Animal Assisted Therapy in Communication Sciences and Disorders: The State of the Evidence

Editor's Note: This text is a transcript of the course, Animal Assisted Therapy in Communication Sciences and Disorders: The State of the Evidence, presented by Sharon Antonucci, PhD, CCC-SLP.

Learning Outcomes

As a result of this course, participants will be able to:

1. Define animal-assisted therapy (AAT).
2. Describe existing evidence regarding the impact of animals on speech, language, and cognitive treatment outcomes.
3. Identify gaps in the existing AAT evidence base.

Introduction

This course is about animal-assisted therapy, which is a true love of mine.

Animal-Assisted Activities

I want to review some terms that are related, but also distinct from one another. As you are working your way through the evidence base, particularly as a clinician, it will be important for you to understand what a specific animal-assisted program was used for.

The first term is animal-assisted activities. This refers to when an animal and handler team provide enrichment, which can be through a number of different ways. The animal and handler teams are available to a variety of people for relatively spontaneous interaction.

In this case, there is often no particular plan for the animal-assisted activity. The handler can see who is interested in having an activity or who wants to engage with the animal. It might be in the context of an individual session or a group session. The animal handler does not usually know who is going to be participating ahead of time, so there are no particular goals that are addressed.

Animal handler teams can visit nursing homes or hospitals and plan a group activity. This way, everyone can meet together and have the opportunity to interact with the animal. They are able to see what the animal can do and pet or help groom the animal. Other times, the animal and the handler will stop into each room and see if the person in the room is interested. Many of us may be familiar with the library visits that have animal-assisted activities. Children can then take turns and interact with the animal. Additionally, we are starting to see more visits to college campuses in order to help with stress relief before exams.

Animal-Assisted Therapy

Animal-assisted activities are different from animal-assisted therapy, which is a clinician-provided service within a clinician's scope of practice. In this case, a client’s progress towards individual goals is documented. Session plans and timing are dictated by the clinical practice.

This type of therapy is just like any other, but then includes the participation of an animal handler team. That team may be separate individuals, a certified volunteer, or co-treating with another clinician. For example, we have a facility animal owned by the recreational therapist. She will often do a lot of co-treating with clinicians who want to incorporate animal-assisted therapy. There is also an option for the clinician to be the handler in the animal handler team.

Animal-assisted therapy is a treatment method similar to any other technique. The animals can be present as communication partners or communication facilitators. Obviously, live animals are not manipulables or materials. They are partners in the therapy.

Remember that animal-assisted therapy is not a meet and greet or unstructured playtime with the animal. It is also important to note that the animal is not the clinician. The animal is our partner while we are the clinicians. It is also not therapy for the animal. In order to become a therapy animal, they have to demonstrate a number of skills and aptitudes. One of the most important things is that the animal needs to demonstrate an active interest in being around people. Animals that are shy or nervous are not going to be good candidates for animal-assisted therapy.

Also, animal-assisted therapy is not the same as getting support from a service animal. Service animals are sometimes involved in animal-assisted therapy sessions, but they are not serving as the therapy animal. They have a specific function that is different from animal-assisted therapy.

Service Animal

A service animal in the United States is defined by the federal government in the Americans With Disabilities Act (ADA). They are animals that are trained to perform specific tasks for an individual with a documented disability. While a therapy animal is not necessarily trained to perform certain tasks and can work with a variety of individuals, they are devoted to working with one person with a documented disability.

Service animals are working animals, not pets. That does not mean that they should not be cared for and loved by their person, but they are still working animals. That is often why you will see people requesting that strangers do not approach a service animal while they are on the job. This way the animal is not distracted from the job that it needs to be doing for its person.

Service animals are the only kind of animals that are protected by law relative to public access. For example, service animals can be brought into a restaurant that would not otherwise allow animals. A therapy animal does not have that protection or right. Another difference is that, per the ADA, dogs are the only animals that can be certified as service animals. On the other hand, animal-assisted activities or therapy animals can be a wider range. There are separate provisions to certify miniature horses as service animals. However, a service animal will most likely be a dog.

Figure 1 is a summary of the differences between animal-assisted activities, animal-assisted therapy and a service animal:

[insert chart from Q3 slide]

In all cases, a trained and certified handler is required. The licensed clinician and the individual who is working with the service animal will differ. Also, the animal must go through a certification and assessment process. A variety of animals are candidates for animal-assisted activities and animal-assisted therapy, but less so for service animals.

