Relating medial temporal lobe volume to frontal fMRI activation for memory encoding in older adults

Neuroimaging research on the brain basis of memory decline in older adults typically has examined age-related changes either in structure or in function. Structural imaging studies have found that smaller medial temporal lobe (MTL) volumes are associated with lower memory performance. Functional imaging studies have found that older adults often exhibit bilateral frontal-lobe activation under conditions where young adults exhibit unilateral frontal activation. As yet, no one has examined whether these MTL structural and frontal-lobe functional findings are associated. In this study, we tested whether these findings were correlated in a population of healthy older adults in whom we previously demonstrated verbal memory performance was positively associated with left entorhinal cortex volume in the MTL (Rosen et al., 2003) and right frontal lobe activation during memory encoding (Rosen et al., 2002). Thirteen, non-demented, community-dwelling older adults participated both in a functional MRI (fMRI) study of verbal memory encoding and structural imaging. MRI-derived left entorhinal volume was measured on structural images and entered as a regressor against fMRI activation during verbal memory encoding. Right frontal activation (Brodmann's Area 47/insula) was positively correlated with left entorhinal cortex volume. These findings indicate a positive association between MTL volume and right frontal-lobe function that may underlie variability in memory performance among the elderly, and also suggest a two-stage model of memory decline in aging.

Nocturnal sleep apnea/hypopnea is associated with lower memory performance in APOE ε4 carriers

The authors investigated the relationship between obstructive sleep apnea/hypopnea (OSAH) and cognition in 36 older adults, 18 APOE ε4 carriers, and 18 non-carriers. Greater numbers of respiratory events negatively impacted memory function in ε4 carriers only. This is the first study to provide preliminary evidence for a negative interaction of APOE ε4 and OSAH on memory in older adults, which may have important implications for treating cognitive decline and delaying dementia onset.

Underreporting of Behavioral Problems in Older Hospitalized Patients

This descriptive study examined reports of behavioral problems among older patients hospitalized in acute care medical settings. Greater numbers of behavioral problems were reported by nursing staff on the Neuropsychiatric Inventory-Questionnaire than were documented in medical charts over the same time period. Such underreporting may have clinical and administrative implications.

Depression and Obstructive Sleep Apnea (OSA)

For over two decades clinical studies have been conducted which suggest the existence of a relationship between depression and Obstructive Sleep Apnea (OSA). Recently, Ohayon underscored the evidence for a link between these two disorders in the general population, showing that 800 out of 100,000 individuals had both, a breathing-related sleep disorder and a major depressive disorder, with up to 20% of the subjects presenting with one of these disorders also having the other. In some populations, depending on age, gender and other demographic and health characteristics, the prevalence of both disorders may be even higher: OSA may affect more than 50% of individuals over the age of 65, and significant depressive symptoms may be present in as many as 26% of a community-dwelling population of older adults. In clinical practice, the presence of depressive symptomatology is often considered in patients with OSA, and may be accounted for and followed-up when considering treatment approaches and response to treatment. On the other hand, sleep problems and specifically OSA are rarely assessed on a regular basis in patients with a depressive disorder. However, OSA might not only be associated with a depressive syndrome, but its presence may also be responsible for failure to respond to appropriate pharmacological treatment. Furthermore, an undiagnosed OSA might be exacerbated by adjunct treatments to antidepressant medications, such as benzodiazepines. Increased awareness of the relationship between depression and OSA might significantly improve diagnostic accuracy as well as treatment outcome for both disorders. In this review, we will summarize important findings in the current literature regarding the association between depression and OSA, and the possible mechanisms by which both disorders interact. Implications for clinical practice will be discussed.

