Abstract
Throughout the centuries, the horse and human relationship has evolved from one of sustenance to one of partnership. Historically, the idea of horses being partnered with humans in a therapeutic capacity is evident from writings of the ancient Greeks to documentation by European physicians and therapists from the 1500s through the 1800s. The impetus for the development of modern day equine-assisted activities and therapies (EAAT) is credited to a Danish dressage rider named Lis Hartel, who won an equestrian silver medal at the 1952 Olympic Games despite being partially paralyzed by polio. Her international accomplishments on the back of a horse demonstrated the potential healing power of riding
In 1870, Chassaigne published the first known study testing the effects riding had on individuals with disabilities. He concluded positive benefits on balance, posture, and muscle control. Research on EAAT was limited until the Scandinavian polio outbreak in in the 1940s. Since that time, numerous publications on the benefits of EAAT have been documented, echoing outcomes of early investigators; however, many publications lack the rigor necessary for credibility in the US medical community. Small sample sizes, heterogeneity of study groups, lack of control groups or randomized treatment assignment, and lack of codified interventions, are all cited as criticisms for peer-reviewed studies.
The physical effects of EAAT on individuals with cerebral palsy remain the most documented area of research. Meta-analyses and systematic reviews of the literature incorporating well-designed research trials investigating the effects of mounted EAAT on individuals with cerebral palsy show conflicting results regarding improvements in gross motor function; however, significant improvements in balance and postural control were found. Randomized clinical trials determining the appropriate type, dose and frequency of EAAT, assignment of horse to participant, and sorting out the true effect of the horse is necessary for the EAAT industry to gain credibility.
Demonstrated efficacy of EAAT is essential for parents, guardians, and participants to know whether EAAT is beneficial and what evidence exists to support this type of monetary and personal investment. In addition, quality research is important for granting agencies to support EAAT programs. Finally, increasing the number of randomized clinical trials testing the efficacy of EAAT will be essential for the field to earn legitimacy in the medical community, support insurance reimbursement, and be viewed as a viable therapeutic option for identified populations.
Although limited, several funding opportunities exist specifically for research in the area of animal-assisted interventions. The Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Horses and Humans Research Foundation are two examples of agencies that support high quality research investigating horse and human interactions. Continued support is essential to provide funding opportunities for research that will further legitimize the EAAT field and move the industry forward.
History
The horse and human connection can be traced back thousands of years, and while the location, date and definition of horse domestication is still widely contested (Kavar and Dovc, 2008), it can generally be agreed on that the horse and human relationship began to take form approximately 6,000 years ago when horses were likely kept or hunted for food (Budiansky, 1998). Evidence of the time frame for horses first being ridden ranges from 3500 to 2000 BC (Brown and Anthony, 1998; Levine, 2005). When the horse–human relationship is examined from a therapeutic standpoint, however; Orbasis of ancient Lydia is thought to have documented the value of riding horses as early as 600 BC. Between 460 and 370 BC, Hippocrates wrote of the physical benefits of horseback riding in his book, Natural Exercise (Riede, 1987). From there, benefits of riding horses, especially at the walk, can be found in the writing of physicians and therapists from Germany, Italy, and France spanning from the late 1500s to early 1800s (Bain, 1965; Tissot, 1965). In the 1900s, Oxford Hospital in England partnered wounded soldiers returning from World War I with cavalry horses for rehabilitation. It wasn't until the 1952 Olympics in Helsinki, Finland, however, that people really began to notice the potential power of the horse–human connection. These particular Olympic games were exceptional because a Danish dressage rider by the name of Lis Hartel won a silver medal in the equestrian sport of dressage, despite being partially paralyzed from polio she had contracted eight years prior (Heipertz, 1977). Few people knew of her paralysis and hard-fought journey until her incredible success at the Olympics. Even though Ms. Hartel needed assistance to mount and dismount her horse, once she began riding, the effects of her disability effectively disappeared. Her experience was pivotal in revealing the potential healing power of the horse to the world at large. She was a pioneer in the field and outspoken champion for the benefits of equine-assisted activities and therapies (EAAT) for individuals with disabilities.
