Derealization during utricular stimulation.

BACKGROUND

Feelings of unreality have been provoked in healthy subjects undergoing stimulation of the semicircular canals, but no studies have assessed the influence of otoliths stimulation on depersonalization/derealization (DD) symptoms.

OBJECTIVE

To assess DD symptoms during unilateral centrifugation in healthy adults.

METHODS

100 subjects participated in the study. They completed a standardized questionnaire of symptoms related to balance (Jáuregui-Renaud 2003), the 17-item Hamilton Depression Rating Scale, the Zung Instrument for Anxiety Disorders and the Cox & Swinson 28-item DD inventory. After unilateral centrifugation (300°/s at 3.5 cm), subjects completed the DD inventory again.

RESULTS

Centrifugation provoked symptoms which subjects denied ever experiencing before. The items most frequently reported were "Body feels strange or different in some way" (56%) and "Time seems to pass very slowly" (55%). The DD total score was related to the score of symptoms related to balance and to the depression inventory with no influence from the general characteristics of the subjects or the responses to vestibular tests. The individual scores of symptoms of vestibular function and derealization were related to the report of the other DD symptoms.

CONCLUSIONS

In healthy subjects, unilateral centrifugation provokes DD symptoms. The results support that distorted vestibular signals may create a misleading frame of reference which mismatch with the other senses, giving rise to 'unreal' perceptions.