Being hospitalized can be a stressful situation for anyone, and for children, it can be extremely stressful.  Because stress can cause complications on top of the reason for the hospitalization, medical personnel try to do their best to reduce stress in hospitalized children.  Animal-assisted therapy (AAT) is used in many medical situations, in homes and in medical facilities to help patients.  This study put the two together by exploring the use of AAT with hospitalized children.

Research of this type can be very useful to all those involved in the care of children in hospitals.  This includes members of the medical community – doctors, nurses, therapists, and counselors – as well as parents.  Treatment outcomes are better for the hospitalized children, the better adults are at reducing stress. 


AAT has been used to reduce stress in hospitalized children, but this technique had not been studied experimentally to determine its effectiveness.  The purpose of this exploratory study was to determine whether AAT affected hospitalized children’s cardiovascular responses, anxiety, and fear.  

Data Collection

Subjects. A convenience sample was used in this study.  The subjects in this study were 15 children (8 girls, 7 boys) between the ages of 7 and 17 who were hospitalized in one of the three participating medical facilities during the research study period and met the other criteria established by the researchers and medical personnel (such as not having cognitive impairment).

Data Collection. The parents of each participating child filled out a demographic questionnaire, which included questions on prior AAT experience and pet ownership.  Two interventions were used so as to be able to compare the results.  One intervention was the AAT; the second was assembling a puzzle with a research assistant.  Children received one of the interventions on the first day of their participation in the study and the other intervention the next day.  Which intervention they received first depended upon the visitation schedule of the therapy dogs.  Each intervention session lasted 6 to 10 minutes.  Children were put into groups based on which therapy they received first.

Children received one of two interventions each day, either ATT or assembling a puzzle.

Children’s blood pressure and heart rate were monitored at regular intervals before, during, and after the therapy.  After each intervention, a revised version of the Child Medical Fear Scale (CMFS), a valid and reliable instrument, was used to gauge children’s fear of health-care experiences.  The scale uses a three-point format (1 = not at all; 2 = a little; 3 = a lot).  The State-Anxiety scale of the State-Trait Anxiety Inventory for Children (STAI-C), also a valid and reliable instrument, was administered to measure anxiety reactions.

Data Analysis

In this study, descriptive statistics and Chi-square tests were used to analyze the demographic data, and t-tests were used to examine the baseline differences between children who received AAT first and those who received AAT second.  All tests were done using a one-way 90% confidence level, meaning p-values of less than 0.1 represented significant results.


In comparing the two groups of children (those who received AAT first and those who received it second), no significant differences were found in gender, race, age, or baseline blood pressure and heart rate. There were, however, several significant findings in other analyses.

Analysis of variance with repeated measures was used to analyze the physiological (blood pressure and heart rate) data. One significant result was that systolic blood pressure (SBP) in patients, decreased from pre- to during to post-AAT intervention. However, for puzzle intervention, SBP  only decreased from pre- to during, but it rose back to pre-intervention levels once the intervention was over. The difference in pre- and post-AAT SBP was statistically-significant.

There was also a significant difference in SBP based on the order of the interventions.  In these analyses, the decrease in SBP from pre- to post-AAT for those who received AAT first was not significant, but it was significant for those who did the puzzle intervention first.  

The use of animal-assisted therapy can result in decreases in blood pressure for hospitalized children.

For diastolic blood pressure (DBP), a significant finding was that DBP increased from pre-therapy to during therapy for both interventions.  However, post-therapy DBP showed a significant drop after AAT but not after the puzzle intervention.  The only significant finding for changes in heart rate (HR) were seen in the increased HR from pre-intervention to during intervention for both AAT and the puzzle activity.  The researchers suspect this was due simply to the increase in activity involved in interacting with the dog and in doing the puzzle.

Analysis of the scores on the Child Medical Fear Scale showed that girls had lower medical fear scores after the puzzle therapy than boys. By age, the older children have significantly less fear after both treatments and significantly less state anxiety after the AAT visit.  Multiple regression also showed the relationship between age and medical fear and state anxiety.

Discussion and Limitations

The authors recognize that while there were a few significant findings – including that animal-assisted therapy may lower systolic blood pressure in hospitalized children – this exploratory study had many limitations and further research into AAT’s benefits are needed.  The limitations include using a sample of convenience instead of a random sample; lack of randomization of the interventions (due mainly to the visitation schedule of the volunteers who brought in the dogs); and a small sample size (a sample of at least 40 children were needed to give the study proper power).  In addition, the study was limited by administering the fear and anxiety scales only after the interventions as opposed to before and after.

The results of the study, though, indicate a need for further research into the effectiveness of AAT on alleviating hospitalized children’s fear and anxiety.  Using larger samples and randomization, as well as before-and-after measures, may show if there are larger effects, which the authors suspect is the case.  The authors further suggest that the families of hospitalized children and pediatric nurses also be part of future studies to determine if AAT provides psychological and physiological benefits to them as well as the patients.


Tsai, C. C., Friedmann, E., & Thomas, S. A. (2010). The effect of animal-assisted therapy on stress responses in hospitalized children. Anthrozoos, 23(3), 245-258.

Author: Neil Starr