ability to maintain and appropriate relationship btwn body segments and btwn the body and environment during tasks

ex: vertical alignment

ability to maintain one's COM(center of mass) within the limits of their BOS (base of support)

aka = balance

reaching for a fly ball while on the run

aka: Jacoby Ellsbury # 46

1. Sensory system = somatosensation, vestibular and visual imput

2. NM system = CNS integration of information

3. MS = execute postural adjustments

during quiet stance = outer rim of the feet in contact with the ground

and center of mass (COM) must be kept within

the BOS to maintain stability

boundaries within which an individual can move or sway and maintain stability without changing their base of support.

Determined by strenght, ROM, task they are performing and the environment.

maintained by mms throughout the body these remain tonically active during quiet stance.

MMS = erector spinae, iliopsoas, gastrocs, glute med, abs, TFL, tib ant, soleus, biceps femoris

Muscle synergy induced by forward sway

(Ankle Strategy)

pushed forward or platform under the feet moves posteriorly

1. Gastroc>Hams>paraspinals

Muscle synergy induced by backward sway

(ankle strategy)

being pushed backward or platform under the feet moves in an anterior direction

1. Tib ant>quads>abs

occurs in response to LARGE or FAST perturbations or when the support surface is COMPLIANT or very NARROW (balance beam)

- stability restored by producing a large, rapid flexion or extension motion at the hip joint

- fires PROXIMAL to DISTAL

push forward or platform moves posteriorly under feet

1. abs>quads

Muscle synergy induced by backward sway

of the hip

push back or platform moves anteriorly

1. Paraspinals>Hamstrings

2. hips extend to restore COM

occurs in repsonse to LARGE and FAST perturbations or when the ankle or trunk musculature is weak - which means that the ankle and hip strategies would be ineffective

- stabilty restored by stepping or hopping in the SAME direction of the perturbation

being pushed sideways

- most mvmt occurs at hip jt

hip ABD and ADD mm groups control loading and unloading of LEs causing lateral mvmt of the pelvis via relative hip ABD of one LE and ADD of the other - LARGER and FASTER perturbations will result in a crossover step

provides the brain with info on the position (verticality) and motion of the head (as the head moves forward/backward surrounding objects move in the opposite direction)

GREATEST = somatosensory>vision>vestibular

LEAST = vestibular

if one becomes impaired there will be an acute onset of balance impairment, but the CNS quickly learns to compensate with the remaining to - to restore stability.

If two or more are impaired balance deficits will ensue and likely persist - compensation difficult

SOT (sensory organization test)

or

clinical test for sensory interaction and balance

(CTSIB)

assesses the adaptation of the CNS with sensory info and assist in determining whether or not one of the 3 senses is impaired or absent

= uses a tilting platform, blindfold, and moving visual surround that moves with body sway 

SOT/CTSIB

measures body sway under 6 different conditions

name them

1. normal vision - fixed support

2. absent vision - fixed support

3. sway/referenced vision - fixed support

4. normal vision - sway referenced support

5. absent vision - sway referenced support

6. sway referenced vision & support

developed by Shumway-Cook & Horak

- simplified SOT/CTSIB

used medium density foam to reduce somatosensory input & DOME placed over individuals head for inaccurate visual info or visual conflict

- young neurologically intact adults should be able to stand for 30 sec for each of the 6 conditions

1. eyes open - on ground

2. eyes closed - on ground

3. dome on head - on ground

4. eyes open - on pad

5. eyes closed - on pad

6. dome on head - on pad

postural synergy mms are activated in the WRONG order

EX: individual may activate abs before tib ant during a SMALL posterior perturbation

both the ant and post postural synergy mms fire, REGARDLESS of the DIRECTION of perturbation

Ex: Parkinson's - riggidity affects both sides of the jt

individual will appear unsteady and easily lose stability

Ex: pt perturbed backwards they may resort to a stepping strategy instead of an ankle strategy

reduced ability to increase the amplitude of response to increasing levels of perturbations

ie (weak mms synergy response will occur regardless of strength of perturbation or excessive mms synergy response to a small perturbation)

NM balance impairments...

Hypermetria

a later scaling problem that causes excessive compensatory sway in the direction OPPOSITE of the initial direction of instability

Ex: pushing an individual post they will overcompensate and excessively sway in an anterior direction possibly falling forward

NM balance impairments...

Motor adaptation problems

individuals with NM lesion may become fixed in stereotyped patterns of mvmt and be unable to adapt the postural synergy to the environment or size of perturbation.

Ex: ankle synergy used regardless of compliancy of support surface or size of perturbation

NM balance impairments...

What neurological diagnosis is likely to have motor adaptation problems

NM balance impairments...

loss of anticipatory control

may cause instability and loss of balance during self-initiated mvmts such as reaching, lifting, and carrying

difficult to treat

1. Disuse atrophy

2. muscle stiffness and loss of ROM

3. abnormal postural alignment (forward flxed kyphotic posture)

4. use of AFO (contractures of the brace because it holds the ankle at 90 degrees)

tested in seated and standing, static and dynamic components are assessed, as well as

anticipatory and adaptive postural control

ability to independently maintain COM within BOS

aka = ability to hold a static position

EX: reaching arms but not moving outside of BOS

** should maintain static balance for 30 sec

static = ask pt to raise arms while maintaining static seated or standing position

dynamic = ask pt to reach outside BOS

static = pt seated nudge them in multiple directions or ask pt to close eyes or stand/sit on foam

dynamic = nudge pt in multiple directions while reaching outside BOS can also be done standing or sitting on foam 

1. timed up and go
2. Berg Balance
3. Functional reach
4. Tinetti
5. Romberg and sharpened Romberg
6. Foam and Dome