Would anyone be able to help clarify ways to differentiate vestibular hypofunction vs central dysfunction upon examination? The slides mention that the patient will be able to suppress nystagmus with visual fixation in peripheral dysfunction, but not with central dysfunction. Any other signs/ symptoms to help differentiate?
In my experience, differentiating between central and peripheral dysfunction starts with their subjective explanation of their symptoms. I listen and probe for key words to help me determine my differential diagnoses (vertigo, imbalance, light-headed, swimming) along with when they experience their symptoms – such as always with head movement or not. I, then, complete a thorough oculomotor exam including individual tests for the CNS and peripheral vestibular system. Collectively, this will help identify any “red flags” implying any undetected CNS involvement such as a tumor. If this is suspected, I would continue my evaluation with cranial nerve testing, reflex testing, etc. Oculomotor testing that is normal with the exception of VOR or head-thrust test would imply vestibular hypofunction and I would further evaluate balance and coordination. A normal oculomotor exam with no apparent peripheral dysfunction would direct me to the possibility of migraines, motion sensitivity, or something of that nature.