Introduction
A number of EAAT are recognized in the US; however, the focus of this review will be on the definitions, reported benefits, and future directions of adaptive/therapeutic riding and hippotherapy research. While both of these EAAT take place on the back of a horse, the distinction between mounted activities with the goal of developing equestrian skills (adaptive/therapeutic riding, or A/TR) vs. therapy with the help of a horse (hippotherapy, or HPOT) is critical. The Professional Association of Therapeutic Horsemanship International (PATH Intl.) defines therapeutic riding as mounted horsemanship activities taught by instructors trained to work with people of different abilities with intention of the individual “progressing in equestrian skills while improving their cognitive, emotional, and/or behavioral skills” (PATH Intl., 2013). Hippotherapy is defined by the American Hippotherapy Association as “a physical, occupational, and speech-language therapy treatment strategy that utilizes equine movement as part of an integrated intervention program to achieve functional outcomes” (AHA, 2010). Examples of functional outcomes may be related to gross motor skills such as standing or walking, improved daily living skills such as feeding or dressing oneself, or the promotion of language skills. Consequently, the primary distinctions between A/TR and HPOT are that: 1) A/TR is taught by a certified therapeutic riding instructor whereas HPOT is facilitated by a physical or occupational therapist or speech-language pathologist who has specialized training in equine movement; and 2) the primary goal of A/TR is to teach equestrian skills while the primary goal of HPOT is to achieve functional outcomes.
Research in EAAT
When we examine the history of research in the field of EAAT, it was the French neurologist Chassaigne who is credited with first studying the effects riding had on individuals with disabilities in 1870. After prescribing riding for a multitude of diseases, he concluded that riding improved balance, posture, and muscle control and was most beneficial for individuals with neurological disorders (Bain, 1965). Eight years later, Ghislani Durant (1878), a physician, authored an entire text on the evident benefits of horseback riding from a medical perspective. Since that time, research in the area of EAAT has continued to evolve from anecdotal evidence to research trials published in peer-reviewed journals.
Historically, research in the EAAT field has focused on physical rehabilitation, and thus the majority of peer-reviewed publications report the effects of mounted human and horse interactions. Modern day EAAT professionals have postulated that one of the reasons horseback riding is so beneficial is because the movement produced in the human pelvis when sitting astride a walking horse is strikingly similar to the movement of the human pelvis during independent symmetrical ambulation (Bertoti, 1988; Fleck, 1997). Empirical support for this theory has been demonstrated in recent years through three-dimensional gait analyses of both humans and horses. Uchiyama et al. (2011) reported that acceleration curves of humans and horses at the walk, though not identical, did overlap, indicating that riding at the walk could produce sensory and motor feedback similar to human ambulation and likely benefit individuals with walking difficulties. Earlier reports by European investigators used film analysis and electrodes to measure displacement of the spine and pelvic rotation of individuals on horseback at the walk and trot (DePauw, 1986). They concluded that there were no detrimental effects of riding and that displacement curves for individuals with spinal problems were more normalized after HPOT (DePauw, 1986).
Investigation into the physical benefits of EAAT has primarily been done with individuals who have cerebral palsy (CP). Cerebral palsy is the most common movement disorder in children caused by injury to the brain during the pre- or perinatal period (Reddihough and Collins, 2003). The consequences may be mild to severe, affecting voluntary motor control as well as vision, hearing, or cognition. A systematic review and qualitative analysis by Whalen and Case-Smith (2012) of 63 peer-reviewed publications revealed nine that met the inclusion criteria of the authors. It was concluded that mounted EAAT (A/TR and/or HPOT) did have a positive effect on gross motor function (Whalen and Case-Smith, 2012). Similarly, a qualitative analysis by Sterba (2007) concluded that evidence supported mounted EAAT as an effective intervention for individuals with CP. In a meta-analysis of the same topic, Tseng et al. (2013) conversely found insufficient evidence from nine studies to support improved gross motor function in children with CP after long-term participation in EAAT. Zadnikar and Kastrin (2011) performed a meta-analysis on the effects of postural control and balance on children with CP who participated in EAAT. Based on the eight publications out of 77 that met their criteria, they concluded that EAAT resulted in significant improvements in balance and postural control for individuals with CP. Additional studies have demonstrated improvements in balance for stroke patients (Beinotti et al., 2010), reduced spasticity and enhanced mental well-being for people with spinal cord injury (Lechner et al., 2007), and improved balance in individuals with multiple sclerosis who participated in mounted EAAT (Bronson et al., 2010). Study limitations such as small samples sizes, in addition to a lack of a control group or random assignment, are frequently cited (Bronson et al., 2010; Borioni et al., 2012; Whalen and Case-Smith, 2012; Tseng et al., 2013).
