Ataxia of stance in different types of alcohol dependence--a posturographic study.

The aim of this study was to assess the prevalence of ataxia of stance in different types of alcohol-dependent patients. Posturographic measurements were performed in 82 abstinent alcohol-dependent patients and 54 healthy controls in order to analyse postural control. According to Lesch and co-workers, alcohol dependence was classified as total abstinence (Type I), drinking without loss of control (Type II), fluctuating course (Type III), and persistent severe drinking (Type IV). The mechanisms of alcohol dependence in these subtypes can be summarized as follows: Type I patients drink alcohol to counteract symptoms of alcohol withdrawal; Type II patients use alcohol as an agent for solving conflicts; Type III patients drink alcohol to 'treat' an affective disorder; and Type IV patients have a history of pre-alcoholic neurological and/or psychiatric disorders. The neurological examination showed pathological findings in 39%, whereas posturographic measurements uncovered impaired postural control in 61% (chi2 = 8.8, P = 0.003). Comparing the different study groups revealed that ataxia of stance was most common in alcohol-dependent patients classified as Type IV (tau = 0.24, P = 0.005). In conclusion, posturographic measurements are superior to the clinical examination in detecting postural imbalance in alcohol-dependent patients. The prevalence of postural imbalance is highest in patients classified by Lesch as Type IV. Consequently, this type of alcohol dependence -- characterized by pre-alcoholic neurological and/or psychiatric disorders, bears the highest risk of developing ataxia of stance.