In this study the researchers compared the performance of people who have become intoxicated by kava using saccade function and cognitive tests. Saccade is defined as the rapid movement of the eye between fixation points. These participants were allowed to drink as much as they found necessary for intoxication. Amounts of kava ranged between 75-375 grams with an average consumption of 205g of kava powder each. This was a group session which continued for 14.4 hours. The amounts of kavalactones consumed were approximately 25 grams or 150 times the clinical dose. Intoxicated drinkers showed saccadic dysmetria which is continual abnormal eye movements. They also showed slowing and reduced accuracy in visual search tasks as the complexity increased. Reaction time and difficult memory tasks showed no issues in chronic kava consumers. It was found kava intoxication was known to produce abnormalities in coordination of movement and visual attention but did not affect complex cognitive function in chronic users.
Cairney S, Clough AR, Maruff P, Collie A, Currie BJ, Currie J. Saccade and cognitive function in chronic kava users. Neuropsychopharmacology. 2003 Feb;28(2):389-96. doi: 10.1038/sj.npp.1300052. PMID: 12589393. https://pubmed.ncbi.nlm.nih.gov/12589393/
Cairney S, Clough AR, Maruff P, Collie A, Currie BJ, Currie J. Saccade and cognitive function in chronic kava users. Neuropsychopharmacology. 2003 Feb;28(2):389-96. doi: 10.1038/sj.npp.1300052. PMID: 12589393. https://pubmed.ncbi.nlm.nih.gov/12589393/