerous risk factors are known, reliable predictors of future falls are still lacking. The objective of this prospective study was to investigate clinical and instrumented tests of balance and gait in both OFF and ON medication states and to verify their utility in the prediction of future falls in PD patients.MethodsForty-five patients with idiopathic PD were examined in defined OFF and ON medication states within one examination day including PD-specific clinical tests, instrumented Timed Up and Go test (iTUG) and computerized dynamic posturography. The same gait and balance tests were performed in 22 control subjects of comparable age and sex. Participants were then followed-up for 6 months using monthly fall diaries and phone calls.ResultsDuring the follow-up period, 27/45 PD patients and 4/22 control subjects fell one or more times. Previous falls, fear of falling, more severe motor impairment in the OFF state, higher PD stage, more pronounced depressive symptoms, higher daily levodopa dose and stride time variability in the OFF state were significant risk factors for future falls in PD patients. Increased stride time variability in the OFF state in combination with faster walking cadence appears to be the most significant predictor of future falls, superior to clinical predictors.ConclusionIncorporating instrumented gait measures into the baseline assessment battery as well as accounting for both OFF and ON medication states might improve future fall prediction in PD patients. However, instrumented testing in the OFF state is not routinely performed in clinical practice and has not been used in the development of fall prevention programs in PD. New assessment methods for daylong monitoring of gait, balance and falls are thus required to more effectively address the risk of falling in PD patients.     

Influence of simulated neuromuscular noise on the dynamic stability and fall risk of a 3D dynamic walking model

Measures that can predict risk of falling are essential for enrollment of older adults into fall prevention programs. Local and orbital stability directly quantify responses to very small perturbations and are therefore putative candidates for predicting fall risk. However, research to date is not conclusive on whether and how these measures relate to fall risk. Testing this empirically would be time consuming or may require high risk tripping experiments. Simulation studies therefore provide an important tool to initially explore potential measures to predict fall risk. This study performed simulations with a 3D dynamic walking model to explore if and how dynamic stability measures predict fall risk. The model incorporated a lateral step controller to maintain lateral stability. Neuronal noise of increasing amplitude was added to this controller to manipulate fall risk. Short-term (λ(S)(*)) local instability did predict fall risk, but long-term (λ(L)(*)) local instability and orbital stability (maxFM) did not. Additionally, λ(S)(*) was an early predictor for fall risk as it started increasing before fall risk increased. Therefore, λ(S)(*) could be a very useful tool to identify older adults whose fall risk is about to increase, so they can be enrolled in fall prevention programs before they actually fall.     

Effect of stable and unstable load carriage on walking gait variability,dynamic stability and muscle activity of older adults

Load carriage perturbs the neuromuscular system, which can be impaired due to ageing. The ability to counteract perturbations is an indicator of neuromuscular function but if the response is insufficient the risk of falls will increase. However, it is unknown how load carriage affects older adults. Fourteen older adults (65 ± 6 years) attended a single visit during which they performed 4 min of walking in 3 conditions, unloaded, stable backpack load and unstable backpack load. During each walking trial, 3-dimensional kinematics of the lower limb and trunk movements and electromyographic activity of 6 lower limb muscles were recorded. The local dynamic stability (local divergence exponents), joint angle variability and spatio-temporal variability were determined along with muscle activation magnitudes. Medio-lateral dynamic stability was lower (p = 0.018) and step width (p = 0.019) and step width variability (p = 0.015) were greater in unstable load walking and step width variability was greater in stable load walking (p = 0.009) compared to unloaded walking. However, there was no effect on joint angle variability. Unstable load carriage increased activity of the Rectus Femoris (p = 0.001) and Soleus (p = 0.043) and stable load carriage increased Rectus Femoris activity (p = 0.006). These results suggest that loaded walking alters the gait of older adults and that unstable load carriage reduces dynamic stability compared to unloaded walking. This can potentially increase the risk of falls, but also offers the potential to use unstable loads as part of fall prevention programmes.     

