Regional cerebral blood flow in chronic alcoholics measured by single photon emission computerized tomography

Research progress on risk factors related to intracranial artery, carotid artery, and coronary artery stenosis

In recent decades, with the rapid development of economy, the acceleration of social aging and urbanization, and the prevalence of unhealthy lifestyles, the number of patients with cardiovascular and cerebrovascular diseases has shown an increasing trend year by year. It has also become one of the important causes of disability and death in all ages and groups. Atherosclerosis is the main pathological change of ischemic cardiovascular and cerebrovascular diseases, which mainly invades the large and medium arteries of the body circulation. In particular, cerebral artery and coronary artery lesions have the most significant impact on life. There is the same pathogenic mechanism between intracranial and extracranial arteries and coronary atherosclerosis, so there is a certain relationship between the degree of atherosclerosis. In this paper, the risk factors related to intracranial and extracranial arteries and coronary artery stenosis were reviewed. It provides a theoretical basis for early detection, early diagnosis and early treatment of intracranial and extracranial artery and coronary artery stenosis to reduce the occurrence and development of cardiovascular and cerebrovascular diseases.

Changes in Hemodynamic Response Function Resulting From Chronic Alcohol Consumption

BACKGROUND

Functional MRI (fMRI) task-related analyses rely on an estimate of the brain's hemodynamic response function (HRF) to model the brain's response to events. Although changes in the HRF have been found after acute alcohol administration, the effects of heavy chronic alcohol consumption on the HRF have not been explored, and the potential benefits or pitfalls of estimating each individual's HRF on fMRI analyses of chronic alcohol use disorder (AUD) are not known.

METHODS

Participants with AUD and controls (CTL) received structural, functional, and vascular scans. During fMRI, participants were cued to tap their fingers, and averaged responses were extracted from the motor cortex. Curve fitting on these HRFs modeled them as a difference between 2 gamma distributions, and the temporal occurrence of the main peak and undershoot of the HRF was computed from the mean of the first and second gamma distributions, respectively.

RESULTS

ANOVA and regression analyses found that the timing of the HRF undershoot increased significantly as a function of total lifetime drinking. Although gray matter volume in the motor cortex decreased with lifetime drinking, this was not sufficient to explain undershoot timing shifts, and vascular factors measured in the motor cortex did not differ among groups. Comparison of random-effects analyses using custom-fitted and canonical HRFs for CTL and AUD groups showed better results throughout the brain for custom-fitted versus canonical HRFs for CTL subjects. For AUD subjects, the same was true except for the basal ganglia.

CONCLUSIONS

These findings suggest that excessive alcohol consumption is associated with changes in the HRF undershoot. HRF changes could provide a possible biomarker for the effects of lifetime drinking on brain function. Changes in HRF topography affect fMRI activation measures, and subject-specific HRFs generally improve fMRI activation results.

Regional cerebral blood flow in opiate dependence relates to substance use and neuropsychological performance

Neuroimaging of opiate-dependent individuals indicates both altered brain structure and function. Magnetic resonance-based arterial spin labeling has been used to measure noninvasively cerebral blood flow (i.e. perfusion) in alcohol, tobacco and stimulant dependence; only one arterial spin labeling paper in opiate-dependent individuals demonstrated frontal and parietal perfusion deficits. Additional research on regional brain perfusion in opiate dependence and its relationship to cognition and self-regulation (impulsivity, risk taking and decision making) may inform treatment approaches for opiate-dependent individuals. Continuous arterial spin labeling magnetic resonance imaging at 4 T and neuropsychological measures assessed absolute brain perfusion levels, cognition and self-regulation in 18 cigarette smoking opiate-dependent individuals (sODI) stable on buprenorphine maintenance therapy. The sODI were compared with 20 abstinent smoking alcohol-dependent individuals (a substance-dependent control group), 35 smoking controls and 29 nonsmoking controls. sODI had lower perfusion in several cortical and subcortical regions including regions within the brain reward/executive oversight system compared with smoking alcohol-dependent individuals and nonsmoking controls. Perfusion was increased in anterior cingulate cortex and globus pallidus of sODI. Compared with all other groups, sODI had greater age-related declines in perfusion in most brain reward/executive oversight system and some other regions. In sODI, lower regional perfusion related to greater substance use, higher impulsivity and weaker visuospatial skills. Overall, sODI showed cortical and subcortical hypoperfusion and hyperperfusion. Relating to neuropsychological performance and substance use quantities, the frontal perfusion alterations are clinically relevant and constitute potential targets for pharmacological and cognitive-based therapeutic interventions to improve treatment outcome in opiate dependence.

Brain perfusion in polysubstance users: relationship to substance and tobacco use, cognition, and self-regulation

BACKGROUND

Brain perfusion is altered in both alcohol dependence and stimulant dependence. Although most substance users also abuse/depend on alcohol concurrently (polysubstance users; PSU), rigorous perfusion research in PSU is limited. Also, the relationships of perfusion abnormalities with cognition, impulsivity, or decision making are not well known.

METHODS

Arterial spin labeling MRI and neuropsychological measures assessed perfusion levels and neurocognition in 20 alcohol-dependent individuals with comorbid-stimulant dependence (PSU), 26 individuals dependent on alcohol only (ALC), and 31 light/non-drinking controls (LD). The patient groups included smokers and non-smokers.

RESULTS

ALC had lower perfusion than LD in subcortical and cortical brain regions including the brain reward/executive oversight system (BREOS). Contrary to our hypothesis, regional perfusion was generally not lower in PSU than ALC. However, smoking PSU had lower perfusion than smoking ALC in several regions, including BREOS. Lower BREOS perfusion related to greater drinking severity in smoking substance users and to greater smoking severity in smoking ALC. Lower regional perfusion in ALC and PSU correlated with worse performance in different cognitive domains; smoking status affected perfusion-cognition relationships in ALC only. Lower BREOS perfusion in both substance using groups related to higher impulsivity.

