Background to Me Grobler’s study:
The purpose of this study was to measure the effect of therapeutic horse riding (Equi-therapy) on the executive functions of Tourette syndrome children.  The executive functions include various loosely related higher-order cognitive processes such as: initiation, planning, hypothesis generation, cognitive flexibility, decision making, regulation, feedback utilisation, jjudgement and self-perception/self-monitoring necessary for conceptual appropriate behaviour – overall organisation and control of conscious activities.  Executive functioning is normally related to the prefrontal regions of the brain, but deficits/impairments are not always localised to these areas, they may also occur in the context of dysfunction to other brain regions and must always be considered in that light.  Certain changes in behavioral aspects that are often related to this syndrome were also analysed qualitatively.

The study consisted of 8 Tourette syndrome children (aged between 9-15 years).  They were non-randomly selected (after referrals of a definite Tourette syndrome diagnosis from various neurologists and pediatricians) and divided into an experimental and control group.
Both groups were evaluated on a battery of 6 neuropsychological tests measuring various aspects of executive function before and after they had been subjected to the therapeutic horse riding.  Behavioral inputs were also analysed qualitatively from checklists that head been completed by their parents.

The experimental group was subjected to the therapeutic horse riding over a 3-month period whilst the control group over the same period were not.  Following this 3-month period the control group were also subjected tot the therapeutic horse riding.  The 2 groups were compared with regard to their executive function performance on the tests, firstly as individuals and then in relation to each other, with the consideration of their subjectivity to the therapeutic horse riding.

The following specific test indice scores related to executive function were obtained and analysed for both the experimental and control groups:
     - Wisconsin Card Sorting Test - categories completed, perseverative errors, failure to maintain set
     -.Stroop Colour Word Test - time in seconds and uncorrected errors.
     - Rey-Osterrieth Complex Figure Test - copy score, delayed recall score and qualitative categorising of the drawing                (“normal” or “frontal”)
     - Trail Making Test A and B - time in seconds and errors
     - Raven’s Standard Progressive Matrices - correct responses on sets A, B and C
     - Symbol Digit Modalities Test - correct substitutions.
     - Lahey Child Behaviour Checklist - used to qualitatively evaluate positive and negative behavioural patterns.

Background to Me Young’ study:
The same subjects were used except that the control group was not assessed.  The following tests were used:
1.  Southern California Sensory Integration Test by A. Jean Ayres, PhD.
2.  Clinical observations of eye and hand usage, postural responses and other neuro-muscular conditions related the learning process and behavior.

The question is:
Are any differences were observed after the intervention, how can one be sure tthat the same effect will be found if this method is generally applied to children with similar problems than those in the study?  Could the encouraging results obtained in the tests after intervention really be ascribed due to the Equi-therapy program followed or was it accidental/chance? The hypothesis is formulated that Equi-therapy can be valuable asset in the approach of the Occupational Therapy.  This can be ascertained by the use of statiscal methods.

In this case where the same group was assessed before and after treatment. With Equi-Therapy the Fischer t-test was regarded as the most applicable.  In the P value is an indication of the probability, expressed as a percentage, that the same results will be found if the same study with similar samples will be repeated one hundred times.  For example the P value of > 0,003 means that in less than three percent of repeated studies other results will be found. The  advantage of using the same subjects in the study for the pre- and post tests is that the influence of other factors are excluded.

The measurements used in this study were also not values on an ordinal scale but rather categories on a nominal scale. The chi square goodness of fit test was regarded as the most appropriate. Since the chi square test requires a larger sample of subjects than was used in this study, the results of the thirteen separate sub-tests were summed to obtain a sample size of one hundred and thirty.

Significant differences measured after a statistical and discriminant analysis using nonparametric tests due to the small sample size of the study were as follows:

Wisconsin Card Sorting Test - This test assesses several aspects of problem solving behavior such as the ability to form    abstract concepts, to shift and maintain set and to utilize feedback.
No significant difference was found at the 5% level of significance (p<0.05) for any of the 3 indices measured for both groups that had and had not been subjected to the therapeutic horse riding.

Although at a the 10% level of significance (p<0.1) scores obtained were significant for categories completed (p=0.0885) and failure to maintain set (p=0.0982) between the experimental group that had been subjected to the therapeutic riding and the control group that had not.  The experimental group achieved higher post-test scores on both indices measured, whereas the control groups post-test scores remained more or less constant, which was expected because they had not been subjected to the therapeutic riding at that point.  Thus the results for this test were in the expected direction showing improvement on problem solving abilities, possibly due to the therapeutic horse riding.

