Hangover Predicts Residual Alcohol Effects on Psychomotor Vigilance the Morning After Intoxication

Jonathan Howland^1,4*, Damaris J. Rohsenow², Caleb A. Bliss¹, Alissa B. Almeida³, Tamara Vehige Calise¹, Timothy Heeren¹ and Michael Winter¹

¹Boston University School of Public Health, 801 Massachusetts Avenue, 4^th Floor, Boston, MA 02118

²Center for Alcohol and Addiction Studies at Brown University, 121 South Main Street, Providence, Rhode Island 02903

³Boston Medical Center 801 Massachusetts Avenue, 1^st Floor, Boston, MA 02118

⁴Department of Emergency Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118

*Corresponding Author:

Jonathan Howland, PhD
Department of Community, Health Sciences
Boston University School of Public Health
801 Massachusetts, Avenue, Room 439, Boston, MA 02118
Tel: 617 638 5158
Fax: 617 638 4483
E-mail: jhowl@bu.edu

Received July 22, 2010; Accepted August 23, 2010; Published August 23, 2010

Citation: Howland J, Rohsenow DJ, Bliss CA, Almeida AB, Calise TV, et al. (2010) Hangover Predicts Residual Alcohol Effects on Psychomotor Vigilance the Morning After Intoxication. J Addict Res Ther 1:101. doi:10.4172/2155-6105.1000101

Copyright: © 2010 Howland J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Abstract

Objectives: Both hangover and performance defi cits have been documented the day after drinking to intoxication after breath alcohol concentration (BrAC) has returned to near zero. But few studies have examined the relationship between hangover and post- intoxication performance.

Method: We performed secondary analyses of data from a previously reported controlled cross-over laboratory study to assess the relationship of hangover incidence and severity to sustained attention/reaction time the morning after drinking to about 0.11 g% BrAC. Relationships were investigated while controlling for gender, type of alcoholic beverage (bourbon or vodka), and neurocognitive performance after placebo.

Results: Hangover severity and neurocognitive performance were signi fi cantly correlated. Participants reporting stronger hangover were more impaired than those reporting little or no hangover. Comparing any to no hangover showed a trend in the same direction of effect.

Conclusions: More intense hangover may indicate less fi tness for duty in workers in certain safety-sensitive occupations, with implications for occupational alcohol policies.

Keywords

Hangover; Residual alcohol effects; Sustained attention; Reaction time; Vigilance

Introduction

“Residual effects of intoxication” refers to any subjective, physiological, and/or behavioral effects of heavy drinking once breath alcohol concentration (BrAC) has returned to zero. Hangover is most accurately defined by symptoms including headache, nausea, and fatigue [34]. We use the term “hangover” to refer to the cluster of symptoms and “residual effects of alcohol” as a broader term covering neurocognitive and occupational impairment in the absence of blood alcohol the morning after intoxication. The causes of hangover are unknown, although several review articles discuss a number of hypotheses [31,48,40]. Some portion (25-30%) of the population appears to be hangover resistant across a variety of laboratory, clinical and survey investigations [15,16]. Little is known, however, about predictors or consequences of resistance to hangover. Hangover resistance was unrelated to gender, age, family history, or average daily volume among heavy drinkers [15].

Although findings are mixed, the residual effects of alcohol can result in occupational and neurocognitive performance impairment the next day [38,32]. Residual effects have been found on simulated industrial work tasks [49] driving-related skills and driving [37,19,45] and simulated aircraft piloting [25-27,30,42,43,51,50] other studies, however, did not find occupational performance effects [10,7,8,14,33,39]. Using neurocognitive tasks, adverse effects were found for codification and identification tasks [28] immediate and delayed (1h) free recall [46] visual, memory and intellectual processing [17,24] time-reaction error in a go-no-go task [1] sustained attention/reaction time [12] and choice reaction time [24,18], although negative results were found for some neurocognitive measures [11,20,22,46]. In several studies, BrAC was still around .04 g% when tested [e.g., 45], leading to a confound. When ensuring that BrAC was zero and comparing multiple tasks, we found the strongest effects for tests requiring both sustained attention and speed [14,35].

