By Susan Coote, PhD; Laura Comber, PhD; Gillian Quinn, PhD; Carme Santoyo-Medina, MSc; Alon Kalron, PhD, PT; Hilary Gunn, PhD
Falls are highly prevalent in people with multiple sclerosis (MS) and result in a range of negative consequences, such as injury, activity curtailment, reduced quality of life, and increased need for care and time off work. This narrative review aims to summarize key literature and to discuss future work needed in the area of fall prevention for people with MS. The incidence of falls in people with MS is estimated to be more than 50%, similar to that in adults older than 80 years. The consequences of falls are considerable because rate of injury is high, and fear of falling and low self-efficacy are significant problems that lead to activity curtailment. A wide range of physiological, personal, and environmental factors have been highlighted as potential risk factors and predictors of falls. Falls are individual and multifactorial, and, hence, approaches to interventions will likely need to adopt a multifactorial approach. However, the literature to date has largely focused on exercise-based interventions, with newer, more comprehensive interventions that use both education and exercise showing promising results. Several gaps in knowledge of falls in MS remain, in particular the lack of standardized definitions and outcome measures, to enable data pooling and comparison. Moving forward, the involvement of people with MS in the design and evaluation of programs is essential, as are approaches to intervention development that consider implementation from the outset.
Int J MS Care. 2020;22:247-255.
The incidence of falls in people with multiple sclerosis (MS) is high, and the consequences of falls are far-reaching for both the person and the health care system. This important topic has received increasing attention as researchers and health care professionals aim to identify the risk factors, context, and consequences and to use these data to develop theory-based interventions. This narrative review and position paper is written by members of the Special Interest Group on Mobility of Rehabilitation in Multiple Sclerosis (RIMS, the European network for best practice and research in MS) and aims to summarize the key literature in the area and to identify gaps in knowledge, challenges, and ways forward.
Incidence of Falls
Falls are common in people with MS, with a large international data set demonstrating that 56% fall at least once within a 3-month period, with 37% of individuals categorized as frequent fallers. Notably, people with MS fall more frequently, are more likely to experience injurious falls, and have different fall circumstances compared with their healthy peers. Over a 6-month study period, 71% of people with MS reported falling versus 41% of healthy controls, with the MS group more likely to attribute their falls to tripping and distraction. Fall rates in people with MS are similar to those in community-dwelling stroke survivors (55%), adults older than 80 years (50%), and people with Parkinson disease (46%).
Interestingly, there is a nonlinear association between falls and level of neurologic disability, with peaks in fall incidence occurring at Expanded Disability Status Scale (EDSS) scores 4.0 and 6.0, with the highest rate of recurrent falls occurring in those who do not yet use a mobility device. Falls are not limited to people with MS who are ambulatory, and although there is less research evaluating falls in people with more advanced MS, studies show that wheelchair and scooter users also have a high incidence of falls (75%). People with progressive MS have a higher incidence of falls,1 and falls have been proposed as a critical incident that signifies a worsening of symptoms that requires clinical attention. Those restricting their activity and avoiding risky behaviors may have a lower fall rate, but this practice is not without consequences and is not a solution to fall prevention.
A key consideration regarding the prevalence and incidence of falls is the way in which fall data are collected. There is a notable underestimation of number of falls by people with MS. Dibble et al found that 6-month recall was 17% accurate, and 63% of responders underestimated the number of falls they had. This underestimation when retrospective recall is used is confirmed by Nilsagård et al, who found that using retrospective recall, 34% were fallers, but using prospective diaries, 63% were. This consistent underestimation of number of falls when using retrospective recall led to recommendations that fall data be collected prospectively using diary-based methods. However, the poor correlation between diary and electronic fall logging with a button push suggests that a truly objective method of fall recording is required to advance this field.
The definition of a faller is inconsistent in MS fall research. The number of falls needed to classify a person with MS as a faller range from one or more falls, to two or more falls, to three or more falls. Likewise, a wide range of fall definitions are used, including “unexpected event that results in the person ending up on the ground, floor, or any lower surface;” “unintentionally coming to the ground or other lower level and other than as a consequence of sustaining a violent blow, loss of consciousness, or sudden onset of paralysis as in stroke or epileptic seizure;” or “any unexpected loss of balance that resulted in whole body contact with the ground.” Some studies fail to define a fall. This heterogeneity in both fall definition and classification limits comparison between studies and data pooling. One potential way to overcome these discrepancies in faller classifications used is to report fall data as fall rate per person year. Fall rate per person-year can be calculated using the following formula: [fall rate = (total number of falls/total number of person-days [all participants]) × 365].
