The effects of alcohol on eye movement behaviour during driving

INTERVENTION: One dose (weighted and sex‐dependent treatment) will be taken orally (by mouth) under supervised administration at each session [i.e. active treatment(s): weighted dose of alcohol (vodka) with orange juice to reach 0.05%Blood Alcohol Concentration (BAC); weighted dose of alcohol (vodka) with orange juice to reach 0.08%BAC; weighted dose of alcohol‐free vodka with orange juice as the placebo treatment (control)]. The order of dosing will be randomised with a one‐week washout period between testing sessions. The active treatments are: 1. Weighted and sex‐specific dose of vodka and orange juice drink to achieve 0.05%BAC 2. Weighted and sex‐specific dose of vodka orange juice drink to achieve 0.08%BAC This will be achieved using an adjustable calculation based on the Watson method of dosing per estimated total body water for men and women (derived from height and weight) rather than only body weight, as per the equation below: 1. Total Body Weight (TBW) men (Litres, L) = 2.2447 ‐ (0.09516 Xage) + (0.1074 Xheight) + (0.03362 Xweight) 2. TBW women (L) = 2.097 ‐ (0.1069 Xheight) + (0.2466 Xweight) For an average 70 kg male person to achieve 0.05%BAC, this will require dosing of 111g of 40% alcohol, or 4 standard drinks (30mL shots) with 334g mixer orange juice (total drink 445g). For 0.08%BAC, it will require 175g of 40% alcohol, or 5.7 standard drinks (30mL shots) with 527g mixer orange juice (total drink volume 703g). Participants are given 10 minutes to finish the drink, which is followed by a 10‐minute absorption period Prior to dosing at each testing visit (each at V1, V2 and V3), participants will provide one saliva sample to screen for evidence of recent use of drugs [amphetamine/d‐methamphetamine, 3,4‐ methylenedi CONDITION: Eye ‐ Normal eye development and function Neurological ‐ Studies of the normal brain and nervous system Neurological;Neurological; ; Neurological ; Neurological PRIMARY OUTCOME: Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and driving performance, shown as weaving of the car, expressed as standard deviation of the lateral position (SDLP).[Weaving of the car, expressed as standard deviation of the lateral position (SDLP), will be assessed using an instrumented electric vehicle (BYD Auto Co., Ltd.) Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and eye movement behaviour (gaze entropy ‐ stationary) during driving.[Stationary gaze entropy will be assessed using the PC‐Driver Monitoring System (PC‐DMS) during each driving test. Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and eye movement behaviour (gaze entropy ‐ transition) during driving.[Gaze transition entropy will be assessed using the PC‐Driver Monitoring System (PC‐DMS) during each driving test. Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] SECONDARY OUTCOME: Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and cognitive and psychomotor performance, measured as a composite score of balance, reaction time, psychomotor vigilance, hand–eye coordination, attention to motion stimuli, and time estimation [Balance, reaction time, psychomotor vigilance, hand–eye coordination, attention to motion stimuli, and time estimation will be assessed and compiled into a composite using the DRUID mobile app (Impairment Science, Inc.). Ascending (15 minutes post‐treatment) and descending BAC levels (95 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and driving performance, measured as number of lane deviations.[The number of lane deviations will be assessed using an instrumented electric vehicle (BYD Auto Co., Ltd.). Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and driving performance, measured as standard deviation of speed (SDS) .[The standard deviation of speed (SDS) will be assessed using an instrumented electric vehicle (BYD Auto Co., Ltd.). Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and driving performance, measured using standard deviation of the steering wheel angle, representing steering variability.[The standard deviation of the steering wheel angle, representing steering variability, will be assessed using an instrumented electric vehicle (BYD Auto Co., Ltd.). Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and eye movement behaviour (fixation count) during driving.[Fixation count will be assessed using the PC‐Driver Monitoring System (PC‐DMS) during each driving test Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and eye movement behaviour (fixation duration) during driving.[Fixation duration will be assessed using the PC‐Driver Monitoring System (PC‐DMS) during each driving test Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and eye movement behaviour (fixation location) during driving.[Fixation location will be assessed using the PC‐Driver Monitoring System (PC‐DMS) during each driving test. Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and eye movement behaviour [percentage of total eye closure time (PERCLOS)] during driving.[The percentage of total eye closure time (PERCLOS) will be assessed using the PC‐Driver Monitoring System (PC‐DMS) during each driving test. Baseline (pre‐treatment), ascending (30 minutes post‐treatment) and descending BAC levels (110 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and lip movement patterns[The effect of alcohol on lip movement patterns will be assessed using the SRAVI app (Liopa). Ascending (25 minutes post‐treatment) and descending BAC levels (105 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and speed of speech. ; [The effect of alcohol on speed of speech will be assessed using the SRAVI app (Liopa). Ascending (25 minutes post‐treatment) and descending BAC levels (105 minutes post‐treatment).] Associations between acute dose of alcohol (0.05%BAC; 0.08%BAC) and subjective sleepiness. ; [The effect of alcohol on subjective sleepiness will be assessed using the Karolinska Sleepiness Scale (KSS). Baseline (pre‐treatment), ascending (10 minutes post‐treatment) and descending BAC levels (90 minutes post‐treatment).] The effect of acute dose of alcohol (0.05%BAC; 0.08%BAC) on self‐perceived estimated blood alcohol content (BAC) confidence.[Participants will be asked to self‐report their confidence in their reported level of perceived intoxication. Participants will indicate their level of confidence in their answer (as defined above) using a 5‐item scale. Items will range from 0 = not at all confident to 5 = extremely confident. Ascending (10 and 60 minutes post‐treatment) and descending BAC levels (105 and 135 minutes post‐treatment).] The effect of acute dose of alcohol (0.05%BAC; 0.08%BAC) on self‐perceived estimated blood alcohol content (BAC)[Participants will be asked to estimate their blood alcohol content (BAC) with the question "What do you estimate is your current Blood Alcohol Content (BAC)?" If participants asked what particular BAC values corresponded to, research assistants gave the following answer: “answers may range from 0.00 (which is sober) to 0.40 (which is the lethal limit), where .05% is the legal limit for intoxication while driving in the state of Victoria. Ascending (10 and 60 minutes post‐treatment) and descending BAC levels (105 and 135 minutes post‐treatment).] The effect of acute dose of alcohol (0.05%BAC; 0.08%BAC) on subjective driving ability.[Participants be asked to rate the perceived quality of their driving performance on the Perceived Driving Quality Scale; a visual analogue scale that ranges from 0 = I drove exceptionally poorly to 20 = I drove exceptionally well) around a midpoint of I drove normally. Ascending (60 minutes post‐treatment) and descending BAC levels (135 minutes post‐treatment).] To identify the effect of acute dose of alcohol (0.05%BAC; 0.08%BAC) and subjective drug effects.[The effects of alcohol on subjective drug effects will be assessed using the Brief‐Biphastic Alcohol Effects Scale (B‐BAES). The B‐BAES is a 6‐item scale, measuring the degree to which participants feel energised, excited, sedated, slow thoughts, sluggish and up. Participants respond on a 6‐point Likert scale from 0 = not at all to 10 = extremely. Ascending (10 and 60 minutes post‐treatment) and descending BAC levels (105 and 135 minutes post‐treatment).] To identify the effect of acute dose of alcohol (0.05%BAC; 0.08%BAC) on mental load, measured using the NASA Task Load Inde X(NASA‐TLX)..[Participants be asked to rate the perceived quality of effort using the NASA Task Load Inde X(NASA‐TLX). Increments of high, medium, and low estimates for each point result in 21 gradations on the scales mental demand, physical demand, temporal demand, performance, effort and frustration. Ascending (60 minutes post‐treatment) and descending BAC levels (135 minutes post‐treatment).] INCLUSION CRITERIA: ‐ Male or female, aged 21 to 55 years ‐ Willing and able to provide written informed consent ‐ Understands and is willing and able to comply with all study procedures ‐ Fluent in written and spoken English ‐ Previous history of alcohol consumption in a single drinking session to an estimated BAC of 0.08% with no known adverse reaction [more than 5 standard drinks (female) or 6 standard drinks (male) on single drinking occasion] ‐ Normal or corrected‐to‐normal vision ‐ Regular driver (>50km/week) with three years of driving with a full Australian or International driver’s licence (no ‘P‐Plate’ drivers) ‐ Weight under 100kg. This limit is critical for participant safety. In this study, alcohol delivery is based on weight, and by defining this limit, we avoid overdosing and hence minimise potential health concerns ‐ Willing to abstain from the following prior to their scheduled visit: ‐ No food or drinks (except water) within 2 hour