Lab 3 Abnormal Postural control Flashcards
Falls and Neurologic Pathology
- Balance is critical to independence in ADLs
Postural control impairments are directly related to imbalance
*Stroke survivors: 25-46% fall rate
36% acute stroke, 46% chronic community-dwelling stroke survivors
Inability to safely walk over obstacles is a predictor of falls among persons with stroke
*Parkinson’s Disease: 40-68% fall rate
*Falls often occur during walking, transfers and stair climbing
Balance and Falls Self-Efficacy
Balance abilities affect balance and falls self-efficacy
* Poor balance and falls self-efficacy are reported in many people with neurologic pathology even without a fall history
* Associated with avoidance of physical activity and restrictions in daily life activities
* Self-efficacy is a major factor predicting participation in community mobility following CVA
Stability and Neurologic Pathology
- Same postural motor control problems seen in patients with different diagnoses
- Problems are related to system impairments, interactions among systems/impairments (THINK ICF)
NOT diagnosis alone - Impaired postural control in patients with neurologic deficits can lead to loss of functional independence
Motor Impaitments
Musculoskeletal Changes _ alignment
- Persons with neurological diseases often have changed alignment secondary to the effects of the disease
- Crouch Gait (working way harder) Demands gets way up.
Motor Impairments
Musculoskeletal Changes
- Alignment determines which movement strategies are effective
- It also determines how muscles are recruited
EXAMPLE
* Children with spastic diplegia CP stand in a crouched posture - Notable coactivation of antagonists in response to perturbations
* Able-bodied children stood in crouched position - Same activation pattern was noted
Motor Impairments
Musculoskeletal changes part 2
Musculoskeletal postural alignment may be a strategy compensating for other impairments
Ex: CVA - Natural asymmetry occurs due to hemiplegia ( changes the activation of the ankle with and OFO)
Constraining movement at a joint
* Effects of solid AFO vs. no AFO, vs dynamic AFO
* Significant impact on timing and sequencing of muscles used for postural control
* Decreased use/availability of ankle strategy
* Delay in onset or absence of ankle muscle activity
* Increased use of hip and trunk muscles
Motor Impairments
Motor Coordination - Sequencing
Reversal in recruitment
* In stance, children with CP recruit proximal to distal in the hemiparetic extremity which leads to increased sway
* Children with spastic diplegia CP recruit top-down
* Prioritize head control (important)
Delayed recruitment of proximal synergists
* Causes excessive knee and hip motion
* Seen in children with Down syndrome, adults post TBI
Co-activation of antagonists
* Causes stiffening of body
* Inefficient for recovery of balance
* Seen in people with CP, CVA, TBI, Down syndrome and Parkinson’s Disease
Motor Impairments
Motor coordination
Delayed activation of postural responses
* Seen with CVA, CP, Down syndrome
Challenges modifying postural control
* Difficulty with postural adaptation (scaling)
* CP: Unable to increase agonist force against large perturbation
* Anterior cerebellar lobe lesions: Over-estimates response and creates a large agonist force
Challenges with quickly modifying postural activity to adapt to changing tasks
* Unable to adjust movement response (pattern, amplitude, and strategy) to match a task (direction of perturbation, width of BOS) or environment
* Seen often in patients with CVA, CP, and PD
Motor Impairments
Clinical Impications with motor impairments
- Reducing impairments with the greatest impact on postural control is first priority
- Resistance training shows some positive effect, though not enough to improve balance control
- Task-oriented approach to strength and balance training highly recommended with all diagnoses
- Functional electrical stimulation (FES) for LE may improve balance
Left side ICF
Motor impairment
Retraining Steady State Balance
Focus on retraining orientation and alignment that assists with obtaining position that is:
* Appropriate for task
* Efficient with respect to vertical
* Maximizes stability
Alignment:
* Alexander technique (breath work)
* Eyes open and closed
* Visual, tactile, and verbal cues (intermittently used)
Maximizes stability—places pt’s vertical line of gravity well within the patient’s stability limits
Visual cues—mirror with vertical line, laser on belt to line up with dots on a wall, plate biofeedback
Tactile—sitting/standing with back against a wall
Motor Impairment
Retraining Proactive/ Anticipatory Balance
- Movement strategies to control the COM can be practiced during voluntary sway
Gradually increase sway area, speed
Use KR - Use manipulation tasks to assist with developing strategies
- Repetition of functional tasks improves performance
Motor impairment
Retraining Reactive Balance
- Goal to help patient develop coordinated multi-joint movements, effective in recovering stability
- Expose patient to external perturbations (perturbation training) of variable speed, direction, and amplitude
- Can attempt to block stepping reaction to encourage hip or ankle strategy—stability limit training
- Tai Chi training significantly enhances balance responses
- Environment matters!