Intervenciones para reducir los riesgos multifactoriales de caídas

This article provides an overview of common intervention strategies used to prevent falls and fall-related injuries in older people. Fall incidence increases with age and causes a tremendous amount of morbidity, mortality, and use of healthcare services. Major risk factors for falling are diverse, and many of them —such as balance impairment, unsteady gait, muscle weakness, drug side effects, and environmental hazards— are potentially modifiable. Medical assessment of fall risks and provision of appropriate interventions is challenging due to the complex nature of falls. Consensus panels of experts have developed evidence-based practice guidelines for fall prevention and management. Numerous fall prevention strategies have been studied, and there is considerable evidence to suggest that certain types of fall prevention strategies are more effective than others. Findings from individual studies have been substantiated by careful meta-analysis of large numbers of controlled clinical trials. These meta-analyses have concluded that the most effective (and cost-effective) fall reduction programs involve systematic fall risk assessment and targeted interventions, exercise programs, and environmental inspection and hazard reduction programs. One large recent meta-analysis showed that interventions using multidimensional risk assessment and risk reduction lowered the risk of falling by 18%, while exercise reduced the risk of falls by 12%. Home modification was effective when incorporated into a multi-factorial intervention, targeted to fall-prone individuals. These findings indicate that the most promising approaches to fall prevention will involve interdisciplinary collaboration in assessment and interventions.     

Dynamic stability of passive dynamic walking on an irregular surface

Falls that occur during walking are a significant health problem. One of the greatest impediments to solve this problem is that there is no single obviously "correct" way to quantify walking stability. While many people use variability as a proxy for stability, measures of variability do not quantify how the locomotor system responds to perturbations. The purpose of this study was to determine how changes in walking surface variability affect changes in both locomotor variability and stability. We modified an irreducibly simple model of walking to apply random perturbations that simulated walking over an irregular surface. Because the model's global basin of attraction remained fixed, increasing the amplitude of the applied perturbations directly increased the risk of falling in the model. We generated ten simulations of 300 consecutive strides of walking at each of six perturbation amplitudes ranging from zero (i.e., a smooth continuous surface) up to the maximum level the model could tolerate without falling over. Orbital stability defines how a system responds to small (i.e., "local") perturbations from one cycle to the next and was quantified by calculating the maximum Floquet multipliers for the model. Local stability defines how a system responds to similar perturbations in real time and was quantified by calculating short-term and long-term local exponential rates of divergence for the model. As perturbation amplitudes increased, no changes were seen in orbital stability (r(2)=2.43%; p=0.280) or long-term local instability (r(2)=1.0%; p=0.441). These measures essentially reflected the fact that the model never actually "fell" during any of our simulations. Conversely, the variability of the walker's kinematics increased exponentially (r(2)>or=99.6%; p<0.001) and short-term local instability increased linearly (r(2)=88.1%; p<0.001). These measures thus predicted the increased risk of falling exhibited by the model. For all simulated conditions, the walker remained orbitally stable, while exhibiting substantial local instability. This was because very small initial perturbations diverged away from the limit cycle, while larger initial perturbations converged toward the limit cycle. These results provide insight into how these different proposed measures of walking stability are related to each other and to risk of falling.     

Can stability really predict an impending slip-related fall among older adults?

The primary purpose of this study was to systematically evaluate and compare the predictive power of falls for a battery of stability indices, obtained during normal walking among community-dwelling older adults. One hundred and eighty seven community-dwelling older adults participated in the study. After walking regularly for 20 strides on a walkway, participants were subjected to an unannounced slip during gait under the protection of a safety harness. Full body kinematics and kinetics were monitored during walking using a motion capture system synchronized with force plates. Stability variables, including feasible-stability-region measurement, margin of stability, the maximum Floquet multiplier, the Lyapunov exponents (short- and long-term), and the variability of gait parameters (including the step length, step width, and step time), were calculated for each subject. Sensitivity of predicting slip outcome (fall vs. recovery) was examined for each stability variable using logistic regression. Results showed that the feasible-stability-region measurement predicted fall incidence among these subjects with the highest sensitivity (68.4%). Except for the step width (with an sensitivity of 60.2%), no other stability variables could differentiate fallers from those who did not fall for the sample included in this study. The findings from the present study could provide guidance to identify individuals at increased risk of falling using the feasible-stability-region measurement or variability of the step width.     

