Physiological and focal cerebellar substrates of abnormal postural sway and tremor in alcoholic women.

BACKGROUND: Posturography analysis of static balance reveals marked sway and tremor in sober alcoholic men related to anterior vermis volume but can be attenuated by simple visual or tactile cues or alterations in stance. Whether alcoholic women, whose ataxia can persist with prolonged sobriety, exhibit the same physiological signature of balance instability and relation to cerebellar vermian volume as alcoholic men or can benefit from stabilizing factors is unknown.
METHODS: Groups comprised 15 alcohol-dependent women, alcohol-free (median 3 months) and 29 control women. Groups were matched in age, demographic features, and finger movement speed and underwent balance platform testing and magnetic resonance imaging scanning.
RESULTS: Alcoholic women exhibited excessive sway path length (.6 SD), more dramatic in the anterior-posterior than medial-lateral direction. Truncal tremor, measured as peak sway velocity frequency, was disproportionately great in the 5 Hz to 7 Hz band of alcoholics. Control subjects and alcoholics exhibited sway and tremor reduction with visual, tactile, or stance-stabilizing conditions, which aided both groups equally well; thus, alcoholic women never achieved normal stability. Smaller anterior vermian volumes selectively correlated with longer sway path and higher 5 Hz to 7 Hz peak sway velocity.
CONCLUSIONS: Sway and tremor abnormalities and the selective relations between greater sway and 5 Hz to 7 Hz tremor and smaller volumes of the anterior vermis had not heretofore been described in abstinent alcoholic women. Reduction in sway and tremor with stabilizing factors indicate that adaptive mechanisms involving sensorimotor integration can be invoked to compensate for vermian-related dysfunction.