CONTEXT

Equine-assisted therapy in different facets aims to improve the clinical condition of children with cerebral palsy. A more comprehensive overview on the overall effects and on the differences between different treatment modalities seems desirable.

OBJECTIVE

We compared the effectiveness of various equine-assisted treatments on motor capabilities and quality of life of children with cerebral palsy.

DATA SOURCES

We conducted systematic searches of PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials.

STUDY SELECTION

Randomized and nonrandomized controlled parallel-group or crossover studies on equine-assisted therapies in comparison with standard of care were included.

DATA EXTRACTION

Data on motor function assessed by different instruments were considered as the primary outcome. Secondary outcomes included global, social, physical, and emotional scores of quality of life.

RESULTS

Strong evidence for a positive effect of equine-assisted therapies, particularly hippotherapy, on global gross motor function and motor capabilities during walking in children with cerebral palsy was identified (SMD 0.24, 95% CI 0.05 to 0.43, P = .01, t2 = 0.00, I2 = 15%; SMD 2.68, 95% CI 1.02 to 4.34, P = .002, t2 = 0.0, I2 = 0%). No evidence for the improvement in quality of life could be shown in the global assessment, nor in any subscore.

CONCLUSIONS

Equine-assisted therapy, particularly hippotherapy, can be a therapeutic tool for children who are learning to walk.

LIMITATION

The heterogeneity of tools used in different studies and the low number of studies addressing quality of life issues limited the number of studies available for distinct analyses.

What’s Known on This Subject:

Animal-based treatments, particularly equine-assisted treatments, are increasingly used to improve motor functions of children affected by cerebral palsy. Studies conducted to date evaluating comparative effectiveness have not been able to provide conclusive evidence.

What This Study Adds:

Equine-assisted therapies, especially hippotherapy, can be recommended as a therapeutic tool, especially for children who are in the process of learning to walk or who have already achieved the ability to walk.

Cerebral palsy (CP), one of the major neurologic diseases in children, mainly derives from brain damage related to preterm birth, more rarely from brain malformation, perinatal asyphyxia, syndromal disorders, or perinatal infarction. CP shows a prevalence of about 2 to 3:1000 live births1  and necessitates lifelong medical support, with physiotherapy, surgical, or conservative orthopedic procedures, botulinum toxin injections and baclofen being the most important treatments. Animal-based treatments, particularly equine-assisted treatments, are increasingly used to improve motor functions of children with CP. This includes live and artificial horses, the latter in a mainly experimental context.27  Whereas “therapeutic riding” includes different equine-based interventions, “hippotherapy” requires a therapist who is specifically trained in using the horse as a dynamic physiotherapeutic tool. An additional horse handler guides the horse according to the therapist’s instructions. The therapist’s qualification (physiotherapist in Germany) may differ from country to country, as may further details of the therapeutic concepts.

An increasing number of studies has addressed the question of which motor or psychosocial domains might be influenced by equine-assisted treatments and by hippotherapy in particular using different outcome measures such as the Gross Motor Function Measure (GMFM), the Pediatric Balance Scale (PBS) or the sitting assessment scale (SAS).827  A series of reviews and some meta-analyses have already focused on distinct aspects of these results, frequently including a limited number of outcome measures such as the GMFM tool, not comparing artificial with living horses, or not including quality of life (QoL).27,28  Hereby, mainly contradictory results have been reported.

The objective of our systematic review and meta-analysis was to evaluate the effect of hippotherapy and other equine-assisted treatments on motor function and QoL parameters in comparison with usual care in children with CP. Compared with previous studies, we decided to include a larger spectrum of outcome parameters. Although hippotherapy is the most established horse-based treatment modality, we also included further live and artificial horse–based treatments to cover the entire spectrum of equine-based therapies. Simultaneously, the meta-analysis tool not only enables evaluation of the overall effect of different therapies on distinct outcome parameters but also of hippotherapy in particular.

The protocol29  of this systematic review and meta-analysis summarizes the prespecified methods in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA) guideline. When performing the review, we strictly adhered to this published protocol. In brief, results of randomized and nonrandomized controlled parallel-group or crossover studies were combined to evaluate the effect of equine-assisted therapies on motor capabilities as the primary outcome and QoL as a secondary outcome in children with CP.

Outcomes are summarized by mean difference (MD) or standardized mean difference (SMD) with 95% confidence intervals (CIs), P values, and estimates of the between-study variability τ2 and I2 to describe heterogeneity. More details of the methods used are provided in Supplemental Information.

A database search performed in May 2019 identified 1653 citations with potential for inclusion, and 2 additional studies30,31  were identified from the reference lists. An updated search in February 2022 before the final analysis revealed 5 additional studies26,27,3234  that met our inclusion criteria. After title, abstract, and full-text screening, a total of 26 studies were selected to be included into the qualitative synthesis. Details of the selection process chosen to identify the randomized controlled trials to be included are depicted in a PRISMA flow diagram (Fig 1).

FIGURE 1

PRISMA flow diagram.

FIGURE 1

PRISMA flow diagram.

Close modal

This meta-analysis reviews data from 26 studies on equine-related treatments conducted in 14 countries (Turkey, the United States, Egypt, Taiwan, Australia, Germany, Korea, Colombia, Spain, Poland, Japan, England, Thailand, and India) between 1998 and 2022. The study of Lerma-Castano,23  which was excluded from the meta-analysis during bias analysis, is not contained herein or in the following sections, but details of this study are provided in the tables on bias assessment, study characteristics, and study data. The same applies to the studies of Lee et al15  because of the lack of a “standard of care” group. Also, the study of Park et al33  was excluded from the meta-analysis because no other study reported on cardiac autonomic function. The studies partly differ considerably with regard to the number of patients, the duration of therapy, drop-out rates, severity of CP, and the tests used to describe outcome.

Overall, data from 755 patients were available for analysis. The male-to-female ratio could be calculated from 20 studies and was approximately 1.3:1. The lowest number of patients was reported in the studies of Benda et al17  and Silkwood-Sherer et al34  (both n = 13), the highest in the study of Kwon et al11  (n = 91). The duration of therapy varied between 1 day and 48 weeks.17,18,35  So far reported, the severity of CP was mostly assessed by the GMFCS, less frequently by the modified Ashworth scale. Children with all types of CP were included, although most studies did not include the most severely affected children.

As mentioned above, we classified those horse-based studies as hippotherapy where the term hippotherapy was found in the title and/or text.812,1719,22,23,25,30,3335  Fewer reported on the effects of therapeutic riding20,21,26,27,30,32  or involved dynamic artificial horses.1416,31 

With the exception of 2 studies comparing living horses with artificial horses,15,36  all remaining studies compared living horses or artificial horses with standard of care. In most studies, classic standard-of-care physiotherapy was applied to the treatment and to the control group.810,12,1922,24,30,31,34  In 3 studies, standard of care was discontinued in the treatment group or no data were provided,14,23,2527,32,35  whereas in the study of Kwon et al,11  standard of care in the control group was supplemented by additional sports. In 2 of the 4 1-day studies, standard of care was applied by sitting on a barrel,17,18  whereas sitting on a static artificial horse represented standard of care in the study of Quint et al.16 

Two major types of outcomes were reported: outcomes focusing on motor abilities or QoL in general or those focusing on distinct motor or QoL subdomains.

Global motor function was assessed with the 66- and/or 88-item versions of the GMFM tool (n = 9).26,3739  This included 7 studies with living horses8,9,11,21,22,25,26,35  and 2 studies with artificial horses, respectively.14,31  If both GMFM measures were available, the GMFM-66 was preferentially included because “the GMFM-66 is a 66 item subset of the original 88 items identified through Rasch analysis to best describe the gross motor function of children with CP of varying abilities” (for details, see https://canchild.ca/en/resources/44-gross-motor-function-measure- gmfm).3740 

GMFM subtests can be used to describe distinct motor subdomains. Hereby, the GMFM-A subtest (lying) was reported in 4,11,21,25,30  the GMFM-B (sitting) in 5,11,14,21,25,30  the GMFM-C (crawling) in 4,11,21,25,30  the GMFM-D (standing) in 6,9,11,21,22,25,30  and the GMFM-E (walking) in 7 studies,9,11,21,22,25,30,35  respectively.