Effects of walking speed, strength and range of motion on gait stability in healthy older adults

Falls pose a tremendous risk to those over 65 and most falls occur during locomotion. Older adults commonly walk slower, which many believe helps improve walking stability. While increased gait variability predicts future fall risk, increased variability is also caused by walking slower. Thus, we need to better understand how differences in age and walking speed independently affect dynamic stability during walking. We investigated if older adults improved their dynamic stability by walking slower, and how leg strength and flexibility (passive range of motion (ROM)) affected this relationship. Eighteen active healthy older and 17 healthy younger adults walked on a treadmill for 5min each at each of 5 speeds (80-120% of preferred). Local divergence exponents and maximum Floquet multipliers (FM) were calculated to quantify each subject's inherent local dynamic stability. The older subjects walked with the same preferred walking speeds as the younger subjects (p=0.860). However, these older adults still exhibited greater local divergence exponents (p<0.0001) and higher maximum FM (p<0.007) than the younger adults at all walking speeds. These older adults remained more locally unstable (p<0.04) even after adjusting for declines in both strength and ROM. In both age groups, local divergence exponents decreased at slower speeds and increased at faster speeds (p<0.0001). Maximum FM showed similar changes with speed (p<0.02). Both younger and older adults exhibited decreased instability by walking slower, in spite of increased variability. These increases in dynamic instability might be more sensitive indicators of future fall risk than changes in gait variability.     

Disturbance type and gait speed affect fall direction and impact location

Since falling to the side and impacting on or near the hip increase hip fracture risk, we examined the fall direction and pelvis impact location resulting from four disturbances (faint, slip, step down, trip) at three gait speeds (fast, normal, slow) in 14 young adults instructed not to attempt recovery. We hypothesized that certain disturbances such as faints and slips and slow walking speed were more likely to result in an impact on the hip. For each trial, the fall direction, impact location and pelvis impact velocity were measured. The results showed that both disturbance type and gait speed significantly affected fall direction and impact location (analysis of covariance with repeated measures, p< or =0.0001) with a significant interaction (p<0.05). Trips and steps down usually resulted in forward falls, with frontal impacts regardless of gait speed. At fast gait speed, slips and faints also usually resulted in forward falls, with frontal impacts. As gait speed decreased, however, slips usually resulted in sideways or backward falls, with impact on the hip or buttocks, and faints resulted in a greater number of sideways falls, with impact near the hip. Therefore, compared to other disturbances and gait speeds, slipping or fainting while walking slowly was more likely to result in an impact on the hip, suggesting a greater risk for hip fracture. Furthermore, 56% of the impact velocities generated were within one standard deviation of the estimate of the mean impact velocity needed to fracture an elderly femur.     

The amplitude sensitivity of mouse inferior collicular neurons in the presence of weak noise

Natural auditory environment consists of multiple sound sources that are embedded in ambient strong and weak noise. For effective sound communication and signal analysis, animals must somehow extract biologically relevant signals from the inevitable interference of ambient noise. The present study examined how a weak noise may affect the amplitude sensitivity of neurons in the mouse central nucleus of the inferior colliculus (IC) which receives convergent excitatory and inhibitory inputs from both lower and higher auditory centers. Specifically, we studied the amplitude sensitivity of IC neurons using a probe (best frequency pulse) and a masker (weak noise) under simultaneous masking paradigm. For most IC neurons, weak noise masking increases the minimum threshold and decreases the number of impulses. Noise masking also increased the slope and decreased the dynamic range of the rate amplitude function of these IC neurons. The strength of this noise masking was greater at low than at high sound amplitudes. This variation in the amplitude sensitivity of IC neurons in the presence of the weak noise was mostly mediated through GABAergic inhibition. These data indicate that in the real world the ambient weak noise improves amplitude sensitivity of IC neurons through GABAergic inhibition while inevitably decreases the range of overall auditory sensitivity of IC neurons.     