Stroop Color Word Test – This test mainly assesses the ease with which a person can shift his or her perceptual set to conform to changing demands, and suppress a habitual response in favour of an unusual one, often referred to as selective attention and cognitive flexibility.

For both groups that had and had not been subjected to the therapeutic horse riding the only significant difference measured at the 5% level of significance (p<0.05) was on Part C of the test for uncorrected errors (p=0.0360).  All participants improved on their uncorrected errors previously made.  Indicating an improvement of self-correction and selective attention for all participants and the possible improvement of their executive functions as increased errors on Part C is often indicative of frontal lobe (executive) dysfunction.  Thus these results were in the expected direction, although this may not be due tot the therapeutic riding alone because the control group also improved their scores, although they had not been subjected to the therapeutic riding at that point.  The latter possibly indicated a learning/ familiarisation ability acquired with regard tot the test from the pre tot the post-test.

However, when scores were analysed for all 8 participants that had been subjected to the therapeutic horse riding significant differences were measured at the 5% level of significance (p<0.05) on Part W time in seconds (p=0.0469), Part W (p=0.0469) and C (p=0.0313) for uncorrected errors made.  Regarding the time in seconds for Part W all participants improved on their time which would normally be indicative of possible frontal lobe (executive) dysfunction if a poorer performance (increase in time to complete the indice) was found.  As for the significant difference measured in the uncorrected errors scores all participants improved on their uncorrected errors previously made.  As previously mentioned indicating an improvement of self-correction and selective attention and the possible improvement of their executive functions as increased errors on Part C and W is often indicative of frontal lobe (executive) dysfunction.  Thus these results are in the expected direction and possibly related tot the subjection tot the therapeutic horse riding.

Symbol Digit Modalities Test – This test assesses visual-associative learning ability, psychomotor/response speed, visuomotor integration and co-ordination.  It is based on the assumption that the associative learning ability, which is required to learn and is the relation between specific symbols and digits, is an indication of general intelligence.

Negative: 

The negative patterns were often just the opposite of the positive patterns for some of the participants as mentioned above, however the following aspects can be singled out:
     -   Restlessness.                                                                       -   The use of swearing or obscene language.
     -   Behaving like the opposite sex.                                               -   Hears voices (hallucinations).
     -   Has an imaginary friend and companion.                                  -   Perfectionism and self-centeredness.
     -   Obsessions with safety (everything is locked and secured)

No other significant differences were found on the other test scores, which is probably due tot the small sample size used in the study.  These tests were the Rey-Osterrieth Complex Figure Test, which assesses visuospatial constructional ability and visual memory.  It is also very helpful in assessing organisational strategies.  These include other cognitive processes such as planning, problem solving strategies, as well as perceptual, motor, and memory functions.  The Trail Making Test A and B, which is a short test of selective attention and cognitive shift abilities, primarily designed to measure adequacy of cerebral functioning, presumably frontal lobe functions, and particularly, conceptual tracking.  The Raven’s Standard Progressive Matrices is measure of non-verbal analogical reasoning in the visual modality and is useful to administer to subjects with expressive language problems, it evaluates intellectual efficiency (learning from immediate experience with problems) and conceptual abilities.

However, when individual differences were analysed on these 3 test scores indices the results were often indicated in an expected direction.  Although it is important to note that negative scores were also found, which could possibly be contributed to by other factors such as the participants backgrounds, emotional statuses, medicational use and degree of additional behavioural disturbances they may have in relation to Tourette syndrome.

With regards to equi-therapy and the effect of sensory integration the above-mentioned information substantiates various aspects of the theory underlining this unique form of therapy, especially in relation to the higher-order functions of the brain.

CONCLUSION:

From an Occupational Therapy point of view, definite changes could be seen on Sensory Integration Level.  This was a combined study where an Occupational Therapist and Psychologist were involved.  The hypothesis from a Sensory Integration point would be that there is a close connection between the Sensory Integration area and the Limbic system which controls your emotions.  Improvement on emotional level may therefore be also due to this.

The Occupational Therapist also assessed the perceptual functions and scholastic performance of the subjects.   Significant positive differences could also be seen but it was not quoted in this study as it was aimed at looking at improvement on Sensory Integration Level.