Animal-assisted therapy targets individualized goals. It provides detailed documentation of lesson plans and goal progress, whereas that is not required for animal-assisted activities. The only type of animal that has federally protected access rights is a service animal.

The Current Evidence

Here is a preview of the evidence that we will be reviewing today:

• Physical health effects
• Human- and nonhuman-animals
• Therapeutic effects
• Communication-specific effects

We will be reviewing some of the evidence on physical health effects related to the human and the nonhuman animals. We will also be looking at some of the evidence related to the therapeutic effects on individuals who participate in animal-assisted therapy. In the cases where some communication-specific effects were reported, we will look at examples of those.

AAT Evidence Related to General Health & Well-being: Nonhuman-Animal

I will be starting with animal-assisted treatment evidence related to the health and wellbeing of the nonhuman animal.  It is important to remember that the well-being of the animal who is involved in the therapy is just as important as the well-being of the patient.

There is a quote from an ethics article that explored use versus exploitation in animal-assisted therapy. It says, “To know for certain that X is not exploiting Y, merely using Y, X must repeatedly make choices that substantively further Y's welfare even when in conflict with X's own prudential motives.”

Regarding whether an animal is appropriate to be certified in animal-assisted activities or therapy, does the animal also benefit from the relationship? There are differences in the level of appropriateness of the use of animals with more documentable and documented preferences and behaviors that we can observe. This would be related to the animal's interest in being with us in the context of the activity. It tends to be different for domesticated animals versus captive dolphins, monkeys, and birds.

In terms of the literature that looks at the effects of participation on the animal participant, most of the work has been done with dogs. There is variability in the literature relative to whether the animal participates in animal-assisted activity versus animal-assisted therapy. People have looked at physiological measures of the animal's comfort and stress level. This includes looking at salivary cortisol levels to get a sense of the animal's stress level before and after the session, as well as heart and respiratory rate, blood pressure, body temperature, and so on.

Also, there have been investigations into the behavioral measures of relative comfort or agitation in the animal. Is the animal doing a lot of panting, even though it is not hot? Is the animal walking around a lot or trying to move away from the humans in the session? Some studies have looked at the effect of relative familiarity as well. This refers to how familiar the animal was with the setting and the level of comfort they had with the handler and the other participants.

It is also important to consider duration and frequency. How long were the sessions? Was the animal given breaks from participation? How many times a week was the animal expected to participate in the sessions? All of these factors can have an effect on the level of stress and tiredness of the animal.

Is a Live Animal Integral to AAT?

People have looked at whether a live animal is integral to animal-assisted therapy. For example, studies have looked into the presence of a real animal versus a stuffed or robotic animal. Another option for this could occur in the virtual realm. One study has been done that looked at a virtual animal versus a virtual human versus nothing.

The benefit that can be attributed to having the live animal present is dependent on the goals and outcomes of the session. For example, one goal could be to facilitate a change in physiological response or movement versus social or communication goals that speech-language pathologists might be interested in. This topic is a relatively small component of the AAT literature and remains ongoing, particularly for situations when it may not be appropriate to have a live animal present.

AAT Evidence Related to General Health & Wellbeing: Human Animal

We will now turn our attention to evidence related to the humans involved in animal-assisted therapy. This is referring to the clients’ wellbeing in general health as opposed to the clinician or handler. There is evidence across a range of bases that discuss physiological benefits to being in the presence of an animal. Other topics include cardiovascular benefits, reductions in blood pressure, reductions in heart rate, and so on.

One example is that AAT can be beneficial for our participants with cardiovascular disease. We also see a mitigation of environmental stress responses, which are known to promote physical healing. There is also some evidence of neurochemical benefits. There are a number of studies that have shown an increase in participants in oxytocin, which is a neurochemical associated with feelings of bonding and social affiliation. Cortisol levels seem to be reduced as well. There is also some neuroimaging evidence that shows an increase in oxygenated blood flow, for example, in the prefrontal cortex of people with clinical depression.

For the studies that have looked into behavioral measures, most of them have focused on the psychosocial benefits and effects of animal interaction. People have reported a reduction in apathy. There can be an increase in interest or motivation to participate in the treatment session. Another aspect could be reduced social anxiety and an overall positive mood.

