Balance, Coordination, and Proprioception in DPT 652

Balance

Dynamic process by which body's position is maintained in equilibrium (at rest or moving); best when Center of Mass (COM) over Base of Support (BOS).

Center of Mass (COM)

The point in a body where the mass is evenly distributed and balanced.

Center of Gravity (COG)

The point where the total weight of a body is concentrated.

Momentum

The quantity of motion an object has, dependent on its mass and velocity.

Base of Support (BOS)

The area beneath an object that includes every point of contact that the object makes with the supporting surface.

Limits of Stability (LOS)

The maximum distance a person can lean in any direction without losing balance.

Ground Reaction Forces (GRF)

The force exerted by the ground on a body in contact with it.

Center of Pressure (COP)

The point of application of the ground reaction force, representing the center of the distribution of vertical forces.

Nervous System

The system responsible for sensory perception of body orientation in space, including visual, vestibular, and somatosensory systems.

Sensorimotor Integration

The process of combining sensory information with motor responses for adaptive and anticipatory postural control.

Motor Strategies

The planning, programming, and execution of movements required for maintaining balance.

Musculoskeletal Contributions

Factors such as postural alignment, flexibility, joint integrity, and muscle performance that affect balance.

Contextual Effects

Environmental factors that influence balance, including the predictability of the environment and the type of support surface.

Support Surface

The type of ground or surface that affects stability, such as firm vs. slippery or stable vs. unstable.

Effects of Gravity

The influence of gravitational forces on body positioning and balance.

Inertial Forces

Forces that affect the body due to its motion or lack of motion.

Sensory Control of Balance

Perception of body in space & movement via peripheral receptors (visual, somatosensory (proprioceptive, joint, cutaneous) and vestibular systems.

Visual system

Info on position of head relative to environment, orientation of head to maintain level gaze, direction & speed of head movements.

Somatosensory system

Info about position & motion of body & body parts relative to each other & support surface (muscle spindles, GTOs, joint receptors, skin mechanoreceptors help).

Vestibular system

Provides info about position & movement of head w/respect to gravity & inertial forces & fast head movements. Receptors in semicircular canals detect angular accel of head; receptors in otoliths detect linear accel & head position w/respect to gravity & slow head movements.

Sensory Organization for Balance Control

Vestibular, visual & somatosensory inputs combined to produce orientation & movement. When 1 system is inaccurate (d/t injury or environment), CNS must suppress inaccurate input and combine appropriate sensory inputs from other 2 systems.

How To Use Info In Intervention - Visual system

Use it when proprioceptive or vestibular inputs are unreliable (d/t damage or on boat or ramp, etc.); by visually fixating on target.

How To Use Info In Intervention - Somatosensory system

When visual or vestibular inputs unreliable.

How To Use Info In Intervention - Vestibular system

When visual & somatosensory inputs unreliable (i.e. pt with DM with certain deficits).

Types of Balance Control

Function requires: static, dynamic, automatic postural reactions.

Feedforward control

For movements that occur too fast to rely on sensory feedback (e.g. reactive responses) or anticipatory aspects of postural control.

Anticipatory control

Activation of postural muscles, in advance of performing skilled movements (e.g. obstacles in environment).

Closed loop control

Used for precision movements that require sensory feedback (e.g. standing on a balance beam).

Motor Strategies for Balance

Need to keep COM over BOS; 3 primary movement strategies.

Balance Muscle Activation Strategies - Ankle Strategy

Quiet stance & small perturbations (slow on large firm surface); activation typically distal to proximal; requires 5-10° of ankle DF; fair to good strength in ankle DF and PF.

Balance Muscle Activation Strategies - Hip

Narrow surfaces, fast or bigger perturbations; requires 30° hip flexion and 5° ext; fair to good strength in hip flexors and extensors.

Balance Muscle Activation Strategies - Stepping

For larger perturbations that move center of gravity outside base of support.

Weight-shift Strategy

Control M/L perturbations; shift body weight laterally from 1 LE to other; hips key points of control using hip abd and add muscles (some help from ankle invertors & evertors).

Suspension Strategy

Quickly lowers COM by flexion knees, causing associated flexion of ankles & hips.

Combined Strategies

Depends on task & environment.

Balance Control Under Varying Conditions

During stance- ankle muscles/glut med/TFL/iliopsoas, paraspinals/abd; like inverted pendulum.

Perturbed standing

Internal (proactive m. act) or external (reactive m.).

COM shift

The movement of the center of mass during lifting.

Anticipated weight and momentum

Consideration of the load and its movement during lifting.

Loss of balance

A condition requiring a stepping response to regain stability.

Lifting style

The method of lifting, either with knees flexed or extended.

Balance During Gait

The center of mass is always outside the base of support except during double limb support.

Controlled fall

A technique to maintain balance by intentionally falling in a controlled manner.

Impaired Balance

A condition caused by disease or injury affecting information processing stages.

Sensory input

Information received from the environment that affects balance.

Proprioceptive deficits

Loss of sensory input from muscles and joints, often due to age or diabetes.

