Three Part Question
In [a child with cerebral palsy] does [swimming with dolphins] have [any health benefits]?
Following a recent request from a parent to write a letter of support for her son with cerebral palsy to have "dolphin therapy", we thought we would look at the evidence base behind this. The mother was applying to a charity for funding to take her son to Florida to swim with dolphins.
A search of Medline 1965 to May 2007
Cochrane Database and Clinical Evidence yielded no results.
"dolphin" AND "cerebral palsy" yielded 0 results, "dolphin" AND "therapy" 132 results of which 0 were relevant, "dolphin" AND "swimming" 88 results of which 0 were relevant, and "dolphin limit child" 20 results of which 0 were relevant.
A Google search using "dolphin and cerebral palsy" resulted in 62 400 hits (14 May 2007) and a search of Google Scholar using "dolphin swimming cerebral palsy" yielded 42 results of which 1 was relevant.
Hand searching and using Google and Google Scholar revealed several reviews of the evidence.
|Author, date and country
||Study type (level of evidence)
|Antonioli and Reveley,||30 adults age 18–65 with a score of at least 11 on the modified 17-item Hamilton rating scale for depression at baseline after 4 weeks without taking antidepressant medication. Randomised to programme involving dolphins (treatment) or outdoor nature programme (control)||Single blind, randomised controlled trial (1b)||Mean severity of depressive symptoms at end of treatment (2 weeks) (Hamilton rating scale and Beck depression inventory)||Mean severity of depressive symptoms were reduced in treatment group compared to control group. Hamilton rating scale: mean difference in change scores 8.38 (treatment)/4.50 (control), p = 0.002. Beck inventory: mean difference in scores 15.46 (treatment)/ 7.58 (control), p = 0.006||Unable to blind participants No follow-up study|
We could find only one randomised controlled dolphin assisted therapy (DAT) study where results have been published in a peer-reviewed journal. This study involved adults with depression and the results were positive but the study sample small
Despite this apparent lack of evidence, there are DAT programs throughout the world. Newspapers frequently publish stories on the success of swimming with dolphins. Furthermore, many support groups (for example, mencap and scope) have sections on their website about dolphin therapy or swimming with dolphins. Scope state that "dolphin therapy does not claim to cure any specific condition but it may help alleviate some symptoms associated with some conditions". They do however conclude "research is on-going but there is not currently clear scientific evidence of lasting benefits. Dolphin therapy is comparatively expensive and not funded via any UK statutory agencies".
Since John Lilly first studied dolphin–human communication in the 1960s, much of the study by researchers in this field has been practice based and uncontrolled "making it impossible to determine whether their results were due to specific effects of DAT or a host of other potentially confounding factors".
In 2003 Humphries looked at a practice based research synthesis focusing on the effectiveness of DAT in children 6 years of age with disabilities, in order to determine the intervention’s implication for practice. She found six papers that met her selection criteria. The children involved in the studies had a range of disabilities including autism, developmental delay, speech disorders and traumatic brain injury, with only two papers specifically including children with cerebral palsy. Some studies included direct observation of the children’s behaviour, others used videotaped observations and one involved a parent survey. Key results included acquisition of skills, cognitive functioning and improvement in psycho-emotional status. Criticisms of study design included small sample size, lack of a control group and respondent and investigator bias. Humphries concluded that better designed and better controlled research is needed to determine whether DAT is truly an effective intervention that should be promoted to parents and practitioners worldwide. She also noted that the cost of these therapies is often high and that there is not enough evidence available currently to support the use of this practice.
After reviewing 20 years of research in 2005, Dr Karsten Brensing concluded "there is still no proof that DAT is more successful than other animal assisted therapies".
Several hypotheses have been proposed to explain how DAT works. One is that dolphins emit healing energy vibrations; another speculation is that the ultrasound from the echolocation clicks of dolphins heals by stimulating the endocrine system. Neither of these theories has been substantiated.
DAT has become an increasingly popular intervention for children with disabilities. Many parents believe it can have a significant positive effect on the "cognitive, physical or social–emotional behaviours" of their disabled child.
As the popularity of DAT has grown, claims of the therapeutic benefit have also grown. Despite much media coverage and support groups discussing its potential benefits, we could find no evidence to date to support the benefit of swimming with dolphins for children with cerebral palsy.
Clinical Bottom Line
There is limited evidence from one small study in adults with depression that dolphin therapy is effective in alleviating symptoms of mild to moderate depression. (Grade A)
Dolphin therapy is comparatively expensive. Prices vary but a week’s therapy in Florida can cost around US$2000 not including travel and accommodation.
There is no conclusive scientific evidence to support the benefit of swimming with dolphins for children with cerebral palsy, although many do report positive effects.
- Humphries TL. Effectiveness of dolphin-assisted therapy as a behavioural intervention for young children with disabilities. Bridges 2003;1(6):1–9.
- Marino L, Lilienfield SO. Dolphin-assisted therapy: flawed data, flawed conclusions. Anthrozoos 1998;11:194–200.
- Lukina LN. Influence of dolphin-assisted therapy sessions on the functional state of children with psychoneurological symptoms of diseases. Hum Physiol 1999;25:676–9.
- Nathanson DE. Using Atlantic bottlenose dolphins to increase cognition of mentally retarded children. In: Lovibond P H, Wilson P H, eds. Clinical and abnormal psychology . Amsterdam: North-Holland, 1989:233–42.
- Nathanson DE. Long-term effectiveness of dolphin-assisted therapy for children with severe disabilities. Anthrozoos 1998;11:22–32.
- Nathanson DE, de Castro D, Friend H, et al. Effectiveness of short-term dolphin assisted therapy for children with severe disabilities. Anthrozoos 1997;10:90–100.
- Nathanson DE, de Faria S. Cognitive improvement of children in water with and without dolphins. Anthrozoos 1993;6:17–29.
- Servais V. Some comments on context embodiment in zootherapy: the case of the Autidolfijn project. Anthrozoos 1999;12:5–15.
- Brensing K. Expert statement on "Swim with the dolphin programs and dolphin-assisted therapy", Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic area: Third Meeting of the Scientific Committee Cairo, Egypt, 2005.
- Antonioli C, Reveley MA. Randomised controlled trial of animal facilitated therapy with dolphins in the treatment of depression. BMJ 2005;331:1231.