Consequences of Falls
Falls can have significant physical, social, and psychological consequences for the individual. In terms of physical impact, injurious falls in people with MS are common, with rates of 0.18 to 0.23 per person per year. Most fall-related injuries are relatively minor, for example, sprains and contusions; however, the risk of serious injury is pervasive, with head injuries and fractures also reported by people with MS who have fallen. A threefold higher risk of hip fracture than age- and sex-matched peers, with greater risk in those prescribed corticosteroids in the previous 6 months, was reported in a population-based cohort. Injurious falls contribute to the high socioeconomic cost associated with MS as a result of increased health care use and decreased labor force productivity. These high rates of injurious falls (42%-58%) are much greater than rates of 23% to 30% seen in the elderly, and after stroke, where rates of 10% have been reported.
The psychological impact of falls presents predominantly as a high level of fear of falling and associated activity modification in both those who have and those who have not experienced an actual fall. Fear of falling has multiple definitions that reflect a multidimensional construct with physiological, cognitive, and behavioral components. Based on a cross-sectional study, people with MS with elevated fear of falling are less likely to participate in leisure-time physical activities. This behavior might be explained as a protective mechanism. However, this protective response may result in some people with MS curtailing their activities inappropriately, resulting in further deconditioning and adversely affecting physical function and independence. This adverse response should be avoided, especially due to the growing body of evidence highlighting the benefits of regular physical activity for people with MS. Most concerning is that studies have consistently found that fallers have lower quality of life than nonfallers. Lower quality of life is associated with higher socioeconomic costs and contributes significantly to the intangible costs and burden for the person with MS related to issues around self-care, pain, anxiety, and depression. Nilsagård et al qualitatively explored the context and impact of accidental falls in people with MS, with participants describing falls as limiting, restricting, and embarrassing.
Factors Associated with and Predictive of Falls
Understanding the factors associated with and predictive of falls can assist in the development of interventions and also identify those in need of treatment. There are many varied fall risk factors highlighted in the literature, confirming the complexity and individual nature of fall prevention. Broadly, fall risk can be considered in terms of physiological, personal, and behavioral risk factors.
The most frequently reported physiological risk is impaired balance. Two meta-analyses that considered data from cross-sectional and prospective studies confirmed that balance is a risk factor for falls. In addition, other indicators of reduced postural control, such as reduced walking speed, increased static postural sway while standing, and the use of a mobility aid, were also identified as fall risk factors in those reviews. These findings are accompanied by prospective cohort studies in which reduced lower-limb strength, reactive stepping,18 and dual-task ability were identified as risk factors for falls. Worth noting, although visual problems are often one of the first symptoms noticed by people with MS and good vision is essential for maintaining balance control, testing of known visual risk factors in other groups (such as edge contrast sensitivity) is not considered a predictor of falls in people with MS. It is possible that other aspects of vision could be an issue for people with MS, but most risk factor studies in MS to date have not included specific visual tests. Nevertheless, visual function is integrated into the EDSS score and traditional balance tests such as the Berg Balance Scale and the Physiological Profile Assessment (PPA). A prospective study with 100 participants found that not having a visual problem (via self-report) was associated with a greater fall risk. This finding may indicate that those with visual problems are inherently more cautious and have a resulting lower risk of falls.
Although balance is impaired in MS fallers, a recent review found that clinical balance measures in isolation are poor at identifying future fallers. This finding suggests that other factors are also important when identifying those at risk of falling and when designing treatments for preventing falls. Other MS symptoms related to falls include fatigue, cognitive impairment, spasticity, and urinary incontinence, although, again, the relationship may not be linear in nature. Similar to the literature in elderly populations, medications, in terms of quantity and class, are associated with higher fall rates in most studies published on this topic. During the past decade, a variety of disease-modifying drugs have been introduced in MS. The challenge is to examine whether immunomodulatory drugs differ when examining falls in the MS community. This issue was partly addressed by Comber et al, who investigated the effect of medication use on falls in MS. They reported increased odds of being a faller for participants taking medications categorized as genitourinary and sex hormones or centrally acting muscle relaxant medications.