The effects of time pressure and experience on the performance of fall techniques during a fall

Although the practice of fall techniques has been introduced in fall prevention programs, it is not clear whether people can apply acquired techniques during a real-life fall. It would be helpful to know the time it takes to initiate and to successfully execute such techniques, as well as the effect of experience on the execution of these techniques. In this study we investigated the neuromuscular control of voluntary fall techniques in five seasoned judokas and nine non-judokas. After they had started falling from a kneeling position, they received an auditory cue prompting either a lateral natural fall arrest (block) or a martial arts (MA) fall. EMG data of shoulder and trunk muscles were collected. The requested technique was successfully applied in 85% of the falls. Following the cue, EMG amplitudes of the fall techniques started to diverge after 180-190 ms. EMG amplitudes were generally similar in both groups, but experience-related differences could be demonstrated in the pectoralis and trapezius. In conclusion, voluntary motor control is possible within the duration of a fall, even in inexperienced fallers. Differences in EMG activity might suggest that experienced fallers changed their reaction to possible falls from a preparation for arm abduction into a preparation for trunk rotation.     

Relationships between amplitudes and kinetics of rapid cytosolic free calcium fluctuations in GH4C1 rat pituitary cells: roles for diffusion and calcium-induced calcium release.

We have examined statistical relationships between the amplitudes and the kinetics (rise times, fall times, and decay constants) of cytosolic free calcium fluctuations (spikes) in a population of 353 individual GH4C1 rat pituitary cells. The fast falling phase was approximated by a single exponential decay, and the decay time constant, tau, increased linearly with spike amplitude in 80% of the cells studied. The slope of the tau versus amplitude plot for each cell was inversely related to the cell's mean spike amplitude. Thus, some process responsible for prolonging the decay phase of spikes appeared to operate strongly in cells with spikes of low amplitude, but to become less prominent in cells with high amplitude spikes. Mean tau correlated more strongly with mean rise and fall times than with mean spike amplitude, indicating that the kinetic properties of spikes were not tightly coupled to spike amplitude. These findings are consistent with a model wherein the rise phase corresponds to entry of extracellular calcium via L-type calcium channels into localized sub-plasmalemmal domains, followed by diffusion of subplasmalemmal calcium into the cell interior; and the falling phase corresponds to further calcium diffusion combined with activation of cytoplasmic calcium-induced calcium release, which prolongs the falling phase.     

The validity of stability measures: A modelling approach

Measures calculated from unperturbed walking patterns, such as variability measures and maximum Floquet multipliers, are often used to study the stability of walking. However, it is unknown if, and to what extent, these measures correlate to the probability of falling.We studied whether in a simple model of human walking, i.e., a passive dynamic walker, the probability of falling could be predicted from maximum Floquet multipliers, kinematic state variability, and step time variability. We used an extended version of the basic passive dynamic walker with arced feet and a hip spring. The probability of falling was manipulated by varying the foot radius and hip spring stiffness, or varying these factors while co-varying the slope to keep step length constant.The simulation data indicated that Floquet multipliers and kinematic state variability correlated inconsistently with probability of falling. Step time variability correlated well with probability of falling, but a more consistent correlation with the probability of falling was found by calculating the variability of the log transform of the step time. Our findings speak against the use of maximum Floquet multipliers and suggest instead that variability of critical variables may be a good predictor of the probability to fall.     

The effects of gait strategy on metabolic rate and indicators of stability during downhill walking

When walking at a given speed, humans often appear to prefer gait patterns that minimize metabolic rate, thereby maximizing metabolic economy. However, recent experiments have demonstrated that humans do not maximize economy when walking downhill. The purpose of this study was to investigate whether this non-metabolically optimal behavior is the result of a trade-off between metabolic economy and gait stability. We hypothesized that humans have the ability to modulate their gait strategy to increase either metabolic economy or stability, but that increase in one measure will be accompanied by decrease in the other. Subjects walked downhill using gait strategies ranging from risky to conservative, which were either prescribed by verbal instructions or induced by the threat of perturbations. We quantified spatiotemporal gait characteristics, metabolic rate and several indicators of stability previously associated with fall risk: stride period variability; step width variability; Lyapunov exponents; Floquet multipliers; and stride period fractal index. When subjects walked using conservative gait strategies, stride periods and lengths decreased, metabolic rate increased, and anteroposterior maximum Lyapunov exponents increased, which has previously been interpreted as an indicator of decreased stability. These results do not provide clear support for the proposed trade-off between economy and stability, particularly when stability is approximated using complex metrics. However, several gait pattern changes previously linked to increased fall risk were observed when our healthy subjects walked with a conservative strategy, suggesting that these changes may be a response to, rather than a cause of, increased fall risk.     

