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Statistically significant improvements in Vocabulary Word Recognition achieved by Special Needs Students as a result of Brain Gym ® intervention - New re-evaluation of data published in Switching On by Paul Dennison (1981)

by Dr Buffy McClelland, 2007.

Introduction:

In this paper, a statistical analysis is reported which was carried in 2007 out on data from a research experiment which was described in the seminal book, Switching On by Paul Dennison, published in 1981. This was Paul Dennison's first book and in it he described "Edu-Kinesthetics", his new movement approach to learning and to overcoming the problems of dyslexia. This book was the precursor to the popular Brain Gym ® technique, the trademark name which was first described by Paul and Gail Dennison in the book Personalised Whole Brain Integration (1985).

In Switching On, Paul Dennison published a table of data obtained by himself from a research experiment carried out at The Poseidon School, Los Angeles, USA. This was a private Special Education school for alienated children of age 12 to 18 years, referred to the school from education authorities, the courts and private sector. The results of the study show that an experimental group of eighteen students made statistically significant improvements in verbal vocabulary, showed improvements in weekly assignment grades and listening skills, and demonstrated reduced levels of anger and hostility, after 6 months of cross-crawl, occular-motor exercises and ear-lobe stimulation (all incorporated as part of the Brain Gym programme, unveiled in 1985, as the exercises now known as Cross-crawl, Brain Buttons and Thinking Cap).

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The Experiment:

The experiment involved eighteen Special Education students from the Poseidon School, Los Angeles. Ability levels in vocabulary word recognition were monitored at the beginning of study in January 1981 and again at the end of the project in June 1981 using the Peabody Picture Vocabulary Test (published by the American Guidance Service in 1981; currently the fourth edition of the test is published by Pearson Assessments (2006)).

The Peabody Picture Vocabulary Test was composed in 1959 and revised in 1981 by Lloyd and Leota Dunn (last updated and revised in 2006). The 1981 revised test, used in this experiment, was an individually administered, norm-referenced test of hearing vocabulary. The child was presented with four simple, black-and-white illustrations arranged in a multiple-choice format, and was asked to choose the picture which they thought best illustrated the meaning of a word presented orally by the test examiner. 175 tests of increasing difficulty were available. When used with native speakers of English, it can be used as a scholastic aptitude test, since vocabulary is a strong predictor of school success, and is very useful for assessing vocabulary levels for children with severe reading difficulties (e.g., severe dyslexia). Breen and Siewert (1983) compared the Peabody Picture Vocabulary Test (PPVT) with the Wechsler Intelligence Scale (WISC) and found a significant correlation between PPVT and WISC scores for a range of ability levels. This correlation allows the PPVT to be used with confidence as a measure of verbal vocabulary.

Raw scores from the PPVT can be converted into a age-normalised value, similar to an Intelligence Quotient, with a value of 100 being representative of an "average" student of any specified age. The test normalisation was based upon a US-based sample of more than 5,000 children and adults including scores from eight special populations (speech impaired, language delayed, language impaired, "mentally retarded" [child and adult], reading disabled, hearing impaired, and gifted) compared with demographically matched control groups.

The intervention predominantly consisted of aerobic cross-motor movements used voluntarily by the eighteen students in the experimental class. Dennnison (1981) described these movements as "any rhythmic, balanced movement which requires the individual to dynamically relate the right side of his body to the left side of his body, while at the same time being aware of the top half of his body and the lower half." Dennison described a particular variant of these cross-motor movements as Cross-crawl (later to become an important part of his Brain Gym programme) and stated that "cross-crawling requires precise switching on and off of muscles by the brain at exactly the right time, and requires feedback and feedforward from and to the muscles to maintain the exercise."

Dennison (1981) noted that many dyslexics did not crawl as infants, and thus the cross-coordination and cooperation between left and right brain hemispheres required for cross-crawling was missed during early brain development. Dennison also pointed out that cooperation between left and right cerebral hemispheres is required for reading and writing. He observed that learning the precise physical coordination between left and right sides and top and bottom of the body often resulted in significant improvements in many academic skills such as reading and writing, particularly for children with learning disabilities.