CONCLUSION

Although regional perfusion was not decreased in PSU as a group, the combination of cigarette smoking and polysubstance use is strongly related to hypoperfusion in important cortical and subcortical regions. As lower perfusion relates to greater smoking severity, worse cognition and higher impulsivity, smoking cessation is warranted for treatment-seeking PSU and ALC.

Alcohol-induced psychotic disorder: a review

While alcohol-induced psychotic disorder (AIPD) is well recognised, relatively little is known about the condition. We undertook a review of the literature to identify studies on the epidemiology, clinical manifestations, underlying neurobiology and treatment of AIPD. Few prospective studies have been conducted on AIPD. Recent advances have focussed on epidemiological, phenomenological, neuro-imaging, treatment and outcome issues. Current evidence suggests AIPD can be clinically distinguished from alcohol-withdrawal delirium and schizophrenia. The disorder may be more common than previously recognised depending on the inclusion criteria applied. AIPD is associated with high co-morbidity with other psychiatric disorders, high re-hospitalization and mortality rates and suicidal behaviour. Concurrent dysregulation of several neurotransmitter systems may be involved in the pathogenesis of hallucinations in alcohol dependence, and neuro-imaging studies suggest perfusion abnormalities to various brain regions. Antipsychotic treatment remains the preferred treatment for AIPD. The prognosis appears less favourable than previously believed, yet usually good when abstinence can be maintained.

Effects of L-glutamine supplementation on maternal and fetal hemodynamics in gestating ewes exposed to alcohol

Not much is known about effects of gestational alcohol exposure on maternal and fetal cardiovascular adaptations. This study determined whether maternal binge alcohol exposure and L-glutamine supplementation could affect maternal-fetal hemodynamics and fetal regional brain blood flow during the brain growth spurt period. Pregnant sheep were randomly assigned to one of four groups: saline control, alcohol (1.75-2.5 g/kg body weight), glutamine (100 mg/kg body weight) or alcohol + glutamine. A chronic weekend binge drinking paradigm between gestational days (GD) 99 and 115 was utilized. Fetuses were surgically instrumented on GD 117 ± 1 and studied on GD 120 ± 1. Binge alcohol exposure caused maternal acidemia, hypercapnea, and hypoxemia. Fetuses were acidemic and hypercapnic, but not hypoxemic. Alcohol exposure increased fetal mean arterial pressure, whereas fetal heart rate was unaltered. Alcohol exposure resulted in ~40 % reduction in maternal uterine artery blood flow. Labeled microsphere analyses showed that alcohol induced >2-fold increases in fetal whole brain blood flow. The elevation in fetal brain blood flow was region-specific, particularly affecting the developing cerebellum, brain stem, and olfactory bulb. Maternal L-glutamine supplementation attenuated alcohol-induced maternal hypercapnea, fetal acidemia and increases in fetal brain blood flow. L-Glutamine supplementation did not affect uterine blood flow. Collectively, alcohol exposure alters maternal and fetal acid-base balance, decreases uterine blood flow, and alters fetal regional brain blood flow. Importantly, L-glutamine supplementation mitigates alcohol-induced acid-base imbalances and alterations in fetal regional brain blood flow. Further studies are warranted to elucidate mechanisms responsible for alcohol-induced programming of maternal uterine artery and fetal circulation adaptations in pregnancy.

Neuroimaging in Alcohol and Drug Dependence

Neuroimaging, including PET, MRI, and MRS, is a powerful approach to the study of brain function. This article reviews neuroimaging findings related to alcohol and other drugs of abuse that have been published since 2011. Uses of neuroimaging are to characterize patients to determine who will fare better in treatment and to investigate the reasons underlying the effect on outcomes. Neuroimaging is also used to characterize the acute and chronic effects of substances on the brain and how those effects are related to dependence, relapse, and other drug effects. The data can be used to provide encouraging information for patients, as several studies have shown that long-term abstinence is associated with at least partial normalization of neurological abnormalities.

Molecular and neurologic responses to chronic alcohol use

This chapter provides an overview of current knowledge on the molecular and clinical aspects of chronic alcohol effects on the central nervous system. This drug is almost ubiquitous, widely enjoyed socially, but produces a diverse spectrum of neurologic disease when abused. Acutely, alcohol interacts predominantly with γ-aminobutyric acid-A (GABA-A) and N-methyl-d-aspartate (NMDA) receptors, but triggers diverse signaling events within well-defined neural pathways. These events result in adaptive changes in gene expression that ultimately produce two major states: addiction and toxicity. Epigenetic modifications of chromatin could lead to long-lived or even transgenerational changes in gene expression, thus producing aspects of the heritability of alcohol use disorders (AUD) and long-term behaviors such as recidivism. The diverse clinical syndromes produced by chronic alcohol actions in the central nervous system reflect the molecular pathology and predominantly involve aspects of tolerance/withdrawal, selective vulnerability (manifest as central pontine myelinolysis, Marchiafava-Bignami disease), and additional environmental factors (e.g., thiamine deficiency in Wernicke-Korsakoff's syndrome). Additionally, deleterious aspects of chronic alcohol on signaling, synaptic transmission, and cell toxicity lead to primary alcoholic dementia. Genetically determined aspects of myelin structure and alcohol actions on myelin gene expression may be a prominent molecular mechanism resulting in a predisposition to, or causation of, AUD and multiple other neurologic complications of chronic alcohol. The dramatic progress made in understanding molecular actions of alcohol holds great promise for our eventual treatment or prevention of AUD and neurologic complications resulting from chronic alcohol abuse.

