Postural Control In Standing

Force of gravity

fundamental force of attraction between any two objects that have mass or energy

Center of gravity (COG) or center of mass (COM)

point where the weight is evenly distributed on all sides, so you have good balance

• at your sacral tube(?)

• will change with height

Line of Gravity

an imaginary, vertical line that extends down from an object's center of gravity to the supporting surface; it represents the direction and line of action of the force of gravity acting on an object

Balance

the ability to control your center of gravity over your base of support

Posture

maintained position of alignment in any position of task

Limits of Stability

• actual vs perceived

actual

• actual balance is better than what the person perceives

• person thinks their balance is not great, but it’s actually better

• e.g., person does not have confidence in balance and won’t attempt their daily activities

• less safety concerns because the person is not taking chances

perceived

• the opposite of ^; actual balance is worse than what the person perceives

• person thinks their balance is really good, but it’s actually worse

• e.g., person keeps trying to get up and walk when they are not ready

• more safety concerns because the person is more impulsive; they need grounding and safety education

Postural set

postural readiness (when doing something)

• e.g., when presenting infront of a class, a person will have 2 feet planted shoulder width apart, with head and trunk up (prevents them from falling over)

CNS Integration of Information

1. Cerebellum

   1. integrating info for postural control + any adjustments

   2. plays a role in balance

2. Basal Ganglion

   1. plays a role in balance

   2. disorder —> e.g., Parkinson’s

      1. == rigidity, bradykinesia, tremors

3. Brainstem

   1. integrates vestibular info and initiates compensatory eye movements

   2. plays a role in balance

Sensory organization that supports upright function

1. Vision

   1. used to track and navigate through the environment

   2. vertical, horizontal, rotational

   3. peripheral

   4. can be tricked (by illusions)

2. Proprioception/somatosensory

   1. e.g., if you have peripheral neuropathy in your feet, you cannot feel where you are walking; this affects feedback to our proprioception and subsequently balance

3. Vestibular

   1. helps to determine head position

   2. you have semicircular canals (functional when shaking or nodding your head)

   3. you have otoliths for linear movement

   4. stabilizes gaze

   5. probably used the least out of everything here

4. Sensory Strategy

Postural Control in Standing

1. Diagnosis

• e.g., stroke, TBI, MS, Guillain-Barré

2. Goals of postural control in standing

3. Postural reactions

• Restore equilibrium (i.e., getting your balance back)

• Synergistic movements (i.e., movements don’t occur in isolation; e.g., hips and ankles will probably move at the same time when regaining balance)

• Automaticity (i.e., restoring balance without being aware of doing it- subconsciously)

4. Types of postural reactions

• Ankle

  • a little sway to keep balance, with toes/heels pointing forward/back

• Hip

  • coming forwards/backwards (flex/extend) and side-to-side

• Stepping

  • increasing the base of support by widening

  • e.g., taking a step when the subway gets you off balance 

Evaluation

1. Observation

   1. look for physical signs

      1. e.g., are they standing shoulder-width apart? is their head in midline? is one shoulder higher than the other? is one hip higher than the other?

   2. look for balance issues

      1. e.g., using their environment to help them (e.g., wall walking), overuse of arms (e.g., holding onto things), getting external support (e.g., leaning against items), too wide a base of support, stiffening or guarding (b/c they are nervous of falling), taking small steps (b/c they are scared to take bigger strides)

2. Subjective Interview

   1. Premorbid health hx

   2. Prior level of function

      1. e.g., goal will not be to stand if the patient originally presented in a wheelchair

   3. Perspective of current functioning 

3. Neurologic

   1. e.g., stroke locations and lesion locations could mean different things for balance

4. Non-Neurologic

   1. e.g., ROM and strength of LE, any orthopedic conditions, any cardiac conditions (which could affect standing and endurance)

5. Component Evaluation

   1. Physical Status

   2. Coordination

      1. static and dynamic

      2. sitting and standing

   3. Gait

   4. Vertigo & Dizziness

      1. e.g., peripheral vertigo if it’s in the inner ear (BPPV)

         1. small particles get dislodged from their normal location in the inner ear and enter the semicircular canals, causing an abnormal sensation of spinning; there are positions you can put your head into to move these particles back into their proper place

6. Balance

   1. BOS (base of support)

      1. small, large?