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Results:

Age-normalised results are shown in figure 1, using data taken directly from the table on p 109 of "Switching On" by Dennison. The tabulated data are not reproduced here for copyright reasons.

Figure 1: showing raw data from Dennison (1981), with Age-Normalised Scores from the Peabody Picture Vocabulary Test before intervention in January 1981 (purple) and Scores after the intervention in June 1981 (green).

Two students left the School before the experiment was finished (students b and f). Of the remaining sixteen students, eleven had an increased score on the test after the intervention, one remained the same, and four had lower scores on the test after the intervention. Of the eleven students with higher scores at the end of the experiment, six students had an increase of score of 10 or more units. The maximum increase in score obtained by an individual student was +14 points.

Figure 2: Histogram of distribution of Age-Normalised scores from the Peabody Picture Vocabulary Test before intervention in January 1981 (purple) and after the intervention in June 1981 (green). Data from Dennison (1981). The histogram shows the number of students with scores in the indicated bands (e.g. scores between 90 and 99).

The distribution of Scores shown in Figure 2 shows an apparent shift upwards after the Intervention programme. Without a statistical analysis, it is not clear whether the changes observed in the PPVT scores are significant and relate to real benefits brought about by the intervention, or whether the changes are simply due to inaccuracies in measurement and the vagaries of testing for ability in the real world.

In order to assess whether the intervention had a real, statistically significant effect on this group of students, I have carried out a T-test on the pairs of data from each student. (For more information on this statistical test, see statistics explanation on this site ).

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Statistical Analysis:

At the start of the experiment, the average Peabody Picture Vocabulary Test score was 101.3, slightly above average (Test score = 100 is average).

After the six-month intervention, the average PPVT score increased to 105.6, an improvement of 4.19 score points for the whole group. Is this a significant increase, indicating real improvements for the group as a whole?

The first stage of the T-test is to decide what is the change one would expect to observe between the first and second measurements of PPVT score, if the intervention had had no effect. Since quoted scores are Age-Normalised values, then the data has already been corrected for the typical age-related improvements that are expected to be seen because the students were 6 months older at the second test. Hence, the expected change in the test results is ZERO, if the intervention had no effect.

The T statistic value is calculated to be 2.34 for an expected zero difference change, and this is greater than the critical 2-tail value of 2.13, indicating that the Peabody Picture Vocabulary Test scores have increased by a value that is significantly greater than the norm for this ability range. The probability level for this change to be due to random chance is P = 0.033 or less than 1 chance in 30.

The Peabody Picture Vocabulary Test data therefore pass the T-Test, and the improvements in reading brought about by the movement programme are statistically significant, with 96.7% confidence.

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Conclusions:

This new analysis indicates that in the experiment described in Dennison (1981), regular short sessions using a small selection of movements (identical to the Brain Gym ® movements now known as Cross-crawl, Brain Buttons and Thinking Cap) throughout a six month period of the school year produced statistically significant improvements in word vocabulary for a group of sixteen alienated students who had "given up on the idea of being able to learn".

 Dennison also commented that their teacher reported improvements in weekly assignment grades and listening skills, and reduced levels of anger and hostility were observed for the group of students who participated in this experiment.

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References:

Breen, M.J. & Siewert, J.C., 1983. Comparison of the Peabody Picture Vocabulary Test-Revised and the Wechsler Intelligence Scale for Children-Revised for Learning-Disabled and Referred Students. Journal of Psychoeducational Assessment, V 1, p 95-99.

Dennison, P.E., 1981. Switching On. Ventura, CA: Edu-Kinesthetics, Inc.

Dennison, P.E. & Dennison, G.E., 1985. Personalised Whole Brain Integration. Ventura, CA: Edu-Kinesthetics, Inc.

How to get Brain Gym books:

The book "Switching On" by Paul Dennison, and other Brain Gym books, are available in the UK from:

Body Balance Books http://www.bbbooks.co.uk

The Oxford Brain Gym   Tel: 01865 776578

Brain Gym ^®  is a registered trademark of the Educational Kinesiology Foundation/ Brain Gym International.

Text, Illustrations and Layout, Copyright © Dr Buffy McClelland, 2007. All rights reserved.

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