The present study investigates whether hangover severity or incidence is associated with the residual effects of alcohol in terms of neurocognitive performance. Two previous studies investigated the relationship of hangover severity to performance. One study found no association between hangover (using a measure of unknown reliability or validity) and psychomotor performance, as measured by choice reaction time, motor coordination, and attention [37]. The other, described below, found that hangover severity (measured on a validated scale) correlated with sustained attention/reaction time (univariate correlation), suggesting that hangover symptoms might contribute to impairment the day after intoxication [35]. Neither of these studies, however, controlled for factors that might also be associated with neurocognitive performance or asked whether absence of hangover meant absence of residual effects on performance.

We used data from the aforementioned randomized cross-over study [35] to determine if hangover severity or incidence were associated with impaired neurocognitive performance the morning after alcohol administration to a mean BrAC of 0.11 g%. Our previous studies have shown strong effects of intoxication on next-day sustained attention/reaction time in a psychomotor vigilance task [35,14], so this performance measure was selected for analysis. We previously reported the simple correlation of hangover severity and sustained attention/reaction time the day after intoxication [35]. Herein, we expanded that analysis and hypothesized that hangover incidence and severity would correlate with the neurocognitive performance scores in the morning, when controlling for other variables that could affect next-day performance scores, such as gender, type of alcoholic beverage (bourbon versus vodka), and baseline (placebo condition) neurocognitive performance.

Methods

Procedures were approved by the Institutional Review Boards at Boston University Medical Center, Brown University, and the University of Michigan.

Participants

Participants were 95 university students or graduates recruited in greater Boston. They were 21 to 33 years of age and met the following criteria: (1) no serious drinking problems (score < 5 on the Short Michigan Alcohol Screening Test [SMAST]) [36] or self-reported history of treatment for chronic alcohol problems; (2) ≥ 5 drinks on a single occasion (≥ 4 if female) at least once 30 days prior to screening; (3) no health problems or current medication use contraindicated for alcohol; (4) fluent English; (5) currently attending, or recently graduated from, an institution of higher learning; and (6) negative pregnancy test and not nursing, if female. Females were not screened for menstrual cycle [44,29,3]. There were no significant differences in background characteristics by beverage type administered and genders did not differ significantly in quantity or frequency of typical drinking.

Study design

The study used a double-blind within-subjects, crossover 2 X 2 X 2 design: alcohol content (alcohol vs. placebo) by order (alcohol on Day 1 vs. alcohol on Day 2) by high or low congener content (bourbon vs. vodka in the alcohol condition). Alcohol content was the within-subjects factor; congener and order were between groups factors.

Procedures

Screening and pre-experimental preparation: Participants responding to advertisements were screened including a physician examination. To reduce potential confounding by sleep pattern variations, participants were instructed to keep a sleep diary, wear an activity monitor, comply with a minimum regimen of 8 hours time in bed, retiring to bed no later than midnight, with confirmation call-ins to a time-stamped answering machine each evening and morning and, no napping for the three days prior to experimental sessions. Participants were required to abstain from alcohol, recreational drugs, sleep aids, and caffeine for 24-hours prior and food/beverages for 3 hours prior to their evening sessions. Individuals who failed to comply were rescheduled; those presenting with a positive BrAC were excluded from further participation.

Session procedures and randomization: Participants returned in groups of three to five for the first of three overnight experimental sessions one week after screening and informed consent. The first night was for sleep screening and acclimatization to polysomnography procedures and the other two were the experimental drinking sessions (a week apart). Participants were accurately told they would receive alcohol one night and placebo the other night, with a 50-50 chance of receiving alcohol the first night. Each night they reported at 4:00 p.m., compliance with prelaboratory regimens was checked, and they had a standardized dinner prior to randomization to beverage condition. Following the beverage administration from 8:30-10:00 p.m., BrAC tests were conducted periodically. At 11 p.m., participants had snacks and lights were turned out for an 8-hour opportunity to sleep. A licensed emergency medical technician observed participants throughout the night.

Participants were awakened each morning at 7:00 a.m. They completed the hangover measure, ate breakfast (no coffee), and were breath-tested. Between 8:00 and 8:30 a.m. they completed the neurocognitive test followed by other measures not reported here (start time delayed if BrAC > .01 until below that). Allowing an hour after waking avoids confounding by sleep inertia [41].

