Abnormal Postural Control

Question 1

In patients with stroke, falls range from __ to __%

Answer 1

25-46%

Question 2

In patients with Parkinson’s disease, falls range from __ to __%

Answer 2

40-68%

Question 3

What are the majority of falls in neurologic pathologies associated with?

Answer 3

• mobility (gait)
• transfers
• climbing stairs

Question 4

Postural control problems vary according to the variability of what 6 things?

Answer 4

• Type of neurological injury
• Degree of lesion
• Location
• Age
• Premorbid condition
• Extent of compensation

Question 5

How do neurologic pathologies affect postural stability?

Answer 5

There are changes in the systems responsible for controlling posture which leads to an inability to adapt to the requirements of stability and orientation within any environment.

Question 6

What 5 things contribute to abnormal postural control?

Answer 6

• Problems in the Action System
• Problems in the Sensory/Perceptual System
• Loss of Anticipatory Postural Control
• Problems in Cognitive System
• Impaired Seated Postural Control

Question 7

What 2 problems in the action system (1) contribute to abnormal postural control?

Answer 7

• Problems in the quiet stance

- Impaired movement strategies during perturbed stance

Question 8

Give 2 examples in which abnormal alignment can cause postural disturbances

Answer 8

• children with CP

- Parkinson’s Disease patients

Question 9

How does postural alignment affect stability?

Answer 9

It influences how muscles are recruited and coordinated for recovery of stability and also determines the characteristics of body sway in quiet stance.

Question 10

How do elderly people in fear of falling position themselves?

Answer 10

In a forward lean posture, with their center of mass displaced anteriorly.

Question 11

Describe postural sway in individuals with Parkinson’s disease

Answer 11

They have abnormal postural sway in stance, including increased sway area and velocity

Question 12

What has been found to decrease spontaneous/postural sway in patients with PD?

Answer 12

L-dopa

Question 13

What sequencing problems can be found in a spastic leg compared to a normal one in response to forward sway?

Answer 13

significantly less torque and larger shifts of the body’s CoM in the spastic leg

Question 14

What is a common postural coordination strategy in people with neurologic conditions (CP, CVA, Down syndrome and PD) as well as in young healthy children?

Answer 14

coactivation

Question 15

Define coactivation

Answer 15

the simultaneous contraction of muscles on both anterior and posterior aspects of the body.

Question 16

What are the downfalls to coactivation strategies?

Answer 16

Rigidity and loss of balance

Question 17

What can also contribute to instability in persons with neurologic deficits?

Answer 17

Delays in the onset of postural responses

Question 18

It has been found that onset latencies in paretic distal muscles of those with neurogenic pathologies is significantly ____ and _____ in amplitude than on the nonparetic side.

Answer 18

longer and smaller

Question 19

How are delays in the activation of distal muscles in the paretic limb compensated for?

Answer 19

By early activation of proximal muscles in the nonparetic limb

Question 20

Another characteristic of people with neurologic pathologies is the inability to _____ postural strategies in response to changing tasks and environmental demands

Answer 20

modify/adapt

Question 21

Why do children with CP tend to have difficulty adapting to changing tasks and environmental demands?

Answer 21

They exhibit difficulty in increasing muscle activity in the gastroc muscle in response to platform perturbations

Question 22

Why do people with cerebellar disorders tend to have difficulty adapting to changing tasks and environmental demands?

Answer 22

They tend to have hypermetric postural responses, which are too large and associated with excessive body sway in the direction opposite the initial direction of instability

Question 23

Why do people with Parkinson’s tend to have difficulty adapting to changing tasks and environmental demands?

Answer 23

They lack movement strategies that help modulate muscle activity pattern quickly to adapt to various support surfaces

Question 24

Normal postural control requires what 2 things from the sensory/perceptual systems (2)?

Answer 24

• organization of sensory information to provide information about body’s position and movement with respect to the environment
• coordination of sensory information with motor action

Question 25

The effect of a loss of sensory input depends on what 3 things?

Answer 25

- the availability of other senses to detect the position of body in space - the availability of accurate orientation cues - the ability to accurately interpret and select sensory information for orientation

Question 26

In what conditions are people who are visually dependent considered "unsteady" or abnormal?

Answer 26

When they are blind-folded on both steady and unsteady surfaces. When they are wearing a visual dome on both steady and unsteady surfaces.

Question 27

In what conditions are people who are surface dependent considered "unsteady" or abnormal?

Answer 27

On unsteady surfaces (eyes open, eyes closed, and with visual dome)

Question 28

In what conditions are people who experience vestibular loss considered "unsteady" or abnormal?

Answer 28

On unsteady surfaces with their eyes closed or when wearing a visual dome.

Question 29

In what conditions are people who experience sensory selection problems considered "unsteady" or abnormal?

Answer 29

When wearing a visual dome on a steady surface and when on unsteady surfaces under any circumstance (eyes open, eyes closed, and with visual dome)

Question 30

What does sensory selection problems refer to?

Answer 30

The inability to appropriately select a sense for postural control in environments in which one or more orientation cues inaccurately report body’s position in space.

Question 31

In what pathological conditions have sensory selection problems been reported?

Answer 31

- stroke - TBI - CP - Down syndrome - learning disabilities

Question 32

What do anticipatory processes (3) do?

Answer 32

activate postural adjustments in advance of potentially destabilizing voluntary movements

Question 33

What is anticipatory postural activity heavily dependent on?

Answer 33

previous experience and learning

Question 34

In what pathological conditions have problems with anticipatory postural control been reported?

Answer 34

- TBI - PD - CVA - CP

Question 35

What do EMG results reveal when children with cerebral palsy are asked to push or pull on a handle while standing?

Answer 35

Onset of activity in postural muscles in the trunk and leg of the intact side preceded activity in the prime movers of the arm. In contrast, in the hemiparetic side, muscle activity in the arm preceded that in the postural muscles.

Question 36

Lesions to what 3 areas can disrupt critical pathways contributing to anticipatory postural control?

Answer 36

- supplementary motor cortex - basal ganglia - cerebellum

Question 37

Under what cognitive situations (4) do people have difficulties maintaining balance?

Answer 37

- dual-task conditions | - in patients with dementia

Question 38

Sitting balance (5) is a critical part of what?

Answer 38

functional independence in ADLs

Question 39

Acquisition of sitting balance is a good predictor of what?

Answer 39

functional outcomes

Question 40

What muscles are important to sitting balance? Explain why...

Answer 40

Trunk muscles play important roles in maintaining sitting balance. Leg muscles are used for support and balance in reaching while seated.