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Symposium; Alternative Therapies

Saturday stream 1 Session 09.00 - 11.10 Length 25 minutes

Neurological Dysfunction as a Significant Factor in Children Diagnosed with Dyslexia

Sally Goddard Blythe

The Institute for Neuro-Physiological Psychology, Chester inpp@virtual-chester.com

Abstract

It is an accepted medical fact* that the continued presence of primitive reflexes above the age of six months and the absence or under-development of postural reflexes beyond three and a half years of age are reliable indicators of neurological dysfunction, which can affect both motor and perceptual development. A series of standardised neurological tests for abnormal reflexes were carried out on a sample of 54 children who had previously received an independent diagnosis of Dyslexia, to see if neurological dysfunction was a significant factor underlying their Dyslexic symptoms. Additional tests were carried out to assess oculo-motor functioning, visual-perceptual performance and cerebellar involvement including dysdiadochokinesia to see if other areas related to motor development were also a significant factor in the sample.

Abnormal primitive and postural reflexes were found to be a universal underlying factor in this sample. A high percentage of the sample also demonstrated difficulties with oculo-motor functioning, visual-perceptual skills and dysdiadochokinesia, suggesting a positive relationship between abnormal reflex activity and immature postural, motor and visual functioning.

Introduction

It is an accepted fact that the presence of primitive and postural reflexes at key stages in development provide reliable indicators of central nervous system maturity and are signs of neurological dysfunction. In the first 6 - 12 months of post natal life, the primitive reflexes should gradually be inhibited by the developing brain to be replaced by postural reflexes; Postural reflexes should be fully developed by three and a half years of age. The transformation from primitive to postural reflex that takes place in the first three and a half years of life, lays the foundations for the control of balance, posture and later motor skills.

If primitive and postural reflexes do not mature at the correct developmental stage, they are said to aberrant. Aberrant reflexes can result in immature motor development despite the acquisition of later developmental skills. When a cluster of abnormal reflexes persist, Neuro-Developmental Delay is said to be present.

The effects of retained primitive reflexes and underdeveloped postural reflexes in the older child are well documented (Bobath & Bobath 1965, Ayres 1972/3, Fiorentino 1981, Levitt 1984). It is also recognised that aberrant reflexes can affect higher cortical functioning particularly in the area of education (Ayres 1972/3, Bender 1976, Blythe McGlown 1979), but 25 years after this research, the concept remains controversial. The role of abnormal reflexes in Dyslexia as a discreet entity has never been conclusively established despite the fact that Dyslexia is sometimes categorised as a developmental and neurological disorder (Rosen, Sherman, Galaburda, 1993, P.89-90, Bax & Whitmore 1999).

In view of the evidence it was decided to investigate whether abnormal primitive and postural reflexes, and dependent motor functions, were a significant factor in a group of children previously diagnosed as being Dyslexic.

Dyslexia

Dyslexia has been defined as, "a disorder in children who, despite conventional classroom experience, fail to attain the language skills of reading, writing and spelling commensurate with their intellectual abilities" (World Federation of Neurology 1968). More recently this definition has been expanded and described as, "a complex neurological condition which is constitutional in origin. The symptoms may affect many areas of learning and function and may be described as a specific difficulty in reading, spelling and written language. One or more of these areas may be affected. Numeracy, notational skills (music), motor function and organisational skills. However, it is particularly related to mastering written language, although oral language may be affected to some degree (British Dyslexia Association, 1998).

Associated Symptoms:

In addition to problems with reading, spelling and written language expression, dyslexic children often manifest problems with motor skills such as hopping and skipping, catching and throwing a ball; learning to ride a bicycle, coordination at gym and sometimes swimming; problems with directionality, such as telling left from right, laying a table correctly and telling the time from an analogue clock. Problems with fine muscle skills may include difficulties tying shoelaces, doing buttons up and manipulating a writing instrument. Sequencing, visual memory and auditory perception may also be affected and there may be ambiguity of laterality (Ott, 1997). Performance in these areas is dependent upon the maturity of the reflex system which underlies motor learning, vestibular functioning and kinesthetic integration.

Reflex abnormalities affect performance in automatic balance, posture and motor skills. For example, a retained Tonic Labyrinthine Reflex will affect balance and distribution of muscle tone depending on head position in relation to the midplane; If the Asymmetrical Tonic Neck Reflex is retained it will affect hand-eye coordination, ability of the hand and sometimes the eyes to cross the vertical midline and the development of cross pattern movements. A retained Symmetrical Tonic Neck Reflex can affect both sitting posture and coordination because it creates a horizontal midline barrier within the body which interferes with integration between upper and lower sections of the body. If the Palmar Reflex remains, it will affect the development of fine finger movements, particularly the ability to hold a writing instrument in a tripod grip. These basic motor abilities are fundamental to many of the skills required for academic learning.