Here is a quote: “There seems to be a fair bit of evidence that the presence of the animal can promote the preconditions for learning.” This means that it can make people more ready to learn because anxiety is reduced, motivation is increased, and self-consciousness is reduced. Additionally, attention to the particular task at hand is increased. In a lot of the AAT literature, the animal's presence is to serve as a social facilitator. There are a number of open questions related to the specificity and the persistence of the effects.

Limitations of the Evidence Base

However, the animal-assisted treatment evidence base needs some work. There has not been adequate control to determine whether any of the observed benefits are actually associated with the animal. There has not been a lot of evidence related to whether the beneficial effects are relatively time-limited and there has not been too much follow-up. Also, it is unclear whether they are duration-dependent, referring to being dependent on the length of the interaction or the number of sessions.

Before we look at the specifics related to the evidence base, I want to point out some limitations:

• Small sample sizes
• Lack of blinding (e.g., outcome assessor)
• Lack of consistent randomization of participants
• Lack or inadequacy of control or usual care groups
• Selection bias
• Poor generalizability
• Minimal reporting of reliability and validity of tools used to measure outcomes, and attrition rates
• Minimal reporting of treatment procedures
• Confounds
• Novelty Effect
• Follow-up and long-term outcomes
• Placebo effect

A small sample size is a concern of a lot of the evidence that speech-language pathologists interact with. We are typically looking at case studies as opposed to a large group.

There is often a lack of blinding. This refers to the participants knowing whether they are participating in animal-assisted therapy or not, as do the clinicians and researchers. Oftentimes, the person who is delivering the treatment or activity is the same as the person who is doing the outcome assessment.

A lack of consistent randomization of participants is another issue. This means inadequacy or a complete lack of control groups or comparison groups. Another aspect is selection bias. This is going to be inherent in any study of animal-assisted activity. There are only going to be a certain number of people who are interested in participating in animal-assisted therapy. To a certain extent, there is a self-selection bias, which can often lead to poor generalizability.

There tends to be minimal reporting of reliability and validity of the tools that are used to measure the outcomes. Oftentimes attrition rates are underreported as well. There is also minimal reporting of treatment procedures. In a lot of cases, there is minimal specification of what the treatment activities and procedures were. There is even more limited information about what the animal was doing in the context of the treatment.

There is also a lack of control for different confounds. An example of this could be the novelty effect. Does the effect of the animal wear off as the person becomes more used to the animal being there? Is there a placebo effect?

Overall, the limitation that I think is the most impactful is the minimal reporting of treatment procedures. That can make it difficult for someone who is new to animal-assisted therapy to understand how to incorporate it into treatment. However, that is not to say that it is not worth taking the time to do. It is something to be aware of as you delve into the literature.

Research Relevant to Speech-Language Pathology

Most of the research that is most likely to be relevant to speech-language pathologists has been done across four communication disorders: Alzheimer's disease, autism spectrum disorder, acquired brain injury and traumatic brain injury, and aphasia. However, I want to point out that this is a non-exhaustive review.

Observational Coding Systems

First, I want to talk about a commonality across the different populations of patients and studies of animal-assisted treatment, and that is the use of observational coding systems. There is evidence of similar systems having been developed to study the effects of AAT and persons with communication disorders. It allows you to code for the presence or absence of different kinds of verbal and nonverbal communication, as well as physical movement. This would also include documentable and observable behaviors associated with emotional state and behavioral information.

AAT and People with Autism

Here are the aspects of AAT and people with autism:

• Earliest account of modern AAT
• Boris Levinson “accidental” “pet therapy”
• Trends in the literature (O’Haire, 2013; 2017; Berry et al., 2013)
• “In the presence of a therapy dog…”
• Increase in “social interaction”
• Increase in verbal communication (to and about the dog)
• Increase in nonverbal communication
• Smiling
• Joint attention
• One study reported increase in stereotyped behavior
• As with other populations, details of treatment procedures underspecified
• AAT + Social Story Method Grigore & Rusu, 2014
• Operationalized outcome measures, targeted behaviors
• Inclusion of animal (dog) into a method with an evidence-base

One of the earliest accounts of modern animal-assisted therapy came from Boris Levinson. He was a psychologist who was working with children who were considered “uncommunicative” in his home. One day, he left an uncommunicative client alone in the room with his dog. When he returned, the client was talking to the dog. Levinson continued to document and provide evidence for the utility of what he called “pet therapy.”