Sensory/Perceptual Deficits
Sensory and Preceptual disorders
- Organization of sensory input is critical for postural control
- Coordination of sensory input with motor responses is also critical
- Both affect the ability to adapt sensory inputs to changes in the task and environmental demands
- Prevent development of accurate internal models of the body for postural control
- May involve loss of one or more sense
Balance can remain intact if two senses are available and accurate
If two or more senses are affected, balance will be impaired
Compensation is expected with loss of one or more system
Use of touch cues can provide considerable improvement in balance (SPC, fingertip, etc) - Challenges with weighting available senses
- Inflexible weighting of sensory information
- Will rely on one sense even if it leads to instability (visual or somatosensory dependence)
- Sensory selection challenges
Inability to select accurate orientation reference
Seen in patients with CVA, TBI, CP, Down’s syndrome, learning disability, and developmental delay
Sensory/Perceptual Deficits
SOT Sensory Organization Test Normal vs abnormal
Conditions 2, 4, and 5 examined the influence of the abnormal sensory inputs (somatosensory, visual, and vestibular inputs) on postural stability
. Visual vestibular pattern (abnormal in conditions 4, 5, and 6) indicates difficulty using visual and vestibular information or vestibular information alone for postural stability
Sensory/Perceptual Deficits
CTSIB ??
Clinical Test for Sensory Interaction in Balance - AKA Foam and Dome
* Modified CTSIB
* Only uses four conditions, eliminating the skewed information in stage 3 and 6
Sensory/Perceptual Deficits
Treating sensory impairments
Use of sensory stimulation (icing, vibration, tapping, electrical stimulation)
* ML sway was significantly decreased in older adults with sensory deficit using 10 minutes of plantar stimulation
* Whole body vibration has been shown to improve joint position sense at the ankle and gait control (speed and step width)
* Interventions MUST be paired with functional task
Retraining sensory organization strategies in complex environments
* Systematically vary the availability and accuracy of one or more senses
Sensory/Perceptual Deficits
Augmenting Sensory Imputs
enhancing it
Touching the index finger to a stationary surface
Providing real-time feedback related to COP
* Visual
* Auditory
* Vibrotactile
* Electrotactile
Cognitive Impairments
Cognitive Strategies - Anticipatory Deficts
Inability to activate postural muscles in advance of voluntary movements
* Creates postural destabilization
* Can improve with training - Stability before Mobility
* Seen in patients with CVA, CP, Down syndrome, and PD
* Damage to supplementary motor cortex, basal ganglia, and cerebellum can cause anticipatory deficits
Cognitive Impairments
Cognitive Resources
Impaired dual-task performance in PD, TBI, CVA
* Verbal tasks and Motor tasks
* Impaired postural control impacts the amount of attention required to maintain balance
Cognitive impairment is a known predictor of falls in older adults, especially those with dementia
Alzheimer’s disease
* Motor components of postural control intact, though may have age-related changes
* Reduced reliance on vision with increasing severity of dementia
Cognitive Impairments
Training Attention
Cognitive dual-task training
* Manual task
* Auditory distraction
* Visual distraction
* Cognitive task
Encourage computer-based classes
Postural Control in Sitting
Good prognostic indicator for functional outcomes in patients with CP, CVA, TBI
* Children with CP - Sitting by 2 years old predictive of walking
* CVA and TBI - Ability to sit independently at admission to rehab correlated with higher FIM scores at discharge
Benefits of Neutral Vertical Alignment
* Alignment for improved function
* Energy efficiency
* Task complexity, refined movement, muscle balance
Benefits of vertical head alignment
- Alignment for upright gaze stability
- Eye contact for improved social interaction
- Head and neck alignment for safe eating and drinking
Balance training in sitting
Use of Targeted Training
* Gradually improves trunk control over an increased number of trunk segments
* The number of degrees of freedom is artificially constrained in a top-down sequence with an external device
* Recommended training is 30 minutes per day, 5-6 days/week