Cognitive ability, expertise, and age differences in following air-traffic control instructions

Differences in cognitive ability and domain-specific expertise may help explain age differences in pilot performance. Pilots heard air-traffic controller messages and then executed them while "flying" in a simulator. Messages varied in length and speech rate. Age was associated with lower accuracy, but the expected Age x Message Difficulty interactions were not obtained. Expertise, as indexed by pilot ratings, was associated with higher accuracy; yet expertise did not reduce age differences in accuracy. The effect of age on communication task accuracy was largely explainable as an age-associated decrease in working memory span, which in turn was explainable as decreases in both speed and interference control. Results are discussed within frameworks of deliberate practice and cognitive mediation of age differences.

THE EFFECT OF OXYBUTYNIN TREATMENT ON COGNITION IN CHILDREN WITH DIURNAL INCONTINENCE

PURPOSE

Oxybutynin is a powerful anticholinergic drug already known to impair cognition in the elderly. The impact of this drug on cognitive functioning in the pediatric population is unknown. We report the results of a study designed to assess the effect of oxybutynin on cognitive function in children.

MATERIALS AND METHODS

A total of 25 patients presenting with the primary symptom of daytime enuresis were recruited for this nonrandomized trial. All subjects initially received 4 weeks of behavior modification, followed by an additional 4 weeks of behavior modification either alone or with oxybutynin for continued treatment of enuresis. Neuropsychological testing was performed at baseline (4 weeks) and after additional therapy (8 weeks).

RESULTS

Patient demographics included a male-to-female ratio of 11:14 and a mean age of 7.2 +/- 1.8 years. A total of 10 patients were assigned to the control group receiving behavior modification, and 15 patients were assigned to the treatment group receiving behavior modification plus oxybutynin. The oxybutynin treated patients had a lower overall performance at baseline pretreatment testing. However, performance in this group improved following treatment with oxybutynin.

CONCLUSIONS

Oxybutynin, a commonly used pharmacological agent in pediatric urology, was not associated with cognitive impairment following treatment. However, we observed lower baseline cognitive functioning in patients whose parents chose oxybutynin over behavior modification alone. This finding may represent a selection bias. However, it also supports the need for a multidisciplinary approach to the treatment of patients with dysfunctional voiding, as some may have cognitive difficulties that have not previously been explored.

Completion of the sequence analysis and comparisons of genome segment 2 (encoding outer capsid protein VP2) from representative isolates of the 24 bluetongue virus serotypes

Bluetongue (BT) is a non-contagious, arthropod-transmitted viral disease of domestic and wild ruminants. It is caused by bluetongue virus (BTV), a double-stranded (ds) RNA virus that is classified within the genus Orbivirus, family Reoviridae. There are at least twenty-four serotypes of BTV worldwide, five of which (1, 2, 4, 9 and 16) have been identified recently in Europe. BTV infects ruminants and its distribution throughout temperate and tropical regions of the world is dependent on the activity and abundance of certain vector-competent species of Culicoides midge. The outer capsid protein VP2 of BTV is a major protective antigen and the primary determinant of virus serotype. For the first time, the authors have completed the sequence analysis of full-length VP2 genes from the reference strains of each of the 24 BTV serotypes and their amino acid sequences were deduced. Multiple alignment of the VP2 gene (protein) sequences revealed that the level of nucleotide (amino acid) sequence variation between serotypes ranged from 29% (23%) to 59% (73%), confirming that segment 2/VP2 is the most variable BTV gene/protein. Phylogenetic analysis of VP2 grouped together the BTV types that are known to cross-react serologically. Low identity between types was demonstrated for specific regions within the VP2 amino acid sequences that have been shown to be antigenic and play a role in virus neutralisation. The sequence data represent the completion of an important step in the creation of a comprehensive BTV sequence database, which will support more rapid molecular methods for diagnosis and identification of BTV 'types', as well as continuing molecular epidemiology and surveillance studies of BTV.

