Abnormal posture

Question 1

Why are CVA survivors at increased risk of hip fracture?

Answer 1

related to increased fall risk

• Strength impairments, sensory deficits, perception impairments, central balance deficits
• Possible decrease in equilibrium reactions
• Decrease in bone density because of decrease in WB on that limb

Question 2

What are the potential problems related to the action systems?

Answer 2

1. Quiet stance impairments
   - Alignment
   - Spontaneous Sway
   - Stability Limits – can’t move far out of BOS w/o losing balance
2. Impaired Strategies during Perturbation
   - Impaired In-Place Movement Strategies
   - Delayed Activation of Postural Responses
   - Difficulty with Modification & Adaptation of Postural Strategies
   - Impaired Stepping Strategy

Question 3

the relationship of body segments to one another, as well as to the position of the body with reference to gravity and the base of support; determines the movement strategies used to control posture; Influences how muscles are recruited and coordinated for recovery of stability

Answer 3

alignment

- poor alignment can lead to inefficient energy expenditure to maintain postural control

Question 4

Both kids with spastic CP who maintain crouched position and kids who mimicked the crouched position both demonstrated abnormal reactions following perturbations. Kids with CP recovered balance with coactivation of leg and trunk muscles while normally developing kids used antagonistic muscles. What does this tell us?

Answer 4

postural alignment AND CNS maintain posture

- NOT just a reaction by the CNS

Question 5

What are the abnormalities with spontaneous postural sway seen in patients with PD?

Answer 5

1. increased sway area and velocity
2. increased ML sway
   - AP sway is close to that of normal adults
   - levodopa and deep brain stimulation causes increased [normalized] postural sway

Question 6

What are the abnormalities with spontaneous postural sway seen in pts with Down syndrome?

Answer 6

1. Increased sway velocity
2. Despite hypotonia, postural stiffness was increased related to increased sway velocity
   - indicates that passive evaluation of tone provides limited information about how the CNS controls posture and movement**
   - Hypothesized this could be a compensatory strategy to improve stability related to co-contraction of musculature during perturbation

Question 7

What are the abnormalities with spontaneous postural sway seen in pts with CP?

Answer 7

1. Increased sway in quiet stance
   - Not always impaired though
2. Increased sway amplitude
3. Increased regularity
4. Hyperfocus on balance = decreased balance
   - External focus lead to improved amount and regularity of sway by preventing too much focus on postural control/standing balance

Question 8

What is the best predictor of gross motor function in children with CP?

Answer 8

if postural stability is maintained with eyes closed

Question 9

What are the abnormalities with spontaneous postural sway seen in pts with CVA?

Answer 9

1. Asymmetric
2. Increased sway area
   - Factors Contributing = Weakness, Abnormal Tone, and Somatosensory Deficits

Question 10

What improvements are seen in pts with CVA in terms of spontaneous postural sway?

Answer 10

1. Sway area
2. WB Asymmetry
3. Nonparetic limb continues to provide most dynamic stabilization

Question 11

What determines quiet stance stability limits?

Answer 11

1. Biomechanics of the body
2. Perception
3. Postural Control Abilities
4. Environment Factors

Question 12

What is a good predictor of quiet stance stability limits in pts with PD?

Answer 12

forward reach

- PD and MS pts are most effected in posterior direction

Question 13

What are possible impaired strategies during perturbation?

Answer 13

1. Impaired In-Place Movement Strategies
2. Delayed Activation of Postural Responses
3. Difficulty with Modification and Adaptation of Postural Strategies
4. Impaired Stepping Strategy

Question 14

Sequencing Problems (Picked the wrong or not most right strategy); Problems with timely activation of postural responses (Delay in postural response); Problems adapting postural activity to changing task and environment demands (Selection problem)

Answer 14

Impaired in-place movement strategies

Question 15

What sequencing problems are seen in children with a hemiplegic leg?

Answer 15

• Non-hemiplegic leg = Gastrocnemius recruited first, Hamstrings recruited second
• Hemiplegic leg = Hamstrings recruited first, Gastrocnemius recruited second
• indicates abnormal sequence resulting in large lateral shifts of the COM

Question 16

What sequence problems are seen in children with spastic diplegia?

Answer 16

tend to recruit muscles proximal to distal– beginning with the neck and moving down and significant coactivation of muscles in the neck and hip with antagonists activated before agonists
- typical response is to use distal strategies first

Question 17

What is the significance of abnormal sequencing?