Brain docosahexaenoic acid [DHA] incorporation and blood flow are increased in chronic alcoholics: a positron emission tomography study corrected for cerebral atrophy

OBJECTIVE

Chronic alcohol dependence has been associated with disturbed behavior, cerebral atrophy and a low plasma concentration of docosahexaenoic acid (DHA, 22∶6n-3), particularly if liver disease is present. In animal models, excessive alcohol consumption is reported to reduce brain DHA concentration, suggesting disturbed brain DHA metabolism. We hypothesized that brain DHA metabolism also is abnormal in chronic alcoholics.

METHODS

We compared 15 non-smoking chronic alcoholics, studied within 7 days of their last drink, with 22 non-smoking healthy controls. Using published neuroimaging methods with positron emission tomography (PET), we measured regional coefficients (K*) and rates (J(in)) of DHA incorporation from plasma into the brain of each group using [1-(11)C]DHA, and regional cerebral blood flow (rCBF) using [(15)O]water. Data were partial volume error corrected for brain atrophy. Plasma unesterified DHA concentration also was quantified.

RESULTS

Mean K* for DHA was significantly and widely elevated by 10-20%, and rCBF was elevated by 7%-34%, in alcoholics compared with controls. Unesterified plasma DHA did not differ significantly between groups nor did whole brain J(in), the product of K* and unesterified plasma DHA concentration.

DISCUSSION

Significantly higher values of K* for DHA in alcoholics indicate increased brain avidity for DHA, thus a brain DHA metabolic deficit vis-à-vis plasma DHA availability. Higher rCBF in alcoholics suggests increased energy consumption. These changes may reflect a hypermetabolic state related to early alcohol withdrawal, or a general brain metabolic change in chronic alcoholics.

A selective insular perfusion deficit contributes to compromised salience network connectivity in recovering alcoholic men

BACKGROUND

Alcoholism can disrupt neural synchrony between nodes of intrinsic functional networks that are maximally active when resting relative to engaging in a task, the default mode network (DMN) pattern. Untested, however, are whether the DMN in alcoholics can rebound normally from the relatively depressed task state to the active resting state and whether local perfusion deficits could disrupt network synchrony when switching from conditions of rest to task to rest, thereby indicating a physiological mechanism of neural network adaptation capability.

METHODS

Whole-brain, three-dimensional pulsed-continuous arterial spin labeling provided measurements of regional cerebral blood flow (CBF) in 12 alcoholics and 12 control subjects under three conditions: pretask rest, spatial working-memory task, and posttask rest.

RESULTS

With practice, alcoholics and control subjects achieved similar task accuracy and reaction times. Both groups exhibited a high-low-high pattern of perfusion levels in DMN regions during the rest-task-rest runs and the opposite pattern in posterior and cerebellar regions known to be associated with spatial working memory. Alcoholics showed selective differences from control subjects in the rest-task-rest CBF pattern in the anterior precuneus and CBF level in the insula, a hub of the salience network. Connectivity analysis identified activation synchrony from an insula seed to salience nodes (parietal, medial frontal, anterior cingulate cortices) in control subjects only.

CONCLUSIONS

We propose that attenuated insular CBF is a mechanism underlying compromised connectivity among salience network nodes. This local perfusion deficit in alcoholics has the potential to impair ability to switch from cognitive states of interoceptive cravings to cognitive control for curbing internal urges.

Resting brain perfusion in alcohol-induced psychotic disorder: a comparison in patients with alcohol dependence, schizophrenia and healthy controls

INTRODUCTION

Alcohol-induced psychotic disorder (AIPD), also known as alcohol hallucinosis, is a rare complication of alcohol abuse. The underlying pathophysiology is poorly understood, and the disorder needs to be differentiated from alcohol withdrawal delirium and schizophrenia. No brain-imaging studies in AIPD have been reported to date. Case reports of brain imaging in AIPD suggest possible dysfunction in the thalamus, basal ganglia, frontal lobes and cerebellum. Our aim was to prospectively compare resting brain perfusion (rCBF) in patients with AIPD, uncomplicated alcohol dependence, schizophrenia and healthy volunteers.

METHODS

Single photon emission computed tomography (SPECT) was utilized to compare rCBF in patients with AIPD (n=19), schizophrenia (n=16), uncomplicated alcohol dependence (n=20) and healthy volunteers (n=19).

RESULTS

Increased rCBF was demonstrated in the right calcarine area in patients with AIPD compared to healthy volunteers, with a trend towards increased rCBF to the frontal and temporal lobes and the right pallidum. Decreased left sided rCBF to the putamen, parietal, mid-frontal and mid-temporal lobes and heterogenous flow to the cerebellum were demonstrated in patients with AIPD when compared to patients with uncomplicated alcohol dependence. The left posterior cingulate and right cerebellum showed higher and lower rCBF respectively in patients with AIPD compared to patients with schizophrenia.

CONCLUSION

Our findings implicate the right occipital lobe and possibly the cerebellum in the pathogenesis of AIPD and have similarities with those previously reported in alcohol withdrawal. Reduced rCBF to the frontal lobes, thalamus and basal ganglia in AIPD as suggested in previous case reports could not be confirmed.

Regional cerebral blood flow in patients with alcohol-related dementia: a SPECT study

The purpose of this study was to investigate regional cerebral blood flow (rCBF) changes using 1110 MBq of Tc-99m ECD SPECT in alcohol-related dementia (ARD) patients. Twenty-five patients with ARD and 22 healthy control subjects were included in the study. Mini-Mental Status Examination was applied to the patients and controls. The ARD patients showed drastically reduced rCBF in the frontal cortices, basal ganglia, and thalami. The results indicate that ARD is associated with hypoperfusion in both cortical and subcortical regions. These findings support previous studies suggesting the association with both cortical and subcortical neuropathology in ARD patients.

