Periodic limb movements during sleep in alcohol dependent patients

Complaints of sleep disturbances are common among alcohol dependent patients during subacute abstinence. Recovered patients may show persistent sleep abnormalities for months or even years. In the present study we studied the issue whether periodic limb movements in sleep and disturbances of nocturnal respiration are more frequent in alcohol dependent patients than healthy subjects and may be of predictive value for sustained abstinence vs. relapse after withdrawal. Forty alcohol dependent patients spent three nights in the sleep laboratory at three time points: 2 to 3 weeks after withdrawal (T0) and at follow-up investigations 6 (T1) and 12 (T2) months after discharge from the hospital. Measurements of PLMS-arousal index and nocturnal respiration were performed during the first laboratory night of each measurement point. Alcohol dependent patients displayed a significantly enhanced PLMS-arousal index at T0 compared to age- and gender-matched healthy subjects, whereas no alterations of nocturnal respiration were found.The PLMS-arousal index at T0 was significantly elevated in patients who relapsed during the next 6 months compared to abstinent patients. In a discriminant function analysis the PLMS-arousal index classified 55 % of the patients correctly with respect to outcome after 6 months. It correctly predicted 80 % of abstainers and 44 % of the patients who relapsed. According to neurobiological models of the generation of PLMS and the etiopathology of alcohol dependence a genetically determined vulnerability of the dopaminergic system is discussed as a factor underlying an increased risk of relapse in a subgroup of alcohol dependent patients.