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1 Primary and Secondary Variabilities of Movement and Optometric Vision Therapy. Caroline M.F. Hurst BSc FCOptom FBABO

2 Themes Cyclical learning of movement and sensory pathways. Primary and secondary variabilities of movement. OVT and the whole person.

3 Vision i Vision Taking meaning ng from all sensory input, relating it to previous experience. Vision is then used to direct action.

4 Vision i Vision Seeing with meaning, understanding di and purpose. The dominant process in human behaviour. Results in a mental and/or physical action.

5 Posture and Postural Control Postural control; a key issue in developmental disorders by Hadders Algra and Carlberg.

6 Posture: Posture and Postural Control The relationship between the parts of the body, and between the body and an external reference frame. Static, and dynamic balance as we make movements, with reference to gravity.

7 Posture and Postural Control Postural control is an active process as the person explores the limits of stability. Reactionary: in response to an external change. Anticipatory: preparing p for a goal directed action. Brandon n Jacobs, 6ft 4in, 265lb 4.52s 40-yard dash

8 Posture and Postural Control Postural control takes sensory input from the visual system, vestibular apparatus and proprioception. Postural control and movement are part of the visual process, and are needed to pass from perception to action.

9 Posture and Postural Control The visual process depends on postural stability to direct action successfully.

Most movements require postural adjustments.

10 How is the visual process learned? Development of postural control and movement intrinsically linked. Most movements require postural adjustments. t Both require a long process of neurodevelopment. Adult postural adjustments are not seen until late adolescence.

11 How is the visual process learned? Development and learning ng in the first year of life establish the relationship between a movement and the perception of the sensory input from that movement.

12 How is the visual process learned? Motor and sensory pathways are learned at the same time. Modified movement Sensory afferent Movement information

13 Early Experience, the Brain and Consciousness, Dalton and Bergenn movement is an intrinsic and ineradicable element of each and every sensory perception.

14 Early Experience, the Brain and Consciousness, Dalton and Bergenn Perceptual knowledge depends on the relationship between:- posture that t furnishes the ground, the spatial position of the object in view, intersensory judgement, and proprioceptive feedback. All four variables and their interrelationship undergo change as a result of growth and changes in mobility.

15 How is the visual process learned? Motor development theories Gesell and Amatruda Kugler, Thelen Hadders Algra

16 Neural Maturation (Gesell, Amatruda 1945) Nature response Predetermined d patterns, Within the constraints of genetics, Increasing cortical control. Late attainment, and/or abnormalities in muscle tone and reflexes.

17 Nurture response s Dynamic Systems Theory (Kugler et al (1980) in Hadders-Algra 2000Aug p 567) The effects of the component parts eg body weight, muscle strength, postural control + The effects of the environmental conditions and task requirements = Spontaneous, specific organisation of behaviour.

18 Dynamic Systems Theory (Thelen et al (1995) in Hadders-Algra 2000Aug p 567) A dynamic system and a self organising g process. A series of states of stability bl and instability bl as patterns of movement m were attempted.

19 Primary and Secondary Variabilities (Hadders-Algra M Aug and Oct) Primary Variability Selection Secondary Variability

20 Neuronal Group Selection Theory (NGST) (Edelman and Tononi 2000)

21 Neuronal Group Selection Theory (NGST) Cortical and subcortical systems organised into variable networks. (Edelman and Tononi 2000) The structure and function of each network is selected by development and behaviour. The units for selection are collections of hundreds to thousands of strongly connected neurones called neuronal groups. The brain selects which groups will be kept or discarded.

22 Neuronal Group Selection Theory (NGST) (Edelman and Tononi 2000) The NGST bases selection on Darwinian principles of population and natural selection. Not only does natural selection apply within species, but applies as somatic selection within a single body to give the variation and selection of individual cell systems. So the selection of a group to be kept depends on the survival of the fittest.

23 Neuronal Group Selection Theory (NGST) (Edelman and Tononi 2000) Natural selection from genetics + Somatic selection from experience + Re-entrant entrant pathways

24 Neuronal Group Selection Theory (NGST) Developmental Selection (Edelman and Tononi Tononi 2000) Initial anatomy determined by genes and inheritance, Neurones extend with extensive variability, diverse primary repertoire of connections.