Sleep/wake disruption in Alzheimer's disease: APOE status and longitudinal course

Disturbed sleep is a major clinical problem in Alzheimer's disease (AD). Apolipoprotein epsilon4 (APOE epsilon4) carrier status may increase risk of AD, yet there are no data on relations between APOE status and progression of sleep disturbance in AD. The objective of this study was to determine if sleep parameters in AD patients change over time as a function of APOE carrier status. Forty-four community-dwelling AD patients with diagnosis of probable AD were followed from early stages of disease. Their sleep/wake parameters were compared according to APOE status. For APOE epsilon4 carriers, only wake after sleep onset (WASO) increased in association with lower cognitive function as indicated by the Mini-Mental State Examination (MMSE); for non-epsilon4 subjects, increases in WASO and declines in total sleep time, sleep efficiency, and the amplitude of the rest/activity circadian rhythm over time were associated with lower performance on the MMSE. In these data, APOE status was associated with the progression of sleep/wake disturbances in AD. Overall, there was greater deterioration on sleep parameters in patients negative for the epsilon4 allele.

Use of a VA pharmacy database to screen for areas at high risk for disease: Parkinson's disease and exposure to pesticides

The purpose of this study was to assess whether pharmacy database information from US Department of Veterans Affairs (VA) medical centers could be used to screen for areas of higher Parkinson's disease prevalence in patients exposed to pesticides. The authors used pharmacy data sets and compared the use of antiparkinsonian medications at 2 VA medical centers in California: one in Palo Alto, near the ocean, and one in Fresno, downwind from extensively farmed parts of the Central Valley. They found that patients at Fresno had higher odds ratios (1.5-1.8) for the use of Parkinson's disease medications than patients at Palo Alto. These data are consistent with the observations of prior epidemiologic studies and suggest that VA pharmacy databases can prioritize locations for further epidemiologic research. However, a thorough exploration of alternative explanations is needed to reach definitive conclusions regarding the findings suggested by this method.

Differential associations between entorhinal and hippocampal volumes and memory performance in older adults

Magnetic resonance imaging-derived entorhinal and hippocampal volumes were measured in 14 nondemented, community-dwelling older adults. Participants were selected so that memory scores from 2 years prior to scanning varied widely but were not deficient relative to age-appropriate norms. A median split of these memory scores defined high-memory and low-memory groups. Verbal memory scores at the time of imaging were lower, and entorhinal and hippocampal volumes were smaller, in the low-memory group than in the high-memory group. Left entorhinal cortex volume showed the strongest correlation (r= .79) with immediate recall of word lists. Left hippocampal volume showed the strongest correlation (r= .57) with delayed paragraph recall. These results suggest that entorhinal and hippocampal volumes are related to individual differences in dissociable kinds of memory performance among healthy older adults.

Categorical versus dimensional approaches to diagnosis: methodological challenges

The arguments pitting categorical versus dimensional approaches to psychiatric diagnosis have been long ongoing with little sign of imminent resolution. We argue that categorical and dimensional approaches are fundamentally equivalent, but that one or other approach is more appropriate depending on the clinical circumstances and research questions being addressed. This paper aims to demonstrate (a) how these two approaches necessarily interdigitate, (b) to clarify the conditions under which one should utilize one approach over the other, and (c) to alert psychiatric clinicians and researchers to issues in the methodology literature that might facilitate their considerations. Using an example from the Infant Health and Development Program (IHDP), we illustrate the importance of using dimensional approaches for hypothesis testing, identify the problems with power and with interpretation that arise from employing a categorical approach, and underscore the importance of identifying the appropriate cutpoints when a categorical approach is necessitated. We argue that failure to utilize the correct approach under the appropriate circumstances can result in impaired clinical and research decision-making.

Unipolar late-onset depression: A comprehensive review

Background

The older population increases all over the world and so also does the number of older psychiatric patients, which manifest certain specific and unique characteristics. The aim of this article is to provide a comprehensive review of the international literature on unipolar depression with onset at old age.

Methods

The authors reviewed several pages and books relevent to the subject but did not search the entire literature because of it's overwhelming size. They chose to review those considered most significant.

