Overview of Vestibular Assessment and Management Flashcards
(50 cards)
Is dizziness common?
Yes
It is the 3rd most reported complaint in outpatient clinics and the 1st complaint in people over 70 years of age
What percentage of true vertigo and balance dysfunction may be inner ear related?
Up to 85%
Will 50% of individuals over 7- years of age experience Benign Positional Vertigo (BPPV)?
Yes
Why are falls important?
Falls are the leading cause of brain injury (TBI) and fractures
Falls are 6th leading cause of death in elderly
20% of those who sustain a hip fracture from a fall will die within a year
20% of those who fall will require placement in a long term care facility
Is dizziness hard to define?
Yes
Could be vertigo, syncope, lightheadedness, disequilibrium, unsteady, floating, rocking, tilting, foggy feeling, motion sick, etc
What is vertigo?
Refers to illusory sense of motion of self or external world (e.g., spinning) and is more likely to be peripheral (i.e., inner ear)
*Dizziness / lightheadedness is more general term and less likely to be peripheral
What does our ability to maintain balance depend on?
Visual, somatosensory and vestibular receptors in the body
The sensory information that is picked up by these receptors is sent to the brainstem for integration and ultimately, to the cortex for perception and processing
The cerebellum and cerebral cortex streamline the process by coordinating incoming impulses and adding information from thinking and memory (learned responses of past experiences)
Visual and Somatosensory information are constantly changing as a function of movement, but the vestibular reference (gravity) is always the same - it is our one constant
Do humans tend to rely more on vestibular input for regular maintenance of balance because gravity doesnt change?
Yes
Particularly rely on this for balance with movement (dynamic balance)
However, when the body is still (i.e. static balance) the vestibular system is much less effective and proprioception is the dominant contributor
Whether static or dynamic, the body relies on consistency and AGREEMENT between all three systems to operate normally
When information from one or more of these sensory systems is ‘different’ from the others (i.e. conflicting), equilibrium is lost
What does peripheral mean?
Inner ear (labyrinth and 8th nerves up to the point it enters the brainstem)
What does central mean?
CNS (brainstem to cortex)
What does vision denied mean?
Eyes closed/covered
Patient without a visual target
What does vision allowed mean?
Eyes open/uncovered
Patient with a visual target
Able to fixate
Do sensory organs in the inner ear project up the the vestibular nuclei in the brainstem?
Yes
Projected by the 8th nerve
What are the two types of sensory structures within the peripheral vestibular system?
Semicircular canals (sensory epithelia = cristae ampullaris)
Otolithic organs (sensory epithelia = maculae)
What are the semicircular canals?
Fluid-filled (endolymph), bony tubes that are interconnected
Detect angular (rotational) acceleration of the head/body
3 SCC per labyrinth (Anterior, Posterior and Horizontal)
Planar orientation for each corresponding to movement
Pitch (shaking head ‘yes’), yaw (shaking head ‘no’), & roll (tilting head to the side) planes
Function in a complimentary ‘push-pull’ fashion with opposite ear (excitatory, inhibitory)
Where are the SCC cristae located?
In the cupula
The cupula is neutrally buoyant (roughly the same density as the endolymph itself)
What happens with the endolymph moves toward or away from the cupula?
Due to a particular head movement, the cupula is deflected resulting in an excitatory and/or inhibitory response
What is ampullopetal endolymph movement?
Toward the ampulla
Initiates an excitatory response
What is ampullofugal endolymph movement?
Away from the ampulla
Initiated an inhibitory response
Are the anterior and posterior canals opposite?
Yes
What are the otolithic/macular organs?
Utricle and saccule
Gelatinous structures with otoconia embedded on top
Detect linear or translational movement including gravitational acceleration and perception of up & down (tilt) relative to gravity
One utricle and one saccule in each labyrinth
Arranged perpendicular to each other
Utricle is superior, larger, oriented horizontally and sensitive to linear horizontal acceleration and tilt
Saccule is inferior, smaller, oriented vertically and sensitive to linear vertical acceleration
What are the 3 important functions of the vestibular system?
To provide a subjective sensation of movement and/or displacement in 3-dimensional space
To maintain upright body posture (“balance”)
To stabilize the eyes during head/body movement
What are the vestibular reflexes?
Vestibulo-ocular reflex (VOR) - generates reflexive eye movements to maintain image stability during head movement
Vestibulocollic reflex (VCR) - acts on the neck musculature to stabilize the head and maintain head in horizonal gaze position independent of trunk movement
Vestibulospinal reflex (VSR) - generates compensatory body movements to maintain head and postural stability in upper and lower limbs
What is the VOR?
Allows for gaze stabilization when the head is moving by keeping an image of interest on the fovea of the retina thus preventing oscillopsia or visual blurring
Generates reflexive eye movements that are equal to but opposite of head movement (i.e. a ‘cancelling’ response)
Deficit = oscillopsia (bumpy vision), retinal slip
