final exam terms

postural control

controlling body’s position in space for dual purposes of stability and orientation

postural orientation

ability to maintain relationship between body segments and between the body and environment for a task

postural stability

ability to control COM in relationship to BOS

types of balance control

1. steady state: ability to control COM relative to BOS in predictable and non-changing conditions
2. reactive: ability to recover a stable position following an unexpected perturbation
3. anticipatory: ability to activate muscles in the legs and trunk for balance control in advance of potentially destabilizing voluntary movements

movement strategies

* fixed support: ankle or hip
* change-in-support: step or reach-to-grasp

sensory reweighting

CNS modifies how it uses sensory info when a sense is not providing optimal or accurate info; critical for maintaining steady-state balance in changing sensory environments and task conditions

attentional resources

info processing resources required to complete a task

dual-task interference

when 2 tasks are performed simultaneously, competition for attentional resources may decrease performance on one or more tasks

postural control outcome measures

* ANPT outcome measure recommendations → stroke, MS, TBI, SCI, PD, vestibular disorders
* activities-specific balance confidence scale (ABC)
* miniBesTest
* Berg Balance Scale
* modified CTSIB

trunk fxns during movement

1. postural control → orientation and stability
2. mobility → adjusts during dynamic activities, subunits of control

development of sitting

occurs cephalic to caudal

* steady state unsupported 6-8mo
* reactive control present as early as 1mo, declines, then returns
* anticipatory control as early as 3mo

steady state sitting

COM aligned at mid thoracic, LOG anterior to hip, lumbar lordosis slightly flattened, weight thru ischial tuberosities; baseline activity in lumbar, thoracic, and cervical paraspinals and abdominals; sway occurs around hips

reactive control in sitting

with perturbations → fixed support (in place, caudal to cranial), or change in support (reach and grasp)

anticipatory control in sitting

with reaching task → cranial to caudal activation of stabilizers prior to prime movers; increased activation with increased task load

dysfunction patterns for seated control

* steady state: altered alignment, altered muscular and postural tone, increased sway
* reactive: cranial to caudal, increased co-activation, delayed onset, more change in support strategies
* anticipatory: delayed onset, decreased speed of movement, use of external support, impaired recruitment
* trunk: issues with alignment change and available ROM/strength, impaired neuromuscular capacity, issues with proprioception and spatial perception, impaired anticipatory control

functional tasks of gait

1. weight acceptance → shock absorption, stability, forward progression
2. single limb stance → stability, forward progression
3. swing limb advancement → swing limb advancement, foot clearance

requirements of gait

1. progression: basic locomotor pattern that produces muscle activation that moves the body in the desired direction
2. postural control: orientation and stability
3. adaptation: ability to modify our gait pattern to accomplish progression and postural control to meet changing task and environmental demands
4. long term viability: ability to tolerate stress to locomotor structures across time as well as the ability to conserve energy

stroke gait deviations

increased lateral displacement of pelvis, lateral trunk lean, flexed or hyperextended knee, decreased PF at late stance, decreased DF in swing, flat foot initial contact

cerebellar dysfunction gait deviations

ataxic steps, reduced step/stride length, slower cadence, decreased hip/knee/ankle ROM in stance

TBI gait deviations

varied presentation; reduced ant-post and increased med-lat COM displacement, increased flexion at IC, excessive knee extension at terminal stance

MS gait deviations

slower velocity, decreased step length, increased double limb support time, increased step width

parkinson’s gait deviations

akinesia, increased co-activation, freezing/festinating gait, hypokinesia, decreased clearance/DF during swing, increased double leg stance time, decreased PF ROM and strength in terminal stance, decreased velocity

stairs

* requirements: progression, stability, and adaptation
* phases: stance and swing; stability demands greatest during single limb support especially from gastroc
* ascent: concentric forces needed are 2x greater than for level gait; knee extensors generate most energy
* descent: eccentric forces
* CNS lesions: decreased velocity, reliance on handrails, step-to pattern

gait outcome measures

1. 10MWT → stroke, PD, SCI, TBI
2. 6MWT → PD, MS, SCI, stroke, huntington’s
3. functional gait assessment (FGA) → stroke, vestibular disorders, PD

STS characteristics

1. progression: generating sufficient torque needed to rise
2. stability: ensuring stability by moving COM from one BOS (feet and butt) to a BOS defined solely by the feet
3. adaptation: ability to modify movement strategies used to achieve these goals depending on environmental/task constraints

