Smoking and balance: correlation of nicotine-induced nystagmus and postural body sway.

Unaccustomed smoking may elicit transient nystagmus, dizziness, unsteadiness, and nausea. Infrared videonystagmography and posturography were performed simultaneously to study the differential effects of nicotine on the association of ocular motor and postural disturbances in 25 non- or occasional smokers. Sixteen showed nicotine-induced nystagmus (NIN) of various directions (mainly horizontal or upbeat) which was associated with a significant increase in postural sway after smoking a cigarette (total sway path (SP) before smoking 2.22 +/- 0.82 m/min (mean +/- s.d.), 1 min after smoking 3.83 +/- 1.41 m/min; p < 0.0004, ANOVA); nine showed neither effect. There was a high correlation between the intensity of the nystagmus (measured as peak slow phase velocity) and the increase in total SP (correlation coefficient 0.78) as well as the time courses of both. Visual fixation of an LED integrated in the mask not only caused a suppression of NIN but also a decrease in body sway. Transient ocular motor and postural effects are compatible with simultaneous nicotine-induced effects on the vestibulo-ocular and vestibulo-spinal functions.