Ethanol self-administration modulation of NMDA receptor subunit and related synaptic protein mRNA expression in prefrontal cortical fields in cynomolgus monkeys

BACKGROUND

Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR) complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication, and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in the alcohol-addicted state.

METHODS AND RESULTS

The effects of chronic ethanol self-administration on glutamate receptor ionotropic NMDA (GRIN), as well as GRIN1 splice variant mRNA expression was studied in the orbitofrontal cortex (OFC; Area 13), dorsolateral prefrontal cortex (DLPFC; Area 46) and anterior cingulate cortex (ACC; Area 24) of male cynomolgus monkeys. Chronic ethanol self-administration resulted in significant changes in the expression of NMDA subunit mRNA expression in the DLPFC and OFC, but not the ACC. In DLPFC, the overall expression of NMDA subunits was significantly decreased in ethanol treated monkeys. Slight but significant changes were observed for synaptic associated protein 102 kD (SAP102) and neuronal nitric oxide synthase (nNOS) mRNAs. In OFC, the NMDAR1 variant GRIN1-1 was reduced while GRIN1-2 was increased. Furthermore, no significant changes in GFAP protein levels were observed in either the DLPFC or OFC.

CONCLUSION

Results from these studies provide the first demonstration of posttranscriptional regulation of iGluR subunits in the primate brain following long-term ethanol self-administration. Furthermore, changes in these transcripts do not appear to reflect changes in glial activation or loss. Further studies examining the expression and cellular localization of subunit proteins and receptor pharmacology would shed more light on the findings reported here.

Alcohol Pathophysiology

There is no specialized alcohol addiction area in the brain; rather, alcohol acts on a wide range of excitatory and inhibitory nervous networks to modulate neurotransmitters actions by binding with and altering the function of specific proteins. With no hemato-encephalic barrier for alcohol, its actions are strongly related to the amount of intake. Heavy alcohol intake is associated with both structural and functional changes in the central nervous system with long-term neuronal adaptive changes contributing to the phenomena of tolerance and withdrawal. The effects of alcohol on the function of neuronal networks are heterogeneous. Because ethanol affects neural activity in some brain sites but is without effect in others, its actions are analyzed in terms of integrated connectivities in the functional circuitry of neuronal networks, which are of particular interest because of the cognitive interactions discussed in the manuscripts contributing to this review. Recent molecular data are reviewed as a support for the other contributions dealing with cognitive disturbances related to alcohol acute and addicted consumption.

The impact of chronic cigarette smoking on recovery from cortical gray matter perfusion deficits in alcohol dependence: longitudinal arterial spin labeling MRI

BACKGROUND

Neuroimaging studies reported cerebral perfusion abnormalities in individuals with alcohol use disorders. However, no longitudinal magnetic resonance imaging (MRI) studies of cerebral perfusion changes during abstinence from alcohol have been reported.

METHODS

Arterial spin labeling MRI was used to evaluate cortical gray matter perfusion changes in short-term abstinent alcohol dependent individuals in treatment and to assess the impact of chronic cigarette smoking on perfusion changes during abstinence. Seventy-six patients were scanned at least once. Data from 19 non-smoking (17 males, 2 females) and 22 smoking (21 males, 1 female) patients scanned at 1 and 5 weeks of abstinence were used to assess perfusion changes over time. Twenty-eight age-equated healthy controls (25 males, 3 females) were scanned for cross-sectional comparison, 13 of them were scanned twice. Given the age range of the cohort (28 to 68 years), age was used as a covariate in the analyses. Mean perfusion was measured in voxels of at least 80% gray matter in the frontal and parietal lobes and related to neurocognitive and substance use measures.

RESULTS

At 1 week of abstinence, frontal and parietal gray matter perfusion in smoking alcoholics was not significantly different from that in non-smoking alcoholics, but each group's perfusion values were significantly lower than in controls. After 5 weeks of abstinence, perfusion of frontal and parietal gray matter in non-smoking alcoholics was significantly higher than that at baseline. However, in smoking alcoholics, perfusion was not significantly different between the time-points in either region. The total number of cigarettes smoked per day was negatively correlated with frontal gray matter perfusion measured at 5 weeks of abstinence. Lobar perfusion measures did not correlate significantly with drinking severity or cognitive domain measures at either time-point.

CONCLUSION

Although cerebral perfusion in alcohol dependent individuals shows improvement with abstinence from alcohol, cigarette smoking appears to hinder perfusion improvement.

Alcohol consumption and cerebral blood flow among older adults

A substantial epidemiological literature now supports the existence of a J or U-shaped association between alcohol consumption and a broad range cardiovascular health outcomes including stroke. Although it is well documented that alcoholics exhibit both global and regional cerebral hypoperfusion in the sober state, little is known regarding the effects of a broader range of alcohol consumption on cerebral blood flow (CBF). The present study employed positron emission tomography with H(2)(15)O to assess quantitative global and regional CBF in 86 participants (51 men and 35 women; mean age 60.1) as a function of self-reported weekly alcohol consumption (none, <1, 1 to <7, 7 to <15, and >15 drinks per week). Analyses controlling for age, gender, and vascular health (carotid intima-media thickness) revealed that, relative to the weighted population mean, global CBF was greater in the lightest alcohol consumption group (<1 per week) and lower in the heaviest (>15 per week). Effects did not vary across regions of interest. This report is the first to describe an inverted J-shaped relationship between alcohol consumption and CBF in the absence of stroke.

