Motor learning and recovery of function
- 1. MOTOR LEARNING & RECOVERY OF FUNCTION PHT 613 Ekechukwu E.N.D (B.MR,PT; M.Sc; Ph.D.)
- 2. Motor Learning • Learning is the process of acquiring knowledge about the world • ML is a set of processes associated with practice or experience leading to relatively permanent changes in the capability for producing skilled action - capability of movt acquisition - results 4m experience or practice - cannot be assessed directly but inferred 4m behaviour - produces relatively permanent changes in behaviour
- 3. Forms of Learning 1. Non-associative Learning • Occurs when animals are given a Single stimulus repeatedly that results in the NS learning about the stimulus eg Habituation and Sensitiation • Habituation: - Decrease in responsiveness that occurs due to repeated exposure to a non-painful stimulus. - It is used in many ways in the clinic eg habituation of dizziness, tactile defensive children.
- 4. Non-associative Learning Cont’d • Sensitization - Increase in responsiveness following a threatening/ noxious stimulus eg tenderness - It counteracts the effect of habituation - Sometimes sensitization is important eg balance training by Increasing awareness of fall
- 5. 2. Associative Learning • Learning that involves the association of ideas eg asking a pt with walking problems to shift of COG & swing • It helps pts to learn how to predict r/ships either of one stimulus to another (Classical Condition) or one’s behaviour to a consequence (operant conditioning)
- 6. Classical Conditioning • A process of learning to pair stimulii • The initially weak stimulus (cs) becomes higly effective in producing a response (cr) when it becomes associated with another stronger stimulus (ucs) • Eg giving a verbal cue in conjunction with physical assistance when making a movt • We generally learn r/ships that are relevant to our survival.
- 7. Operant/Instrumental Conditioning • Basically trial and error learning • We learn to associate a certain response from among many that we have made with consequence eg rewards and punishment • Law of effect “behaviours that are rewarded tend to be repeated at the cost of other behaviours … and vice versa” • Implication: operant conditioning determines behaviour of pt referred for PT eg falls
- 8. Procedural & Declarative Learning • Associative learning classification Based on the type of knowledge acquired & ability to recall learned information • Procedural learning - Learning tasks that can be performed w/o attention or conscious thought - Devs slowly thru repetition of an act over many trials - Repeating a movt under varying conditions leads to procedural learning i.e automatically learning the rules for movt eg transfer
- 9. P & D Learning • Declarative Learning - Results in knowledge that can be consciously recalled and thus requires awareness, attention & reflection - DL can be expressed in declarative sentences eg button the top button, then the next one. - Constant repitition can transform DL to PL - DL learning encourages mind rehearsal of movt
- 10. Theories of Motor learning • A group of abstract ideas about the nature and cause of the acquisition/modification of movt • Adam’s Closed Loop theory - Sensory feedback used to organise skilled movt - Proposes 2types of memory: memory & perceptual traces - Memory trace used in the selection & initiation of movt - Perceptual trace built up over a period of practice & becomes internal reference of correctness. - After movt is initiated, the traces takes over to carry out the movt & detect error.
- 11. Adam’s Closed Loop theory Cont’d • Clinical Implication: The more the practice of a particular movt, the stronger the perceptual trace • Limitations - Movts can be made w/o sensory feedback (open- loop movt) - Not possible to store a separate perceptual trace for every movt ever performed - Variation of movt practice may improve motor performance
- 12. Schmidt’s Schema Theory • Emphasised open-loop control processes and generalized MP concept • That MPs don’t contain the specifics of movt but the rules for specific class of movt • Central concept of schema: abstract rep stored in memory following multiple presentations of a class of info eg seeing many dogs • Two types of schema: Recall and recognition schema • Variability strengthens the generalized schema
- 13. Schmidt’s Schema Theory Cont’d • Clinical implication: Optimal learning occurs if task is practiced under many varying conditions • Limitations - Lacks specificity - Inability to account for immediate acquisition of new types of coordination eg quadruped gait in centipedes.
- 14. Ecological Theory • Karl Newell proposed that ML is a process that improves the coordination btwn perception and action consistent with task & environment • Search for appropriate perceptual cue is as important as search for motor response • It emphasised on the dynamic exploratory activity of the perceptual-motor workspace to create optimal strategies for performing a task. • Clinical Implication: Teaching pts to distinguish relevant perceptual cues eg size, texture, vol, wt etc • Limitation: No RCT
- 15. Stages of Learning • Fits & Posner 3-stage Model - Cognitive stage: understanding the nature of task, dev strategies, how task can be performed - Associative stage: refining of the best selected strategy - Autonomous stage: the automaticity of skills with low degree of attention. Attention focused on other aspect of the skill
- 16. Stages of Learning Cont’d • System 3-stage model (Verejken et al, 1992): DF are constrained when a novice learns skill eg use of hammer. - Novice stage: simplifies movt, freezes DF - Advanced stage: muscle synergy used to create well coordinated movt - Expert stage: all DF released, learns to take adv of the mechanics of the MSK system & the environment - Explains coactivation, rationale for devt stage rehab (biomechanical not neural perspective), providing external support during early neurorehab
- 17. Stages of Learning Cont’d • Gentiles 2-stage model: based on the goal of the learner - To dev understanding of task dynamics eg learning to distinguish regulatory features - Fixation/diversification stage: goal for refining the movt
- 18. Practical Application of ML • Feedback: all sensory info due to a movt (response-produced feedback) – Intrinsic & Extrinsic (concurrent/terminal) • Practice - Massed vs Distributed practice - Constant vs variable practice - Random vs Blocked practice - Whole vs part training - Transfer/ carryover effects - Mental practice (SMA)
- 19. Recovery of function • ML- the acquistion or modification of movt in normal suject while recovery of fxn relates to re- acquisition of movt skills lost thru injury • Recovery – achieving fxnal goal in same way it was performed pre-injury • Compensation – behavioural substitution i.e alternative behavioural strategies adopted to complete a task • Sparing fxn – when a fxn is not lost despite injury • Spontaneous vs Forced recovery
- 20. Factors Contributing to Functional Recovery • Effect of age • Characteristics of the lesion: size, onset • Effect of experience: enrichment (pre-op & post-op) • Effect of pharmacology: trophic factors, NT, anti-toxic, circulation , anti-oxidant etc • Effects of training
- 21. Conclusion • Knowledge of ML is inevitable to neurorehab • Functional return may be due to recovery & compensatory process • My 3stage model of stroke rehab