Examining the social and emotional benefits of EAAT is a less explored but growing area of research. Bass et al. (2009) found that children with autism who participated in 12 weeks of therapeutic riding demonstrated greater social motivation and sensory sensitivity, as well as less distractibility and inattention compared with wait-listed controls. Similarly, Gabriels et al. (2012) found a significant improvement in self-regulation behaviors in children with autism spectrum disorders who participated in 10 weeks of therapeutic riding compared with the wait-listed control subjects.
It has been observed that clients who engage with horses are positively motivated to participate in therapy and more readily communicate their thoughts and emotions (Rothe et al., 2005; Trotter et al., 2008; Feldmann, Home on the Range, Sentinnel Butte, ND, personal communication, 2013). The authors agree with these observations based on personal experiences as well as a multitude of similar anecdotal observations made by colleagues in the EAAT field throughout the years. The bond formed between horse and participant is very likely a powerful motivating factor for individuals engaging in many of the tasks they are asked to perform; however, no definitive works could be found that wholly supported that assumption. A qualitative study by Bizub et al. (2003) reported that adults with a history of psychiatric illness who participated in a 10-week therapeutic horseback riding program formed strong, deep connections to their horses. Additionally, they experienced an enhanced sense of self-efficacy and self-esteem as a result of learning basic horsemanship skills, despite initial fear. Yorke et al. (2008) described the value of the horse–human bond in recovery from trauma, noting that gaining confidence, trust, and self-worth are essential and that these qualities can be acquired when interacting with equids. Limitations of these studies were great, however, and echo those of some previously described, including small sample sizes, heterogeneity of the study group, lack of a control group or random assignment, and the inclusion of evaluations conducted by practitioners involved with the therapeutic intervention, potentially influencing responses.
Future Challenges with EAAT Research
Challenges to EAAT research are great, yet must be overcome for the field to gain credibility and move forward. Limited funding sources combined with the variability in study participants, horses, instructors, and the environment inherent to the EAAT field all contribute to difficulties with this type of work (Freund et al., 2011). In addition, participants cannot be blind to the treatment because they know whether they are receiving the equine intervention or not, so the potential exists for biased results. While randomized clinical trials have demonstrated efficacy of EAAT in some areas (MacKinnon et al., 1995; Davis et al., 2009; Käll et al., 2012), additional rigorous studies with appropriate sample sizes, homogeneity of the study population, random group assignment, standardized protocols, and evaluators blinded to the treatments are essential to answer research questions. The medical community and insurance companies require randomized clinical trials to demonstrate efficacy of an intervention. Further, participants and their families deserve to know whether the EAAT they are participating in is the most appropriate one and whether it is likely or unlikely to produce beneficial results. Determining the appropriate type, dose, and frequency of EAAT as well as the short- and long-term effects is imperative. Elucidating the role of emotional attachment between humans and horses and determining how to best measure that impact is essential to gain insight into the unique relationship. Developing procedures to best match horse and human participants will facilitate an optimal experience for both parties. Determining the optimal instruments to measure physical, cognitive, social, or behavioral changes in participants of EAAT programs will strengthen results. Implementing standardized protocols would more readily enable the comparison of EAAT studies. Finally, determining appropriate methods to measure the true impact of the horse with a multitude of other variables present in the EAAT environment such as instructors or therapists, other participants and/or animals, support personnel, fluctuating weather, and interactions of these variables is essential. Industry professionals and academicians involved in this field are passionate and poised to move forward, and although grant dollars are extremely limited, there are funding sources dedicated to research in the field of EAAT (Freund et al., 2011).
Conclusion
The ultimate goal of EAAT is to positively impact the quality of life of individuals. That impact may come in the form of greater self-confidence resulting from successfully guiding a horse through a trail pattern, or improved trunk control after 12 weeks of hippotherapy. Equine-assisted activities and therapies can provide significant opportunities for individuals of all abilities to reach their potential. The art of identifying which EAAT horse and facilitator are the most appropriate, determining the appropriate frequency of EAAT, and implementing best industry practices based on well-designed research all must be thoughtfully considered for the future success of the industry. These issues are important pieces of the puzzle that will enable the EAAT industry to continue to move forward as a legitimate means of improving the physical, cognitive, mental, and emotional well-being of humankind.
Literature Cited
