According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder defined by deficits in social interaction skills, communication (verbal and non-verbal), and restricted repetitive patterns of behaviour [1
]. Research has suggested that children with ASD have delayed gross motor development [2
] and, consequently, reduced participation in physical activity in comparison to typically developing children [3
]. This reduced participation in physical activity has implications for the physical health of children with ASD, as a sedentary lifestyle can lead to cardiovascular disease, obesity, type-II diabetes, and other related health issues [4
]. Not only can a child’s physical health be compromised by physical inactivity, but so can their mental health—both of which have implications on a child’s overall well-being [5
Well-being has been previously defined as an individual’s overall state of health, including physical, psychological, social and emotional health [6
]. Improved well-being promotes a better self-image, positive interactions with family and peers, and a greater sense of happiness [7
]. The effects of physical activity have been extensively researched in typically developing children, showing reduced levels of anxiety and depression, improved self-perception and academic performance [8
]. Similar benefits have been proposed for children with ASD, indicating they too may benefit from physical activity [10
In the past, a variety of funded therapeutic options have been available for children with ASD, including speech and language therapy, behavioural interventions, and occupational therapy. However, these treatment options do not specifically focus on physical activity and fail to address gross motor skill and coordination deficits, which are prevalent in this population [2
]. Without proficient gross motor skills, the ability for children with ASD to participate in physical activity may be reduced [12
]. This may be particularly evident in the school environment, where running, jumping, hopping, kicking, throwing and catching are just some of the necessary gross motor skills required to participate in play and games with peers. A child’s inability to participate in these activities may lead to social isolation which, consequently, could further reduce mental health and well-being [5
Hydrotherapy (or water-based activity) is an environment that may be conducive to encouraging physical activity in children with ASD. The buoyancy of water can assist with movement, balance, and coordination [13
]. Water also provides an opportunity for social interaction through aquatic games and activities [14
]. Hydrotherapy may include aquatic programs, water-based activities or swimming programs. A previous systematic review by Mortimer, Privopolous and Kumar in 2014 [15
] revealed four previous studies that had explored the effectiveness of hydrotherapy in the treatment of social and behavioural aspects of children with ASD. However, they concluded that the literature was limited by a lack of controlled trials and standardised outcome measures to evaluate the effects. This pilot study aims to address this concern and to contribute further to this field of empirical research literature. Therefore, this study aims to determine whether hydrotherapy (or water-based therapy) influences behaviours related to the mental health and well-being of children with ASD. Specifically, the study aims to explore the effects of hydrotherapy on (i) emotional behaviours related to the domain of internalising problems (i.e., syndromes of anxious/depressed, withdrawn/depressed and somatic complaints); (ii) emotional behaviours related to the domain of externalising problems (i.e., syndromes of rule breaking behaviour and aggressive behaviour) and; (iii) behaviours impacting social functioning (i.e., syndromes of social problems, thought problems and attention problems).
This randomised crossover-controlled pilot trial aimed to explore the effects of a 4 week hydrotherapy (water-based) program on behaviours impacting the mental health and well-being of children with ASD. The major findings of the present study demonstrated that children with ASD may benefit from a hydrotherapy program to improve their internalising behaviours, specifically anxious and depressed behaviours, as well as reducing thought and attention problems.
Significant improvements were observed over the intervention period for the Anxious/Depressed, Thought Problems and Attention Problems syndromes for G1 and G2 combined. No differences were observed between G1 and G2 at baseline (week 0) for all CBCL domains and syndromes nor were any significant changes found over the control period. This indicates that these significant improvements in behaviours impacting mental health and well-being may be due to the hydrotherapy sessions carried out during the intervention periods, however it is possible that a number of confounding variables may have impacted the results and these are discussed further in the limitations section below.
The CBCL syndromes that are reported in the empirical literature to be most predominately elevated for children with ASD are Social Problems, Thought Problems, and Attention Problems [29
]. In the present study, significant decreases were observed over the intervention period (see Table 5
) for the Thought Problems Syndrome (p
= 0.03) and Attention Problems Syndrome (p
= 0.01), with Social Problems Syndrome approaching significant levels (p
= 0.08). These significant and near significant improvements in the CBCL syndromes which are most characteristic of children with ASD, indicate the potential for hydrotherapy to improve the syndromes most commonly associated with ASD.