Apart from the GMFM-B, all further subtests were only performed in studies on living horses. Results of further tests also evaluating capabilities during sitting were available from the modified functional reach test,20  from force plate testing,10  from SAS testing,14,24  and from GMFM-B data reanalyzed by Rasch analysis.36 

Effects of equine-assisted treatments on abilities during sitting and standing were assessed by means of the PBS.11,15,22,26,31  One additional method to study the abilities during walking is gait analysis.22,26,34,35  Hereby, a limited set of gait analyses (cadence, step length, and/or walking speed) could be included.

Further tools focusing on spasticity were the modified Ashworth scale,12,20,21  trunk asymmetry,17,18  as well as Formetric analysis19  and the hip range of movement.16,22,27 

As for QoL assessment, we only included data on caregivers’ assessment of their children’s QoL. In this context, 2 measures investigated QoL in general, for example, the KIDSCREEN8,9  and the Pediatric Evaluation of Disability Inventory.25  QoL subscores were provided by the CP-QoL-Child,8  the Pediatric Evaluation of Disability Inventory,25  the Pediatric Quality of Life Inventory,32  and the Child Health Questionnaire.8,9  Hereby, 3 comparable QoL subscores were available from at least 2 studies: a physical subscore and a subscore on social wellbeing,8,9,25,32  and an emotional subscore.8,9,32 

Further descriptions of the individual study characteristics are provided in Table 1.

