PRC Cranial, Visual & Vestibular Integration

Question 1

According to PRI, what role does the visual system play in maintaining postural asymmetry?

Accepted Answer

It can override proprioceptive input and maintain asymmetrical postural patterns

Answer

It exclusively regulates anterior/posterior balance through the optic nerve

Answer

It has no direct relationship to postural muscle tone in adults

Answer

It solely controls head position through the oculomotor system

Question 2

Which cranial nerve primarily carries vestibular signals that influence postural muscle tone?

Accepted Answer

Cranial nerve VIII (Vestibulocochlear)

Answer

Cranial nerve V (Trigeminal)

Answer

Cranial nerve VII (Facial)

Answer

Cranial nerve XI (Spinal Accessory)

Question 3

In PRI theory, what is 'ocular lock' and why is it clinically significant?

Accepted Answer

A state where the visual system fixes gaze on a target, perpetuating associated postural compensations

Answer

A surgical procedure to fix extraocular muscle imbalance

Answer

The resting position of the eyes during sleep that resets postural tone

Answer

A condition where the eyes cannot converge, causing chronic postural strain

Question 4

How does achieving horizontal gaze level influence PRI treatment outcomes?

Accepted Answer

Level eye positioning reduces compensatory cervical and postural muscle activation needed to maintain gaze

Answer

Horizontal gaze is only relevant in balance disorders, not musculoskeletal PRI work

Answer

It must be established in the lower extremity before addressing visual factors

Answer

Horizontal gaze level has no measurable effect on postural muscle activation

Question 5

What is the vestibulo-ocular reflex (VOR) and its clinical relevance in PRI?

Accepted Answer

A gaze-stabilizing reflex linking head movement to eye movement that can affect postural tone when dysfunctional

Answer

A reflex coordinating blinking with head movement to protect the cornea

Answer

An involuntary reflex that adjusts pupil size based on vestibular acceleration

Answer

A reflex that causes convergence of the eyes during forward trunk flexion

Question 6

Which muscle serves dual roles in vestibular function and left AIC patterned positioning according to PRI?

Accepted Answer

Sternocleidomastoid

Answer

Rectus abdominis

Answer

Psoas major

Answer

Serratus anterior

Question 7

How does cranial base asymmetry affect breathing and postural patterns in PRI?

Accepted Answer

Cranial base asymmetry can alter dural tension, cervical mechanics, and diaphragmatic positioning

Answer

It exclusively disrupts visual field symmetry without affecting breathing

Answer

It has no effect on breathing; only ribcage mechanics matter

Answer

Cranial base asymmetry only affects temporomandibular joint loading