In terms of literature trends, most use the phrase “in the presence of a therapy dog.” That is about the limit of what we get in terms of information about the actual therapy. However, people have documented increases in social interaction and verbal communication, both to and about the animal. Again, it is mostly dogs who are the animal in the research. There can be increases in nonverbal communication as well, such as the number of times the person is smiling and the amount of joint attention episodes. One study did report an increase in stereotyped behavior. This is important because we do have to look for less appropriate effects as well.

The details of the treatment procedures tend to be fairly underspecified. Therefore, it is difficult to know exactly what was done during the sessions. Another thing to keep in mind is that different studies will use different definitions of what constitutes a social interaction, verbal communication, and so on.

One study from 2014 did a good job of defining their outcome measures and targeted behaviors. It looked at the use of combined animal-assisted therapy and the social story method with individuals with autism. I thought it was interesting and relatively novel to include an animal into another method that already had an evidence base.

AAT and People with Dementia

Here are the points on AAT and people with dementia:

• Inconsistent use of AAA vs. AAT (re: patient-specific goals)
• Trends in the literature (e.g., Bernabei et al., 2013; Rodrigo-Claverol et al., 2020)
• Communication and “coping”
• Reduction in agitation behaviors
• Positive changes in mood and social communication behaviors (in presence of dog)
• Cognitive Function & Depression
• Inconsistent findings across studies on standardized measures (e.g., Kanamori et al. 2001; Menna et al., 2019; Moretti et al, 2011; Santaniello et al., 2020)
• Mini-Mental State Exam (Folstein, Folstein, & McHugh, 1975)
• Geriatric Depression Scale (Yesavage et al., 1983)
• Persons with CI in assisted-living Friedman et al., 2015
• Activities with dog-handler team vs. Reminiscence activities
• Outcomes
• Depression: decreased with AAA
• Apathy: decreased with AAA, increased in R
• ADLs : >2 SE change in AAA group
• Physical activity: increased with AAA, decreased in R
• Agitation Behaviors:  decreased with AAA
• Changes in med use: none

There is inconsistent use of animal-assisted activities versus animal-assisted therapy in the reported literature for those with dementia.

In terms of trends, we see reports of increases in both communication and coping behaviors. There are also reductions in behaviors associated with agitation. Also, there are reports of positive changes in mood and social communication behaviors in the presence of the dog.

An aspect that is less established is any potential effect on standardized assessment of cognitive function or depression. Typically, the assessment of cognitive function will be the Mini-Mental State Exam, which is more of a screening tool than a full assessment. The Geriatric Depression Scale is used frequently to assess depression.

There was another study that was done, specifically about people with cognitive impairments who are living in an assisted living facility. It compares activities with a dog handler team with reminiscence activities. It describes the procedures as activities, as opposed to treatment.

Positive outcomes were reported, including a reduction in depression associated with animal-assisted activities. There was a reduction in apathy with animal-assisted activity and an increase in apathy in the reminiscence activities. There was some evidence of an increase in the ability to perform activities of daily living (ADLs) in the animal-assisted activities group. There were also some benefits in respect to physical activity and agitation behaviors. Finally, in neither context was there any change in the medications that were needed for the individuals.

AAT and People with Acquired Brain Injury (ABI)

Here are some factors regarding AAT and people with ABI:

• Hediger et al., 2020 (see also Gocheva et al., 2017)
• AAT compared to ‘conventional therapy’ (neurorehab)
• Outcomes measures related to “social competence and engagement”
• During AAT (relative to neurorehab without animal)
• Observation and tracking over time of
• Behaviors/vocalizations associated with emotions
• Increase in positive (e.g., smiling, laughing)
• Decrease in neutral
• No change in negative (e.g., mouth corners down, crying)
• Increase in verbal and nonverbal communication
• Increase in treatment motivation and satisfaction
• Clinician and self-report

Acquired brain injury is a subset, as people who have sustained strokes are combined with people who have sustained traumatic brain injuries. There have been a series of studies that have looked at these individuals and where behaviors have been documented relative to an observational coding system.