TABLE 1

Characteristics of Included Studies

StudyLanguage/CountryHippo-therapyaStandard of CareStudy DesignNumber Recruited or Randomized (Analyzed)Treatment DurationStudy DurationAge Distribution, Mean (SD)Sex Distribution Male/Female
Standard of care versus standard of care with additional riding therapy (living horse) 
 Ahn et al32  (2021) English/Korea No Usual daily activities Randomized, parallel group design 23/24 (23/23) Twice a wk for 40 min over 16 wk 20 wk Intervention 7.78 (1.68) y; control 7.30 (1.61) y Intervention 12/11; control 11/12 
 Alemdaroglu et al20  (2016) English/Turkey No Conventional rehabilitation Nonrandomized, parallel-group-design 9/7 (9/7) Twice a wk for 30 min over 5 wk 5 wk Total 7.5 (1.7) y Total 9/7 
 Baik et al27  (2014) English/Korea No Conventional rehabilitation Nonrandomized parallel-group design 8/8 (8/8) Twice a wk for 60 min over 12 wk 12 wk Intervention 12.12 (3.6) y; control 8.12 (2.58) y No data 
 Benda et al17  (2003) English/US Yes Not performed, only one treatment Randomized, parallel group design 7/8 (7/6) Once for 8 min 1 d Total range 4–12 y No data 
 Mc Gibbon et al18  (2009) English/US Yes Not performed, only one treatment Randomized, parallel group design 25/22 (25/19) Once for 10 min 1 d Intervention 8 (range 5–12) y; control 8 (range 8–12) y Intervention 16/9; control 11/11 
 El Meniawy et al19  (2012) English/Egypt Yes Conventional exercise program Randomized, parallel group design 15/15 (15/15) Once a wk for 13 wk 13 wk 7 (0.5) y No data 
 Cherng et al21  (2004) English/Taiwan No Regular physical therapy Nonrandomized, crossover design 20/20 (9/5) Twice a wk for 40 min over 16 wk 33 wk Total 92.6 (27.4) mo Total 8/6 
 Davis et al8  (2009) English/Australia Yes Normal routines (eg, physiotherapy) Randomized, parallel-group design 50/49 (35/36, 35/37, or 10/11) Once a wk for 30–40 min over 10 wk 10 wk Intervention 7.4 (2.5) y; control 7.9 (2.4) y Intervention 17/18; control 20/16 
 Deutz et al9  (2018) English/Germany Yes Conventional physiotherapy Randomized, crossover design 35/38 (31/35) One to 2 times a wk over 16–20 wk 50 wk Total 9.1 (3.3) y Total 44/29 
 Kang et al10  (2012) English/Korea Yes Physical therapy Randomized, parallel-group design 15/15 (14/15) Semiweekly for 30 min over 8 wk 8 wk Intervention 8.2 (1.1) y; control 8.2 (1.2) y Intervention 7/7; control 8/7 
 Kang et al30  (2013) English/Korea No Physical therapy Nonrandomized, parallel-group design 7/7 (7/7) Twice a wk for 30 min over 8 wk 8 wk Intervention 7.6 (3.7) y; control 7.0 (2.8) y Intervention 6/1; Ccontrol 6/1 
 Kwon et al22  (2011) English/Korea Yes Conventional physiotherapy 2 times a wk for 30 min over 8 wk Nonrandomized, parallel-group design 16/16 (16/16 or 12/11) Twice a wk for 30 min over 8 wk 8 wk Intervention 6.4 (1.7) y; control 6.1 (1.7) y Intervention 11/5; control 10/6 
 Kwon et al11  (2015) English
Korea 
Yes Conventional physiotherapy + sports Randomized parallel-group design 46/46 (45/46) Two times per wk for 30 min over 8 wk 8 wk Intervention 5.7 (1.9) y;control 5.9 (1.8) y Intervention 20/25
Control 29/17 
 Lerma-Castano et al23  (2017) Spanish/Colombia Yes Usual rehabilitation therapy (Bobath) Nonrandomized, parallel-group design 7/7 Three times a wk for 45 min over 10 wk 10 wk Total range 1–14 y;control median 3 (range 1–6) y; experimental median 6 (range 2–14) y Total 10/4 
 Lucena-Anton et al12  (2018) English/Spain Yes Conventional physical therapy twice a week Randomized, parallel-group design 24 /24 (22/22) Once a wk for 45 min over 12 wk 12 wk Intervention 9.5 (2.7) y; control 8.2 (2.4) y Intervention 13/9; control 15/7 
 Matusiak et al24  (2016) English/Poland Yes None Nonrandomized, parallel-group design 19/20 Once a wk for 30 min over 12 wk 12 wk Intervention 8.4 (2.2) y; control 8.3 (2.6) y Intervention 10/9; control 11/9 
 Mutoh et al35  (2019) English/Japan Yes Recreation program once a week Randomized, parallel-group-design 12/12 (12/12) Once a wk for 30 min over 48 wk 1 y + 3 mo follow up Intervention 8(3) y; control 9(3) y Intervention 5/7; control 6/6 
 Park et al25  (2014) English/Korea Yes Physical and occupational therapy once a week Nonrandomized, parallel-group design 45/21 (34/21) Twice a wk for 45 min over 8 wk 8 wk Intervention 6.7 (2.6) y; control 7.8 (3.7) y Intervention 15/19; control 10/11 
 Park et al33  (2020) English/Korea No Usual daily activities Randomized, parallel-group design 13/13 (13/13) Twice a wk for 40 min over 16 wk 16 wk Intervention 8.15 (1.91) y; control 7.54 (1.56) y Intervention 6/7; control 8/5 
 Silkwood-Sherer et al34  (2020) English/US Yes Usual physical and occupational therapy Randomized parallel group design 19 (13) Once a wk for 12 wk 12 wk Intervention 3-6 y; control 3-6 y Intervention 6/3; control 2/2 
 Suk and Kwon26  (2022) English/Korea No Usual physical therapy Randomized parallel group design 23/23 (23/23) Twice a wk for 40 min over 16 wk16 16 wk Intervention 7.74 (1.63) y; control 7.22 (1.48) Intervention 12/11; control 12/11 
Standard of care versus standard of care with additional riding therapy (artificial horse) 
 Fernandes et al31  (2008) English/India n.a. Conventional therapy 3 times a week for 60 min over 6 wk Randomized, parallel-group design 15/15 (15/15) Three times a wk for 15 min over 6 wk 6 wk Intervention 6.9 (1.4);control 7.6 (2.1) Intervention 7/8; control 9/6 
 Quint and Toomey16  (1998) English/England n.a. Artificial static horse Randomized parallel group design, matched pairs 15/15 (13/13) Ten times per day for 10 min on 20 d 4 wk Range 9 to 16 y No data 
 Herrero et al14  (2012) English/Spain n.a. Hippotherapy simulator switched off once a wk for 15 min over 10 wk Randomized, parallel-group design 19/19 (19/18) Once a wk for 15 min over 10 wk 10 wk Intervention 9.95 (1.5); control 9.05 (1.5) Intervention 14/5; control 10/9 
Riding therapy with living horse versus riding therapy with artificial horse 
 Lee et al15  (2014) English/Korea Yes Horseback riding simulator Randomized, parallel-group design 13/13 (13/13) Three times a wk for 60 min over 12 wk 12 wk Intervention 10.8 (1.6); control (simulator) 10.0 (2.2) Intervention 8/5; control (simulator) 9/4 
 Temcharoensuk et al36  (2015) English/Thailand No Horseback riding simulator, 1 group dynamic and the other static Randomized, parallel-group design 10/10 (10/10) 30 min once 1 d Intervention 10.7 (1.7); control (simulator) 10.1 (1.7) Intervention 5/5; control (simulator) 4/6 
StudyLanguage/CountryHippo-therapyaStandard of CareStudy DesignNumber Recruited or Randomized (Analyzed)Treatment DurationStudy DurationAge Distribution, Mean (SD)Sex Distribution Male/Female
Standard of care versus standard of care with additional riding therapy (living horse) 
 Ahn et al32  (2021) English/Korea No Usual daily activities Randomized, parallel group design 23/24 (23/23) Twice a wk for 40 min over 16 wk 20 wk Intervention 7.78 (1.68) y; control 7.30 (1.61) y Intervention 12/11; control 11/12 
 Alemdaroglu et al20  (2016) English/Turkey No Conventional rehabilitation Nonrandomized, parallel-group-design 9/7 (9/7) Twice a wk for 30 min over 5 wk 5 wk Total 7.5 (1.7) y Total 9/7 
 Baik et al27  (2014) English/Korea No Conventional rehabilitation Nonrandomized parallel-group design 8/8 (8/8) Twice a wk for 60 min over 12 wk 12 wk Intervention 12.12 (3.6) y; control 8.12 (2.58) y No data 
 Benda et al17  (2003) English/US Yes Not performed, only one treatment Randomized, parallel group design 7/8 (7/6) Once for 8 min 1 d Total range 4–12 y No data 
 Mc Gibbon et al18  (2009) English/US Yes Not performed, only one treatment Randomized, parallel group design 25/22 (25/19) Once for 10 min 1 d Intervention 8 (range 5–12) y; control 8 (range 8–12) y Intervention 16/9; control 11/11 
 El Meniawy et al19  (2012) English/Egypt Yes Conventional exercise program Randomized, parallel group design 15/15 (15/15) Once a wk for 13 wk 13 wk 7 (0.5) y No data 
 Cherng et al21  (2004) English/Taiwan No Regular physical therapy Nonrandomized, crossover design 20/20 (9/5) Twice a wk for 40 min over 16 wk 33 wk Total 92.6 (27.4) mo Total 8/6 
 Davis et al8  (2009) English/Australia Yes Normal routines (eg, physiotherapy) Randomized, parallel-group design 50/49 (35/36, 35/37, or 10/11) Once a wk for 30–40 min over 10 wk 10 wk Intervention 7.4 (2.5) y; control 7.9 (2.4) y Intervention 17/18; control 20/16 
 Deutz et al9  (2018) English/Germany Yes Conventional physiotherapy Randomized, crossover design 35/38 (31/35) One to 2 times a wk over 16–20 wk 50 wk Total 9.1 (3.3) y Total 44/29 
 Kang et al10  (2012) English/Korea Yes Physical therapy Randomized, parallel-group design 15/15 (14/15) Semiweekly for 30 min over 8 wk 8 wk Intervention 8.2 (1.1) y; control 8.2 (1.2) y Intervention 7/7; control 8/7 
 Kang et al30  (2013) English/Korea No Physical therapy Nonrandomized, parallel-group design 7/7 (7/7) Twice a wk for 30 min over 8 wk 8 wk Intervention 7.6 (3.7) y; control 7.0 (2.8) y Intervention 6/1; Ccontrol 6/1 
 Kwon et al22  (2011) English/Korea Yes Conventional physiotherapy 2 times a wk for 30 min over 8 wk Nonrandomized, parallel-group design 16/16 (16/16 or 12/11) Twice a wk for 30 min over 8 wk 8 wk Intervention 6.4 (1.7) y; control 6.1 (1.7) y Intervention 11/5; control 10/6 
 Kwon et al11  (2015) English
Korea 
Yes Conventional physiotherapy + sports Randomized parallel-group design 46/46 (45/46) Two times per wk for 30 min over 8 wk 8 wk Intervention 5.7 (1.9) y;control 5.9 (1.8) y Intervention 20/25
Control 29/17 
 Lerma-Castano et al23  (2017) Spanish/Colombia Yes Usual rehabilitation therapy (Bobath) Nonrandomized, parallel-group design 7/7 Three times a wk for 45 min over 10 wk 10 wk Total range 1–14 y;control median 3 (range 1–6) y; experimental median 6 (range 2–14) y Total 10/4 
 Lucena-Anton et al12  (2018) English/Spain Yes Conventional physical therapy twice a week Randomized, parallel-group design 24 /24 (22/22) Once a wk for 45 min over 12 wk 12 wk Intervention 9.5 (2.7) y; control 8.2 (2.4) y Intervention 13/9; control 15/7 
 Matusiak et al24  (2016) English/Poland Yes None Nonrandomized, parallel-group design 19/20 Once a wk for 30 min over 12 wk 12 wk Intervention 8.4 (2.2) y; control 8.3 (2.6) y Intervention 10/9; control 11/9 
 Mutoh et al35  (2019) English/Japan Yes Recreation program once a week Randomized, parallel-group-design 12/12 (12/12) Once a wk for 30 min over 48 wk 1 y + 3 mo follow up Intervention 8(3) y; control 9(3) y Intervention 5/7; control 6/6 
 Park et al25  (2014) English/Korea Yes Physical and occupational therapy once a week Nonrandomized, parallel-group design 45/21 (34/21) Twice a wk for 45 min over 8 wk 8 wk Intervention 6.7 (2.6) y; control 7.8 (3.7) y Intervention 15/19; control 10/11 
 Park et al33  (2020) English/Korea No Usual daily activities Randomized, parallel-group design 13/13 (13/13) Twice a wk for 40 min over 16 wk 16 wk Intervention 8.15 (1.91) y; control 7.54 (1.56) y Intervention 6/7; control 8/5 
 Silkwood-Sherer et al34  (2020) English/US Yes Usual physical and occupational therapy Randomized parallel group design 19 (13) Once a wk for 12 wk 12 wk Intervention 3-6 y; control 3-6 y Intervention 6/3; control 2/2 
 Suk and Kwon26  (2022) English/Korea No Usual physical therapy Randomized parallel group design 23/23 (23/23) Twice a wk for 40 min over 16 wk16 16 wk Intervention 7.74 (1.63) y; control 7.22 (1.48) Intervention 12/11; control 12/11 
Standard of care versus standard of care with additional riding therapy (artificial horse) 
 Fernandes et al31  (2008) English/India n.a. Conventional therapy 3 times a week for 60 min over 6 wk Randomized, parallel-group design 15/15 (15/15) Three times a wk for 15 min over 6 wk 6 wk Intervention 6.9 (1.4);control 7.6 (2.1) Intervention 7/8; control 9/6 
 Quint and Toomey16  (1998) English/England n.a. Artificial static horse Randomized parallel group design, matched pairs 15/15 (13/13) Ten times per day for 10 min on 20 d 4 wk Range 9 to 16 y No data 
 Herrero et al14  (2012) English/Spain n.a. Hippotherapy simulator switched off once a wk for 15 min over 10 wk Randomized, parallel-group design 19/19 (19/18) Once a wk for 15 min over 10 wk 10 wk Intervention 9.95 (1.5); control 9.05 (1.5) Intervention 14/5; control 10/9 
Riding therapy with living horse versus riding therapy with artificial horse 
 Lee et al15  (2014) English/Korea Yes Horseback riding simulator Randomized, parallel-group design 13/13 (13/13) Three times a wk for 60 min over 12 wk 12 wk Intervention 10.8 (1.6); control (simulator) 10.0 (2.2) Intervention 8/5; control (simulator) 9/4 
 Temcharoensuk et al36  (2015) English/Thailand No Horseback riding simulator, 1 group dynamic and the other static Randomized, parallel-group design 10/10 (10/10) 30 min once 1 d Intervention 10.7 (1.7); control (simulator) 10.1 (1.7) Intervention 5/5; control (simulator) 4/6 

n.a., not applicable; EAA, equine-assisted activity.

a

Hippotherapy is defined by “the therapy was conducted by a certified trainer”, and the term “hippotherapy” was used in the abstract and/or the text.