Eye movements may also be affected as a result of the links between the labyrinths and the eyes via the vestibular-ocular-reflex arc (VOR). Neurological connections also exist between the vestibular and the auditory systems. Although these two systems are considered separately, the cochlear and the semi-circular canals of the vestibular apparatus adjoin within the inner ear, they share the same fluid and a common pathway for the transmission of signals to the brain along the 8th cranial nerve. Dysfunction in one system can affect the processing and perception of information from the other.

Literature Review

1. Neurological Factors in Dyslexia

Ever since Dyslexia was first identified it has been hypothesised that structural abnormalities in the brain may underlie the disorder. Post natal examination of the brains of five male and three females who had Dyslexia revealed two consistent findings in the group: developmental neuropathology and symmetry of language related regions of the brain (Galaburda and Kemper, 1979, Galaburda et al., 1985, Humphreys, Kaufman and Galaburda, 1990).

The last 25 years of research into Dyslexia have focused upon 4 main areas of difficulty:

1. Difficulties with automatic balance originating from dysfunction in the vestibular-cerebellar loop (Levinson 1974, De Quiros and Shrager 1978, Nicolson and Fawcett 1990, Fawcett et al 1996).

2. Immature Motor Skills (Blythe and McGlown, 1979, Augur 1985, Denckla et al 1985, Goddard 1996).

3. Auditory processing problems (Geschwind and Levitsky 1968, Tallal and Piercy 1974) and the Phonological Deficit Theory (Geschwind and Galaburda 1985, Dalby 1986, Johansen 1988, Shayvitz 1996, Tallal 1996).

4. Abnormal processing of visual information (Galaburda et al 1986, Pavlidis and Miles 1987, Chase and Jenner 1993).

In 1996, Fawcett and Nicolson concluded that, "children with dyslexia have deficits in phonological skill, speed of processing and motor skill. These deficits are well characterised as problems in skill automisation, which are normally masked by the process of conscious compensation".

The automisation of skills depends upon the maturity of subcortical supporting systems within the brain of which the reflex system (mediated at the level of the brain stem and the midbrain) is one of those underlying structures. Postural reflexes are important for maintenance of posture and the execution of controlled movements in cooperation with other centres such as the cerebellum, basal ganglia and motor cortex..

2. The Impact of Primitive Reflexes on Education

In 1970, Gustafson carried out a study in which she compared the reflex levels of a group of neurologically impaired children with a group of children who had no known neurological impairment. The comparison revealed that 8 out of 19 of the children in the group with no known neurological impairment displayed some reflex abnormalities but all of the children in the group with neurological impairment had abnormal reflexes, and in greater numbers than the normal children.

Both groups were also tested using the Purdue-Perceptual Motor Survey. The results showed that a relationship did exist between the reflex test results and the childrens' performance on some of the sub tests of the Purdue Perceptual Motor Survey: Those children whose postural and balance reactions were intact performed well on the balance and rhythmic areas. An additional finding was that the 8 children from the normal group who exhibited primitive reflex patterns also had problems in the classroom; one had behaviour problems, and the remainder had either reading and/or writing difficulties. Writing difficulties were particularly prevalent in this group.

In 1972, Rider carried out a study to assess the prevalence of abnormal reflex responses in normal second grade children compared to a group of learning disabled children. The study revealed that the learning disabled children had significantly more abnormal reflex responses than the normal children (although the normal children also displayed some abnormal reflexes). Wide Range Achievement Test (WRAT) scores were then compared on the basis of whether there were abnormal reflex responses or not. Children with no reflex abnormalities scored higher on the achievement tests than the children with abnormal reflex responses.

In 1976, Bender examined the effect of just one reflex, the Symmetrical Tonic Neck Reflex (STNR) on education, and found that it was present in 75% of a group of learning disabled children but not present in any of a comparison group of children who had no history of learning disabilities.

Wilkinson (1994) carried out a replica of Rider's 1972 study. A group of normal year 3 children aged between 7.7 and 8.6 years consisting of 28 boys and 35 girls from four schools were tested on four primitive reflexes, The Wide Range Achievement Test and the Non-Reading Intelligence Test. The results indicated that abnormal primitive reflexes were a contributory factor in learning difficulty and underachievement

O'Dell and Cook (1997), found the Symmetrical Tonic Neck Reflex was a significant factor in a group of children who had writing problems, Attention Deficit Disorder (ADD) and Attention Deficit Hyperactive Disorder (ADHD).

