Elsevier

Archives of Gerontology and Geriatrics

Volume 38, Issue 1, January–February 2004, Pages 11-26
Archives of Gerontology and Geriatrics

Predicting falls within the elderly community: comparison of postural sway, reaction time, the Berg balance scale and the Activities-specific Balance Confidence (ABC) scale for comparing fallers and non-fallers

https://doi.org/10.1016/S0167-4943(03)00082-7Get rights and content

Abstract

Simple reaction time, the Berg balance scale, the Activities-specific Balance Confidence (ABC) scale and postural sway were studied in order to determine cut-off scores as well as develop a model used in the prevention of fallers within the elderly community. One hundred and twenty-five subjects, 45 fallers and 80 non-fallers were evaluated throughout the study and results indicated that non-fallers have significantly faster reaction times, have higher scores on the Berg balance scale and the ABC scale as well as sway at slower frequencies when compared to fallers. Furthermore, all risk factors were subsequently entered into a logistic regression analysis and results showed that reaction time, the total Berg score and the total ABC score contributed significantly to the prediction of falls with 89% sensitivity and 96% specificity. A second logistic regression was carried out with the same previous variables as well as all questions of the Berg and ABC scales. Results from the logistic analysis revealed that three variables were associated with fall status with 91% sensitivity and 97% specificity. Results from the following study would seem rather valuable as an assessment tool for health care professionals in the identification and monitoring of potential fallers within nursing homes and throughout the community.

Introduction

Falls present a substantial health problem among the elderly population. Approximately one-third of community-dwelling people over 65 years of age will experience one or more falls each year (Stelmach and Worringham, 1985, Tinetti et al., 1988, Powell and Myers, 1995, Spirduso, 1995, Hausdorff et al., 1997, Shumway-Cook et al., 1997a). Subsequently, the frequency increases to nearly 40% for those individuals over 80 years of age and affects women more than men (Nickens, 1985, Powell and Myers, 1995). Fall related injuries are the leading cause of non-fatal injury. Nearly 40% of falls occurring in the 65 years of age and over population are admitted to the hospital for some type of treatment (Tideiksaar, 1988, Shumway-Cook et al., 1997a). In 15% of the cases, the injuries suffered include fractures, bruises, soft tissue injuries and loss of dependence (Powell and Myers, 1995). Serious injury occurs in 6% of the elderly population, resulting in some instances, in accidental death (Baker et al., 1984, Spirduso, 1995). Approximately 40–50% of fallers admitted to hospitals will be admitted to nursing homes (Tinetti et al., 1988, Shumway-Cook et al., 1997a). Of those who did not suffer serious injury, many may experience significant restrictions in daily activities (Tinetti et al., 1988). As a result, the elderly population develops a fear of falling complex, a decrease in self confidence to accomplish normal activities of daily living and adopt a lifestyle of inactivity resulting in significant muscular atrophy, most noticeable in lower extremity strength (Tinetti, 1987, Maki et al., 1991, Wolfson et al., 1995).

This serious health problem deserves immediate attention due to the fact that human life expectancy has continually been increasing throughout history. In fact, it is in the present century that this increase has shown a dramatic acceleration. In Canada, individuals 65 years and older represented approximately 13% of the population in 2001, and this percentage is expected to increase to nearly 15% by the year 2016 and 19% by the year 2021 (Statistics Canada, 2001). This “graying” effect is also reflective in the population who are aged 75 years and older (Timiras, 1994). This group also represents a fast growing portion of the total population increasing to an estimated 7% by the year 2016 and 8% by the year 2021 (Statistics Canada, 2001). In light of this increase, health care professionals must address several problems occurring within this particular population. One of the most important and common problems is related to falls (Baker et al., 1984).

Many studies have focused on the possible risk factors associated with falling in the elderly population (Nickens, 1985, Tinetti et al., 1988, Campbell et al., 1989, Robbins et al., 1989, O’Loughlin et al., 1993, Myers et al., 1996). Typically, these risk factors are categorized into two distinct groups: intrinsic and extrinsic. Extrinsic factors are a direct result of one’s environment such as improper footwear and unstable living conditions, whereas intrinsic factors consist of those factors related to the physiological changes associated with aging (Tideiksaar, 1997). Throughout the past two decades, many researchers have identified several intrinsic factors that have been found to be rather successful in the prediction of falls. These factors have been identified as medication use (Blake et al., 1988, Spirduso, 1995), loss of balance (Overstall et al., 1977), syncope (Tinetti et al., 1988), postural instability (Overstall et al., 1977, Okuzumi et al., 1996), visual impairment (Okuzumi et al., 1996), neurological disabilities (Morris et al., 1987), muscle weakness (Whipple et al., 1987, Shumway-Cook et al., 1997b), as well as sensorimotor deficiencies (Stelmach and Worringham, 1985).

Balance has been shown to be an important predictor of falls within the elderly population (Berg et al., 1992). It is a component that is needed to accomplish a wide variety of daily living activities such as gardening, reaching for items in a cupboard as well as walking. Throughout the years, several instruments have been developed as a means of quantitatively measuring balance in the elderly population. These screening tools have been instrumental in evaluating the ability to maintain balance and, subsequently, in the identification of those individuals who present a substantial risk of falling in the very near future. In fact, it has been noted that of all the functional tests, the Berg balance scale was, indeed one of the most effective predictors for falls within community-dwelling adults (Shumway-Cook et al., 1997a). However, it has been reported that this tool is not entirely representative in relation to its predictability of completing more complex tasks or activities that are concerned with measuring steady-state postural control as well as anticipatory postural adjustments (Shumway-Cook and Woollacott, 2001).

