A closer look at subjective caloric sensations: Is there more to vertigo than spinning?

Abstract

There is a prevailing opinion that spinning sensations signify a peripheral vestibular pathology while non-spinning sensations are not of vestibular origin. 1) Characterize the subjective sensations reported by patients during caloric testing. 2) Assess if the sensation was correlated with the peak slow phase velocity (SPV). Retrospective chart review at a Canadian adult tertiary-quaternary care balance centre for patients undergoing diagnostic caloric testing between December 2014 and September 2015. Of 163 patients included, 122 had normal calorics and 41 demonstrated unilateral weakness. Spinning/rotatory movements were the most commonly reported sensations (55-70%). No sensation was reported among 10-20% of patients. Other non-rotatory sensations were reported 20-25% of the time. Both lack of sensation and other sensations were more likely to be correlated with SPVs that were significantly lower than those associated with spinning/rotating sensations. However, 18% of patients with normal calorics and robust SPVs with warm irrigation still reported non-spinning sensations. During caloric irrigation, subjective sensations other than spinning and rotating are reported 20-25% of the time and these tend to be associated with lower peak SPV. Non-spinning vertigo is not uncommon as a subjective description of vestibular sensation even in normal patients with strong SPVs.