Functional Balance Physiology and CVS, PVS

Primary goals of the balance system

prevent falls

provide perception of body in environment along with direction and speed of movement

control eye movement to stabilize vision with individual and environment in motion

sensory systems for balance

vestibular

visual

somatosensory

What’s included in the central vestibular system?

everything after the vestib nerve

brainstem, cerebellum, oculomotor pathways, thalamus and cortex, vestibulospinal pathways

Why is central vestib knowledge important

explain dizziness with normal test findings

red flags for neuro referral

guides vestibular rehabilitation expectations

supports differential dx

Central or peripheral when someone has poor fixation suppression?

central

Central or peripheral when someone has direction changing nystagmus?

central

Where does velocity storage take place?

cerebellum

velocity storage mechanism

allows for us to maintain visual stability during sustained rotation

ex., nystagmus continues after spinning and coming to an abrupt stop

Alexander’s law

Nystagmus will decrease when looking towards the affected ear, and increase when looking towards the healthy ear.

if it follows Alexander’s law it is peripheral

peripheral lesion sx nystagmus

unidirectional nystagmus

fixation suppression present

central lesion sx nystagmus

direction changing nystagmus

poor fixation suppression

central patterns for central lesion (oculomotors)

saccadic pursuit

dysmetric saccades

asymmetric OKN or pursuit

inability to hold gaze

gaze evoked nystagmus