When considering personal factors associated with and predictive of falls, reduced balance confidence and reduced fall self-efficacy have been shown to be predictive of future falls in people with MS, with concerns about falling being associated with changes in postural control in fallers. Other personal factors that have also been highlighted as contributing factors for falls in MS are unrealistic appraisal of ability, poor organization/planning of activities, adjustment/ replacement of activities, and emotional adaption through awareness and acceptance of limitations. Gunn et al examined physiological risk and perceived risk in 416 people with MS and found that approximately 50% of individuals had disparities between their physiological risk (using the PPA) and perceptual risk (using the Falls Efficacy Scale [international]) of falls, with most having a perceived risk greater than their physiological risk. It is hypothesized that those with excessive perceptual risk may be at increased likelihood of fear of falling and associated activity curtailment, whereas those with excessive physiological risk may engage in risk-taking behaviors through an unrealistic appraisal of ability.
Understanding the environmental context of falls will improve management of falls in MS. Studies suggest that falls most often occur inside the home, in the morning or afternoon, and during general mobility without the execution of any other specific task. It is likely that the circumstances associated with falls differ among those who are ambulant or wheelchair users, with one study suggesting that most falls occur during transfers for wheelchair users.
An additional method to uncover risk factors for falls in MS is to ask individuals what they attribute their falls to. According to Matsuda et al, people with MS attribute their falls to trips/slips, fatigue, failing to use an assistive device when needed, rushing, and not paying attention. Similarly, Peterson et al found that poor balance, lower-extremity malfunction, and use of assistive devices were the leading causes of falls. More recently, Gunn et al reported that one-third of falls were associated with feeling fatigued and/or loss of balance, with tripping, legs giving way, and being distracted each accounting for 10% of falls.
About the Consortium of MS Centers
The mission of the CMSC is to develop and sustain successful models of care to address the disease spectrum of multiple sclerosis (MS). The group seeks to stimulate and facilitate research in the field of MS and develop mechanisms with which to share information and knowledge among MS practitioners and all those affected by MS. To learn more, visit mscare.org.
Although cognitive impairment in isolation has been identified as an independent risk, difficulty with dual tasking has also been shown to be associated with falls in people with MS. Those who prioritize cognitive tasks over walking are at greater risk of falling,64 which similarly has been found in other populations, resulting in strategies such as balance first or slow down and concentrate.
The proliferation of factors associated with and predictive of falling has led to several authors investigating multivariate risk prediction models using prospective study designs to identify those at future risk of falls, and hence treatment. Models included simple clinical variables such as the EDSS score, Ashworth score, and fine motor control assessed using the Nine-Hole Peg Test. Some of these models require instrumented tools such as gait analysis devices, strength assessment using the Biodex Multipoint System, and the PPA. Regarding clinical utility, these fall risk prediction models have varying levels of sensitivity (69%-71%) and specificity (70%-88%), with 80% sensitivity regarded as an important cutoff level for fall screening tools. Only two studies included the area under the receiver operating characteristic curve, reporting values of 0.7119 and 0.73,16 suggesting moderate and acceptable levels of discriminative ability because the values are greater than 0.7. Despite these many well-designed multivariable studies, Cameron et al advocate identifying those at risk of future falls by simply asking about fall history. A fall in the past year was the best predictor of falls or injurious falls in the following 6 months. However, limitations of this approach are that 1) predicting future falls based on previous falls requires the person to fall at least once (and, therefore, experience the negative consequences associated with this) and 2) people with MS with memory deficits might not report accurately. Asking a simple question also relates to the recent emphasis on patient-reported outcomes, with a previous study demonstrating that self-report measures have higher levels of discriminative ability than performance-based measures, although they did not report corresponding measures of clinical utility.
Mazumder et al identified contextual differences in falls between middle-aged people with MS and controls. The authors found that healthy adults most often fall outdoors, whereas people with MS showed a higher rate of indoor falls. In addition, healthy adults were more likely to report falls due to a slippery surface, whereas people with MS were more likely to report falls due to a distraction or tripping, fatigue, or excess heat. This finding suggests that when fall prevention programs for people with MS are designed the unique risk factors for falling in this cohort need to be addressed.
Part II of this article will include a discussion of Treatment, Gaps in Knowledge, Challenges, and Conclusions and Way Forward. Part II will appear next month.
Editor’s Note: This article, which is in 2 parts, appears with permission from the Consortium of Multiple Sclerosis Centers; references have been deleted for brevity, but can be found with the original article at the URL below. Part II will appear next month. The original article, “Falls in People with Multiple Sclerosis: Risk Identification, Intervention, and Future Directions,” by the same authors, appeared in the International Journal of MS Care. 2020;22:247-255, available at https://meridian.allenpress.com/ijmsc/article/22/6/247/443994/Falls-in-People-with-Multiple-SclerosisRisk. LER is pleased to partner with the CMSC to bring this important information to our readers.