   2. Limits of stability

      1. real vs. perceived

   3. Clinical Test of Sensory Interaction and Balance

      1. see what their balance is like when…

         1. when standing upright on a flat surface

         2. when standing upright on a flat surface w/ eyes closed

            1. getting rid of their vision

            2. if they’re having problems with this, it’s likely that they are over-relying on their vision

         3. when standing upright on a flat surface w/ a dome over a person’s head

            1. not getting rid of their vision, but their vision is not accurate

            2. if they’re having problems with this, it’s likely that they are over-relying on their vision

         4. when standing upright on an unbalanced surface

         5. when standing upright on an unbalanced surface w/ eyes closed

         6. when standing upright on an unbalanced surface w/ a dome over a person’s head

   4. Balance grading 

7. Functional Measure (standardized)

   1. Berg Balance Scale (BBS)

      1. vestibular disorders, stroke, SC, pulmonary disorders, PD, Osteoarthritis, older adults, limb loss/amputation, brain injury

      2. 14 items, 0-4 Likert scale, 15-20 minutes, no formal training needed

      3. Higher scores mean better performance

      4. Older adults: <45 greater risk of falls

   2. Timed Up and Go (TUG)

      1. vestibular disorders, stroke, spinal cord, PD, older adults, Osteoarthritis, AD, progressive dementia, brain injury

      2. 1 item with use of assistive device if needed (sit in chair, stand up, walk 3 meters, turn, walk back, and sit down); < 3 min, no formal training

      3. Older adults: >12 seconds is a risk of falls

   3. Functional Reach Test (FRT)

      1. vestibular disorders, stroke, SC, PD, older Adults

      2. Patient stands next to the wall, but not touching, with the arm closer to the wall, with the shoulder 90 degrees, with the fist (with a yard stick parallel to the floor), measure from the 3rd metacarpal, and say “reach as far as you can forward without taking a step”, then record the location of the 3rd metacarpal

      3. 5 trials- 2 practice then average last 3.

      4. Older adult in community dwellings: <7 inches (unable to leave neighborhood without help, limited mobility skills, most restricted in ADLS)

   4. Tinetti Performance Oriented Mobility Assessment (POMA) or TMT (Tinetti mobility)

      1. Balance and gait sections

      2. stroke, older adults, ALS

   5. TASK ANALYSIS!; make note of…

      1. Simple to complex

         1. e.g., adding bilateral coordination and crossing midline 

      2. Combination & weighting of physical and cognitive skills

         1. e.g., trying activities that require more cognition (IADLs > ADLs)

      3. Environmental factors

         1. e.g., what surfaces will they be walking on at home (e.g., carpet, hardwood, rug, etc.)?, how much light is there in the home?, what kinds of environmental obstacles are there?

         2. generally, should also try to replicate the home as best as possible

      4. Fatigue

         1. e.g., having trouble maintaining their balance, shakiness, having trouble breathing, leaning/holding onto things for support

Balance Grading Review

Assistance level for sitting (static/dynamic) balance

• Independent static/dynamic sitting

• Contact Guard (CG)

  • touching for reassurance and support

• Min assist

• Mod assist

• Max assist

• Total assist

Berg Balance Scale (BBS)

• performance-based test that assesses a person's static and dynamic balance through 14 tasks

• each task is scored on a scale from 0 (unable to perform) to 4 (normal performance), with a total possible score of 56

  • scores below 45 may indicate a higher risk of falling in older adults, while a score of 45 or above suggests good balance

Timed Up and Go (TUG)

• quick assessment of an individual's balance and functional mobility, commonly used for older adults and those with neurological conditions

• to perform the test, a person stands up from a chair, walks three meters, turns around, walks back to the chair, and sits down

Tinetti Performance Oriented Mobility Assessment (POMA) or TMT (Tinetti mobility)

• What the test assesses

  • Balance: Evaluates the ability to maintain balance in various situations, such as sitting, standing, and turning

  • Gait: Measures a person's walking pattern, including step length, foot clearance, and step symmetry

• How it's scored

  • Each item is scored on a three-point scale, from 0 (highest impairment) to 2 (independence)

  • The total score combines the balance and gait scores

  • The maximum possible score is 28, with a maximum of 16 for the balance section and 12 for the gait section

Task Analysis