It has been documented that the ability to maintain balance or a postural task involves additional attentional requirements (Lajoie et al., 1993, Lajoie et al., 1996, Shumway-Cook and Woollacott, 1999, Marsh and Geel, 2000). In fact, the attentional demands are subsequently increased in relation to the complexity of the task at hand. More specifically, it was found that dynamic balance or even the ability to maintain an upright standing position under various perturbations is substantially more attention demanding when compared to a normal sitting condition (Lajoie et al., 1993). It was further demonstrated that reaction times measured during these various attention demanding tasks illustrated higher measures in a broad support stance phase as opposed to a sitting position in a sample of young adults. When the notion of attentional demands was studied on a geriatric population, results showed that healthy elderly subjects displayed significantly slower reaction times in a narrow base support standing position when compared to the younger experimental group (Lajoie et al., 1996). These results would imply that additional attentional resources are required by the elderly population in order to maintain balance or an upright posture. It would be interesting to investigate if any significant differences would arise in a geriatric population who has a previous history of falling and those individuals who have not experienced a fall.

Psychological factors, more commonly referred to the “fear of falling syndrome”, have been linked to significant reductions of daily activities in fallers resulting in a loss of independence (Maki et al., 1991). Interestingly enough, this fear of falling has been observed in healthy subjects as well as those individuals who have a previous fall history (Silverton and Tideiksaar, 1989). As a result, this functional tool would present rather confounding results when used as an independent measure of fall status.

Reaction time has been studied extensively throughout the literature and this entity is defined as the length of time measured between the presentation of an unexpected stimulus and the onset of a response to that stimulus (Schmidt, 1993). Research within this area has shown that reaction time responses increase as one ages (Pierson and Montoye, 1958, Clarkson, 1978, Loveless, 1980, Gottsdanker, 1982). In fact, it has been stated that reaction time was one of the most sensitive markers of structural and functional deterioration in the aging central nervous system (Birren et al., 1980). This is a rather interesting factor because it has been hypothesized that the aged lose the ability to process relevant information when compared to younger subjects (Haywood, 1993). Based on the foundation of the “information loss model”, it is believed that both young and old subjects alike process and respond to external stimuli in a sequential order of steps, with each step lasting a precise amount of time and dependent upon the inverse relationship of the information available in the subject’s environment. This would suggest that if very little information were available, the amount of time to process through each step would increase, whereas if more information were available the process would be significantly shorter. As a result, older adults would ultimately spend more time during each step when compared to younger subjects (Myerson et al., 1990). This increase is even more noticeable when tasks become more attention demanding (Jordan and Rabbitt, 1977, Stelmach and Worringham, 1985). In light of this evidence, it would seem fitting to study this parameter as a function of falls due to the fact that seniors must process many attention demanding factors when faced with the possibility of preventing a fall. By combining this factor with other well documented functional measures, namely the Berg balance scale, the ABC scale, as well as postural sway, we believe to be focusing on the three entities that make up postural control; steady-state reactive and steady-state anticipatory responses (Shumway-Cook and Woollacott, 2001).

The purpose of the present study is to evaluate reaction time, the Berg balance scale, the Activities-specific Balance Confidence (ABC) scale (Powell and Myers, 1995), as well as postural sway and to determine an effective model with the underlying purpose of predicting falls in community-dwelling older adults. In addition, we would like to produce important cut-off scores with regards to the aforementioned variables in order to provide health care professionals with a valuable tool allowing them to successfully monitor fall status for the aged in the community and in senior residences.

Section snippets

Subjects

One hundred and twenty-five subjects were tested during the course of this study after giving informed consent. Table 1 illustrates the descriptive statistics with regards to our study population.

The subject pool was subsequently divided into two groups one of which consisted of 45 subjects and was categorized as fallers while the other group consisted of 80 non-fallers. All participants were selected within the Sudbury community, the local Young Men’s Christian Association (YMCA), nursing

Attentional demands

The mean and standard deviations of simple reaction time for healthy elderly and fallers are presented in Fig. 1. A one-way analysis of variance revealed a significant (Group) difference (F(1,123)=156, P<0.01). These results would seem to indicate that the healthy elderly group displayed significantly faster reaction times than the faller experimental group.

Postural sway

The mean and standard deviations of postural sway frequency modes for healthy elderly and fallers are presented in Fig. 2. Postural

Discussion

The main purpose of this study was to evaluate the several risk factors linked to the phenomenon of falling and to produce a predictive model in the hope of correctly identifying those individuals susceptible to falling. Several risk factors were evaluated as possible contributors to fall incidence in the elderly population. The risk factors included were the Berg balance scale, the Activities-specific Balance Confidence (ABC) scale, simple reaction time and postural sway. Each factor was

Conclusion

The physical act of falling is a very common occurrence in the elderly population and one that presents a substantial health problem among the elderly due to the overwhelming rise in human life expectancy. The purpose of the following study was to develop a relatively simple fall predictive model that can be used by the vast majority of health care professionals, in various settings, with the hope of monitoring and preventing this terrible occurrence in the aged. This would allow nurses,

Acknowledgements

The authors would like to thank Annie Girard and Julie Cloutier for their help in data acquisition and analysis. They would also like to acknowledge Dr. Olivier Serresse and Dr. Rashmi Garg for the editorial and statistical support. Lastly, the authors are very grateful to Francis Thériault for the development of a software program to meet our testing needs. This project was supported by NSERC grants to Dr. Yves Lajoie.

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