Risk of bias varied from low to high risk of bias. Bias in randomized studies was assessed with the Risk of Bias 2 tool (RoB 2) and was judged in all randomized controlled trials but 1 with “some concerns”, mainly because information on randomization and concealment was insufficient, the proportions of missing data were different across groups, and the assessor of the subjective outcomes was not blinded.

Bias in nonrandomized studies was assessed with the Risk of Bias in Nonrandomized Studies of Interventions tool. Four20,21,25,27  out of 8 studies were judged with serious risk of bias mainly due to potential confounding. Three studies24,30,31  were evaluated with a moderate risk of bias. Because of critical selection bias, the study of Lerma-Castano et al23  was excluded from the meta-analysis.

We provided a summary of the bias assessment within studies in Tables 2 and 3.

TABLE 2

Bias Assessment in Randomized Controlled Trials with RoB 2 in Categories Low/High/Some Concerns

StudyBias Arising from the Randomization ProcessBias Because of Deviation from Intended InterventionsBias Because of Missing Outcome DataBias in Measurement of the OutcomeBias in Selection of the Reported ResultOverall Risk of Bias
Ahn et al32  (2021) Some concerns Some concerns Low Some concerns Some concerns Some concerns 
Benda et al17  (2003) Low Low Low Some concerns Low Some concerns 
Davis et al8  (2009) Low Low Some concerns Low Low Some concerns 
Deutz et al9  (2018) Some concerns Low Low Low Low Some concerns 
El Meniawy et al19  (2012) Some concerns Low Low Some concerns Low Some concerns 
Fernandes et al31  (2008) Some concerns Low Some concerns Some concerns Low Some concerns 
Herrero et al14  (2012) Low Low Low Some concerns Some concerns Some concerns 
Kang et al10  (2012) Some concerns Low Low Some concerns Low Some concerns 
Kwon et al11  (2015) Some concerns Low Low Low Low Some concerns 
Lee et al15  (2014) Some concerns Low Low Some concerns Some concerns Some concerns 
Lucena-Anton et al12  (2018) Some concerns Low Low Low Low Some concerns 
Mc Gibbon et al18  (2009) Some concerns Low Low Low Low Some concerns 
Mutoh et al (2019)35 Some concerns Low Low Low Low Some concerns 
Park et al33  (2020) Some concerns Some concerns Low Low Some concerns Some concerns 
Quint and Toomey16  (1998) Some concerns Low Low Low Low Some concerns 
Silkwood-Sherer et al34 (2020) Low Some concerns Low Low Some concerns Some concerns 
Suk and Kwon26  (2022) Low Low Low Low Low Low 
Temcharoensuk et al36 (2015) Some concerns Low Low Some concerns. Low Some concerns 
StudyBias Arising from the Randomization ProcessBias Because of Deviation from Intended InterventionsBias Because of Missing Outcome DataBias in Measurement of the OutcomeBias in Selection of the Reported ResultOverall Risk of Bias
Ahn et al32  (2021) Some concerns Some concerns Low Some concerns Some concerns Some concerns 
Benda et al17  (2003) Low Low Low Some concerns Low Some concerns 
Davis et al8  (2009) Low Low Some concerns Low Low Some concerns 
Deutz et al9  (2018) Some concerns Low Low Low Low Some concerns 
El Meniawy et al19  (2012) Some concerns Low Low Some concerns Low Some concerns 
Fernandes et al31  (2008) Some concerns Low Some concerns Some concerns Low Some concerns 
Herrero et al14  (2012) Low Low Low Some concerns Some concerns Some concerns 
Kang et al10  (2012) Some concerns Low Low Some concerns Low Some concerns 
Kwon et al11  (2015) Some concerns Low Low Low Low Some concerns 
Lee et al15  (2014) Some concerns Low Low Some concerns Some concerns Some concerns 
Lucena-Anton et al12  (2018) Some concerns Low Low Low Low Some concerns 
Mc Gibbon et al18  (2009) Some concerns Low Low Low Low Some concerns 
Mutoh et al (2019)35 Some concerns Low Low Low Low Some concerns 
Park et al33  (2020) Some concerns Some concerns Low Low Some concerns Some concerns 
Quint and Toomey16  (1998) Some concerns Low Low Low Low Some concerns 
Silkwood-Sherer et al34 (2020) Low Some concerns Low Low Some concerns Some concerns 
Suk and Kwon26  (2022) Low Low Low Low Low Low 
Temcharoensuk et al36 (2015) Some concerns Low Low Some concerns. Low Some concerns 
TABLE 3

Bias Assessment in Nonrandomized Controlled Trials with ROBINS-I in Categories Low/Moderate/Serious/Critical/No Information

StudyBias Because of ConfoundingBias in Selection of Participants into the StudyBias in Classification of InterventionsBias Because of Deviations from Intended InterventionsBias Because of Missing DataBias in Measurement of OutcomesBias in Selection of the Reported ResultOverall Risk of Bias
Alemdaroglu et al20  (2016) Serious Low Low Low Low No inform. Low Serious 
Baik et al27  (2014) Serious Serious Low Low Low Moderate Low Serious 
Cherng et al21  (2004) Serious Low Low Low Serious Low Low Serious 
Kang et al30  (2013) Moderate Low Low Low No inform. No inform. Low Moderate 
Kwon et al22  (2011) Moderate Low Low Low Low Low Low Moderate 
Lerma-Castano et al23  (2017) Critical Critical Low Low No inform. No inform. Low Critical 
Matusiak et al24  (2016) Moderate Low Low Low No inform. No inform. Low Moderate 
Park et al25  (2014) Serious Low Low Low Serious No inform. Low Serious 
StudyBias Because of ConfoundingBias in Selection of Participants into the StudyBias in Classification of InterventionsBias Because of Deviations from Intended InterventionsBias Because of Missing DataBias in Measurement of OutcomesBias in Selection of the Reported ResultOverall Risk of Bias
Alemdaroglu et al20  (2016) Serious Low Low Low Low No inform. Low Serious 
Baik et al27  (2014) Serious Serious Low Low Low Moderate Low Serious 
Cherng et al21  (2004) Serious Low Low Low Serious Low Low Serious 
Kang et al30  (2013) Moderate Low Low Low No inform. No inform. Low Moderate 
Kwon et al22  (2011) Moderate Low Low Low Low Low Low Moderate 
Lerma-Castano et al23  (2017) Critical Critical Low Low No inform. No inform. Low Critical 
Matusiak et al24  (2016) Moderate Low Low Low No inform. No inform. Low Moderate 
Park et al25  (2014) Serious Low Low Low Serious No inform. Low Serious 

The following different types of treatment were distinguished: equine-assisted therapy, treatment based on living and artificial horses; hippotherapy, true hippotherapy as described above; therapeutic riding, living equine-assisted treatment not fulfilling the criteria of hippotherapy; living equine-assisted therapy, comprising both hippotherapy and therapeutic riding; and artificial horse, nonliving equine-assisted therapy using a horse-riding simulator.

Global motor function was assessed by the GMFM total score, applying either the GMFM-66-tool or the GMFM-88 tool. We found evidence of improved motor function measured by GMFM total scores among children with CP and usual care compared with those with additional equine-assisted therapy (hippotherapy = 6; therapeutic riding = 2; and artificial horse = 2) (SMD, 0.24; 95% CI, 0.05 to 0.43; P = .01; τ2 = 0.00; I2 = 15%; Fig 2). In addition, a significant treatment effect could be shown for the subdomain E of the GMFM score (hippotherapy = 5; and therapeutic riding = 2) (SMD, 2.68; 95% CI, 1.02 to 4.34; P = .002; τ2 = 0.0; I2 = 0%; Fig 3). In no other subdomain of the GMFM score evidence for an improved motor function could be proven (Figs 47).

FIGURE 2

GMFM total: data from parallel-group designs and crossover studies with living and artificial horses combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). If GMFM-66 and GMFM-88 were available, then GMFM-66 data were included.

FIGURE 2

GMFM total: data from parallel-group designs and crossover studies with living and artificial horses combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). If GMFM-66 and GMFM-88 were available, then GMFM-66 data were included.