Beverage administration: Alcoholic beverage administration was designed to attain. 10 g%, since this level is required for reliable hangover induction [4]. Total beverage volume was determined by dosing tables with the amount of beverage adjusted by gender per [13] and by weight (1.2 g/kg for men, 1.1 g/kg for women). Participants were breath-tested 15 minutes after completing two thirds of their portions. The ratio of actual to target BrAC was used to determine the additional amount of beverage administered for those below target. To enhance blinding, some placebo participants also received extra non-alcoholic beverage. The individual who prepared beverages and conducted breath tests had no other contact with participants; all other study assistants working directly with participants were blinded to participants’ beverage assignments.

The alcoholic beverages were bourbon (101 proof Wild Turkey®, Austin Nichols Distilling Co., Lawrenceburg, KY) or 100 proof vodka (Absolut®, V&S Vin & Spirit, AB, Stockholm, Sweden), mixed with chilled caffeine-free cola (Coke®, The Coca Cola Co., Atlanta, GA), with a ratio of 1 part vodka or bourbon to 4 parts cola. The placebo for both of these beverages was chilled caffeine-free cola, in an amount equivalent to the alcoholic beverage, with a few drops of vodka or bourbon floated on top, designed to mask beverage color differences and taste. Participants received $450.

Measures

Individual difference and screening measures: Questionnaires assessed demographics and exclusionary criteria. Urine pregnancy tests used over-the-counter test cups. BrAC was assessed using Intoximeters’ Alco-Sensor IV (Intoximeters, Inc., St. Louis, MO) automated handheld breath alcohol instrument. Recent drinking practices were assessed by asking: 1) “Considering all your drinking times in the past 30 days, about how often did you have any beer, wine or liquor?”, rated from 1 “once a day” to 7 “did not drink” with each point anchored; and, 2) “In the past 30 days, on a typical day that you drank, about how much did you have to drink in one day?”, rated from 1 to 8, with choices of 1 to 7 drinks and “8 or more drinks”; those choosing the latter were asked to give a number. One drink was defined as 12 oz of beer or wine cooler, 4 oz of wine or 1 oz of liquor. Average daily volume (ADV) was the product of these responses.

Hangover: Hangover severity was the mean score from the nine-item valid and reliable Acute Hangover Scale (AHS), with each symptom rated on an 8-point scale ranging from 0 (none) to 7 (incapacitating) [34]. Hangover incidence was defined as rating the first item, “hangover”, as zero (none) vs. any other rating on the 8-point scale.

Sustained attention/reaction time: The handheld Psychomotor Vigilance Task (PVT; Ambulatory Monitoring, Inc, Ardsley, NY) [9] measured sustained attention/reaction time. Participants pressed a button with their preferred hand as quickly as possible in response to numbers scrolling on the screen, with a random 3-7 second interstimulus interval. Median reaction time in sec was scored.

Data analyses: The relationship of PVT scores the morning after alcohol administration to hangover incidence was investigated with multiple regression (least squares approach), with the single hangover rating coded as “yes” versus “no” as the predictor variable and entering gender, beverage type (bourbon versus vodka), average daily alcohol volume, and baseline PVT score under placebo condition as covariates. (PVT score under placebo condition was included to control for differences in participants’ attention/reaction time in the absence of alcohol.) The regression was repeated for severity of hangover symptoms by changing the predictor variable to AHS total score. Since the square semi-partial coefficient (sr²) indicated the percentage of variance for each variable when adjusted for all other variables, these also can be used to indicate effect sizes, with 2% of variance being small and 14% being medium [6]. R² is reported for each of the regression models.

Results

Participant characteristics are shown in Table 1. The range for peak BrAC was .09 to .15 g%. In the alcohol condition, 21% reported no hangover (rating = 0 on the hangover question); 45% rated their hangover as mild (rating = 1-2); 34% as moderate (rating = 3-5); and none as severe (rating 6-7). As previously reported [35], mean of the median reaction time was significantly longer the day after alcohol relative to placebo (M = 229.8 mls [± 30.9] versus 220.8 ms [± 24.5]).

Table 1: Participant Characteristics and Within-Session Breath Alcohol Concentration.

Table 2: Regressions of Alcohol Hangover Scale and of Hangover Incidence Predicting PVT Score the Day after Alcohol Administration, Covarying Gender, Beverage Type, Usual Drinking, and Placebo PVT Score.

Table 3: Covariate-adjusted Mean of Median Reaction Time Scores in PVT by Beverage Condition and Hangover Incidence after Alcohol.