Answer 17

1. results in less torque
2. results in large lateral shifts of COM
3. Less efficient

Question 18

What sequencing problems are seen in pts with down syndrome and TBIs?

Answer 18

delay in recruitment of proximal m synergies

Question 19

Characterized by the simultaneous contraction of muscles on the anterior and posterior aspects of the body.; Results in stiffening & controlling degrees of freedom; Inefficient for balance recovery

Answer 19

coactivation

- strategy seen in: Very young healthy children, CP, CVA, TBI, Down Syndrome, PD

Question 20

What are the delayed activation of postural responses seen in paretic limbs?

Answer 20

postural m activity demonstrates deficits in:

1. sequencing
2. timing
3. amplitude

Question 21

What delayed activations of postural responses are specifically seen in pts with CVA that increases their fall risk?

Answer 21

1. Postural response in the paretic limb was slower and smaller in amplitude
2. Activation of the proximal synergist (rectis femorus) was significantly delayed in both paretic and nonparetic limbs
3. This suggests impaired intralimb coupling of synergies (Didn’t use LEs in the way they should have for recovery)
   - also seen in Down’s and MS

Question 22

How can we encourage modifications in postural strategies in pts with neurologic injuries?

Answer 22

give many perturbations repeatedly and they can learn to use hip vs ankle strategies
- many have difficulty with modification of postural responses

Question 23

When there is no neurologic injury present, what control mechanisms are used to maintain posture?

Answer 23

feedback and feedforward control are utilized to determine need for modification to maintain postural control

Question 24

What part of the brain is responsible for feedback for adaptation of postural strategies?

Answer 24

cerebellum

Question 25

What postural control strategy is impaired in pts with PD?

Answer 25

Stepping strategy

• lack anticipatory lateral weight shift and delayed onset of lateral stepping strategy
• impairment leads to incr falls
• PD requires multiple small steps

Question 26

Sensory problems disrupt postural control by:

Answer 26

1. Affecting ability of an individual to adapt sensory input to change in TASK and ENVIRONMENT demands
2. Preventing the development of accurate internal models of the body for postural control

Question 27

Provision of _________ improves postural stability in those with neurologic injury, including those with peripheral neuropathy

Answer 27

haptic (tactile) cues

Question 28

Many research studies support that when one sensory system is impaired, others will _______

Answer 28

heighten

• pts with peripheral neuropathy rely on vision
• blind pts use other sensory systems for exploring their environment

Question 29

What neural structures are involved with anticipatory control?

Answer 29

1. supplementary motor cortex
2. BG
3. Cb

Question 30

What is anticipatory control heavily dependent on?

Answer 30

previous experience and learning

Question 31

What is seen in pts with problems with anticipatory control?

Answer 31

1. Inability to activate postural muscle in anticipation of voluntary arm movements
2. Difficulty initiating preparatory postural musculature (Opening a heavy door)
   - pts don’t recognize motor problem, nor recognize the strategy to overcome those problems

Question 32

What conditions often result in loss of anticipatory postural control?

Answer 32

1. CVA
2. TBI
3. CP
4. DS
5. PD

Question 33

What is a good prognostic indicator of functional ambulation in those with spastic diplegic CP?

Answer 33

age of sitting onset at 18-24 months

Question 34

What is impaired sitting balance on admission to a rehab unit associated with in pts with CVA and TBI?

Answer 34

dependence in locomotion and transfers at discharge and one year following

Question 35

What is most predictive of discharge FIM scores in pts with TBI?

Answer 35

sitting independently

-FIM = functional independence measure

Question 36

In adults with neurologic pathology, what do impairments in seated postural control result from?

Answer 36

1. perceptual impairments
2. motor loss
3. impaired postural control
   - result from difficulty activating trunk musculature

Question 37

In those with CVA, what is the ability to reach in sitting is associated with?

Answer 37

the ability to use the affected leg in balance

Question 38

In those with CVA, what is the recovery of trunk function associated with?

Answer 38

improved upper extremity function with reach and grasp

Question 39

What is seen in impaired seated postural control in the pediatric population?

Answer 39

1. Top-Down recruitment for recovery of balance following perturbation
2. High levels of co-activation of antagonistic muscles for increased stability
   - crouch sit-in position may be a compensatory mechanism to gain stability