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FIGURE 3

GMFM-E (walking): data from parallel-group designs and crossover studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). For this analysis, only data from studies with living horses were available.

FIGURE 3

GMFM-E (walking): data from parallel-group designs and crossover studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). For this analysis, only data from studies with living horses were available.

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FIGURE 4

GMFM-D (standing): data from parallel-group designs and crossover studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). For this analysis only data from studies with living horses were available.

FIGURE 4

GMFM-D (standing): data from parallel-group designs and crossover studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). For this analysis only data from studies with living horses were available.

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FIGURE 5

GMFM-C (crawling): data from parallel-group designs and crossover studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). For this analysis, only studies with living horses were available.

FIGURE 5

GMFM-C (crawling): data from parallel-group designs and crossover studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). For this analysis, only studies with living horses were available.

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FIGURE 6

Motor abilities as assessed during sitting by means of GMFM-B, GMFM-B by Rasch analysis, SAS, MFRT and force plate testing: data from parallel-group designs and crossover studies combined by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 6

Motor abilities as assessed during sitting by means of GMFM-B, GMFM-B by Rasch analysis, SAS, MFRT and force plate testing: data from parallel-group designs and crossover studies combined by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 7

GMFM-A (lying): data from parallel-group designs and cross-over studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 7

GMFM-A (lying): data from parallel-group designs and cross-over studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

Close modal

Motor function assessed while sitting was not only evaluated with GMFM-B but also with the modified functional reach test,20  the SAS,24  force plate testing,10  and GMFM-B reanalyzed by Rasch analysis.36  Combined analysis of all these data also failed to demonstrate a significant treatment effect (SMD, 0.42; 95% CI, 0.00 to 0.84; P = .0524; τ2 = 0.29; I2 = 79%; Fig 6). Motor function as assessed by the PBS describes motor abilities during sitting and standing and was reported by 5 studies. Evidence of treatment effect could be identified on PBS testing associated with high statistical heterogeneity (SMD, 0.67; 95% CI, −0.12 to 1.23; P = .02; τ2 = 0.29; I2 = 85%; Fig 8).

FIGURE 8

Balance as assessed by the PBS during sitting: data from parallel-group designs combined by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 8

Balance as assessed by the PBS during sitting: data from parallel-group designs combined by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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Motor function as assessed by gait analysis was reported by up to 4 studies on hippotherapy applying 3 different subtests (eg, step length, walking speed, and cadence. Hippotherapy compared with standard of care resulted in significantly higher step length (MD, 10.66; 95% CI, 2.73 to 18.59; P = .008; τ2 = 28.21; I2 = 84%; Fig 9) but not in improved walking speed (SMD, 2.34; 95% CI, −0.11 to 4.80; P = .06; τ2 = 4.67; I2 = 95%; Fig 10) or cadence (MD, 2.22; 95% CI, −25.31 to 29.75; P = .87; τ2 = 332.39; I2 = 84%; Fig 11).

FIGURE 9

Gait analysis, step length (cm): data from parallel-group designs combined by SMD in a random effects model (RevMan 5.3.5).

FIGURE 9

Gait analysis, step length (cm): data from parallel-group designs combined by SMD in a random effects model (RevMan 5.3.5).

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FIGURE 10

Gait analysis, walking speed (m/min or cm/s): data from parallel-group designs combined by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 10

Gait analysis, walking speed (m/min or cm/s): data from parallel-group designs combined by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 11

Gait analysis, cadence (step/min): data from parallel-group designs combined by MD in a random effects model (RevMan 5.3.5).

FIGURE 11

Gait analysis, cadence (step/min): data from parallel-group designs combined by MD in a random effects model (RevMan 5.3.5).

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No evidence of improved motor function measured by different spasticity parameters was identified (hippotherapy = 5; therapeutic riding = 3; and artificial horse = 1) (SMD, −0.44; 95% CI, −0.90 to −0.02; P = .06; τ2 = 0.31; I2 = 64%; Fig 12). However, the I2 (of 64%) points to a considerable heterogeneity between studies. Subgroups with respect to different instruments assessing spasticity reduced heterogeneity to 32% between studies using Ashworth, 19% using hip range of motion, and 59% using electromyography asymmetry scores (Fig 12).

FIGURE 12

Pooled analysis of different spasticity parameters: data from the modified Ashworth scale, hip range of motion, electromyography asymmetry, score and Formetric analysis combined by SMD in a random effects model (RevMan 5.3.5). Data of Cherng 2004 from the first Period was included. Secondary outcomes: functioning during daily life, QoL (eg, Pediatric Evaluation of Disability Inventory [PEDI], CHQ, KIDSCREEN, and CP-QoL-CHILD).

FIGURE 12

Pooled analysis of different spasticity parameters: data from the modified Ashworth scale, hip range of motion, electromyography asymmetry, score and Formetric analysis combined by SMD in a random effects model (RevMan 5.3.5). Data of Cherng 2004 from the first Period was included. Secondary outcomes: functioning during daily life, QoL (eg, Pediatric Evaluation of Disability Inventory [PEDI], CHQ, KIDSCREEN, and CP-QoL-CHILD).

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QoL assessment was performed in 4 studies,8,9,25,32  whereas only data on global QoL as well as on physical, social, and emotional QoL subscores could be included. QoL data from Silkwood-Sherer and McGibbon’s study34  were not included, as they were derived from children and parents. Our analysis could not demonstrate evidence for the improvement for any of the QoL scores (global QoL: SMD, −0.11; 95% CI, −0.15 to 0.37; P = .40, τ2 = 0.0; I2 = 0%; Fig 13; physical QoL: SMD, 0.08; 95% CI, −0.26 to 0.42; P = .63; τ2 = 0.06; I2 = 43%; Fig 14; social QoL: SMD, −0.02; 95% CI, −0.26 to 0.22; P = .87, τ2 = 0.0; I2 = 0%; Fig 15; emotional QoL: SMD, −1.58; 95% CI, −1.36 to 4.51; P = .29; τ2 = 6.49; I2 = 97%; Fig 16).

FIGURE 13

QoL (global): data from parallel-group designs and crossover studies combined for different QoL assessment (Kidscreen, PEDI) by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 13

QoL (global): data from parallel-group designs and crossover studies combined for different QoL assessment (Kidscreen, PEDI) by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 14

QoL (physical): data from parallel-group designs and crossover studies combined for different QoL assessment (CHQ, PEDI) by SDM using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 14

QoL (physical): data from parallel-group designs and crossover studies combined for different QoL assessment (CHQ, PEDI) by SDM using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 15

QoL (social): data from parallel-group designs and crossover studies combined for different QoL assessment (CHQ, PEDI) by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 15

QoL (social): data from parallel-group designs and crossover studies combined for different QoL assessment (CHQ, PEDI) by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 16

QoL (emotional): data from parallel-group designs and crossover studies combined for different QoL assessment (CP-QoL-Child, KIDSCREEN-27) by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). Subgroup and sensitivity analyses.

FIGURE 16

QoL (emotional): data from parallel-group designs and crossover studies combined for different QoL assessment (CP-QoL-Child, KIDSCREEN-27) by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5). Subgroup and sensitivity analyses.

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As we could not pool more than 10 studies, we did not create a funnel plot to explore possible small study biases for the primary outcome. A registered study protocol in a publicly accessible database was available for the studies of Herrero et al14,41  and Ahn et al.32  Whereas the protocol included several outcomes, only data on the GMFM, SAS testing, or PedsQL were reported in the final study. Mutho et al13  provided a protocol as a supplement29 . For this study, no deviation between publication and protocol was noted.

A comparison of GMFM total measurements between types of equine-assisted therapy revealed a nonsignificant difference between hippotherapy, therapeutic riding, and artificial horse (P = .07; Fig 17) as well as a nonsignificant difference between therapy with living and therapy with artificial horses (P = .83; Fig 18).

FIGURE 17

Subgroup analysis, GMFM total, hippotherapy versus therapeutic riding versus artificial horse including formal test for subgroup interaction: data from parallel-group designs and crossover studies combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 17

Subgroup analysis, GMFM total, hippotherapy versus therapeutic riding versus artificial horse including formal test for subgroup interaction: data from parallel-group designs and crossover studies combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 18

Subgroup analysis, GMFM total, living versus artificial horses including formal test for subgroup interaction: data from parallel-group designs and crossover studies combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 18

Subgroup analysis, GMFM total, living versus artificial horses including formal test for subgroup interaction: data from parallel-group designs and crossover studies combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

Close modal

Comparison of motor function between fewer or at least 8 weeks’ duration of therapy also did not show a significant difference with respect to GMFM total score (P = .80; Fig 19).