The results of the present study relate to previously published findings from studies examining the effects of physical activity in typically developing children. A meta-analysis conducted by Ahn and Fedewa in 2011 [8
], showed exercise had small to moderate effects in reducing depression, anxiety, psychological stress, and emotional disturbances in children ranging from ages 3–18 years. These outcomes are mirrored in a cohort study conducted by Galper and colleagues in 2006 [32
], examining the relationship between physical activity and mental health in men and women aged 20-88 years. They discovered higher levels of habitual physical activity were associated with lower symptoms of depression and greater emotional well-being. Hydrotherapy has traditionally been under-utilised as a treatment modality in previously reported literature, compared to dry land activities, when exploring the effects of physical activity on mental health and well-being. However, there has been a recent increase in research on the effects of hydrotherapy programs for people with disabilities, and particularly children with ASD [15
Although there were no significant results to suggest specific improvements in social well-being, anecdotal evidence received from parents indicated a noticeable improvement. One parent mentioned her child being ‘more sociable’, seeking company from family and instigating friendly physical play with another child. Multiple parents reported their children being “more relaxed” and ‘less agitated’ following hydrotherapy interventions. This was reported to the therapists to have led to a better home environment and less strained parent–child relationship.
Improvements from hydrotherapy were well maintained over four weeks in the Withdrawn/Depressed and Rule Breaking syndromes for G1. Any gains in the remaining CBCL syndromes were not maintained for G1, and either returned to or approached baseline levels (see Figure 2
and Figure 3
). This result indicates a small carry over effect was found for select CBCL domains in this study. A similar study observed the effects of aquatic exercise on sleep in children with ASD [33
]. A carry over effect was observed in total sleep hours and sleep latency 4 weeks after the intervention period had concluded. Similarly, Pan and colleagues in 2010 [34
] showed that improvements of aquatic skills in children with ASD were maintained for 10 weeks after a water exercise swimming program. Therefore, certain benefits of hydrotherapy may extend beyond the period of hydrotherapy treatment, although this study did not investigate these findings over a prolonged follow-up period. Whilst the results of this study indicate an immediate improvement in some behaviours impacting mental health and well-being, the lack of carry over beyond the intervention period for some syndromes may be related to the dose of hydrotherapy input over the intervention period with only one session per week. Future research in this area could consider increasing the frequency of hydrotherapy sessions over a similar period and examining the immediate and carry over effects. However, the real-world viability for families to attend repeated hydrotherapy sessions in addition to other commonly utilised therapies for children with ASD should be remain a critical consideration.
The present study had a high participation rate, with an 87.25% overall group attendance (100% combined attendance when factoring in make-up sessions) from participants and yielded significant results, demonstrating improvements in several aspects of mental health and well-being. This study has presented hydrotherapy as an enjoyable physical activity for children with ASD, which may improve behaviours impacting their mental health and well-being.
4.2. Limitations and Future Research
This pilot study had several limitations and the results should be considered with caution. The statistical power of this study could have been improved by increasing the sample size. Likewise, the limited number of intervention sessions in this study may have affected the statistical strength and limited the intervention effect. Many recent hydrotherapy intervention studies investigating effects on children with ASD have employed 2–3 interventions per week for 10 or more weeks [34
]. Extending the intervention period and/or increasing the frequency of hydrotherapy sessions may be an advantageous addition to future studies, with the potential to magnify the intervention effects and control period carry over seen in this study. Additionally, due to the limited intervention period, this study did not explore the effects of the hydrotherapy sessions on physical activity or motor skills of the children involved and future research could consider this domain of health.
Another limitation was the use of the enjoyment scale during the hydrotherapy interventions. A child’s score on the scale did not always coincide with observations made by therapists and parents. This was particularly evident with children who were non-verbal and exhibited more severe symptoms of ASD. These children often chose a low score, but were observed to be smiling, laughing, and enjoying themselves throughout the sessions. It is possible that some children preferred their hydrotherapy interactions with one instructor more than another on an alternate therapy day and thus the child’s responses may be reflective of their social interactions with the instructor or their peers on the day, rather than their enjoyment levels of the task. Future studies may benefit from utilising alternative methods of assessing a child’s enjoyment during therapeutic activities. Alternatively, trialing the enjoyment scale in other areas of the child’s life may be beneficial. Incorporating the enjoyment scale into activities of varying enjoyment levels and observing the child’s scores and reactions may increase the validity of this tool in the hydrotherapy setting for children with ASD, and this warrants further research. A further important limitation was our inability to guarantee that our participant cohort was representative of the wider population of children with ASD, considering that 30% of our study population had additional comorbidities and this should be considered when interpreting the results of our pilot study. Future studies beyond this pilot trial are necessary to replicate this work with larger samples. Further prospective studies could consider a using a control group, matching participants in the intervention group by age, gender, cognition and comorbidities (e.g., ADHD), controlling for variables such as individual versus group intervention ratios and should consider a longer-term follow-up assessment beyond the intervention period.