Results

The prevalence of major depression is estimated to be 2% in the general population over 65 years of age. The clinical picture of geriatric depression differs in many aspects from depression in younger patients. It is not yet clear whether it also varies across cultures and different socio-economic backgrounds. Biological data suggest that it is associated with an increased severity of subcortical vascular disease and greater impairment of cognitive performance. Many authors consider the existence of a somatic disorder to be related to the presence of depression in late life, even constituting a negative prognostic factor for the outcome of depression. Most studies support the opinion that geriatric depression carries a poorer prognosis than depression in younger patients. The therapeutic intervention includes pharmacotherapy, mainly with antidepressants, which is of established value and psychotherapy which is not equally validated.

Conclusion

A significant number of questions regarding the assessment and treatment of geriatric depression remain unanswered, empirical data are limited, and further research is necessary.

Age and disease severity predict choice of atypical neuroleptic: a signal detection approach to physicians' prescribing decisions

OBJECTIVE

We used a novel application of a signal detection technique, receiver operator characteristics (ROC), to describe factors entering a physician's decision to switch a patient from a typical high potency neuroleptic to a particular atypical, olanzapine (OLA) or risperidone (RIS).

METHODS

ROC analyses were performed on pharmacy records of 476 VA patients who had been treated on a high potency neuroleptic then changed to either OLA or RIS.

RESULTS

Overall 68% patients switched to OLA and 32% to RIS. The best predictor of neuroleptic choice was age at switch, with 78% of patients aged less than 55 years receiving OLA and 51% of those aged greater than or equal to 55 years receiving OLA (chi(2)=38.2, P<0.001). Further analysis of the former group indicated that adding the predictor of one or more inpatient days to age increased the likelihood of an OLA switch from 78% to 85% (chi(2)=7.3, P<0.01) while further analysis of the latter group indicated that adding the predictor of less than 10 inpatients days to age decreased the likelihood of an OLA switch from 51% to 45% (chi(2)=7.0, P<0.01).

CONCLUSIONS

ROC analyses have the advantage over other analyses, such as regression techniques, insofar as their "cut-points" are readily interpretable, their sequential use forms an intuitive "decision tree" and allows the potential identification of clinically relevant "subgroups". The software used in this analysis is in the public domain (http://mirecc.stanford.edu).

Psychoactive drugs and pilot performance: a comparison of nicotine, donepezil, and alcohol effects

The cholinergic system plays a major role in cognitive abilities that are essential to piloting an aircraft: attention, learning, and memory. In previous studies, drugs that enhance the cholinergic system through different pharmacologic mechanisms have shown beneficial effects on cognition; but dissimilar cognitive measures were used and samples were not comparable. A comparison within the same cognitive tasks, within comparable samples appears desirable. Toward this aim, we compared effect sizes (ES) of performance-enhancing doses of nicotine (a nicotinic receptor agonist) and donepezil (an acetylcholinesterase inhibitor) as found in our prior work on pilot performance. We also compared cholinergic ES to those of performance-impairing doses of alcohol. In three randomized, placebo-controlled trials, we assessed the flight performance of aircraft pilots in a Frasca 141 simulator, testing I: the acute effects of nicotine gum 2 mg; II: the effects of administration of 5 mg donepezil/day for 30 days; and III: the acute and 8 h-carryover effects of alcohol after a target peak BAC of 0.10%. We calculated the ES of nicotine, donepezil, and alcohol on a flight summary score and on four flight component scores. Compared to placebo, nicotine and donepezil significantly improved, while alcohol significantly impaired overall flight performance: ES (nicotine)=0.80; ES (donepezil)=1.02; ES (alcohol acute)=-3.66; ES (alcohol 8 h)=-0.82. Both cholinergic drugs showed the largest effects on flight tasks requiring sustained visual attention. Although the two tested cholinergic drugs have different pharmacologic mechanisms, their effects on flight performance were similar in kind and size. The beneficial effects of the cholinergic drugs on overall flight performance were large and the absolute (ie nondirectional) sizes were about one-fourth of the absolute ES of acute alcohol intoxication and roughly the same as the absolute 8 h-carryover ES of alcohol.