25 Neuronal Group Selection Theory (NGST) Developmental Selection (Edelman and Tononi Tononi 2000) Neurones strengthen and weaken their connections according to individual patterns of electrical activity. Neurones that fire together wire together, forming closely connected groups. Slight reduction in variability after selections have been made.

26 Neuronal Group Selection Theory (NGST) Experiential Selection (Edelman and Tononi Tononi 2000) Secondary repertoires develop thru experiential selection. Overlaps developmental selection and continues throughout life. Synapse connection selections within the repertoires of neurological groups that are determined by behavioural experience.

27 Neuronal Group Selection Theory (NGST) Experiential Selection (Edelman and Tononi Tononi 2000) Selection on the basis of the afferent sensory information produced by a behaviour, movement or experience. Experiential selection allows for situation-specific specific neuronal groups, and allows for development of volitional variable behaviour which can be adapted to environmental situations.

28 Neuronal Group Selection Theory (NGST) Re-entrant entrant mapping (Edelman and Tononi Tononi 2000) Re-entryentry Neuronal groups across the cortex and thalamus are arranged as maps. There are reciprocal re-entrant entrant pathways that link across the brain from one area to another.

in the local area. Allows different parts of the brain to respond to the same stimulus.

29 Neuronal Group Selection Theory (NGST) Re-entrant entrant mapping (Edelman and Tononi Tononi 2000) There are reciprocal pathways that link maps that are alike, maps with associated function and also maps that are in the local area. Allows different parts of the brain to respond to the same stimulus. As the re-entrant entrant pathways form a dense meshwork any disturbance in one area of the meshwork can be felt rapidly elsewhere.

30 Neuronal Group Selection Theory (NGST) Re-entrant entrant mapping (Edelman and Tononi Tononi 2000) Re-entry entry allows integration of information from neuronal groups across the thalamus and cortex, without the need for a central coordinating area. The synchronisation of the activity of neuronal groups in different brain maps.

31 Neuronal Group Selection Theory (NGST) Re-entrant entrant mapping (Edelman and Tononi Tononi 2000) Therefore, re-entry entry is the central mechanism by which the space and time co-ordination ordination of motor and sensory events take place. Re-entry entry Feedback.

32 Neuronal Group Selection Theory (NGST) Re-entrant entrant mapping (Edelman and Tononi Tononi 2000) So, Developmental and Experiential selections provide the bases for great variability and differentiation of groups. Re-entry entry allows the integration of information between and within the primary and secondary repertoires.

other major re-entry entry functions Synchronisation of

33 Neuronal Group Selection Theory (NGST) Re-entrant entrant mapping (Edelman and Tononi Tononi 2000) Two other major re-entry entry functions Synchronisation of the space and time co-ordination ordination of movements. Distinguishing g between figure and ground based on interactions between brain areas for visual movement and shape.

34 Primary and Secondary Variabilities (Hadders-Algra M Aug and Oct) Primary Variability Selection Secondary Variability

35 Primary and Secondary Variabilities Primary Variability (Hadders Hadders-Algra M Aug and Oct) All forms of goal directed motor behaviours start with primary variability. The primary variability develops during foetal life and infancy as a fundamental phenomenon, showing enormous variation. Neural system explores all motor possibilities by self generated activity + self-generated afferent information, within the constraints of genetics.

36 Primary and Secondary Variabilities Selection (Hadders Hadders-Algra M Aug and Oct) Experiential selection of most effective motor patterns and their associated groups. Transient minor reduction in variation of motor behaviour. Begins during infancy at function specific c ages, eg reaching and grasping at 4 to 5 months.

37 Primary and Secondary Variabilities Secondary Variability (Hadders Hadders-Algra M A and O) Secondary variability shows a time of rapid increase in synapse formation and elimination. Creation of secondary neural repertoires with a large collection of parallel channels due to exposure to a multitude of experiences. The long duration of the developmental processes in secondary variability means it may take years to reach efficient motor solutions for each specific movement.

38 Primary and Secondary Variabilities Secondary Variability (Hadders Hadders-Algra M A and O) Mature situation task constraints: ability to adapt each movement exactly and efficiently to task specific conditions, or multiple motor solutions or strategies for a single task. Onset: function specific from mid-infancy infancy onwards. Starting to bloom at 2-3 years; mature in adolescence.