FIGURE 19

Subgroup analysis, GMFM total, 8 weeks and less versus more than 8 weeks’ duration of therapy, including formal test for subgroup interaction: data from parallel-group designs and crossover studies combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 19

Subgroup analysis, GMFM total, 8 weeks and less versus more than 8 weeks’ duration of therapy, including formal test for subgroup interaction: data from parallel-group designs and crossover studies combined for different GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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Limiting the analyses to studies at low risk or some concerns of bias provided evidence for improved motor function as assessed by the GMFM total (SMD, 0.25; 95% CI, −0.04 to 0.46; P = .02; τ2 = 0.02; I2 = 18%; Fig 20) and by the GMFM subdomain E (hippotherapy = 4; therapeutic riding = 1) (SMD, 2.51; 95% CI, −0.68 to 4.34; P = .007; τ2=0.00; I2 = 0%; Fig 21).

FIGURE 20

Sensitivity analysis, GMFM total by limiting analyses to studies at low risk or some concerns of bias: data from parallel-group designs and crossover studies combined for different for GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 20

Sensitivity analysis, GMFM total by limiting analyses to studies at low risk or some concerns of bias: data from parallel-group designs and crossover studies combined for different for GMFM assessment by SMD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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FIGURE 21

Sensitivity-analysis, GMFM-E by limiting analyses to studies at low risk or some concerns of bias: data from parallel-group designs and cross-over studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

FIGURE 21

Sensitivity-analysis, GMFM-E by limiting analyses to studies at low risk or some concerns of bias: data from parallel-group designs and cross-over studies combined by MD using the generic inverse variance approach in a random effects model (RevMan 5.3.5).

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A large number of reviews have already addressed the impact of equine-assisted treatments on children with CP, including 6 meta-analyses.2,4,5,7,28,42  This, however, is the first meta-analysis that is based on a prepublished protocol, includes studies on living and artificial horses, and focuses on both motor function and QoL.

Riding on a horse involves a large number of body muscles, which confounds its use for treatment of motor disturbances. The therapeutic use of animal horses in general is called therapeutic riding, whereas the term hippotherapy implies guidance by a trained therapeutic person, such as a physiotherapist or occupational therapist, experienced in this treatment.43  For all animal-based studies included in the present meta-analysis, the involvement of trained therapists was reported, indicating a high standard of treatment. Only those 14 studies, however, that contained the term hippotherapy in the manuscript were finally classified as hippotherapy studies.

The primary question of this meta-analysis was related to motor outcome, which we at first addressed by pooling studies on living and artificial horses, which used the GMFM total tool. We preferentially included data on the GMFM-66 tool, as this was specifically developed for patients with CP,3740  and found a significant effect, suggesting that equine-assisted therapy does positively affect global motor function. Astonishingly, this effect was chiefly based on studies using the GMFM-88 tool, although subgroup analyses on three studies that reported on GMFM-66 and GMFM-88 data did not reveal a significant difference between both measures.11,22,25  Moreover, this effect of different horse-based treatments on the GMFM total score could still be observed when restricting the analysis to studies with no or low risk of bias (Fig 20).

Previous meta-analyses have already focused on the impact of horse-related treatment on global gross motor function. Tseng et al4  did not find improved total GMFM-66 scores or GMFM-88 scores when pooling studies with hippotherapy and therapeutic riding, respectively.4,18,21,22,44,45  No controls had been provided by 2 of the included studies.44,45  Wang et al7  included studies on artificial and living horses. They found no significant effects when studying GMFM-66 total or GMFM-88 total data alone but a significant effect in favor of the intervention when pooling GMFM-66 with GMFM-88 total data. Stergiou et al2  and Charry-Sanchez et al3  analyzed the same 4 studies on children with CP and did not find a significant effect of hippotherapy on motor function as assessed by the GMFM-66 total measure. Santos et al28  also failed to detect a treatment effect of hippotherapy when analyzing 3 different studies.

During further subgroup analyses (Figs 1719), we addressed differences in GMFM total scores when comparing living with artificial horses, therapeutic riding with hippotherapy, as well as longer with shorter treatment duration. Hereby, no significant differences between these groups could be detected. Kwon et al11  compared children of different Gross Motor Function Classification System (GMFCS) levels reporting on significantly increased GMFM-66 for children with levels II, III, and IV and significantly increased GMFM-88 scores for children with all GMFCS levels, suggesting no major impact of the GMFCS on the effect of equine-assisted therapy. In our previous study,9  we did not find a relationship between the number of treatments and the GMFM total measure.

We further addressed the impact of horse-related treatment on distinct motor subdomains mostly assessed by the GMFM tool focusing on lying (dimension A), sitting (dimension B), crawling (dimension C), standing (dimension D), and walking (dimension E). These data were complemented by data on subdomains assessed by further instruments such as gait analysis, SAS, or PBS.

As for dimensions A, C, and D, and for motor function during sitting, we did not find significant treatment effects. A significant treatment effect, however, was detected for GMFM dimension E based on 5 studies with hippotherapy and 2 studies with therapeutic riding. This effect was still visible when confining the analysis to 5 studies with low and moderate risk of bias indicating a strong effect (hippotherapy, n = 4; and therapeutic riding, n = 1). Analyzing results from studies with gait analysis as outcome parameter confirmed this positive effect on gait, revealing significant effects of animal-based treatments on step length (Fig 9). The 2 studies analyzed for step length showed significant heterogeneity, so this effect should be taken with caution. Compared with the study of Mutoh et al,35  the study of Kwon et al22  recorded a decrease of cadence, a stronger increase in step length, and a similar increase in walking speed. In the study of Kwon et al,22  children were younger and less severely affected (GMFCS I/II vs II/III), which may contribute to this heterogeneity. As sufficient data were not available, GMFCS as a possible source of heterogeneity could not be evaluated. Studies on motor function during sitting showed a comparably high degree of heterogeneity, possibly because the different tests applied did not measure identical sitting capabilities. Moreover, the study of Temcharoensuk et al36  was the only one involving artificial horses and a reanalysis of GMFM data by Rasch analysis.

Spasticity is one further major problem in children with CP. Combined analysis of 9 studies on different spasticity parameters did not reveal a significant reduction of spasticity during equine-assisted therapy. This contrasts with the recent meta-analysis of Hyun et al,42  who, however, also included case series and repeated measure designs.

Results from comparable meta-analyses on motor subdomains in the literature are contradictory. As for the GMFM-E domain, Tseng et al4  analyzed 2 studies with hippotherapy and 2 studies with therapeutic riding.21,22,44,45  They did not find significant effects, neither when studying both groups separately nor when pooling the 4 studies. As for stride length, they analyzed 2 studies,22,46  also not finding any improvement. As for the asymmetry score, they found reduced asymmetry after hippotherapy.17,18  Little et al6  analyzed 3 studies with hippotherapy and 3 with therapeutic riding, among others focusing on GMFM domains E and D. They did not find significant effects for dimension D or dimension E. Wang et al7  pooled data from studies with artificial and living horses. They did not observe a significant effect with regard to dimension B and dimension D, whereas a significant effect in favor of the intervention was observed for dimension E. Dominguez et al47  performed a meta-analysis on artificial horses, not detecting a significant effect on GMFM dimension B. Zadnikar et al5  performed a meta-analysis on 11 studies applying hippotherapy, therapeutic riding, or artificial horse therapy, which measured outcome by a variety of different tests. In their pooled analysis, they reported a significant effect on postural control and balance. Santos et al28  did not find significant effects when analyzing 3 studies for GMFM dimension E, 3 studies for GMFM dimension D, and 2 studies for cadence, stride length, and walking speed, respectively.