In regressions, hangover AHS score was a significant predictor of PVT score after alcohol, controlling for covariates; hangover incidence was borderline significant (p = .057) (see Table 2 for details). Hangover incidence accounted for 2% and AHS accounted for 5% of residual variance in PVT score (small effect sizes). To illustrate the direction of effects for the trend for incidence, PVT scores by hangover incidence are shown in Table 3.

Discussion

These results suggest a relationship between hangover incidence or severity and performance deficits the day after intoxication, although only a small about of variance was accounted for by these variables. Our study cannot determine whether hangover was causally related to performance impairment. It might be that feeling worse was distracting or used up some cognitive resources, or that using the extra energy needed to engage in cognitive activities increased hangover discomfort. Alternatively, congeners (substances other than ethanol and water) in alcoholic beverages, various metabolites of congeners or alcohol, or alcohol-induced elevation in cytokine production may have a direct effect on the nervous system in addition to increasing hangover; thus, hangover and performance impairment could have been two separate but related residual effects of drinking to intoxication. These are, however, speculations given the absence of more complete knowledge of the etiology of hangover and residual alcohol effects. Our findings indicate that people who are resistant to hangover symptoms in terms of reporting no hangover may also be relatively resistant to residual alcohol effects on performance. The fact that the trend for hangover incidence missed significance may be due to the loss of power inherent in dichotomizing a variable, since people reporting no hangover showed virtually no change in PVT scores after alcohol compared to placebo and since the effects of greater severity are lost.

Many safety-sensitive occupations require that workers be able to pay close attention to a number of tasks over a period of time, and to respond quickly with the right choices (e.g., commercial pilots or monitoring assembly lines). Since the severity of hangover may be a useful indicator of impairment for workers in those safety sensitive occupations, self-policing is one approach. Such workers should consider that heavy drinking could impair their performance the next morning and be more moderate on the nights before work. However, other policies might be needed for such occupations given that self-policing often is not sufficient. Given the association between intoxication and problems at work [21,2] and the residual alcohol effects on ability to operate aircraft or cars reviewed above, such residual impairment could have serious consequences [47]. The 8-hour “bottle to throttle” regulation for commercial aircraft pilots and air traffic controllers [5] is clearly insufficient as it allows pilots to work when affected by residual alcohol, [50] specifically tasks that require sustained attention with rapid decisions such as traffic avoidance [51]. Policy changes might be needed for safety sensitive occupations.

Limitations of this study include the restricted range of BrACs required for safety reasons, the young age of the participants, and not using measures of occupational performance. It is unclear why our result differed from those to [37] who found no correlation between hangover and psychomotor impairment the day after intoxication. We note, however, that their study was small compared to ours (30 vs. 95 participants) and thus results might have been affected by low statistical power. Nonetheless, these conflicting findings underscore the need for further research to explore the hangover/performance relationship.

Acknowledgements

ClinicalTrials.Gov Identifier: NCT00183170 & NCT00247585. This research was supported by: (1) the National Institute on Alcohol Abuse and Alcoholism (NIAAA) Grant # RO1 AA12087 to the Boston University School of Public Health; and the (2) the National Center for Research Resources (NCRR), grant # M01 RR00533, a component of the National Institute of Health (NIH). Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the NCRR or NIH.