Alcohol: effects on neurobehavioral functions and the brain

Alcoholism results from an interplay between genetic and environmental factors, and is linked to brain defects and associated cognitive, emotional, and behavioral impairments. A confluence of findings from neuroimaging, physiological, neuropathological, and neuropsychological studies of alcoholics indicate that the frontal lobes, limbic system, and cerebellum are particularly vulnerable to damage and dysfunction. An integrative approach employing a variety of neuroscientific technologies is essential for recognizing the interconnectivity of the different functional systems affected by alcoholism. In that way, relevant experimental techniques can be applied to assist in determining the degree to which abstinence and treatment contribute to the reversal of atrophy and dysfunction.

Patterns of prefrontal dysfunction in alcoholics with and without Korsakoff's syndrome, patients with Parkinson's disease, and patients with rupture and repair of the anterior communicating artery

This study compared patterns of frontal-lobe dysfunction in alcoholics with Korsakoff's syndrome (KS: n = 9), non-Korsakoff alcoholics (AL: n = 28), patients with Parkinson's disease (PD: n = 18), and patients with rupture and repair of the anterior communicating artery (ACoA: n = 4) relative to healthy non-neurological control (NC) participants (n = 70). The tests administered were sensitive to functions of dorsolateral prefrontal and orbito-frontal subsystems. Measures included perseverative errors on the Wisconsin Card Sorting Test (WCST-pe), errors on object alternation (OA), errors on Trails B, number of words generated on the Controlled Oral Word Association Test (COWAT), and number of categories completed on the WCST (WCST-cc). KS patients were as impaired as AL participants on orbitofrontal measures and, on dorsolateral prefrontal measures, were impaired relative to AL participants, whose performance did not differ from controls. Patients with PD also were impaired on tests of orbitofrontal and dorsolateral prefrontal functioning but to a lesser extent than the KS patients. Moreover, most of the PD deficits were driven by the impaired performance of patients whose initial symptoms were on the right side of the body. The ACoA patients were significantly impaired on tests of orbitofrontal but not dorsolateral prefrontal functioning relative to the control group. Together, the results confirm different patterns of frontal-system impairments in patient groups having compromised frontal lobe functioning consequent to varying etiologies.

Cerebral blood flow velocity and erythrocyte deformability in heavy alcohol drinkers at the acute stage and two weeks after withdrawal

OBJECTIVE

The aim of the study was to measure changes in blood flow velocity (V(mean)) and erythrocyte deformability (ED) in heavy alcohol drinkers after withdrawal and the relationship between them.

METHODS

The subjects were 32 heavy alcohol drinkers, mean age 47 years (22 men and 10 women). V(mean) was determined by a transcranial 2 MHz pulsed Doppler probe. ED was estimated by the method of cation-osmotic haemolysis (COH). The results were compared with those for 20 healthy volunteers.

RESULTS

The study revealed a significant decrease in V(mean) and ED after admission. V(mean) in the left middle cerebral artery (MCA) was 45.1+/-10.2 cm/s as compared with 59.1+/-7.5 cm/s in controls; in the right MCA, it was 46.8+/-11.3 cm/s as compared with 59.0+/-7.6 cm/s in controls (p < 0.001 in each case). But while V(mean) was significantly increased after 14 days withdrawal (54.4+/-10.4 cm/s in the left MCA, p < 0.001, and 54.3+/-12.1 cm/s in the right MCA, p < 0.01), ED showed only small change. A significant difference between V(mean) in men and women was found.

CONCLUSION

The changes in V(mean) after withdrawal are more influenced by plasma composition than by changes in ED.

Using Virtual Reality to Study Alcohol Intoxication Effects on the Neural Correlates of Simulated Driving

The use of virtual reality in the form of simulated tasks can provide a realistic environment in which to study complex naturalistic behaviors. Many of the behavioral effects of alcohol intoxication are well known, but there is relatively little imaging evidence examining how alcohol exposure might transiently modulate brain function, especially in the context of task performance. In this review, we provide a brief synopsis of previous work using functional magnetic resonance imaging (fMRI) to study the neural correlates of alcohol intoxication. We describe in detail two studies from our published work, the first involving a visual perception paradigm, and the second involving virtual reality through a naturalistic behavior; simulated driving. Participants received single-blind individualized doses of beverage alcohol designed to produce blood alcohol content (BAC) of 0.04 and 0.08 or placebo. Subjects were fMRI scanned after training to asymptote performance. In both studies we found specific circuits that were differentially modulated by alcohol, we revealed both global and local effects of alcohol, and we examined relationships between behavior, brain function, and alcohol blood levels.

Single photon emission computed tomography and statistical parametric mapping analysis in cirrhotic patients with and without minimal hepatic encephalopathy

OBJECTIVE

The early diagnosis and treatment of cognitive impairment in cirrhotic patients is needed to improve the patients' daily living. In this study, alterations of regional cerebral blood flow (rCBF) were evaluated in cirrhotic patients using statistical parametric mapping (SPM). The relationships between rCBF and neuropsychological test, severity of disease and biochemical data were also assessed.

METHODS

99mTc-ethyl cysteinate dimer single photon emission computed tomography was performed in 20 patients with non-alcoholic liver cirrhosis without overt hepatic encephalopathy (HE) and in 20 age-matched healthy subjects. Neuropsychological tests were performed in 16 patients; of these 7 had minimal HE. Regional CBF images were also analyzed in these groups using SPM.

