Understanding Proprioception and Balance Systems

Static Balance

Ability to maintain the body in some fixed posture.

Static Balance

Ability to maintain postural stability and orientation with the center of mass over the base of support and body at rest.

Dynamic Balance

Ability to transfer the vertical projection of the center of gravity around the supporting base of support.

Dynamic Balance

Ability to maintain postural stability and orientation with the center of mass over the base of support while the body parts are in motion.

Proprioceptive System

Part of the body that provides awareness of where our body is in space.

Proprioceptors

Receptors located within the skin, joints, and muscles that provide feedback to the central nervous system.

Feedback

Reactive control used for error correction.

Feedforward

Predictive control that involves anticipatory postural adjustments.

Joint Position Sense

Sense of joint/limb positioning that helps maintain posture and limb position without visual input.

Kinesthesia

Awareness of motion of the human body, including duration, direction, amplitude, speed, acceleration, and timing of movements.

Sense of Force

Sense of effort, heaviness, tension, or the force that allows reproduction of a desired level of force.

Sense of Change in Velocity (SoV)

Ability to detect vibration and changes in speed of limb movement.

Pacinian Corpuscles

Type of proprioceptor that detects pressure and vibration.

Meissner's Corpuscles

Type of proprioceptor that detects light touch.

Merkel's Discs

Type of proprioceptor that detects sustained pressure and texture.

Ruffini Corpuscles

Type of proprioceptor that detects skin stretch and sustained pressure.

Golgi Tendon Organs (GTO)

Located within muscle-tendon, they detect and respond to changes in tension.

Muscle Spindles

Proprioceptors that gauge the stretch of a muscle and its rate of change of length.

Free nerve endings

Type of proprioceptor that detects pain and temperature.

Reciprocal Inhibition

Spinal process of inhibition of a motor neuron pool when the antagonist motor neuron pool is activated.

Autogenic Inhibition

A reduction in excitability of a contracting or stretched muscle, allowing it to relax while experiencing increased tension.

Vestibular System

Located within the inner ear

Function of Vestibular System

Equilibrium and balance, maintains head in upright vertical position, coordination of head and eye movements, influences tone

Postural Responses

Vestibulo-Spinal Reflex - keep the body upright and prevent falls when the body is unexpectedly knocked off balance

Ocular-motor Responses

Vestibulo-Ocular Reflex - allows the eyes to remain steadily focused while the head is in motion

Visceral Responses

Vestibulo-Colic Reflex - helps keep the head and neck centered, steady, and upright on the shoulders

Head Rotation Measurement

The vestibular system measures head rotation and head acceleration through semicircular canals and otolith organs (utricle and saccule)

Causes of Proprioception Impairments

Localized tissue damage, edema (swelling), competitive nociceptive inputs (presence of pain)

Factors Affecting Proprioception

Temporary impairment from a compromised state (drunk), age-related changes, brain injuries; multiple sclerosis (MS); stroke; Parkinson's disease; Huntington's disease; ALS (amyotrophic lateral sclerosis); health conditions: herniated disc; arthritis; autism spectrum disorder (ASD); diabetes; peripheral neuropathy; post-surgery: joint replacement surgery, such as hip replacement or knee replacement; MSK conditions: ankle sprains, ACL injuries, shoulder dislocations and tendinopathies, whiplash-associated disorders

Vestibular Pathology

Vestibular dysfunction can occur through a variety of mechanisms, including infection, direct trauma, and neoplasm

Peripheral Vestibular Disorders

Originate from problems in the inner ear or vestibular nerve

Peripheral Vestibular Disorders

BPPV, Vestibular Neuritis, Meniere’s

Central Vestibular Disorders

Result from brainstem or cerebellar involvement

Central Vestibular Disorders

CVA, TIA, MS, Vestibular Migraine, Head Trauma

Symptoms of Central Vestibular Disorders

Typically chronic or progressive, affecting coordination, balance, and causing dizziness without necessarily triggering hearing loss