STS phases

1. weight shift: high stability, forward motion of trunk by erector spinae, hip and trunk flexion
2. lift off: transfer of momentum from upper body to total body, requires stability, activation of hip and knee extensors
3. extension: vertical movement of body, extension of hip and knees, increased stability
4. stabilization: task dependent motion is complete

STS requirements

* generation of propulsive forces in both horizontal and vertical directions
* horizontal propulsion force must be balances by braking impulse to bring body to stop
* preprogrammed relationship between propulsive and breaking force

STS strategies

1. momentum-transfer: generate forward momentum thru hip flexion to shift COM over feet; trunk extensors eccentrically contract to brake horizontal motion; concentric contraction of LE extensors to lift COM; less stable but requires less LE force
2. zero-momentum: forward flexion of trunk until COM is within BOS; vertical lift of body into standing; more stable but requires more LE force

STS dysfunction with stroke

asymmetrical alignment or increased lateral movement due to asymmetrical strength; decreased velocity or increased reliance on UE; initial placement of paretic foot too far forward; instability due to impaired selectivity

STS dysfunction with parkinson’s

decreased velocity; impaired extension phase; impaired stabilization due to difficulty switching from extension to flexion

STS outcome measures

1. 5xSTS
2. TUG → stroke, PD
3. TUGCog

bed mobility characteristics

1. progression
2. postural control
3. adaptation

bed mobility strategies

1. momentum
2. force control/zero momentum

rolling patterns

* non-segmental (mass): rotation around axis in transverse plane, UE and LE move at same time
* segmental: rotation around diagonal axis, UE and LE initiated separately

Richter’s components for rolling

UE

* lift and reach below shoulder level
* lift and reach above shoulder level
* push and reach
* push

LE

* bilateral lift
* unilateral lift
* unilateral push
* bilateral push

normal development of rolling

1. side lying to supine 1-2mo
2. supine to side lying 4-5mo
3. prone to supine 4mo
4. supine to prone 6-8mo

abnormal rolling

* issues with selecting appropriate movement pattern
* issues with force production
* issues with inter-joint coordination
* issues with selective movement
* requires multiple steps/use of force control strategy
* requires compensations

supine to sit

* components: UE movement, LE movement, trunk movement
* requirements: generate force for vertical movement; control COM as it changes; adapt to environment
* development pattern (6-10mo): prone, prone on elbows/quad, side sit, long sit

abnormal supine to sit

* issues with selecting appropriate movement pattern
* issues with force production
* issues with inter-joint coordination
* issues with selective movement
* requires multiple steps/use of force control strategy
* difficulty changing COM into new BOS
* impaired postural control

bed mobility outcome measures

1. boston university Am-PAC 6 clicks → inpatient setting
2. postural assessment scale for stroke (PASS) → stroke, older adults

UE constraints of R&G

* task: pointing vs. R&G
* environmental: object size/weight/shape, distance, distractions
* individual: neural control (sensory, cognitive, motor) and non-neural (ROM, muscles, biomechanics)

reach, grasp, manipulate (RGM) components

1. locating the target: vision to locate object and interpret what you see
2. reach: motor control of UE to move hand to target, anticipatory trunk/postural control
3. grasp: application of functionally effective forces by hand to an object; understanding of object attributes and forming appropriate hand shape
4. in-hand manipulation: force needed to hold object for lift or task, coordination at individual fingers

temporal links of RGM

* hand opening linked with start of hand movement
* max hand opening at peak deceleration of hand
* exact temporal relationship depends on goal of task, object, and experience

development of RGM

* ability to visually locate target at birth and improves throughout first 5 months of life
* reach present at birth, grasp begins 4-5mo; precision grasps take 9-13mo
* manipulation skill control develops thru 10-12yo

R&G feedforward control

proactive strategy that uses sensory info obtained from experience to predict consequences of sensory input to be received; visual pathways (dorsal parietal stream, ventral temporal stream) and somatosensory pathways (position of limb in space)

R&G feedback control

uses sensory info received during movement to adjust output; visual pathways (assist final accuracy) and somatosensory pathways (detect error, cutaneous feedback for grip)

R&G cognitive systems

* posterior parietal cortex: coordinates info from visual and somatosensory pathways to encode goal for movement; planning and control
* premotor/cerebellum: predictive control of grip forces
* supplementary motor/BG: bimanual tasks, internally-generated tasks
* primary motor cortex

R&G motor systems

* anticipatory trunk control
* descending control mainly thru corticospinal and corticobulbar tracts
* movement adjustments during deceleration phase
* reactive postural control

abnormal RGM

* locating target: vision issues, visual neglect/extinction, gaze stabilization issues
* R&G: loss of selective movement, issues with interjoint coordination, issues with timing, issues with visual/somatosensory systems, issues with cognition, issues with coupling, issues with bimanual control, impairments in postural control
* manipulation: issues with grip force, impaired finger coordination, issues with release