39 How does our understanding of primary reflexes fit with these theories? Part of the genetically determined primary repertoire that is developed in the foetus. For safety net, need to retain access to both primary and secondary repertoires of motor response. A choice of motor response depending on the situation, and state of the individual e.g. fatigue, stamina, nutrition etc - 1º, 2º, or primitive reflex.

40 If a primary reflexive response to a stimulus is their movement of choice it could be:- they haven t developed the secondary repertoire associated with that stimulus, they have a secondary repertoire but cannot access it, they haven t developed the efficient sensory pathways to enable the development of secondary variability,

41 If a primary reflexive response to a stimulus is their movement of choice it could be:- both primary and secondary repertoires in place, but they are unable to fine tune their motor output to specific tasks, they may have developed d both primary and secondary repertoires but lost them, or lost access to them due to TBI, CVA etc, the stress of the situation, and state of the person. Primitive reflex responses and gross motor skills assessment - exploring and probing the primary and secondary repertoires as well.

42 But where is the visual process in all this? The motor development processes depend on the sensory afferent pathway to make selections. But also, the sensory input links with previous experience to give vision. Therefore, the visual process is part of every neuronal selection made to develop motor movements, and every movement made develops the sensory pathways. movement is an intrinsic ns and ineradicable element of each and every sensory perception. Dalton

43 How do we learn the visual process? By developmental learning of movement, and sensory afferent information processing skill, initially from the primary variabilities, including the learning from the primitive reflexes, and then from more complex movements gaining g postural control and secondary variabilities of movement. This developmental learning builds to give a reference base of previous experience.

44 Visual Process Assessment The Visual Process

45 Visual Process Assessment Have they made the age appropriate postural control and movement development? Have they made the movement pattern learning that they should have made from the primitive reflexes? Can they locate themselves s in space and know how and where their body parts fit in space? Can they direct themselves and their body parts toward a meaningful end?

46 Visual Process Assessment Can they locate and identify significant others (things and people) as objects of action? Have they the balance, poise, posture and understanding to move accurately, automatically and gracefully through space with their body, eyes and mind? Can they take in the input, process and make the accurate action, without expending excess energy?

47 Optometric t Vision i Therapy We need to view the whole patient. Look for weaker areas within the visual process. With OVT we could access the visual process at any point on this helix to make changes and influence both motor and sensory pathways.

48 Optometric Vision Therapy OVT includes movements that open up access to the primary and secondary repertoires of normal movement development. With neural plasticity the patient is gaining the opportunities to increase variability and make selections, and gain the range of motor responses that they would normally have made.

49 When you assess the patient, whatever their age, there is only the whole person; Bottom up? their performance with their visual process, dependent on their developmental learning.

50 Principal References Dalton TC, Bergenn VW, (2007) Early Experience, the Brain, and Consciousness Lawrence Erlbaum Associates, NY. Edelman GM and Tononi G (2000) A Universe of Consciousness, Basic Books, New York, USA. Gesell A (1949) Vision: It s Development in Infant and Child, OEPF, Santa Ana, CA, USA. Hadders-Algra M (2000 Aug) The neuronal group selection theory: a framework to explain variation in normal motor development. Dev Med Child Neurol Aug;42(8): Hadders-Algra M (2000 Oct) The neuronal group selection theory: promising principles for understanding and treating developmental motor disorders. Dev Med Child Neurol.;42(10):

51 Principal References Hadders-Algra M (2001) Early Brain Damage and the Development of Motor Behaviour in Children: Clues for Therapeutic Invention? Neural Plasticity 8; 1-2, Hadders-Algra M (2003) Developmental Coordination Disorder: Is Clumsy Behaviour Caused By a Lesion of the Brain at an Early Age? Neural Plasticity 10, 1-2, Hadders-Algra M, Brogren Carlberg E, (2008) Postural Control: A Key Issue in Developmental l Disorders (Clinics in Developmental Medicine MacKeith Press McClelland JL, Siegler R,(2001) Mechanisms of Cognitive Development: Behavioral and Neural Perspectives (Carnegie Mellon Symposium on Cognition), Psychology Press. Piaget J (1936) The Origin of Intelligence in the Child, Penguin Books Ltd, England.

52 Thank you, and enjoy the rest of ICBO!

Early Assessment and Intervention

Early Assessment and Intervention S A M E E R R A H I M P H Y S I O T H E R A P I S T R C W M C H S A M E E R. R A H I M @ W E S T E R N C A P E. G O V. Z A What is early intervention Developmental theories