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.     

Dynamic balance in persons with multiple sclerosis who have a falls history is altered compared to non-fallers and to healthy controls

Around 60% of persons with multiple sclerosis (MS) experience falls, however the dynamic balance differences between those who fall and those who don’t are not well understood. The purpose of this study is to identify distinct biomechanical features of dynamic balance during gait that are different between fallers with MS, non-fallers with MS, and healthy controls. 27 recurrent fallers with MS, 28 persons with MS with no falls history, and 27 healthy controls walked on a treadmill at their preferred speed for 3 min. The variability of trunk accelerations and the average and variability of minimum toe clearance, spatiotemporal parameters, and margin of stability were compared between groups. Fallers with MS exhibited a slower cautious gait compared to non-fallers and healthy controls, but had decreased anterior-posterior margin of stability and minimum toe clearance. Fallers walked with less locally stable and predictable trunk accelerations, and increased variability of step length, stride time, and both anterior-posterior and mediolateral margin of stability compared to non-fallers and healthy controls. The present work provides evidence that within a group of persons with MS, there are gait differences that are influenced by falls history. These differences indicate that in persons with MS who fall, the center of mass is poorly controlled through base of support placement and the foot is closer to the ground during swing phase relative to the non-fallers. These identified biomechanical differences could be used to evaluate dynamic balance in persons with MS and to help improve fall prevention strategies.     

Non-linear biological responses to environmental noise affect population extinction risk

Non-linearities are commonly observed in the responses of organisms to environment. They potentially modify the qualitative and quantitative properties of population dynamics. We studied how non-linear responses to environment, or "noise filters", influence population variability and extinction risk by introducing coloured noise to the growth rate in the Hassell single-species model. The consequences of noise filtering were analysed by comparing the model dynamics with linearly filtered and non-linearly filtered noise that have the same mean. Three biologically plausible filters we used: saturating, unimodal optimum type, and sigmoid responses.
Filtering can either decrease or increase population variability when compared to linear noise response. The effect of noise filtering on variability is most pronounced with stable population dynamics and the outcome depends on the filter type, population growth rate, and noise colour.
Non-linear noise filtering predominantly increases extinction risks when population growth rate is low (R<5). As an exception, saturating filter has a window of decreased risk at very low growth rate and reddened environment. In the unstable range of the dynamics (15These results suggest that accounting for the non-linear responses to environment should be considered when estimating extinction risks and population variability. Moreover, the non-linear responses make noise colour a more important factor in these analyses.     

Prediction of Falls and/or Near Falls in People with Mild Parkinson’s Disease

Objective

To determine factors associated with future falls and/or near falls in people with mild PD.

Methods

The study included 141 participants with PD. Mean (SD) age and PD-duration were 68 (9.7) and 4 years (3.9), respectively. Their median (q1–q3) UPDRS III score was 13 (8-18). Those >80 years of age, requiring support in standing or unable to understand instructions were excluded. Self-administered questionnaires targeted freezing of gait, turning hesitations, walking difficulties in daily life, fatigue, fear of falling, independence in activities of daily living, dyskinesia, demographics, falls/near falls history, balance problems while dual tasking and pain. Clinical assessments addressed functional balance performance, retropulsion, comfortable gait speed, motor symptoms and cognition. All falls and near falls were subsequently registered in a diary during a six-month period. Risk factors for prospective falls and/or near falls were determined using logistic regression.

Results

Sixty-three participants (45%) experienced ≥1 fall and/or near fall. Three factors were independent predictors of falls and/or near falls: fear of falling (OR = 1.032, p<0.001) history of near falls (OR = 3.475, p = 0.009) and retropulsion (OR = 2.813, p = 0.035). The strongest contributing factor was fear of falling, followed by a history of near falls and retropulsion.

Conclusions

Fear of falling seems to be an important issue to address already in mild PD as well as asking about prior near falls.     

Understanding the Relationship between Type 2 Diabetes Mellitus and Falls in Older Adults: A Prospective Cohort Study

Background

Older adults with type 2 Diabetes Mellitus are at increased risk of falling. The current study aims to identify risk factors that mediate the relationship between diabetes and falls.