Which Alzheimer patients are at risk for rapid cognitive decline?

In the current study of 1062 Alzheimer's disease (AD) patients, we employed receiver operating characteristic curve analysis to identify characteristics of patients at increased risk for rapid cognitive decline. The patients are participants at one of the nine Alzheimer's Disease Research Centers of California. Rapid decline was defined as a 3-point or greater loss on the Mini-Mental State Examination (MMSE) per year, post visit. The independent variables were age at clinic visit, age at symptom onset of AD, MMSE at patient visit, years of education, gender, ethnicity, living arrangement, presence of aphasia, delusions, hallucinations, and extrapyramidal signs. Receiver operating characteristic curve analysis indicated that AD patients presenting with moderate to severe aphasia, age at clinic visit of 75 years or less, and an MMSE greater than 7 were at increased risk for rapid cognitive decline. This information could help clinicians target these patients for pharmacologic interventions, facilitate long-term care planning, and potentially create savings by delaying or stabilizing the course of the disease.

The role of transferrin saturation as a screening test for hereditary haemochromatosis in an Irish population seeking medical care

BACKGROUND

Genetic studies have indicated a high prevalence of mutations for hereditary haemochromatosis (HH) in Irish populations. Given the high cost of genetic screening and the ethical implications thereof, we assessed the role of transferrin saturation (TS) as a primary screening test for HH in an Irish population seeking medical care.

METHODS

TS and ferritin were measured on 330 consecutive blood specimens received in the laboratory for routine screening. Patients with TS > 45% were genetically screened for the C282Y and H63D mutations.

RESULTS

Twenty-six patients had TS values > 45%. Of these, specimens were available for genetic screening on 20 patients. Three previously undiagnosed patients were found to be C282Y homozygotes and one a compound heterozygote (C282Y/H63D). The prevalence of C282Y homozygotes was 0.93%, which is similar to the reported prevalence found in Irish populations by genetic screening.

CONCLUSION

Given the number of positive findings in this study, we conclude that, in the absence of a national programme, TS could be used as part of a health-screening panel in the Irish setting. Patients expressing iron overload would be detected before organ damage occurred, leading to less severe clinical disease and better patient prognosis.

Variable effects of aging on frontal lobe contributions to memory

Declarative memory declines with age, but there is profound variation in the severity of this decline. Healthy elderly adults with high or low memory scores and young adults viewed words under semantic or non-semantic encoding conditions while undergoing fMRI. Young adults had superior memory for the words, and elderly adults with high memory scores had better memory for the words than those with low memory scores. The elderly with high scores had left lateral and medial prefrontal activations for semantic encoding equal to the young, and greater right prefrontal activation than the young. The elderly with low scores had reduced activations in all three regions relative to the elderly with high memory scores. Thus, successful aging was characterized by preserved left prefrontal and enhanced right prefrontal activation that may have provided compensatory encoding resources.

Cognitive and physiologic correlates of subclinical structural brain disease in elderly healthy control subjects

CONTEXT

Healthy elderly persons commonly show 4 types of change in brain structure-cortical atrophy, central atrophy, deep white-matter hyperintensities, and periventricular hyperintensities-as forms of subclinical structural brain disease (SSBD).

OBJECTIVES

To characterize the volumes of SSBD present with aging and to determine the associations of SSBD, physiology, and cognitive function.

DESIGN

Cross-sectional study.

SETTING

University of California, Los Angeles, Neuropsychiatric Institute.

SUBJECTS

Forty-three community-dwelling healthy control subjects, aged 60 through 93 years.