References

1. Alford C, Wadling S (2004) Comparative effects of caffeine and alcohol bedtime drinks on sleep, performance and mood in young adults. J Psychopharmacol 18: A41.
2. Ames GM, Grube JW, Moore RS (1997) The relationship of drinking and hangovers to workplace problems: An empirical study. J Stud Alcohol 58: 37-47.
3. Brick J, Nathan PE, Westrick E, Frankenstein W, Shapiro A (1986) The effects of menstrual cycle on blood alcohol levels and behavior. J Stud Alcohol 47: 472-477.
4. Chapman LF (1970) Experimental induction of hangover. Q J Stud Alcohol 5: 67-86.
5. Code of Federal Regulations [Online] US Government Printing Office . Available at: http://www.gpoaccess.gov/ cfr/index.html
6. Cohen J (1988) Statistical power analysis for the behavioral sciences. 2nd ed Hillsdale NJ: L. Erlbaum Associates.
7. Collins WE (1980) Performance effects of alcohol intoxication and hangover at ground level and at simulated altitude. Aviat Space Environ Med 51: 327- 335.
8. Collins WE, Chiles WD (1980) Laboratory performance during acute alcohol intoxication and hangover. Human Factors 22: 445-462.
9. Dinges DF, Powell JE (1985) Microcomputer analyses of performance on a portable, simple visual RT task during sustained operations. Behavior Research Methods, Instruments, and Computers 17: 652-655.
10. Dowd PJ, Wolfe JW, Cramer RL (1973) Aftereffects of alcohol on the perception and control of pitch attitude during centripetal acceleration. Aerosp Med 44: 928–930.
11. Finnigan F, Hammersley R, Cooper T (1998) An examination of next-day hangover effects after a 100 mg/100 ml dose of alcohol in heavy social drinkers. Addiction 93: 1829-1838.
12. Finnigan F, Schulze D, Smallwood J, Helander A (2005) The effects of self-administered alcohol-induced “hangover” in a naturalistic setting on psychomotor and cognitive performance and subjective state. Addiction 100: 1680–1689.
13. Friel PN, Logan BK, O’Malley D, Baer JS (1999) Development of dosing guidelines for reaching selected target breath alcohol concentrations. J Stud Alcohol 60: 555-565.
14. Howland J, Rohsenow DJ, Greece JA, Littlefi eld CA, Heeren T, et al. (2010) The effects of binge drinking on college students’ next-day academic testtaking performance and mood state. Addiction 105: 655-665.
15. Howland J, Rohsenow DJ, Allensworth-Davies D, Greece JA, Almeida AB, et al. (2008) The incidence and severity of hangover the morning after moderate alcohol intoxication. Addiction 103: 758-765.
16. Howland J, Rohsenow JD, Edwards EM (2008) Are some drinkers resistant to hangover? A literature review. Curr Drug Abuse Rev 1: 42-46.
17. Kim DJ, Yoon SJ, Lee HP, Choi BM, Go HJ (2003) The effects of alcohol hangover on cognitive functions in healthy subjects. Int J Neurosci 113: 581-594.
18. Kruisselbrink LD, Martin KL, Megeney M, Fowles JR , Murphy RJ (2006) Physical and psychomotor functioning of females the morning after consuming low to moderate quantities of beer. J Stud Alcohol 67: 416–420.
19. Laurell H, Törnros J (1983) Investigation of alcoholic hangover effects on driving performance. Blutalkohol 20: 489–499.
20. Lemon J, Chesher G, Fox A, Greeley J, Nabke C (1993) Investigation of the “hangover” effects of an acute dose of alcohol on psychomotor performance. Alcohol Clin Exp Res 17: 665-668.
21. Mangione TW, Howland J, Amick B, Cote J, Lee M, et al. (1999) Employee Drinking Practices and Work Performance. J Stud Alcohol 60: 261-270.
22. McCaul ME, Turkkan JS, Svikis DS, Bigalow GE (1991) Alcohol and serobarbital effects as a function of familial alcoholism: Extended intoxication and increased withdrawal effects. Alcohol Clin Exp Res 15: 94-101.
23. McKinney A, Coyle K (2004) Next day effects of a normal night’s drinking on memory and psychomotor performance. Alcohol Alcohol 39: 509–513.
24. McKinney A, Coyle K (2006) Alcohol hangover effects on measures of affect the morning after a normal nights drinking. Alcohol and Alcoholism 41: 54– 60.
25. Morrow D, Leirer V, Yesavage J (1990) The influence of alcohol and aging on radio communication during flight. Aviat Space Environ Med 61: 12-20.
26. Morrow D, Leirer V, Yesavage J, Tinklenberg J (1991) Alcohol, age, and piloting: judgment, mood, and actual performance. Int J Addict 26: 669-683.
