Abstract
Equine assisted activities (hippotherapy and therapeutic riding) improve balance in patients with disabilities such as cerebral palsy, but have not been systematically studied in older adults, at risk of falls due to balance deficits. We conducted a 10-week, single blind, controlled trial of the effect of a therapeutic horseback riding course on measures of balance in community-dwelling adults 65 years and older. Nine riders and six controls completed the trial. Controls were age matched to riders and all participants were recruited from the local community. Both groups showed improvements in balance during the trial, but did not reach statistical significance. Sample size was small, participants had relatively high initial balance scores, and controls tended to increase their physical activities, likely influencing outcomes. No adverse events occurred and the supervised therapeutic riding program appeared to be a safe and effective form of exercise to improve balance in older adults. A power analysis was performed to estimate numbers of participants needed for a larger study.
Background
Falls are a significant cause of morbidity in older age groups with one in three community community-dwelling residents over 65 years experiencing at least one fall per year (American, British Geriatrics Societies, 2000). Balance plays an important role in determining which individuals present a high fall risk and those with gait impairments experience three times the fall rate and associated morbidity of those without such disabilities (Hernandez & Rose, 2008). Balance represents a complex interaction of sensory and musculoskeletal systems and deficits in either can lead to falls. At any age, including childhood and adolescence, exercise leads to faster postural reflexes, and improved balance and mobility. (Fong, Fu, & Ng, 2012; Fong & Ng, 2012; Johnson, Salzberg, &Stevenson, 2011). A Cochrane Database Review of exercise and balance in older people identified 34 studies in which those who exercised showed statistically significant improvements in balance over individuals with usual activity (Gillespie et al., 2003).
Hippotherapy (HPOT) and therapeutic (horseback) riding (TR) have become important methods of providing both a pleasurable activity and physical exercise for individuals with developmental and acquired disabilities. HPOT is defined as a physical, occupational or speech therapy treatment strategy that utilizes equine movement, usually as part of an integrated treatment program to achieve functional outcomes. TR utilizes mounted activities including traditional riding disciplines or adaptive riding activities conducted by a PATH International (Professional Association for Therapeutic Riding International, Denver, Colorado) certified instructor. Both have been shown in clinical trials to improve dynamic postural stabilization, muscle cocontraction, joint stability, weight shift, postural and equilibrium responses, and gross motor function in children with cerebral palsy (CP), although some studies utilized small numbers of patients or lacked non riding controls.(Sterba, 2007). TR has also been shown to improve balance in individuals with mental retardation (Biery & Kaufmann, 1989). However, no systematic studies of the potential benefit of equine assisted therapies have been undertaken in older individuals. The objectives of this study were to investigate the practicality, safety, and potential improvements of TR in a select group of relatively healthy community-dwelling older individuals compared to a similar control group. The hypothesis was that the TR group would show benefits in the outcome measures of balance compared to the nonriding control group.
Method
Design Overview
The study was approved by the Bronson Methodist Hospital (Kalamazoo, Michigan) Institutional Review Board. An age matched sample of healthy individuals over the age of 65 years selected to participate in a 10-week TR course and were age matched to a control group also continuing their usual activities. After obtaining physician clearance, all participants gave informed consent and underwent a health screening. Exclusion criteria included any chronic condition known to affect balance including chronic neurological disease, post stroke, and middle ear disease, fear of horses, history of substance abuse, or recreational horseback riding within 1 year of enrollment. Entry into the study was at the discretion of the physician investigator (Douglas N. Homnick). All participants also completed a composite physical function scale (CPF), a validated screening questionnaire of 12 questions, to determine level of functioning in activities of daily living ranging from the ability to care for personal needs such as self dressing to the ability to undertake strenuous activities such as athletics and moving heavy objects (Rikli & Jones, 1998). Balance tests were administered to both groups immediately before and at the end of the 10-week course by a licensed and experienced physical therapist (Charlene V. Swain). The physical therapist was blinded to the intervention received by the participants.
