Neuro AI 2 - Week 1 SG.docx.pdf

1 S. Taylor Week 1: Motor Control & Motor learning FoR Motor control theory o Ability to regulate or direct the mechanisms essential to movement o Development of postural con...

1 S. Taylor Week 1: Motor Control & Motor learning FoR Motor control theory o Ability to regulate or direct the mechanisms essential to movement o Development of postural control generally follows: ▪ Cephalo-caudal path: Control of head posture develops first, then trunk in sitting, then trunk & LE in stance ◊ Head control ◊ Upper trunk control ◊ Sitting upright ◊ Standing w/support ◊ Standing w/out support ▪ Proximodistal path: Middle of body to distant limbs o Individual ▪ Action: CNS regulation & organization of muscles & jnts. during a functional activity (e.g. walk, jump, sit, etc.) ▪ Perception: Integration of sensory info into meaningful info ▪ Cognition: Intent that drives a motor task ◊ Task: Nature of a task determines the movement required ◊ Grouping tasks/establishing a progression ❖ Functional: Bed mobility, gait, transfers, ADLs ❖ Discrete (start/stop - throw a ball) or continuous (gait) ❖ Stability 🡪 mobility task (moving & throwing ball) 🡪 manipulation (using hands to manipulate ball) ❖ Closed task (repetitive motion) vs. open task (move a tennis racket in different ways) o Environment ▪ Regulatory: Aspects of the environment that shape the movement ◊ Ex: Picking up a mug vs. glass  2 S. Taylor ▪ Non-regulatory: Movement that doesn’t have to conform to these features in the environment, can affect performance, noise & distractions ◊ Ex: Playing in silence vs. in front of a large crowd Reflex theory o Complex behavior is the combined action of individual reflexes chained together ▪ Reflex causes & drives movement o Limitations ▪ Spontaneous & voluntary movements aren’t initiated by an outside stimulus ▪ Movement can occur w/out sensory stimulus ▪ Movement can occur faster than sensory stimulus ▪ Single stimulus can produce varying results ▪ Novel movements are not explained Hierarchical theory o Higher cognitive centers are in control of the lower centers o Normal motor dev. in children can be attributed to increasing corticalization of the CNS o Current concepts ▪ Top down control isn’t always true ▪ Lower levels can exert control over higher levels ▪ Each level of the CNS can act on the other depending upon the task Motor programming theories o Patterns of movement can be activated by sensory stimulus or central processes o Central pattern generators ▪ Specific neural circuit that is hardwired ▪ Spinal walking w/cats o Central motor pattern controls movement & tells your body what movement to do ▪ Rules for generating movements ◊ Rules can be applied in a variety of settings  3 S. Taylor ▪ Perform name writing exercise ◊ Ex: Writing your name in a variety of settings (e.g. on ipad), writing big/small, etc. o Clinical significance ▪ Retrain movements for functional tasks not just movements in isolation ▪ Relearn the correct “rules” for a movement Systems theory o Incorporates the whole body, gravity, and inertia not just the CNS ▪ You can teach reaching, grasping, etc. but you have mult. df which incorporates the whole body o Multiple df in the body ▪ Teach simple movement patterns 🡪 then learn more df o Hierarchical control to activate synergies to control df ▪ Ex: Biceps & triceps o Stable vs. unstable movement patterns ▪ Stable: Less variability ◊ Ex: Learning to ice skate ▪ Unstable: Greater variability (common w/new tasks or prior to changing to a more stable pattern) ◊ Ex: Olympic ice skaters o Clinical implications ▪ Must examine the musculoskeletal system as well as the CNS for loss of motor control ▪ Explore variable movement patterns to achieve performance goals Ecological theory o Goal oriented behavior o Perceptions guide behavior o Environment in a large factor in movement o Patients should explore different ways to accomplish a task Integrated theory of motor control  4 S. Taylor Rood approach o Created by Margaret Rood (OT & PT, started w/CP) o Heavy work muscles: Stabilization, reflexively controlled o Light work muscles: Movement, voluntary controlled o Muscle tone: state of stiffness/tension in muscles o Use sensory stimuli to elicit specific motor responses ▪ Normalize tone ▪ Begin at person’s current developmental level & work up from there Brunnstrom’s movement therapy o Hemiplegia after CA o Normal dev. involves progression of reflex dev. o Stereotypical limb movement patterns – limb synergies (flexion/ext.) ▪ These are normal after CNS damage b/c CNS is reverting to early dev. stage ▪ Synergies dependent upon brain & there’s varying degrees ◊ Flexor synergy is more common o Don’t inhibit but utilize synergies ▪ Ex: Flexor synergy – brush teeth, newspaper under arm ▪ Ex: Extensor synergy – open drawer, maybe open door, wipe table, pet dog o Levels of recovery: ▪ Flaccid: No reflexes, use sensory stim ▪ Reflexes normalize ▪ Involuntary synergies: Hypertonicities come back w/flexors or extensors ▪ Voluntary