RESULTS

On SPM analysis, cirrhotic patients showed regions of significant hypoperfusion in the superior and middle frontal gyri, and inferior parietal lobules compared with the control group. These areas included parts of the premotor and parietal associated areas of the cortex. Among the cirrhotic patients, those with minimal HE had regions of significant hypoperfusion in the cingulate gyri bilaterally as compared with those without minimal HE.

CONCLUSIONS

Abnormal function in the above regions may account for the relatively selective neuropsychological deficits in the cognitive status of patients with cirrhosis. These findings may be important in the identification and management of cirrhotic patients with minimal HE.

Neuropathological alterations in alcoholic brains. Studies arising from the New South Wales Tissue Resource Centre

Alcohol dependence and abuse are among the most costly health problems in the world from both social and economic points of view. Patterns of drinking appear to be changing throughout the world with more women and young people drinking heavily. Excessive drinking can lead to impairment of cognitive function and structural brain changes--some permanent, some reversible. Patterns of damage appear to relate to lifetime alcohol consumption but, more importantly, to associated medical complications. The most significant of these is the alcohol-related vitamin deficient state, the Wernicke-Korsakoff syndrome (WKS), which is caused by thiamin deficiency but is seen most commonly in alcoholics. Careful selection and classification of alcoholic cases into those with and without these complications, together with detailed quantitative neuropathological analyses has provided data that gives clues to the most vulnerable regions and cells in the brain. Brain shrinkage is largely accounted for by loss of white matter. Some of this damage appears to be reversible. Alcohol-related neuronal loss has been documented in specific regions of the cerebral cortex (superior frontal association cortex), hypothalamus and cerebellum. No change is found in basal ganglia, nucleus basalis, or serotonergic raphe nuclei. Many of these regions which are normal in uncomplicated alcoholics are damaged in those with the WKS. Dendritic and synaptic changes have been documented in alcoholics and these, together with receptor and transmitter changes, may explain functional changes and cognitive deficits, which precede more severe structural neuronal changes. A resource to provide human brain tissues for these types of studies has been developed at the University of Sydney--the New South Wales Tissue Resource Centre. The aim of this facility is to provide research groups throughout the world with fresh and/or frozen tissues from well-characterized cases of alcohol-related brain damage and matched controls. The development of new technologies in pathology and molecular biology means that many more questions can be addressed using appropriately stored human brain tissues. Examples of the application of some of these techniques, involving neurochemical, neuropharmacological, neuroimaging and gene expression studies are included in this paper. Important public health outcomes have arisen from some of these studies including the enrichment of bread flour with thiamin for the whole of Australia. Researchers with an interest in alcohol studies can access tissues from this brain bank.

Regional cerebral blood flow and neuropsychological functioning in early and late onset alcoholism

The aim of the study was to compare late and early onset alcoholism with regard to regional cerebral blood flow (rCBF) and neuropsychological functioning. Ten late onset and 13 early onset male alcoholics were included in the study, the criterion being the age of onset for alcohol abuse. Six healthy male volunteers were included as a control group. Regional measures of cortical cerebral blood flow were assessed using Tc-99m-HMPAO single photon emission computed tomography (SPECT) after a detoxification period. When compared with the control group, the early onset group showed reduced relative perfusion in the left superior frontal region, while relative perfusion in the late onset group was deficient in both right and left superior frontal regions. Both groups of alcoholic patients also displayed impairment in frontal lobe functions and non-verbal memory. The results of this study indicate that early onset alcoholism is associated with hypoperfusion in the left superior frontal region while the late onset subtype is characterized by uniformly hypoperfused left and right superior frontal regions. Additionally, both groups of alcoholic patients exhibit an almost identical pattern of neuropsychological abnormalities mainly related to frontal lobe functions and non-verbal memory. Collectively these findings support previous evidence suggesting a key role of frontal lobe pathology in understanding the neurobiology of alcoholism.

Cerebral perfusion defects in combined cocaine and alcohol dependence

BACKGROUND

Cocaine abuse has been associated with widely distributed areas of significant cerebral blood flow (CBF) reductions or hypo-perfusion as well as CBF hyper-perfusion, but these perfusion abnormalities have not been examined using newer technologies such as statistical parametric mapping (SPM). These areas of abnormal CBF may be more likely among those who abuse cocaine and alcohol together.

METHODS

Using SPECT with HMPAO for CBF we compared proportional scaling (PS) to histogram normalization (HEQ) in SPM among 20 controls and 32 recently abstinent cocaine abusers. We then separated the cocaine abusers into two groups (12 cocaine plus alcohol abusers and 20 cocaine alone abusers) and compared both groups to the 20 controls for brain areas of hypo- and hyper-perfusion.

RESULTS

Sensitivity to hypo-perfusion was greater with HEQ than PS. Hypo-perfused areas were more likely in the 12 alcohol plus cocaine abusers than in the 20 cocaine alone abusers or 20 controls, and hyper-perfused areas were significantly more likely among the cocaine abusers than controls. The type of CBF abnormality varied by brain location with hypo-perfusion significantly more likely in occipital and temporal cortex or cerebellum and hyper-perfusion more likely in frontal and parietal cortex.

CONCLUSIONS

These abnormalities in brain perfusion are consistent with previous non-SPM approaches that showed more hypo-perfusion in cocaine abusers than controls and appear to reflect vasospasm and potential compensations in cerebral blood flow.