Visual loss or deficits

Diminished or impaired vision affecting balance.

Damage to vestibular system

Injury to the inner ear structures affecting balance, often due to infection, TBI, or aging.

Damage to BG, CB, SMA

Injury to the basal ganglia, cerebellum, or supplementary motor area affecting balance.

Motor output

The physical response generated by the musculoskeletal or neuromuscular system.

Musculoskeletal impairments

Issues related to posture, range of motion, and muscle performance.

NM system impairments

Neuromuscular issues affecting coordination and pain.

Balance Deficits with Aging

Challenges in balance due to complex interactions of multiple risk factors.

Matter of Balance program

A published guideline for fall prevention.

Declines in sensory systems

Deterioration of sensory functions and information processing with age.

Compromised APAs

Impaired anticipatory postural adjustments affecting balance.

Fear of falling

Anxiety that can impact balance and mobility.

Balance Deficits from Medications

Increased fall risk in older adults taking more than four medications.

Examination & Evaluation of Balance

A comprehensive assessment including history of falls and sensory input evaluation.

Static Balance Tests

Tests such as Romberg and Single Leg Balance Stance Test to assess static balance.

Dynamic Balance Tests

Tests involving movement on unstable surfaces or transitions between positions.

Anticipatory Postural Control Tests

Tests requiring voluntary movements to counteract predicted disturbances.

Functional Reach Test

A measure of reach distance with less than 10 inches indicating increased fall risk.

Reactive Postural Control Tests

Assessment of responses to external perturbations affecting balance.

Pull Test

A test to assess postural stability by pulling the patient backward.

Push and Release Test

A test to evaluate balance by pushing the patient forward and observing their response.

Clinical Test of Sensory Integration on Balance Test (CTSIB)

A test that evaluates how well a person can maintain balance under various sensory conditions.

Sensory Organization Test (SOT)

The computerized version of the Clinical Test of Sensory Integration on Balance Test.

Tinneti Performance-Oriented Mobility Assessment (POMA)

A test used to assess a person's mobility and balance.

Timed Up and GO Test (TUG)

A test that measures the time it takes for a person to stand up from a seated position, walk three meters, turn around, walk back, and sit down.

Berg Balance Scale

A 14-item test that assesses balance through various functional tasks.

Four Square Step Test

A test that assesses dynamic balance by having a person step in multiple directions.

Dynamic Gait Index (DGI)

An 8-item test that evaluates a person's ability to modify balance while walking.

Functional Gait Assessment

A test designed to assess gait and balance during functional tasks.

HiMAT

High-level Mobility Assessment Tool, used to evaluate high-level balance and mobility.

Four Step Square Test (FSST)

A test that assesses dynamic balance in older adults by moving the center of gravity outside the base of support.

Berg Balance Test

A validated tool that assists in determining the need for assistive devices based on a scoring system.

Activities Specific Balance Confidence Scale (ABC)

A scale that measures a person's confidence in performing various activities without falling.

Falls Efficacy Scale

A scale that assesses a person's fear of falling during various activities.

Balance Training: Static Control

Training that involves maintaining balance in a stationary position.

Balance Training: Dynamic Control

Training that involves maintaining balance while in motion.

Balance Training: Reactive Control

Training that focuses on responding to external forces to maintain balance.

Balance Training: Sensory Organization

Training aimed at decreasing reliance on visual, somatosensory, or vestibular inputs for balance.

Fall Prevention Programs for Elderly

Programs designed to reduce falls among elderly individuals through various interventions.

Fall Prevention for High Risk Elderly

Strategies specifically tailored for elderly individuals at high risk of falling, including home exercises and Tai Chi.

Balance Exercise Progression

A structured approach to gradually increase the difficulty of balance exercises.

Coordination

The ability to use different parts of the body together smoothly and efficiently, which is not synonymous with balance.

Cerebellum

Major section of brain responsible for planning, coordinating and refining movement based on previous experience, sensory feedback before, during and after movement

Coordination Disorders

Ataxia - inability to coordinate timely muscle activations while adjusting for movements at other joints

Causes of Uncoordinated Movement

Injury to cerebellum, nerve, joint

Assessing Coordination

Describe quality of movement: smooth, asynergia, decomposition (robot-like) movement, tremor (intention vs. resting vs. terminal)

Intervention

Base on functional goals with a rehabilitative approach

Proprioception

Unconscious activation of the dynamic restraints surrounding a joint in response to sensory stimuli

Anatomical Structures Involved in Proprioception

Muscle Spindle - Within muscle fibers and kept on slight stretch by gamma motor neuron, stimulated by stretch

Assessment of Proprioception

Stabilize proximal segment, touching lightly, change position in sagittal plane of more distal joint

Proprioception Interventions

Closed chain activities throughout ROM, higher level balance activities

Examples of Interventions

Hands on wobble board 3x30sec has been shown to increase proprioception in shoulders.

Conclusions

Just as with strengthening, be specific to functional outcome and never skip balance/proprioception in treatment