Methods

199 older adults (104 with diabetes and 95 healthy controls) underwent a medical screening. Gait (GAITRite®), balance (AccuGait® force plate), grip strength (Jamar®), and cognitive status (Mini-Mental State Examination and Clock Drawing Test) were assessed. Falls were prospectively recorded during a 12-month follow-up period using monthly calendars.

Results

Compared to controls, diabetes participants scored worse on all physical and cognitive measures. Sixty-four participants (42 diabetes vs. 22 controls) reported at least one injurious fall or two non-injurious falls (“fallers”). Univariate logistic regression identified diabetes as a risk factor for future falls (Odds Ratio 2.25, 95%CI 1.21–4.15, p = 0.010). Stepwise multiple regressions defined diabetes and poor balance as independent risk factors for falling. Taking more medications, slower walking speed, shorter stride length and poor cognitive performance were mediators that reduced the Odds Ratio of the relationship between diabetes and faller status relationship the most followed by reduced grip strength and increased stride length variability.

Conclusions

Diabetes is a major risk factor for falling, even after controlling for poor balance. Taking more medications, poorer walking performance and reduced cognitive functioning were mediators of the relationship between diabetes and falls. Tailored preventive programs including systematic medication reviews, specific balance exercises and cognitive training might be beneficial in reducing fall risk in older adults suffering from diabetes.     

Active responses decrease impact forces at the hip and shoulder in falls to the side.

Active responses, such as using the arm to break the fall, may be an effective means of decreasing likelihood of injury in a fall and may help explain why only a small percentage of falls result in a fracture. We quantified the impact force at the hip and shoulder in falls to the side from a kneeling position under three conditions: (1) attempting to break the fall by using an arm; (2) falling with the body relaxed; and (3) falling with the body tensed. Subjects fell from a kneeling position onto a force platform array covered with foam padding and impact force data were recorded. The ground reaction force-time curve was generally bimodal due to sequential impacts of the hip and shoulder. Impact forces at the hip and shoulder were 12 and 16% less for the slap condition (p < 0.05) than for the tensed condition. The impact forces for the relaxed and tensed conditions were not significantly different, although impact forces tended to be less in the relaxed condition. We concluded that active responses reduce the impact forces experienced at the hip and shoulder in falls to the side. Decreased effectiveness of protective responses, due to increases in reaction time and decreases in strength with age, may help explain why so many hip fractures occur in the elderly but so few occur in younger people.     

Falls in People with Multiple Sclerosis Compared with Falls in Healthy Controls

Objective

To compare the risk, circumstances, consequences and causes of prospectively recorded falls between people with multiple sclerosis (PwMS) and healthy controls of similar age and gender.

Methods

58 PwMS and 58 healthy controls, who are community-dwelling, were recruited in this 6-month prospective cohort study. 90% of PwMS and 84% of healthy controls completed the study. Participants counted falls prospectively using fall calendars and noted fall location, fall-related injuries, and the cause of the falls. Kaplan Meier survival analysis and log-rank tests were performed to compare the distributions of survival without falling between PwMS and healthy controls.

Results

40.8% of controls and 71.2% of PwMS fell at least once. 48.1% of PwMS and 18.4% of healthy controls fell at least twice. 42.3% of PwMS and 20.4% of health controls sustained a fall-related injury. After adjusting for age and gender, the time to first fall (HR: 1.87, p = 0.033) and the time to recurrent falls (HR: 2.87, p = 0.0082) were significantly different between PwMS and healthy controls. PwMS reported an almost equal number of falls inside and outside, 86% of the falls in healthy controls were outside. Healthy controls were more likely to fall due to slipping on a slippery surface (39.5% vs 10.4%). PwMS more often attributed falls to distraction (31% vs 7%) and uniquely attributed falls to fatigue or heat.

Conclusions

Fall risk, circumstances, consequences, and causes are different for PwMS than for healthy people of the same age and gender. PwMS fall more, are more likely to be injured by a fall, and often fall indoors. PwMS, but not healthy controls, frequently fall because they are distracted, fatigued or hot.