Abnormal posture Flashcards
Why are CVA survivors at increased risk of hip fracture?
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
What are the potential problems related to the action systems?
- Quiet stance impairments
- Alignment
- Spontaneous Sway
- Stability Limits – can’t move far out of BOS w/o losing balance - Impaired Strategies during Perturbation
- Impaired In-Place Movement Strategies
- Delayed Activation of Postural Responses
- Difficulty with Modification & Adaptation of Postural Strategies
- Impaired Stepping Strategy
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
alignment
- poor alignment can lead to inefficient energy expenditure to maintain postural control
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?
postural alignment AND CNS maintain posture
- NOT just a reaction by the CNS
What are the abnormalities with spontaneous postural sway seen in patients with PD?
- increased sway area and velocity
- increased ML sway
- AP sway is close to that of normal adults
- levodopa and deep brain stimulation causes increased [normalized] postural sway
What are the abnormalities with spontaneous postural sway seen in pts with Down syndrome?
- Increased sway velocity
- 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
What are the abnormalities with spontaneous postural sway seen in pts with CP?
- Increased sway in quiet stance
- Not always impaired though - Increased sway amplitude
- Increased regularity
- 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
What is the best predictor of gross motor function in children with CP?
if postural stability is maintained with eyes closed
What are the abnormalities with spontaneous postural sway seen in pts with CVA?
- Asymmetric
- Increased sway area
- Factors Contributing = Weakness, Abnormal Tone, and Somatosensory Deficits
What improvements are seen in pts with CVA in terms of spontaneous postural sway?
- Sway area
- WB Asymmetry
- Nonparetic limb continues to provide most dynamic stabilization
What determines quiet stance stability limits?
- Biomechanics of the body
- Perception
- Postural Control Abilities
- Environment Factors
What is a good predictor of quiet stance stability limits in pts with PD?
forward reach
- PD and MS pts are most effected in posterior direction
What are possible impaired strategies during perturbation?
- Impaired In-Place Movement Strategies
- Delayed Activation of Postural Responses
- Difficulty with Modification and Adaptation of Postural Strategies
- Impaired Stepping Strategy
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)
Impaired in-place movement strategies
What sequencing problems are seen in children with a hemiplegic leg?
- 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
What sequence problems are seen in children with spastic diplegia?
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
What is the significance of abnormal sequencing?
- results in less torque
- results in large lateral shifts of COM
- Less efficient
What sequencing problems are seen in pts with down syndrome and TBIs?
delay in recruitment of proximal m synergies
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
coactivation
- strategy seen in: Very young healthy children, CP, CVA, TBI, Down Syndrome, PD
What are the delayed activation of postural responses seen in paretic limbs?
postural m activity demonstrates deficits in:
- sequencing
- timing
- amplitude
What delayed activations of postural responses are specifically seen in pts with CVA that increases their fall risk?
- Postural response in the paretic limb was slower and smaller in amplitude
- Activation of the proximal synergist (rectis femorus) was significantly delayed in both paretic and nonparetic limbs
- 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
How can we encourage modifications in postural strategies in pts with neurologic injuries?
give many perturbations repeatedly and they can learn to use hip vs ankle strategies
- many have difficulty with modification of postural responses
When there is no neurologic injury present, what control mechanisms are used to maintain posture?
feedback and feedforward control are utilized to determine need for modification to maintain postural control
What part of the brain is responsible for feedback for adaptation of postural strategies?
cerebellum
What postural control strategy is impaired in pts with PD?
Stepping strategy
- lack anticipatory lateral weight shift and delayed onset of lateral stepping strategy
- impairment leads to incr falls
- PD requires multiple small steps
Sensory problems disrupt postural control by:
- Affecting ability of an individual to adapt sensory input to change in TASK and ENVIRONMENT demands
- Preventing the development of accurate internal models of the body for postural control
Provision of _________ improves postural stability in those with neurologic injury, including those with peripheral neuropathy
haptic (tactile) cues
Many research studies support that when one sensory system is impaired, others will _______
heighten
- pts with peripheral neuropathy rely on vision
- blind pts use other sensory systems for exploring their environment
What neural structures are involved with anticipatory control?
- supplementary motor cortex
- BG
- Cb
What is anticipatory control heavily dependent on?
previous experience and learning
What is seen in pts with problems with anticipatory control?
- Inability to activate postural muscle in anticipation of voluntary arm movements
- Difficulty initiating preparatory postural musculature (Opening a heavy door)
- pts don’t recognize motor problem, nor recognize the strategy to overcome those problems
What conditions often result in loss of anticipatory postural control?
- CVA
- TBI
- CP
- DS
- PD
What is a good prognostic indicator of functional ambulation in those with spastic diplegic CP?
age of sitting onset at 18-24 months
What is impaired sitting balance on admission to a rehab unit associated with in pts with CVA and TBI?
dependence in locomotion and transfers at discharge and one year following
What is most predictive of discharge FIM scores in pts with TBI?
sitting independently
-FIM = functional independence measure
In adults with neurologic pathology, what do impairments in seated postural control result from?
- perceptual impairments
- motor loss
- impaired postural control
- result from difficulty activating trunk musculature
In those with CVA, what is the ability to reach in sitting is associated with?
the ability to use the affected leg in balance
In those with CVA, what is the recovery of trunk function associated with?
improved upper extremity function with reach and grasp
What is seen in impaired seated postural control in the pediatric population?
- Top-Down recruitment for recovery of balance following perturbation
- High levels of co-activation of antagonistic muscles for increased stability
- crouch sit-in position may be a compensatory mechanism to gain stability
