PHYS THER
Vol. 87, No. 11, November 2007, pp. 1491-1493
DOI: 10.2522/ptj.20060326.ic
Invited Commentary
Catherine M Said
CM Said, BAppSci (Physio), PhD, is Physiotherapy Site Manager, Heidelberg Repatriation Hospital, and NHMRC Research Fellow, University of Melbourne. Dr Said's contact address is: Physiotherapy Department, Allied Health Treatment Centre, Heidelberg Repatriation Hospital, Austin Health, PO Box 5444, Heidelberg West, 3084 Victoria, Australia
Address all correspondence to Dr Said at: Cathy.Said{at}austin.org.au
I congratulate Pai and Bhatt on this elegant review,1 which provides a comprehensive overview of the very exciting work on slips done by their research team. I agree with the authors that this work is highly relevant given the high costs of falls in our society, particularly as the majority of falls occur during dynamic tasks, such as walking. The novel method that they have developed and utilized for quantifying stability during dynamic tasks has allowed the team to develop new insights into the mechanisms behind slips and falls. In addition, the model and method they have developed will allow stability during other dynamic tasks to be explored. In this commentary, however, I will focus on the implications of this research for clinical practice.
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An Early Predictor of Fallers?
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Although the authors emphasize the implications of their research for training, future development of this research also may lead to better identification of people at risk for falling. Current testing methods are able to identify people who are at high risk for falls or who are already falling.2 However, early identification of people who are at risk for becoming a "faller" is still difficult. A test such as the "slip" test may be more sensitive than other tests. The slip test is challenging, as it provides an unexpected external perturbation during a dynamic task. Currently, there are no clinical tests widely available that test this aspect of postural control. In addition, performance on the test can be quantified. These features may assist in early identification of people who are at risk for falls. This would allow targeted treatment programs to be implemented earlier, which may help prevent falls. However, to date, the relationship between falls and performance on the slip task in the laboratory and falls in the "real world" has not been examined. So, although there is real potential for this research to lead to changes in the way in which people at risk for falls are identified, prospective exploration of the laboratory/real-world relationship would be necessary.
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A Novel Method of Fall Prevention
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As pointed out by the authors, current interventions for fall prevention or balance training do not focus on promoting reactive strategies. Currently, clinical balance retraining is strongly focused on training proactive control of stability. This review presents evidence that reactive strategies also can be trained. Upon repeated exposure to the slip condition, participants modified their movement patterns both proactively and reactively to reduce the chance of a fall. There is evidence that these modifications can be retained over time, with a relatively low intensity of training. But before therapists start training reactive balance control in their clients, some issues need to be considered.
First, it is not known how applicable these findings are to the types of clients physical therapists currently treat. Generally, we treat clients who have a balance problem and are at high risk of a fall. All of the subjects included in these trials to date have been unimpaired and have no history of falls or balance problems. Although the results of these studies are promising and indicate that reactive strategies can be trained, the same level of improvement may not be observed in subjects with balance problems. People with a history of falls also may experience greater levels of fear and anxiety during training,3 which also may affect the success of training. Examination of training protocols in clinical populations is an important area of future investigation.
Second, whether training reactive strategies in the laboratory or clinical environment can transfer to the real world has yet to be established. Several factors may limit transfer of the skill trained using this paradigm. In these experiments, even though there were a number of "nonslip" trials, participants were all aware that there was a chance that a slip may occur. In addition, subsequent slips were all under exactly the same environmental conditions, and no competing demands or distractions were placed on subjects. This differs from the real-world environment, where slips are not always predicted and occur under varying environmental conditions and often with competing attentional demands. The motor learning literature suggests that for optimal transfer of a skill, practice needs to occur under variable conditions,4 so it is likely that practice under more varied conditions is required to maximize the transferability of this skill. Although the results of these studies are promising, training and testing need to be undertaken in more ecologically valid conditions, and additional evidence about the effectiveness of this training on fall prevention is required.
Finally, how training of reactive strategies can practically be performed in the clinical environment needs to be considered. To train reactive strategies, a person must lose stability, which carries with it the risk of a fall. The risk of a fall is probably greater in clinical environments, as clients usually have a balance problem. In addition, safety equipment such as the harness system used in the laboratory setting is not always available in the clinical setting. Common methods of reducing falls risk during balance training are to have a wall or rail alongside the patient or to have a therapist beside the patient to assist in balance recovery. Both of these methods are suboptimal. Relying on upper-limb support to assist balance recovery changes the nature of the reactive strategies utilized5; therefore, training may not be optimal. Relying on a therapist to provide assistance if stability cannot be regained may place the therapist at unacceptable risk of injury; a risk that would be even greater while training reactive strategies. Before reactive balance training can be widely incorporated into clinical practice, consideration needs to be given to the ready availability of appropriate safety devices, such as harnesses.
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Conclusion
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The review by Pai and Bhatt highlights training of reactive strategies as an underutilized tool in the prevention of falls. Their research to date provides a solid foundation for further work to address many questions of clinical importance. This area of investigation may lead to significant changes in the way fall prevention and balance retraining programs are provided.
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References
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- Pai YC, Bhatt TS. Repeated-slip training: an emerging paradigm for prevention of slip-related falls among older adults.
Phys Ther. 2007;87:1482–1495.
- Lord SR, Ward JA, Williams P, Anstey KJ.Physiological factors associated with falls in older community-dwelling women.
J Am Geriatr Soc. 1994;42:1110–1117.[Web of Science][Medline]
- Jorstad EC, Hauer K, Becker C, Lamb SE. Measuring the psychological outcomes of falling: a systematic review.
J Am Geriatr Soc. 2005;53:501–510.[CrossRef][Web of Science][Medline]
- Krakauer JW. Motor learning: its relevance to stroke recovery and neurorehabilitation.
Curr Opin Neurol. 2006;19:84–90.[Web of Science][Medline]
- Maki BE, McIlroy WE. Control of rapid limb movements for balance recovery: age-related changes and implications for fall prevention.
Age Ageing. 2006;35(suppl 2):ii12–ii18.
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Copyright © 2007 by the American Physical Therapy Association.
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A Novel Method of...
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