The interaction between living horses and human beings may also affect QoL. Focusing on this hypothesis, we did not detect a significant effect regarding global QoL, the physical, social, or emotional subdomains, respectively. Several reasons may account for this observation: The low number of studies available and the heterogeneity of QoL domains assessed in different studies made it difficult to combine studies for meta-analytic procedures. Equine-assisted treatments might also affect QoL domains other than those included in this analysis, such as family cohesion.8  Marked heterogeneity was also observed with regard to emotional QoL outcome, which may be related to the fact that the Kidscreen-27 tool used by Deutz et al9  was developed to measure general health-related QoL, whereas the CP-QoL tool used by Davis et al8  focuses on QoL in children with CP.42 

Major limitations of this meta-analysis are the heterogeneity of tools used in different studies and the low number of studies addressing QoL issues, factors that limit the number of studies available for distinct analyses. Apart from the GMFM total measure and the GMFM subdomains, the capabilities assessed by various measures differed markedly, which could explain the heterogeneity found in some analyses.

We found strong evidence for a positive effect of equine-assisted therapy on GMFM total, particularly on motor capabilities during walking. This effect may in part be based on improved balance and can be effectively monitored by applying the GMFM total, the GMFM-E, and the PBS tools, respectively. The effect of equine-assisted treatments on the GMFM total score and on the GMFM dimension E was strong and still present when excluding studies with high risk of bias. The treatment standard in the studies on therapeutic riding that were included in the analysis of GMFM total (n = 2) and GMFM dimension E (n = 1) were high and comparable to hippotherapy standards. This recommends living horse-assisted therapy, particularly hippotherapy, as a therapeutic tool for children with CP who are about to learn walking or already have achieved the ability to walk. The high professional therapeutic level described in most studies also recommends providing comparably high treatment standards in clinical settings. Whereas the overall treatment duration ranged from 1 day to 1 year, most children received weekly sessions for a period of 2 to 3 months, so first therapeutic effects should be observed within this timeframe. Further studies on the effects of equine-assisted therapy on motor function should always include the GMFM tool to facilitate data comparison, although additional methods, for example, focusing on spasticity, will be necessary to broaden the view on different therapeutic effects. As for QoL assessment, a broad approach may be necessary to detect more QoL subdomains that are positively influenced by equine-assisted therapies.

We thank Dr Dorothée Debuse (Faculty of Health and life Sciences, Northumbria University, Newcastle Upon Tyne, UK) and Mrs Sanna Mattila-Rautiainen (President of HETI, the Federation of Horses for Education and Therapy International) for advising us with the selection of studies to be included.

Prof Häusler, designed the clinical part of the study, set up the search strategy and conducted the literature search, screened the eligible studies, performed the bias assessment, conducted the data extraction, interpreted the results, and drafted the manuscript; Prof Heussen finalized the manuscript, designed the methodological part of the study, screened the eligible studies, performed the bias assessment, conducted the data extraction and the statistical analysis, and interpreted the results; and both authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

This trial has been registered with the International Prospective Register of Systematic Reviews (https://www.crd.york.ac.uk/prospero/) (identifier CRD42018096403) and was published in BioMed Central Systematic Reviews (Häusler M, Heussen N. Protocol for a systematic review and meta-analysis on the effect of hippotherapy and related equine-assisted therapies on motor capabilities in children with cerebral palsy. Syst Rev. 2020;9(1):48).

FUNDING: No external funding.

CONFLICT OF INTEREST DISCLOSURES: The authors have indicated they have no conflicts of interest relevant to this article to disclose.

