Several objective responses to alcohol were also found to be highly reproducible between HD cohorts. Psychometric (Grooved Pegboard and DSST) and eye tracking performance impairment was most evident at peak BrAC in both cohorts, suggesting HD’s cognitive and psychomotor function are impaired at the same time they are reporting highest stimulating and hedonically rewarding effects. While the effect of alcohol on smooth pursuit gain, pro- and anti-saccade latency, and pro-saccade velocity was highly similar between samples, other eye movement measures failed to meet the standards for replication. Anti-saccade accuracy was significantly impaired by alcohol in the original cohort and would have been in the second cohort as well under normal statistical standards (p < 0.05), but did not meet the corrected alpha (p = 0.004) used in the current study. It is not necessarily surprising that pro- and anti-saccade accuracy were either not affected by alcohol or not reproducible in both cohorts, as several studies have failed to find an effect of alcohol on saccade accuracy (Blekher et al. 2002a, b; Lehtinen et al. 1979; Moser et al. 1998; Vassallo