MAIN OUTCOME MEASURES

Volumetric magnetic resonance imaging, neuropsychological testing, and quantitative electroencephalographic coherence (functional connectivity) between brain regions.

RESULTS

Regression models demonstrated significant relationships between SSBD volumes, age, cognitive performance, and connectivity. Cortical and central atrophy and periventricular hyperintensities had significant associations with age while deep white-matter hyperintensities did not. Posterior atrophy showed stronger associations with age than did anterior atrophy. Only a subset of subjects at older ages showed large SSBD volumes; older subjects primarily showed increasing variance of SSBD. Although all subjects scored within the normal range on cognitive testing, SSBD volume was inversely related to performance, most notably on the Trail-Making Test part B and the Shipley-Hartford Abstract Reasoning test. Coherence had significant associations with SSBD. Path analysis supported mediation of the effects of deep white-matter hyperintensities and periventricular hyperintensities on cognition by altered connectivity. For several measures, cognitive performance was best explained by coherence, and only secondarily by SSBD.

CONCLUSIONS

Modest volumes of SSBD were associated with decrements in cognitive performance within the normal range in healthy subjects. Lower coherence was associated with greater volumes of SSBD and increasing age. Path analysis models suggest that brain functional connectivity mediates some effects of SSBD on cognition.

Cognitive status and behavioral problems in older hospitalized patients

OBJECTIVES: (a) To determine the quantity and quality of behavioral problems in older hospitalized patients on acute care units; (b) to determine the burden of these behaviors on staff; and (c) to identify predictors of behavioral problems. METHODS: Upon admission, patients performed the Mini-Mental State Exam (MMSE), the Geriatric Depression Scale (GDS), and information was obtained on age, ethnicity, level of education, living arrangement, and psychiatric history. Two days post-admission, a clinical staff member caring for each patient, performed the Neuropsychiatric Inventory-Questionnaire (NPI-Q) to assess patients' behavioral problems and staff distress. PARTICIPANTS AND SETTING : Forty-two patients, over 60 years of age, admitted to medical and surgical units of the Veterans Affairs Hospitals in Palo Alto and San Francisco, participated. RESULTS: Twenty-three of 42 (55%) patients exhibited behavioral problems. Anxiety, depression, irritability, and agitation/aggression were the most frequently observed behaviors. The severity of the behavioral problems was significantly correlated with staff distress. Lower performance on the MMSE at admission was significantly associated with higher NPI-Q ratings. Specifically, of those cases with scores less than or equal to 27 on the MMSE, 66% had behavioral problems during hospitalization, compared to only 31% of those with scores greater than 27. CONCLUSION: Behavioral problems in older hospitalized patients appear to occur frequently, are a significant source of distress to staff, and can result in the need for psychiatric consultation. Assessment of the mental status of older adults at admission to hospital may be valuable in identifying individuals at increased risk for behavioral problems during hospitalization.

Modeling the prevalence and incidence of Alzheimer's disease and mild cognitive impairment

A number of systems have been proposed for classifying older adults who suffer from cognitive impairment or decline but do not yet meet criteria for Alzheimer's disease (AD). The classification, Mild Cognitive Impairment (MCI), has attracted much attention. It uses relatively specific diagnostic criteria and individuals who meet these criteria appear to be at substantial risk for the development of AD. However, little data is available to define the prevalence of MCI in any age group. We propose a simple mathematical model for the progression of patients from Non-Affected (NA) to MCI to AD. This first-order Markov model defines the likely prevalence of MCI at specific ages. Primary assumptions of the model include an AD prevalence of 1% at age 60 increasing to 25% at age 85 and a conversion rate from MCI to AD of 10% constant across all ages considered. We used the best available information for our model and found (1) that the MCI prevalence increased from 1% at age 60 to 42% at age 85 and (2) that the conversion rate from NA to MCI increased from 1% per year at age 60 to 11% at age 85. In conclusion, this model allows estimation of prevalence of MCI and conversion from NA to MCI based upon known prevalences of AD, conversion rates of MCI to AD, and death rates. Due to its substantial prevalence, MCI may be an important target for screening and possible intervention.