In this series of studies, it was about animal-assisted therapy as opposed to activities, and AAT was compared to what they called conventional therapy, or neurorehabilitation. Most of the outcome measures were related to social competence and engagement. There was less of a focus on cognitive or linguistic outcomes.

During animal-assisted therapy relative to neurorehabilitation without the animal, there were increases in positive behaviors and vocalizations. There was a decrease in neutral behaviors. Also, there was no change in negative behaviors or vocalizations associated with emotions. However, there were reported increases in verbal and nonverbal communication, as well as in treatment motivation and satisfaction. This was determined by both clinician reports and self report from the participants.

AAT and People with Traumatic Brain Injury (TBI)

Here are points to take away regarding people with TBI:

• Trends in the literature
• Primarily soldiers and veterans
• Animals providing anxiety and stress relief (physiological & psychological), communication and reminiscence partner
• Combat zone
• Return to home
• Service animals
• Mobility, vision, hearing, seizure alert
• In specific circumstances, for psychosocial and emotional support
• Therapy animals (dogs)
• “Canine-assisted therapy”
• Much of the AAT research being done in context of OT
• Psychological and psychosocial benefits vs. cognitive-linguistic skills

Most of the literature specific to people with traumatic brain injury has been done with veterans and people on active duty. It primarily looks at the animals and how they are able to provide anxiety and stress relief, both physiological and psychological. This was either in the context of the combat zone or returning home. Most of the studies involved service animals. Remember that these animals are trained to do particular jobs for an individual. Once the animal and the individual are trained, the animal lives with the person.

There has been less work done with therapy dogs than there has been with service animals in this population. Additionally, most of it has been done in the context of occupational therapy as opposed to speech-language therapy. Sometimes there is the incorporation of the service animal into therapeutic activities, as opposed to the separate use of a certified handler team in animal-assisted activities. In the literature, there is more evidence of psychological and psychosocial benefits. There is some anecdotal evidence related to cognitive-linguistic skills, but not too much literature-based evidence.

AAT and People with Aphasia

There have been a few reports of animal-assisted therapy being incorporated into treatment for people with stroke aphasia. The first one was in 1997 and it surrounded working with a participant who had post-two cerebrovascular accidents (CVAs) with dementia, a diagnosis of nonfluent aphasia, apraxia, and cognitive decline.

There was a primary treatment goal of correct word initiation. It was reported that there were two dogs present during the treatment sessions. There is limited information as to what the dogs were doing, but there were some descriptions of the tasks that were employed for word initiation. It included use of “wh” questions about the dogs, as well as a picture identification activity that incorporated pictures of dogs and daily life related to being with dogs.

There was also the use of carrier phrase activities used to interact with the dogs to give them commands or cues. There was a reported increase in correct responses to “wh” questions, picture identification, and the proportion of verbal relative to nonverbal social behaviors. The latter may be related to the fact that there was also an increase in social opportunities for communication with the animal, as well as the humans in the room. There were no changes reported on the Boston Diagnostic Aphasia Examination.

Next, there was another study in 2006 that looked at whether animal-assisted therapy is effective for people with aphasia, compared to traditional therapy. It also looked at the self-reports of the participants with aphasia relative to differences in their motivation and attitude. In this case, there were three individuals with a status of post-left CVA. All of them had chronic nonfluent aphasia.

There were specific linguistic goals. The treatment comparisons were traditional therapy and animal-assisted treatment. The traditional therapy included confrontation naming with cueing hierarchy. Animal-assisted treatment involved confrontation naming, carrier phrase practice with cueing, and communication with a Pet Partners-certified dog.

There was no change in the Western Aphasia Battery scores, but participants did meet their specific language goals in both treatments. Additionally, patient responses indicated that the participants believed that they achieved greater progress during AAT and experienced greater motivation to attend treatment when the dog would be present. Also, there were anecdotal findings of reduced effortfulness of language output when communication was directed to the dog, as opposed to when it was directed to the clinician. There was a trend toward an increase in spontaneous communication directed to the dog as well.