Cortical metabolite alterations in abstinent cocaine and cocaine/alcohol-dependent subjects: proton magnetic resonance spectroscopic imaging

Chronic abuse of cocaine or alcohol is associated with structural, neuropathological and cognitive impairments that have been documented extensively. Little is known, however, about neurobiochemical changes in chronic substance abusers.We performed MRI and multi-slice brain proton magnetic resonance spectroscopic imaging (MRSI) to assess neuronal viability (via N-acetylaspartate (NAA)) and white matter metabolite status in 22 4-months-abstinent individuals dependent on crack cocaine only and on both crack cocaine and alcohol. Compared to 11 non-dependent controls we found (1) significantly lower NAA measures in the dorsolateral prefrontal cortex of the combined cocaine-dependent groups; (2) comparable spatial distribution and magnitude of these NAA effects for both cocaine-dependent groups; (3) higher choline-containing metabolites in frontal white matter of individuals dependent on both cocaine and alcohol; (4) absence of brain atrophy in both abstinent cocaine-dependent samples; and (5) partial recovery from prefrontal cortical NAA loss, primarily with abstinence from alcohol. The MRSI findings suggest preferential neuronal damage to the frontal cortex of both cocaine-dependent samples and gliosis in frontal white matter of individuals dependent on both alcohol and cocaine, conditions that persist for more than 4 months of abstinence.

Structural and functional neuroimaging findings in substance-related disorders

Intoxication with alcohol results in depressed global glucose metabolism that continues into the stages of withdrawal and abstinence. The decrease in metabolism, however, is not equal across the brain, with certain regions more affected than others. Such a pattern of disturbance suggests that the effect of alcohol on the brain cannot simply be a nonspecific depressant effect secondary to decreased blood flow or glucose transport into the cells but may be related to the dysfunction of the various neurotransmitter systems. Different authors have suggested the dysfunction to be related to the GABAergic, cholinergic, and dopaminergic systems. Long-term alcoholism is associated with atrophy of several brain regions. The frontal lobes and limbic structures seem to be most vulnerable. The data are encouraging with regard to the normalization in brain metabolism and in size of vulnerable brain regions with continued abstinence. In addition to findings of improvement in cognitive functioning and many health parameters, these findings arm clinicians with further data on the benefits of abstinence in the struggle to aid patients in maintaining their sobriety. Several areas remain to be addressed. In particular, clinicians are in need of data, neuroimaging and otherwise, that serve as prognostic indicators, thus allowing patients at higher risk for relapse to be identified and provided with more intensive treatment. A similar need exists for indicators of diagnostic heterogeneity that would guide the development of more highly tailored treatment regimens for identified subgroups of patients. Currently, we have rudimentary knowledge of the gender differences of the effects of alcohol and cocaine on the brain.

Corpus callosum atrophy and cerebral blood flow in chronic alcoholics

The corpus callosum atrophy and cerebral blood flows were investigated in chronic alcoholics without Marchiafava-Bignami disease. Fifteen cases of chronic alcoholics and 15 age-matched healthy controls were studied. The sagittal plane of magnetic resonance imaging of the head was scanned into a computer and the corpus callosum was measured and the callosal index was calculated. Cerebral blood flows were measured using stable xenon computed tomography (CT) method. Regional cerebral blood flows in the frontal, temporal, parietal and occipital cortex, frontal, temporal and occipital white matter, caudate nucleus, putamen and thalamus were measured. The corpus callosum area, the thickness of the genu, the thickness of the trunk, the thickness of the splenium, and the callosal index were significantly smaller in the chronic alcoholic group than in the healthy control group. Blood flows in the cerebral cortex, thalamus and putamen were significantly lower in the chronic alcoholic group than in the healthy control group. Significant positive correlations were present between the corpus callosum atrophy and the cerebral cortex blood flows. Corpus callosum atrophy and decreased cerebral blood flows may be seen in chronic alcoholics without Marchiafava-Bignami disease.

Brain imaging. Functional consequences of ethanol in the central nervous system

In recent years, sophisticated methods have been developed to view structure and function within the living brain. Functional imaging methods are used to visualize dynamic chemical processes that are linked to brain activity. Increased neural activity, for example, leads to greater glucose and oxygen consumption and greater regional rates of blood flow to meet elevated energy demands. Mapping these changes provides quantitative visual descriptions of localized changes in brain activity that result from behavioral or pharmacological manipulations. This chapter first describes several current methods and how they are used to study the effects of alcohol on brain function. In the second part, the effects of acute intoxication are discussed with emphasis on the complex nature of alcohol's effects in the central nervous system, which depend on dose, time since administration, and environmental context. In the final part, the functional consequences of long-term exposure to alcohol as well as diseases associated with chronic alcoholism are reviewed.

Executive cognitive functioning in alcohol use disorders

Executive cognitive functioning (ECF) has been identified as an important determinant in the etiology of alcoholism. ECF represents a "higher-order" cognitive construct involved in the self-regulation of goal-directed behavior. The prefrontal cortex and its subcortical connections represent the primary neurological substrate that subserves ECF. Both alcoholics and individuals at high risk for alcoholism exhibit a mild dysfunction in ECF. However, this deficit appears to be significantly stronger in alcoholics with a comorbid diagnosis of an antisocial personality disorder. Individuals with other disorders that are also highly comorbid with alcoholism, such as attention deficit hyperactivity disorder and conduct disorder, also demonstrate deficits in ECF. As such, compromised ECF may not be specific to alcoholism, but instead, might be a potential underlying etiologic substrate for a number of disorders of behavioral excess-disinhibition. Subsequent to reviewing the literature implicating ECF deficits in alcoholism and comorbid disorders, the authors present a heuristic cognitive-neurobehavioral model of alcoholism implicating the frontostriatal system. Finally, recommendations for the prevention and treatment of alcoholism, based on this model, are discussed.