27. Morrow D, Yesavage J, Leirer V, Dohlert N, Taylor J, et al. (1993) The timecourse of alcohol impairment of general aviation pilot performance in a Frasca 141 simulator. Aviat Space Environ Med 64: 697-705.
28. Myrsten AL, Rydberg U, Idelström CM, Lamble R (1980) Alcohol intoxication and hangover: Modification of hangover by chlormethiazole. Psychopharmacology 69: 117–125.
29. Niaura RS, Nathan PE, Frankenstein W, Shapiro AP, Brick J (1987) Gender differences in acute psychomotor, cognitive, and pharmacokinetic response to alcohol. Addict Behav 12: 345-356.
30. Petros T, Bridewell J, Jensen W, Ferraro FR, Bates JA, et al. (2003) Postintoxication effects of alcohol on flight performance after moderate and high blood alcohol levels. The International Journal of Aviation Psychology 13: 287–300.
31. Prat G, Adan A, Sanchez-Turet M (2009) Alcohol hangover: a critical review of explanatory factors. Hum Psychopharmacol 24: 259-267.
32. Prat G, Adan A, Perez-Pamies M, Sanchez-Turet M (2008) Neurocognitive effects of alcohol hangover. Addict Behav 33: 15-23.
33. Rohsenow DJ, Howland J, Minsky SJ, Arnedt JT (2006) Effects of heavy drinking by maritime academy cadets on hangover, perceived sleep, and next-day ship power plant operation. J Stud Alcohol 67: 406-415.
34. Rohsenow DJ, Howland J, Minsky SJ, Greece J, Almeida A, et al. (2007) The acute hangover scale: A new measure of immediate hangover symptoms. Addict Behav 32: 1314-1320.
35. Rohsenow DJ, Howland J, Arnedt JT, Almeida AB, Greece J, et al. (2010) Intoxication with bourbon versus vodka: Effects on hangover, sleep and nextday neurocognitive performance in young adults. Alcohol Clin Exp Res 34: 509-518.
36. Selzer ML, Vinokur A, Van Rooijen L (1975) A self-administered Short Michigan Alcoholism Screening Test (SMAST). J Stud Alcohol 36: 117-126.
37. Seppälä T, Leino T, Linnoila M, Huttunen M, Ylikahri R (1976) Effects of hangover on psychomotor skills related to driving: Modifi cation by fructose and glucose. Acta Pharmacol Toxicol(copenh) 38: 209–218.
38. Stephens R, Ling J, Heffernan TM, Heather N, Joes K (2008) A review of the literature on the cognitive effects of the alcohol hangover. Alcohol Alcohol 43: 163-170.
39. Streufert S, Pogash R, Braig D, Gingrich D, Kantner A, et al. (1995) Alcohol hangover and managerial effectiveness. Alcohol Clin Exp Res 19: 1141-1146.
40. Swift R, Davidson D (1998) Alcohol hangover: Mechanisms and mediators. Alcohol Health Res World 22: 54-60.
41. Tassi P, Muzet A (2000) Sleep inertia. Sleep Med Rev 4: 341-353.
42. Taylor JL, Dohlert N, Morrow D, Friedman L, Yesavage JA (1994) Acute and 8-hour effects of alcohol (0.08% BAC) on younger and older pilots’ simulator performance. Aviat Space Environ Med 65: 718-725.
43. Taylor JL, Dolhert N, Friedman L, Mumenthaler M, Yesavage JA (1996) Alcohol elimination and simulator performance of male and female aviators: A preliminary report. Aviat Space Environ Med 67: 407-413.
44. Terner JM, deWit H (2006) Menstrual cycle phase and responses to drugs of abuse in humans. Drug Alcohol Depend 84: 1-13.
45. Törnros J, Laurell H (1991) Acute and hang-over effects of alcohol on simulated driving performance. Blutalkohol 28: 24-30.
46. Verster JC, van Duin D, Volkerts ER, Schreude AH, Verbaten MN (2003) Alcohol hangover effects on memory functioning and vigilance performance after an evening of binge drinking. Neuropsychopharmacology 28: 740-746.
47. Verster JC (2008) The alcohol hangover – a puzzling phenomenon. Alcohol Alcohol 43: 124-126.
48. Wiese JG, Shlipak MG, Browner WS (2000) The alcohol hangover. Ann Intern Med 132: 897-902.
49. Wolkenberg R, Gold C, Tichauer E (1975) Delayed effects of acute alcoholic intoxication on performance with reference to work safety. Journal of Safety Research 7: 104-119.
50. Yesavage JA, Leirer VO (1986) Hangover effects on aircraft pilots 14 hours after alcohol ingestion: a preliminary report. Am J Psychiatry 143: 1546- 1550.
51. Yesavage JA, Dolhert N, Taylor JL (1994) Flight simulator performance of younger and older aircraft pilots: effects of age and alcohol. J Am Geriatr Soc 42: 577-582.

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