Setting and Participants
Participants underwent balance testing and the TR intervention at the Cheff Therapeutic Riding Center (Augusta, Michigan). The Cheff Center is a PATH Premier accredited therapeutic riding center, established in 1970, that serves multiple types of clients including children and adults with physical, developmental, and psychological disabilities. Nine participants (7 females, 2 males, mean age 70.1 years) completed the TR course and six participants (3 females, 3 males, mean age 69.3 years) served as controls.
Interventions
After completing the health screening and CPF, a convenience sample of individuals from the local community and participants presenting to the Cheff Center desiring to undertake a TR course were recruited. All participants underwent two balance tests after screening and upon entry into the study. These included two validated measures, the Berg Balance Scale (BBS) and the Fullerton Advanced Balance Scale (FABS; Berg, Maki, Williams, Holliday, & Wood-Dauphinee, 1998; Rose, Lucchese, & Wiersma, 2006). The BBS is considered the “gold standard” of balance tests and consists of 14 maneuvers to assess various aspects of dynamic and static balance. The test takes approximately 15 to 20 min to complete and each measure is given a score of 0 to 4 (high to low fall risk) with a possible total of 56. The FABS is also a validated test of static and dynamic balance and is especially suited to higher functioning individuals with slightly more challenging tasks. It consists of 10 maneuvers scored from 0 to 4 (high to low fall risk) with a total possible score of 40 and takes approximately 20 min to complete. The FABS has been found to have high test-retest (intrarater) and interrater reliability and has been validated against the BBS. The order of administration was the BBS followed by the FABS for each participant.
Nine participants completed a 10-week TR course consisting of a once per week one hour session with a PATH trained and certified TR instructor investigator (Tamara D. Homnick and Kim M. Henning). The TR session included grooming and tacking, mounting, a warm up exercise on the horse, riding skills, and dismounting. The riding portion of the session lasted approximately 45 min and consisted of walking and/or trotting, depending on the skill of the rider. One to three volunteers assisted the rider to maintain safety. Close observation of the rider was maintained at all times for early detection of fatigue, discomfort, and so forth.
Statistical Analysis
The mean and standard deviation were calculated to demonstrate age and gender distribution of the study population. The Mann-Whitney U test was used to evaluate balance test results within the intervention and control groups. The Mann-Whitney U was chosen over the t test since normality of the population distribution could not be assumed and is more robust against outliers in small sample sizes. The tests were conducted at a 0.05 significance level.
Power analyses were carried out on the groups both at the start and end of the study. These were used to estimate the sample size necessary to achieve 80% power for each test. Results are shown in the Table 1 and discussed in the text. Minitab 16 (Minitab, Inc., State College, PA) statistical software was used for the analyses.
Balance Test Results [mean (SD)].
Note: TR = therapeutic riding; FABS = Fullerton Advanced Balance Scale; BBS = Berg Balance Scale; SD = standard deviation.
total score possible is 40, btotal score possible is 56, csample size needed for 80% power.
Mann-Whitney.
Results
All participants indicated no difficulty in doing daily activities as measured by the CPF (data not shown). The TR and control participants both showed improvement in balance scores during the study although this did not reach statistical significance (Table 1). Improvement appeared to be greatest with the FABS versus the BBS although this could not be definitively determined during this study. All participants completed the balance tests without incident and those in the TR arm experienced no safety issues.
Discussion
Falls are common in older individuals and have an important impact on quality of life. They are also expensive with the cost of fall injuries reaching US$20.2 billion in 1994 and estimated to increase to US$32.4 billion in 2020, likely due to an increasing senior population as baby boomers age (Englander, Hodson, & Terregrossa, 1996). Exercise reduces fall risk in older adults including those with disabilities (Nowalk, Prendergast, Bayles, D’Amico, & Colvin, 2001; Cyarto, Brown, Marshall, & Trost, 2008; Miller, Magel, & Hayes, 2010; Gillespie et al., 2009).
