Chapter 5: standing balance

Question 1

what forces disturb balance?

Answer 1

gravity
forces from muscle contraction
interaction b/w segments during movement
disturbances from unexpected perturbations

Question 2

What are the goals of postural adjustments?

Answer 2

1. support the head and body against gravity and other external forces
2. to maintain CoM aligned and balanced over the base of support
3. to stabilise parts of the body while other parts are moved

Question 3

what systems are involved in postural adjustments?

how are each of them affected in stroke patients?

Answer 3

cognitive processing - inadequate allocation of attention
perception of verticality - abnormal movement strategies
sensory integration and reweighing (CNS) - inability to switch and rely on different systems
sensory modalities - decreased proprioception and sensation
biomechanical constraints - reduced ROM and muscle strength

Question 4

what is the distribution of sensory weighing in normal individuals?

Answer 4

stable surface - 70% som, 20% Vest, 10% vision

unstable surface - 60% vest. 30% Vis, 10% Som

Question 5

what are the essential components of standing?

why are they important?

Answer 5

ability to make preparatory and ogoing postural adjustments for either motor tasks or standing still

Question 6

what assessments can be done for standing balance?
what is the cut off scores?
what is the MCID?

Answer 6

Berg balance scale - 45/56 for independent and safe ambulation
MCID (acute stroke) - 6.0-8.1
MCID (chronic stroke) - 2.5-4.66

miniBEStest - less than or equal to 17.5 (stroke fallers)
MCID - 26 good discharge outcomes

Question 7

when doing a general observation of standing balance, what movements should the assessor analyse?

Answer 7

looking behind
looking up 
reaching forward 
sideways 
backwards 
weight shifting side to side 
standing one one leg 
picking objects from the floor

Question 8

what strategies are utilised in response to perturbation

Answer 8

the 3 postural synergies

1) ankle strategy
- postural adjustments are made mainly at the ankle joint
- anterior lower limb muscles to correct for the postural stabilisation (backward sway)
- posterior lower limb muscles to correct for anterior stabilisation

2) hip strategy
- stronger perturbation or narrower support
- larger multijoint movements to bring CoM back within BOS
- postural adjustments are mainly at the hip

3) stepping
- rapid steps, hopping/ stumbling
- to form new base of support

Question 9

What are anticipatory postural adjustments

Answer 9

self-initiated movements to compensate for destabilising effects of movements