The last case study is from 2007. It looked at a gentleman with a post-CVA status,  chronic nonfluent aphasia, and poor auditory comprehension. This is an example of minimal reporting regarding what happened during the therapy. This is because all of the data was collected after the animal-assisted therapy session had ended. The information was actually gathered during an accompanied walk back to the ward that the person was in. The study observed overt social, verbal, and nonverbal behaviors of the participant in several contexts during this walk back from the therapy.

In the study, they compared a walk without the animal handler team, to a walk with just the handler, to a walk with both the dog and the handler. The results indicated that in the presence of the dog-handler team, relative to the other conditions, there was an increase in overt communicative behaviors, cheerfulness, and an increase in the number of opportunities. For example, during walks back with the team and the animal, the person had the opportunity to communicate with the dog, the handler, and other people who were passing by.

The literature trends for animal-assisted therapy show that people with aphasia improve their performance relative to targeted behaviors, linguistic or non-linguistic. There has been no report of change of performance on standardized aphasia batteries. Also, the treatment procedures are underspecified, which makes it difficult to replicate the findings.

AAT Evidence Related to General Health & Wellbeing: Human-animal

In summary, there is evidence about animal-assisted therapy and cognitive-linguistic neurorehabilitation with less attention to cognitive-linguistic outcomes relative to motivation, positive mood, and satisfaction with treatment. There is more information related to psychosocial and effective increases in the context of AAT, speech-language pathology services, reductions in apathy, social anxiety and positive mood. All of these aspects can lead to an increase in the willingness to practice communication attempts.

The animal can act as a social facilitator. In many cases, animals are a primary communication partner. They can also act as a motivator to participate in treatment activities and communication opportunities.

Evidence-Based Practice

Regarding evidence-based practice and the American Speech-Language-Hearing Association (ASHA), there are limited resources. As of September 2020, ASHA has no practice policy statements about animal-assisted therapy or animal-assisted treatment-specific evidence maps.

Finding Publicly-Available Research

Finally, I want to give some resources for literature that is publicly available for clinicians.

I also have included some useful keywords to use in your evidence searches:

• Animal-assisted therapy
• Animal-facilitated therapy
• Canine-assisted therapy (e.g., armed services)
• Human-animal interaction
• Animal-assisted intervention

Three public websites that can help are PubMed, National Institutes of Health (NIH) Reporter, and Clinical Trials. PubMed includes any study that has been funded by the federal government. You can sort the cases by year or by full texts that are free.

NIH Reporter is another free, public-facing website that you can use to find any NIH-funded grants. If you are interested in the funding of a particular researcher who you know is doing animal-assisted therapy, you can put that in a text search. I recommend that you be careful and make sure that you are using animal-assisted or animal-facilitated keywords in your text searches, or else you will come up with grants that involve animal testing.

You can also conduct searches at Clinical Trials. Any clinical trial that is going on needs to be reported, so you can search for what stage the trial is at, and so on. All three of these sites are going to be useful for everyone.

Questions and Answers

Does the literature talk about whether outcomes were better when AAT was introduced closer to injury? An example of this would be AAT being introduced one week after a TBI or stroke in an inpatient setting, versus one month later in an outpatient setting.

Regarding neurorehabilitation, the vast majority of the literature is about chronic individuals. There is less evidence with respect to acute care or peri-acute care. I am not aware of any study that has compared the timing of the introduction of the AAT, chronic versus acute. However, that is a great idea and hopefully some of you will be able to start contributing to the animal-assisted therapy literature.

What are the next steps in beginning the journey to use a dog for animal-assisted therapy?

You need to consider whether the animal you are thinking about is appropriate for animal-assisted therapy. Would they actively enjoy, engage and benefit from animal-assisted therapy?

I strongly recommend going through the process of getting certified as an animal handler. There are a number of programs that you can go through to do that. It involves some training and assessments of you and your animal. Also, make sure that your facility allows animal-assisted therapy. We will be talking more about all of this next week.

Do you plan on talking about hippotherapy in the second part of this series?

I will be talking about hippotherapy, especially in the context of the certification process. Again, most of the literature and the practice is with smaller animals.

Does the literature identify any outcomes related to dementia and the Global Deterioration Scale (GDS) level of the patient?

The reporting tends to be minimal, especially in the context of any group reports. This could be in terms of where the person is in their progress of decline. An example of being appropriate and safe in animal-assisted therapy would be making sure the individual is not suffering from active, violent outbursts.