     
  • CI

    confidence interval

  •  
  • CP

    cerbral palsy

  •  
  • GMFCS

    Gross Motor Function Classification System

  •  
  • GMFM

    gross motor function measure

  •  
  • PBS

    Pediatric Balance Scale

  •  
  • QoL

    quality of life

  •  
  • RoB 2

    Risk of Bias 2 tool

  •  
  • SAS

    Sitting Assessment Scale

  •  
  • SMD

    standard mean difference

1
Surveillance of Cerebral Palsy in Europe
.
Surveillance of cerebral palsy in Europe: a collaboration of cerebral palsy surveys and registers. Surveillance of Cerebral Palsy in Europe (SCPE)
.
Dev Med Child Neurol
.
2000
;
42
(
12
):
816
824
2
Stergiou
A
,
Tzoufi
M
,
Ntzani
E
,
Varvarousis
D
,
Beris
A
,
Ploumis
A
.
Therapeutic Effects of horseback riding interventions: a systematic review and meta-analysis
.
Am J Phys Med Rehabil
.
2017
;
96
(
10
):
717
725
3
Charry-Sanchez
JD
,
Pradilla
I
,
Talero-Gutierrez
C
.
Effectiveness of animal-assisted therapy in the pediatric population: systematic review and meta-analysis of controlled studies
.
J Dev Behav Pediatr
.
2018
;
39
(
7
):
580
590
4
Tseng
SH
,
Chen
HC
,
Tam
KW
.
Systematic review and meta-analysis of the effect of equine assisted activities and therapies on gross motor outcome in children with cerebral palsy
.
Disabil Rehabil
.
2013
;
35
(
2
):
89
99
5
Zadnikar
M
,
Kastrin
A
.
Effects of hippotherapy and therapeutic horseback riding on postural control or balance in children with cerebral palsy: a meta-analysis
.
Dev Med Child Neurol
.
2011
;
53
(
8
):
684
691
6
Little
K
,
Nel
N
,
Ortell
V
,
Wyk
HV
,
Badenhorst
M
,
Louw
Q
.
The clinical effect of hippotherapy on gross motor function of children with cerebral palsy
.
S Afr J Physiother
.
2013
;
69
(
2
):
26
34
7
Wang
G
,
Ma
R
,
Qiao
G
,
Wada
K
,
Aizawa
Y
,
Satoh
T
.
The effect of riding as an alternative treatment for children with cerebral palsy: a systematic review and meta-analysis
.
Integr Med Int
.
2014
;
1
(
4
):
211
222
8
Davis
E
,
Davies
B
,
Wolfe
R
, et al
.
A randomized controlled trial of the impact of therapeutic horse riding on the quality of life, health, and function of children with cerebral palsy
.
Dev Med Child Neurol
.
2009
;
51
(
2
):
111
119
,
discussion 88
9
Deutz
U
,
Heussen
N
,
Weigt-Usinger
K
, et al
.
Impact of hippotherapy on gross motor function and quality of life in children with bilateral cerebral palsy: a randomized open-label crossover study
.
Neuropediatrics
.
2018
;
49
(
3
):
185
192
10
Kang
H
,
Jung
J
,
Yu
J
.
Effects of hippotherapy on the sitting balance of children with cerebral palsy: a randomized control trial
.
J Phys Ther Sci
.
2012
;
24
(
9
):
833
836
11
Kwon
JY
,
Chang
HJ
,
Yi
SH
,
Lee
JY
,
Shin
HY
,
Kim
YH
.
Effect of hippotherapy on gross motor function in children with cerebral palsy: a randomized controlled trial
.
J Altern Complement Med
.
2015
;
21
(
1
):
15
21
12
Lucena-Antón
D
,
Rosety-Rodríguez
I
,
Moral-Munoz
JA
.
Effects of a hippotherapy intervention on muscle spasticity in children with cerebral palsy: a randomized controlled trial
.
Complement Ther Clin Pract
.
2018
;
31
:
188
192
13
Mutoh
T
,
Mutoh
T
,
Tsubone
H
, et al
.
Effect of hippotherapy on gait symmetry in children with cerebral palsy: a pilot study
.
Clin Exp Pharmacol Physiol
.
2019
;
46
(
5
):
506
509
14
Herrero
P
,
Gómez-Trullén
EM
,
Asensio
A
, et al
.
Study of the therapeutic effects of a hippotherapy simulator in children with cerebral palsy: a stratified single-blind randomized controlled trial
.
Clin Rehabil
.
2012
;
26
(
12
):
1105
1113
15
Lee
CW
,
Kim
SG
,
Na
SS
.
The effects of hippotherapy and a horse riding simulator on the balance of children with cerebral palsy
.
J Phys Ther Sci
.
2014
;
26
(
3
):
423
425
16
Quint
C
,
Toomey
M
.
Powered saddle and pelvic mobility: an investigation into the effects on pelvic mobility of children with cerebral palsy of a powered saddle which imitates the movements of a walking horse
.
Physiotherapy
.
1998
;
84
:
376
384
17
Benda
W
,
McGibbon
NH
,
Grant
KL
.
Improvements in muscle symmetry in children with cerebral palsy after equine-assisted therapy (hippotherapy)
.
J Altern Complement Med
.
2003
;
9
(
6
):
817
825
18
McGibbon
NH
,
Benda
W
,
Duncan
BR
,
Silkwood-Sherer
D
.
Immediate and long-term effects of hippotherapy on symmetry of adductor muscle activity and functional ability in children with spastic cerebral palsy
.
Arch Phys Med Rehabil
.
2009
;
90
(
6
):
966
974
19
El-Meniawy
GH
,
Thabet
NS
.
Modulation of back geometry in children with spastic diplegic cerebral palsy via hippotherapy training
.
Egypt J Med Hum Genet
.
2012
;
13
(
1
):
63
71
20
Alemdaroğlu
E
,
Yanıkoğlu
İ
,
Öken
Ö
, et al
.
Horseback riding therapy in addition to conventional rehabilitation program decreases spasticity in children with cerebral palsy: a small sample study
.
Complement Ther Clin Pract
.
2016
;
23
:
26
29
21
Cherng
RJ
,
Liao
HF
,
Leung
HWC
,
Hwang
AW
.
The effectiveness of therapeutic horseback riding in children with spastic cerebral palsy
.
Adapt Phys Activ Q
.
2004
;
21
(
2
):
103
121
22
Kwon
JY
,
Chang
HJ
,
Lee
JY
,
Ha
Y
,
Lee
PK
,
Kim
YH
.
Effects of hippotherapy on gait parameters in children with bilateral spastic cerebral palsy
.
Arch Phys Med Rehabil
.
2011
;
92
(
5
):
774
779
23
Lerma-Castaño
PR
,
Rodríguez-Laiseca
YA
,
Falla
JD
,
López-Roa
LM
,
Puentes-Luna
LM
,
Romaña-Cabrera
LF
.
Effects of hippotherapy on gross motor function in children with spastic cerebral palsy: quasi-experimental study
.
Rev Mex de Pediatria
.
2017
;
84
(
4
):
143
148
24
Matusiak-Wieczorek
E
,
Małachowska-Sobieska
M
,
Synder
M
.
Influence of hippotherapy on body balance in the sitting position among children with cerebral palsy
.
Ortop Traumatol Rehabil
.
2016
;
18
(
2
):
165
175
25
Park
ES
,
Rha
DW
,
Shin
JS
,
Kim
S
,
Jung
S
.
Effects of hippotherapy on gross motor function and functional performance of children with cerebral palsy
.
Yonsei Med J
.
2014
;
55
(
6
):
1736
1742
26
Suk
MH
,
Kwon
JY
.
Effect of equine-assisted activities and therapies on cardiorespiratory fitness in children with cerebral palsy: a randomized controlled trial
.
J Integr Complement Med
.
2022
;
28
(
1
):
51
59
27
Baik
K
,
Byeun
JK
,
Baek
JK
.
The effects of horseback riding participation on the muscle tone and range of motion for children with spastic cerebral palsy
.
J Exerc Rehabil
.
2014
;
10
(
5
):
265
270
28
Santos de Assis
G
,
Schlichting
T
,
Rodrigues Mateus
B
,
Gomes Lemos
A
,
Dos Santos
AN
.
Physical therapy with hippotherapy compared to physical therapy alone in children with cerebral palsy: systematic review and meta-analysis
.
Dev Med Child Neurol
.
2022
;
64
(
2
):
156
161
29
Häusler
M
,
Heussen
N
.
Protocol for a systematic review and meta-analysis on the effect of hippotherapy and related equine-assisted therapies on motor capabilities in children with cerebral palsy
.
Syst Rev
.
2020
;
9
(
1
):
48
30
Kang
OD
,
Lee
WS
,
Ko
YJ
.
Effects of therapeutic riding in children with spastic cerebral palsy
.
J Anim Sci Technol
.
2013
;
55
(
6
):
559
565
31
Fernandes
LC
,
Chitra
J
,
Metgud
D
,
Khatri
SM
.
Effectiveness of artificial horse riding on postural control in spastic diplegics - RCT
.
Indian J Physiother Occup Ther
.
2008
;
2
:
36
40
32
Ahn
B
,
Joung
YS
,
Kwon
JY
, et al
.
Effects of equine-assisted activities on attention and quality of life in children with cerebral palsy in a randomized trial: examining the comorbidity with attention-deficit/hyperactivity disorder
.
BMC Pediatr
.
2021
;
21
(
1
):
135
33
Park
IK
,
Lee
JY
,
Suk
MH
, et al
.
Effect of equine-assisted activities on cardiac autonomic function in children with cerebral palsy: a pilot randomized-controlled trial
.
J Altern Complement Med
.
2021
;
27
(
1
):
96
102
34
Silkwood-Sherer
DJ
,
McGibbon
NH
.
Can hippotherapy make a difference in the quality of life of children with cerebral palsy? A pragmatic study
.
Physiother Theory Pract
.
2022
;
38
(
3
):
390
400
35
Mutoh
T
,
Mutoh
T
,
Tsubone
H
, et al
.
Impact of long-term hippotherapy on the walking ability of children with cerebral palsy and quality of life of their caregivers
.
Front Neurol
.
2019
;
10
:
834
36
Temcharoensuk
P
,
Lekskulchai
R
,
Akamanon
C
,
Ritruechai
P
,
Sutcharitpongsa
S
.
Effect of horseback riding versus a dynamic and static horse riding simulator on sitting ability of children with cerebral palsy: a randomized controlled trial
.
J Phys Ther Sci
.
2015
;
27
(
1
):
273
277
37
Palisano
R
,
Rosenbaum
P
,
Walter
S
,
Russell
D
,
Wood
E
,
Galuppi
B
.
Development and reliability of a system to classify gross motor function in children with cerebral palsy
.
Dev Med Child Neurol
.
1997
;
39
(
4
):
214
223
38
Avery
LM
,
Russell
DJ
,
Rosenbaum
PL
.
Criterion validity of the GMFM-66 item set and the GMFM-66 basal and ceiling approaches for estimating GMFM-66 scores
.
Dev Med Child Neurol
.
2013
;
55
(
6
):
534
538
39
Avery
LM
,
Russell
DJ
,
Raina
PS
,
Walter
SD
,
Rosenbaum
PL
.
Rasch analysis of the gross motor function measure: validating the assumptions of the Rasch model to create an interval-level measure
.
Arch Phys Med Rehabil
.
2003
;
84
(
5
):
697
705
40
Wood
E
,
Rosenbaum
P
.
The gross motor function classification system for cerebral palsy: a study of reliability and stability over time
.
Dev Med Child Neurol
.
2000
;
42
(
5
):
292
296
41
Herrero
P
,
Asensio
A
,
García
E
, et al
.
Study of the therapeutic effects of an advanced hippotherapy simulator in children with cerebral palsy: a randomised controlled trial
.
BMC Musculoskelet Disord
.
2010
;
11
:
71
42
Hyun
C
,
Kim
K
,
Lee
S
,
Ko
N
,
Lee
I-S
,
Koh
S-E
.
The short-term effects of hippotherapy and therapeutic horseback riding on spasticity in children with cerebral palsy: a meta-analysis
.
Pediatr Phys Ther
.
2022
;
34
(
2
):
172
178
43
Debuse
D
,
Gibb
C
,
Chandler
C
.
Effects of hippotherapy on people with cerebral palsy from the users’ perspective: a qualitative study
.
Physiother Theory Pract
.
2009
;
25
(
3
):
174
192
44
Hamill
D
,
Washington
KA
,
White
OR
.
The effect of hippotherapy on postural control in sitting for children with cerebral palsy
.
Phys Occup Ther Pediatr
.
2007
;
27
(
4
):
23
42
45
Sterba
JA
,
Rogers
BT
,
France
AP
,
Vokes
DA
.
Horseback riding in children with cerebral palsy: effect on gross motor function
.
Dev Med Child Neurol
.
2002
;
44
(
5
):
301
308
46
McGee
MC
,
Reese
NB
.
Immediate effects of a hippotherapy session on gait parameters in children with spastic cerebral palsy
.
Pediatr Phys Ther
.
2009
;
21
(
2
):
212
218
47
Dominguez-Romero
JG
,
Molina-Aroca
A
,
Moral-Munoz
JA
,
Luque-Moreno
C
,
Lucena-Anton
D
.
Effectiveness of mechanical horse-riding simulators on postural balance in neurological rehabilitation: systematic review and meta-analysis
.
Int J Environ Res Public Health
.
2019
;
17
(
1
):
E165

Supplementary data