In view of the evidence, it was decided to examine 54 children who had received an independent diagnosis of Dyslexia from an Educational Psychologist, for the presence of abnormal primitive and postural reflexes and related motor skill dysfunctions. Additional tests were therefore carried out for cerebellar dysfunction, dysdiadochokinesia, oculo-motor functioning and visual-perceptual performance, to determine whether Neuro-Developmental Delay was a significant factor underlying their Dyslexic symptoms.

Aim

To investigate whether neurological dysfunction confirmed by a cluster of abnormal primitive and postural reflexes was a significant factor in a group of children diagnosed with Dyslexia, and whether abnormal reflexes were present together with dysfunctions in other areas related to motor development (cerebellar functioning, dysdiadochokinesia, oculo-motor functioning and visual-perceptual performance).

Method

Participants

54 children aged between 8 and 15 years were selected from a wider group of children who had been assessed for neurological dysfunction. The criterion for selection was that all the participants had previously received an independent diagnosis of Dyslexia. (ie. all had been assessed by an Educational Psychologist using the WISC). Their dyslexic symptoms had not significantly improved as a result of standard remediation. Of the 54, one had an additional diagnosis of Attention Deficit Disorder and one had subsequently developed Anorexia. The sample group comprised a significantly higher incidence of males than females (46 males and 8 females; the subject with Anorexia was female).

Neurological assessment was carried out at the request of the parents, and one or both parents were present throughout the assessment procedure. The research project was approved and overseen by Peter Blythe PhD., Director of the The Institute for Neuro-Physiological Psychology. All of the group was put through a battery of standardised diagnostic tests in 6 categories:

1. Tests for the continued presence of primitive reflexes
2. Tests for the presence of postural reflexes
3. Oculo-motor functioning.
4. Visual-perceptual performance.
5. Cerebellar involvement.
6. Dysdiadochokinesia

Test Battery

Tests for Primitive and Postural Reflexes
A full description of the reflex tests may be found in Field J, Blythe P 1995, and Goddard 1996.

Tests for Cerebellar Involvement and Dysdiadochokinesia

The standard medical tests for cerebellar functioning and dysdiadochokinesia were utilised.

Oculo-Motor Functioning

1. Visual Tracking

Test position: Standing feet together, arms by the sides. The child was then instructed to follow the coloured tip of a ballpoint pen with his/her eyes without moving the head. The pen was held at a distance from the face equivalent to the distance between the end of the child's fingertips and the elbow, three inches below eye level. The tester moved the stimulus slowly from side to side for 10 movements. Eye movements were observed for ability to follow the movements of the pen without anticipation, jumping or head movement.

2. Hand-Eye Tracking

Test position: Standing feet together, arms by the sides. The procedure was identical to the test for visual tracking except that the child held the pen in his/her writing hand and was responsible for moving the pen from side to side without moving the head.

3. Near Point Convergence

The child was instructed to focus on the coloured point of the non writing end of a ball point pen held at eye level at a distance of arm's length from the face and was instructed to follow the coloured dot as it was moved towards the subject until the the eyes converged.

4. Reestablishment of Binocular Vision

The procedure was the same as for near-point convergence with the addition that the child was asked to say "stop" when the image began to blur. The pen was then moved away and the test subject was asked to say, "stop" when the coloured point became clear again. The distance between the point going out of focus and returning to focus again was measured. If the distance exceeded two to three inches, reestablishment of binocular vision was slow.

Visual-Perceptual Tests

Participants' drawings of the Tansley Standard Figures, Daniels and Diack and Bender Visual Motor Gestalt Figures were analysed for visual discrimination and visual-motor integration ability.

Stimulus bound effect was measured by asking the test subject to complete a line through the centre of two rectangles, one measuring 13 centimetres across by 8 centimetres down, and the other measuring 8 centimetres across by 6 centimetres down. If the line deviated significantly towards the edge of the rectangles and the deviation was greater with the smaller rectangle, stimulus bound effect was said to be present. (stimulus bound effect describes the inability to ignore irrelevant visual stimuli within a given visual field)

Scoring

Scoring during the test procedure was based on a standardised scale of 0 - 4
(Capute et al. 1984)
0 = no abnormality detected (nad)
A positive result indicating deviation from 0 (no abnormality detected) was scored in increments of 25% (1,2,3,4)
A score of 4 = a fully retained primitive reflex, absence of a postural reflex or inability to carry out the test.

Analysis

A score of 0 is the currently accepted norm on the above tests; a score of > 0 indicating dysfunction. For this study, a score of 1 or greater than 1 was recorded as a positive score. The number of participants with a positive score on each test was recorded and expressed as a percentage.

