Saccadic eye movements are associated with a family history of alcoholism at baseline and after exposure to alcohol
Objective: To evaluate the influence of family history of alcoholism (FHA) on the response of saccadic eye movements to alcohol. Method: Saccadic performance was evaluated in 54 healthy adult subjects with a FHA (family historypositive) and 49 controls (family history-negative). Alcohol and placebo sessions were presented in counterbalanced order. Alcohol was administered intravenously to achieve and maintain a target breath alcohol concentration of 60 mg/100 ml (60%) for 160 min in each subject. During each session, saccadic eye movement testing was performed at baseline (before infusion of alcohol) and twice during the steady-state target breath alcohol concentration. The saccadic testing elicited visually guided saccades (VGS) and antisaccades (AS). Saccadic latency and velocity and the percentage of AS errors were quantified and analyzed using multivariate analysis of variance. Results: The family history-positive and family history-negative groups showed an overall difference at baseline in AS and VGS latencies and velocities in the alcohol and placebo sessions (p = 0.006). Alcohol delayed saccades such that AS and VGS latencies increased (p = 0.0001) and slowed the execution of saccades such that peak velocities decreased (p = 0.0002). The percentage of AS errors decreased after alcohol administration, but no significant effect of alcohol (alcohol versus placebo session) was observed (p = 0.1). Latency of AS saccades demonstrated a significant overall FHA effect (p = 0.02) and a significant interaction between FHA and response to alcohol over time (p = 0.02). Conclusions: Differences in operational characteristics of the saccadic control system are associated with FHA in adult social drinkers, both at baseline and when the brain is exposed to ethanol at 60 mg/100 ml.