RGM outcome measures

1. functional reach test → older adults, stroke, PD, SCI, vestibular disorders
2. 9 hole peg test → TBI, stroke, MS, PD
3. purdue peg board test → PD, nonspecific pops
4. wolf motor function test → stroke, TBI
5. action research arm test → stroke

motor performance

demo of a movement or skill; ability to perform a skill immediately following practice but without retention or generalizability

motor learning

internal processes associated with practice or experience leading to a relatively permanent change in skill behavior; acquisition of a new skill or reacquisition of a skill lost due to dysfunction/damage

Fitts & Posner model of motor learning

1. cognitive stage: must understand nature of task, develop strategies to carry out task, and determine how success/failure should be evaluated
2. associative stage: focus on refining chosen strategy for movement
3. autonomous stage: increased automaticity and decreased attention needed to perform task

Gentile’s 2 stage model of motor learning

1. task planning stage: develop an understanding of task and movements necessary to complete
2. fixation/diversification stage: refine the movement to adapt to changing task and environment; focus on consistency and efficiency

Bernstein’s model of motor learning

1. novice: movement simplified to reduce DOF
2. advanced: begin to increase DOF, develop motor plans
3. expert: no limits to DOF, movement is efficient and coordinated

explicit/declarative learning

knowledge that can be consciously recalled; repetition can move explicit learning to more implicit knowledge; can be practiced in ways other than the one in which it was learned; instructive/strategy-based learning

implicit/non-declarative learning

complex info acquired largely independently of the subject’s awareness of the process of acquisition or knowledge base acquired; requires repetition; several types involving various brain regions and mechanisms:

* non-associative
* associative/reinforcement
* procedural/exercise dependent
* sensorimotor adaptation

instructive/strategy based learning

* process: use of specific external feedback which prompts development of intentional error reducing movement strategies
* structures: prefrontal cortex
* considerations: requires attention, awareness, etc; fast time scale to learn if cognitively intact
* example: tell pt to shift weight onto paretic side during stance

non-associative learning

* process: habituation; repeated stimulation decreases response
* structures: short term presynaptic changes (Ca2+); long term postsynaptic changes
* considerations: requires repeated exposures for long term effects
* example

associative/reinforcement learning

* process: driven by binary outcome based feedback of success or failure; classical conditioning (learning to pair 2 stimuli) and operant conditioning (use of rewards or adverse stimuli to increase/decrease behaviors)
* structures: basal ganglia
* considerations: role of cognitive processes unclear; slower rate of learning but larger retention
* example

procedural/exercise dependent learning

* process: process of acquiring skill at a task through repetition, adaptive or maladaptive; LTP and LTD
* structures: motor cortex and spinal cord (CNS)
* considerations: slow to learn, requires numerous reps; harder to unlearn; requires engagement in task; must be challenging/skilled
* example

sensorimotor adaptation

* process: learning driven by sensory prediction errors; actual sensory consequences of movement differs from predicted sensory conflict
* structures: cerebellum
* considerations: thought to occur independent of intentional, voluntary modifications; fast time scale for learning; show characteristic “after effect”
* example

verbal instruction

concise; focus of attention = external → quicker time scale, greater retention of task

demonstration

critical for pts with language or cognitive deficits; activates mirror neurons

task considerations: distribution

* massed: amount of time performing task > rest
* distributed: amount of time performing task < rest
* blocked: practice same task before moving onto next
* random: practice different tasks in different orders
* constant: practice same task in same environment
* variable: practice same task in different environments
* whole practice: perform whole task at once
* part practice: break down into steps

feedback types

1. intrinsic (inherent): sensory input from the movement
2. extrinsic (augmented): from the environment


1. knowledge of performance
2. knowledge of results

cerebellar dysfunction and motor learning

* use of guided practice
* blocked, high reps
* augmented feedback

stroke and motor learning

* dependent on severity of stroke
* increasing task difficulty improves learning
* mental practice beneficial
* no consensus on task distribution

TBI and motor learning

* issues with attention and motivation
* explicit learning more difficult
* distributed and blocked practice early on

SCI and motor learning

* autonomy and salience are key
* part-whole practice
* highlight intrinsic, self-generated feedback

parkinson’s and motor learning

* need increased time
* not able to generalize
* difficulty with dual tasking

MS and motor learning

* depends largely on location of lesions
* overall more issues with explicit learning