movements Proprioceptive neuromuscular facilitation (PNF) o CP & MS o Hastens/promotes response of neuromuscular mechanism through stimulation of the proprioceptor & diagonal movement patterns to get people to move o Reversing movements (flexing then extending & vice versa) o Balance of antagonistic muscles o Frequent stimulation & motor repetition support retention of learned motor abilities o Stimulation: Physical contact of therapist, visual cues, verbal commands  5 S. Taylor Bobath’s neurodevelopmental treatment (NDT) o Neurologist & physiotherapist – frequently used in adult hemiplegia o learning the sensation of movement o Start w/basic postural movements o Tx: Abnormal patterns inhibited & normal ones elicited w/sensory stim 🡪 handling Motor learning & task oriented approach o Neuro-facilitation approaches have evolved to include function not just suppression of reflex o Task-oriented or motor learning approach ▪ Dev. from newer theories of motor control ▪ Tx based on functional tasks ▪ Learn by solving problems ▪ Must be able to adapt to changes in the environment Motor learning o More long-term, permanent vs. more immediate results & temporary (motor control) o Performance = temporary changes & learning = permanent changes ▪ Retention across time ▪ Transfer to other tasks & conditions Types of motor learning o Implicit learning: Learning unconsciously ▪ Non-associative: Single stimulus repeatedly ◊ Habituation: Nonpainful ◊ Sensitization: Noxious ▪ Associative: Forming relationships btwn. stimuli ◊ Classical conditioning: Pavlov’s dog ◊ Operant conditioning: Trial & error ▪ Procedural learning: Learning automatic tasks, habits ◊ Not dependent on awareness, attention, higher cortical processes ◊ Dev. slowly after many repetitions, varying circumstances  6 S. Taylor ◊ Learn the rules o Explicit (declarative) learning: Learning consciously, awareness ▪ Can be consciously recalled & articulated ▪ Requires higher cortical processes awareness, motivation, attention, reflection, ability to relate new info to things they already know ◊ Read instructions, maybe watch demo, practice ▪ Can be enhanced by mental practice ▪ Constant repetition transforms declarative to procedural Motor learning theories o Adam’s closed loop theory ▪ Sensory feedback necessary to learn skilled movement ▪ “Internal reference of correctness” is stored w/repetition of correct movement ◊ Specificity should increase learning ◊ Errors & variability will decrease learning ▪ Limitations: Doesn’t explain accurate performance of novel movements or movements made w/out feedback (open-loop) o Schmidt’s schema theory ▪ Open loop ▪ Generalized motor program ◊ Recall schema to select a response ◊ Recognition schema to eval. the response ◊ Error signal used to modify schema ▪ More info is better b/c variability should increase learning ◊ Variability in dif. environments, dif. ways, etc. ▪ Limitation: Inability to account for immediate acquisitions of new types of coordinator or new forms of movement o Ecological ▪ Search for optimal strategies to solve the task ▪ Find appropriate motor response & appropriate perceptual cues  7 S. Taylor ▪ Learn to distinguish relevant perceptual cues & match these to motor strategies ▪ Perception: Used to understand the task (goals & movements needed) & as feedback (both during & after movement) ▪ Learn to match appropriate movement dynamics to dif. conditions ▪ Learn how to solve motor problems, not perform a specific movement pattern Stages of motor learning o Stage 1: Acquisition ▪ More cognitive, novice, understand the movement ▪ Decrease variability ▪ Freeze df ▪ Understanding/attending to movement o Stage 2: Skill refinement ▪ Associative, advanced, refine the movement o Stage 3: Skill retention ▪ Autonomous, expert Task-specific training o Umbrella intervention term for motor learning o The active, repetitive practice of functional activities to learn or relearn a motor skill o Repeated, challenging practice of functional, goal-oriented activities o Used for restoring or remediating UE motor control Principles of task-specific training o Practice of a movement results in improvement in that movement o Large amounts of practice are required to truly master a motor skill, but the ideal dose of practice is unknown ▪ Better to do a whole lot of practice rather than little bits here & there o Learning requires solving the motor problem, not rote repetition of overlearned tasks o Learning does not occur in the absence of feedback o Intrinsic feedback is optimal for promoting self-learning & generalization o Optimal learning occurs w/high levels of motivation & engagement o Variable practice conditions are optimal for learning & generalization o Within-session, massed practice promotes learning better than within-session distributed practice o Practice of a whole task results in better learning than practice of parts of the task, unless the task can be broken down into clearly separable components  8 S. 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