Donepezil and flight simulator performance: effects on retention of complex skills

We report a randomized, double-blind, parallel group, placebo-controlled study to test the effects of the acetylcholinesterase inhibitor, donepezil (5 mg/d for 30 days), on aircraft pilot performance in 18 licensed pilots with mean age of 52 years. After 30 days of treatment, the donepezil group showed greater ability to retain the capacity to perform a set of complex simulator tasks than the placebo group, p < 0.05. Donepezil appears to have beneficial effects on retention of training on complex aviation tasks in nondemented older adults.

Apolipoprotein E epsilon4 allele affects the relationship between stress and depression in caregivers of patients with Alzheimer's disease

We examined the effect of the apolipoprotein E (apo E) epsilon4 allele on the relationship between self-reported stress and mood in caregivers of patients with Alzheimer's disease. Eighty-six female subjects between the ages of 28 and 82 years who were community-dwelling AD patient caregivers participated in the study. A cross-sectional analysis of stress and mood was performed using the Revised Memory and Behavior Problem Checklist and the Geriatric Depression Scale. All subjects were evaluated for normal cognitive function (Mini-Mental Status Examination) and apo E genotype. The results indicated that increased levels of stress were associated with increased levels of depressive symptoms in nondemented caregivers with the epsilon4 allele. This relationship was not observed in caregivers without the epsilon4 allele. These results suggest that carriers of the epsilon4 allele may respond differently to psychological stress than do individuals without the epsilon4 allele.

Therapeutic approaches to age-associated neurocognitive disorders

The United Nations projects that the number of individuals with dementia in developed countries alone will be approximately 36,7 million by the year 2050. International recognition of the significant emotional and economic burden of Alzheimer's disease has been matched by a dramatic increase in the development of pharmacological and nonpharmacological approaches to this illness in the past decade. Changing demographics have underscored the necessity to develop similar approaches for the remediation of the cognitive impairment associated with more benign syndromes, such as mild cognitive impairment (MCI) and age-associated cognitive decline (AACD). The present article aims to provide an overview of the most current therapeutic approaches to age-associated neurocognitive disorders. Additionally, it discusses the conceptual and methodological issues that surround the design, implementation, and interpretation of such approaches.

Influence of the menstrual cycle on flight simulator performance after alcohol ingestion

OBJECTIVE

Previous studies investigating the influence of the menstrual cycle on cognitive functioning of women after alcohol ingestion have obtained inconsistent results. The present study tested the hypothesis that flight simulator performance during acute alcohol intoxication and 8 hours after drinking differs between the menstrual and the luteal phase of the menstrual cycle.

METHOD

White female pilots (N = 24) were tested during the menstrual and the luteal phases of their menstrual cycles. On each test day they performed a baseline simulator flight, consumed 0.67 g/kg ethanol, and performed an acute-intoxication and an 8-hour-carryover simulator flight.

RESULTS

Subjects reached highly significant increases in estradiol (E2) as well as progesterone (P) levels during the luteal test day. Yet, there were no significant differences in overall flight performance after alcohol ingestion between the menstrual and luteal phases during acute intoxication or at 8-hour carryover. We found no correlations between E, or P levels and overall flight performance. However, there was a statistically significant Phase x Order interaction: Pilots who started the experiment with their menstrual day were less susceptible to the effects of alcohol during the second test day than were pilots who started with their luteal day.

CONCLUSIONS

The tested menstrual cycle phases and varying E2 and P levels did not significantly influence postdrink flight performance. Because the present study included a comparatively large sample size and because it involved complex "real world" tasks (piloting an aircraft), we believe that the present findings are important. We hope that our failure to detect menstrual cycle effects will encourage researchers to include women in their investigations of alcohol effects and human performance.