HPOT and TR are forms of exercise with proven rehabilitative potential and are pleasurable activities for those with disabilities. The exact therapeutic benefit of horseback riding is unknown but thought to be due to displacement of the horse’s center of gravity three-dimensionally leading to rhythmical movements similar to a human gait and eliciting neurosensory and neuromuscular responses from underused muscles groups (Shurtleff, Standeven, & Engsberg, 2009). It may also improve vestibular responses to alterations in posture leading to improved fall protection.
In this pilot study, we demonstrated small but measurable improvements in two balance measurement systems in a group of generally healthy, active, community-dwelling older adults serving as controls or undergoing a 10-week TR program. In retrospect, several study design issues may have influenced the outcomes. First, it is evident from the initial balance (Table 1) and CPF scores (data not shown) that the groups had few balance problems at study entry; that is, may have been “too healthy,” that is, lacked sufficiently large balance deficits to provide a measurable response to the intervention. This was confirmed by an assessment of the unrestricted activities undertaken during the study by the control group, which included participants attending a gym, dancing, walking, gardening, playing tennis, and so forth. It is possible that screening for a group with established balance deficits but who are otherwise healthy would prove more likely to show significant benefits of TR. The FABS has been determined to be most sensitive in predicting subsequent falls in older adults at a cut off score of 25/40 (Hernandez & Rose, 2008). Additional issues include determining optimal frequency and duration of TR or HPOT therapy for balance and whether there is a sustained effect over time, once therapy is discontinued.
It was unclear from this study which of the two measures, FABS or BBS may be the more sensitive in eliciting small improvements in the intervention group. However, due to a relatively large difference in mean balance scores compared to standard deviation (except in the case of the end of study BBS in the controls), the power analysis showed relatively small participant numbers would be needed to attain a statistical power of 80%. Although this represents a statistical end point, it does not necessarily indicate one that is clinically significant. The sine qua non of improvement in balance scores is how they relate to eventual fall reduction and secondarily to decrease in fear of falling. As there is no pilot data relating a specific TR intervention to degree of improvement in balance scores and associated measured reduction of fall risk, it is difficult to determine an accurate number of participants to enroll in a trial to obtain statistical power. A longer, perhaps one year study of a TR intervention group with periodic balance testing and ongoing assessment of number of falls in participants with known fall risk (FABS ≤ 25) compared to a matched nonintervention group would clarify the clinical benefits of TR. In addition, choice of test may also depend on the baseline level of functioning of participants enrolled as the FABS may be better suited to higher functioning individuals. It should be pointed out that in each case the BBS was administered immediately before the FABS and has some similarities in activities. It is possible that learning and practice occurred during the administration of the BBS with residual effect on the FABS activities, affecting outcomes and FABS scores.
In conclusion, this study demonstrated safety and suggests potential efficacy of a TR intervention in community-dwelling older adults. Although TR has been proven to be effective in improving balance in various neurologic conditions, it has yet to be proven to be beneficial in the treatment of older adults with established balance deficits. However, older individuals are likely to benefit from many forms of consistent exercise in which axial muscle stabilization and perhaps vestibular stimulation play a prominent role. Older adults who find equine activities to be pleasurable will likely find benefit from this activity. However, larger trials would help clarify the benefit of this therapy in older age groups and would further advance information on the benefits of various exercises and activities on improvement of balance. In addition, the ultimate measure of fall risk should also be measured over a longer term to assess the meaningful clinical benefit of therapies designed to improve balance in older individuals.
Footnotes
Acknowledgements
The statistical services of Robert Flikkema, MS, Department of Statistics, Western Michigan University, Kalamazoo, Michigan was greatly appreciated.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was funded in-kind by the Cheff Therapeutic Riding Center, Augusta, Michigan.