Results: The findings for the major areas under consideration are:

Table 1
Number of particpants out of 54 with a score of >1

As a result of these figures it is possible to conclude that neurological dysfunction (abnormal primitive and postural reflexes) and other factors related to motor development were a significant factor in this sample of children with Dyslexia.

Reflexes

The Asymmetrical Tonic Neck (ATNR) and the Tonic Labyrinthine Reflexes (TLR) were present in all of the subjects. Reflexes which have a direct affect upon vestibular functioning (Asymmetrical Tonic Neck, Tonic Labyrinthine and Moro reflexes) were all highly significant. Other reflexes found to be significant were: The Symmetrical Tonic Neck Reflex (STNR), the Spinal Galant reflex, the Palmar reflex, the Plantar reflex and the Rooting reflex.

The lack of fully developed postural reflexes was also apparent in a large percentage of the sample.

Oculo-Motor dysfunction was found in 92% of the sample of which:
83 % had difficulty with hand/eye coordination.
59% had difficulty with near point convergence.
42% had difficulty with visual discrimination.
77% showed evidence of stimulus bound effect.
98% had difficulty with visual motor integration (VMI or hand-eye coordination)

The results suggest that whilst individual reflex abnormalities impair functioning in specific skills, the combined effect of a cluster of aberrant reflexes will have an impact upon learning in general, particularly those areas of learning which require cooperation with the motor system. Reading may be affected because it requires a level of oculo-motor functioning. Writing is a motor task which depends upon coordination of the hands and the eyes with automatic support from the postural system.

The postural reflexes also come under the control of the cerebellum in combination with other centres. Whilst on the one hand underdeveloped postural reflexes indicate immaturity in the functioning of the central nervous system, failure to develop fully may also impede the cerebellum in the regulation and automisation of specific skills dependent upon the postural reflexes, and may be an important link to the findings of other authors that individuals diagnosed with Dyslexia or at risk of developing Dyslexia show difficulties with control of automatic balance (Levinson 1984, Fawcett et al. 1996, Schrager 2000)

Cerebellar Involvement and Dysdiadochokinesia

Tests for cerebellar involvement revealed dysfunction in a relatively small number of the sample although there was a marked difference between accuracy when performing the tests with the eyes open and with the eyes closed suggesting that the participants relied heavily on visual cues to know where distal parts of their body were in space. In other words, they had poor proprioceptive - spatial awareness in the absence of visual cues.

The tests for dysdiadochokinesia revealed significant difficulties with fine muscle coordination in the fingers, rapid alternate pronation of the hands and alternate movement of the feet. These abilities come under the influence of the cerebellum together with the motor cortex, but can also be affected by a retained Palmar reflex (fingers), and Asymmetrical Tonic Neck Reflex (fingers, hands, feet and the ability to carry out independent movements on either side of the body).

Discussion

Earlier research has linked abnormal primitive and postural reflexes to problems with balance and coordination (Ayres 1972, Pyfer and Johnson 1981), and children with learning disabilities (Rider 1972, Wilkinson 1994). The relatively high incidence of abnormal reflexes together with difficulties carrying out related motor tasks in this sample, suggests that abnormal reflexes do affect the acquisition and automisation of more complex motor dependent skills.

Although it is generally acknowledged that abnormal primitive and postural reflexes cannot exist in the absence of neurological dysfunction, the results from this sample suggest that the incidence of abnormal reflex activity may be higher within the general population than has hitherto been recognised. This may be a useful area for future research.

Testing for abnormal primitive and postural reflexes could be more widely used as a method of assessment to identify children who are underachieving and for whom underlying neurological dysfunction may be a significant but hitherto unsuspected factor in their presenting difficulties.

Conclusion

In view of the evidence, it seems reasonable to conclude that neurological dysfunction confirmed by the presence of abnormal primitive and postural reflexes was a significant factor in this group of children diagnosed with Dyslexia, and that abnormalities in early patterns of motor development do affect the acquisition and automisation of higher more complex skills. Immature postural and adaptive mechanisms interfere with a child's ability to express his/her intelligence at written language and motor dependent tasks. These underlying faults at a physical and neurological level should be identified, assessed and treated, if a child with reflex abnormalities is to achieve his/her full potential in the classroom.

Too often, physical factors are overlooked when a child is diagnosed with Dyslexia. Assessment of primitive and postural reflexes in the older child can help to isolate underlying factors so that recommendations for remedial treatment also include appropriate reflex stimulation and inhibition exercises in addition to specialist teaching. The results of this study suggest that examination for patterns of motor development, oculo-motor functioning and visual-perceptual performance should be more widely used as part of the assessment procedure of a child suspected of having Dyslexia. 3843 words

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Acknowledgements

David Hyland for advice on analysis of results.