Transient frontal hypoperfusion in Tc-99m hexamethylpropyleneamineoxime single photon emission computed tomography imaging during alcohol withdrawal

BACKGROUND

Regional brain perfusion in patients during alcohol-withdrawal has been relatively less studied with brain SPECT technique. In this study, the hypothesis that possible regional cerebral blood flow (rCBF) alterations due to alcohol withdrawal might be transitory in a homogenous group of alcoholic patients in terms of their physical-nutritional and cognitive functional conditions was investigated.

METHODS

Fifteen right-handed male inpatients with alcohol-withdrawal, diagnosed according to DSM-IIIR criteria, and 6 male physically-mentally healthy control subjects were included in the study. The first Technetium 99m-hexamethylpropyleneamineoxime (Tc-99m-HMPAO) brain SPECT investigation was performed on the day of admission in nonmedicated conditions and the second one was performed after all the withdrawal symptoms had subsided in the patients. As an indicator of the change in the brain perfusion, a relative perfusion index was used and the relative tracer activity was expressed as the ratio of mean cortical region of interest activity to mean the whole cortical brain activity.

RESULTS

We found significantly reduced left frontal and right frontal, parietal and temporal rCBF values in the patients during the alcohol-withdrawal compared to those of their remitted state while they were not different from in the control group (p < 0.05).

CONCLUSIONS

Our data indicate that the alterations in rCBF during the alcohol-withdrawal are more pronounced both in the frontal cortex and in overall right hemisphere regions. Furthermore, the frontal hypoperfusion may be transitory with recovery from alcohol-withdrawal whereas temporal hypoperfusion may continue after recovery probably depending on the previously administered high-dose benzodiazepines.

Regional cerebral blood flow during acute and chronic abstinence from combined cocaine-alcohol abuse

Regional cerebral blood flow (rCBF) was assessed using SPECT and HMPAO in ten cocaine abusers within 72 h of last cocaine use and then after 21 days of abstinence. In comparison to normals the cocaine abusers had significantly reduced rCBF in 11 of 14 brain regions with the largest reductions in the frontal and parietal cortex and greater rCBF in the brain stem. These perfusion defects appeared to be primarily due to combined alcohol and cocaine abuse and frontal but not parietal defects appeared to resolve partially during 21 days of abstinence.

Brain imaging in alcoholism

Copyright Rapid Science Ltd

The cerebral cortex is damaged in chronic alcoholics

There is some controversy in the literature concerning whether chronic alcohol consumption damages the cerebral cortex. While decreased neuronal density in specific cortical regions is well described in chronic alcoholics, a recent study by Badsberg Jensen and Pakkenberg using unbiased stereological methods questions whether neurodegeneration occurs. In order to assess selective neurodegeneration in the cerebral cortex of chronic alcoholics, regional volumes and unbiased estimates of regional neuronal number (including neuronal identification with calcium-binding proteins) were calculated for 14 chronic alcoholics and 21 controls. Cases were carefully screened to exclude any interfering pathologies. Lifetime and maximum daily alcohol consumption was determined, and homogeneous groups were identified (four chronic alcoholics with Wernicke's encephalopathy and Korsakoff's psychosis, four chronic alcoholics with Wernicke's encephalopathy alone, six chronic alcoholics without Wernicke's encephalopathy or Korsakoff's psychosis, and 21 controls). Brain volume analysis revealed that discrete regions were significantly smaller in the chronic alcoholics compared to controls. As previously shown, white matter regions (particularly in the frontal lobe) were the most significantly reduced in volume. Alcoholics with Wernicke's encephalopathy (either alone or in combination with Korsakoff's psychosis) had significantly smaller white matter volumes than controls or alcoholics without these complications. Medial temporal lobe regions and the thalamus were also reduced in volume. Regression analyses revealed that the volume of both the white matter and thalamus negatively correlated with alcohol consumption. Consistent with the interpretation of previous neuronal density studies, selective neuronal loss was found in the superior frontal association cortex of chronic alcoholics, while no loss occurred from the motor cortex. The number of parvalbumin-, calbindin- and calretinin-immunoreactive neurons was found to be unaltered in chronic alcoholics, suggesting that the neurodegeneration is confined to the non-GABAergic pyramidal neurons. As neurodegeneration was observed in all alcoholic groups, damage to the frontal association cortex is not restricted to alcoholics with the amnesia of Korsakoff's psychosis. These results are consistent with the notion that chronic alcohol consumption is associated with selective neuronal vulnerability. The selective frontal neurodegeneration and the frontal focus of white matter atrophy are supported by neuropsychological, regional blood flow, and magnetic resonance imaging studies of frontal lobe dysfunction in chronic alcoholics and may correlate with abnormalities in working memory.

Brain impairment in well-nourished chronic alcoholics is related to ethanol intake

To determine the influence of chronic ethanol intake on the central nervous system, we studied 40 asymptomatic, well-nourished, chronic alcoholics (mean age, 42.6 +/- 9.1 years) and 20 age-, sex-, and education-matched control subjects. Studies included neuropsychological testing, visual and short-latency auditory evoked potentials, and morphometric analysis of computed tomography scans. The mean daily ethanol consumption of the alcoholics was 204 gm over an average of 26.4 years. Compared to control subjects, chronic alcoholics exhibited a significant prolongation of the P100 latency of visual evoked potentials, and a prolongation and reduction in the amplitude of the latency of the V wave of short-latency auditory evoked potentials. These abnormalities were related to the lifetime dose of ethanol consumed. Brain morphometric analysis showed that alcoholics had a significantly greater degree of brain shrinkage with age, compared to control subjects. The cortical atrophy index correlated significantly with the lifetime ethanol consumption. Neuropsychological testing in alcoholics compared to controls revealed a significant impairment of frontal skills that was related to age, degree of scholarship, and the presence of frontal atrophy. In conclusion, well-nourished chronic alcoholics exhibited significant brain impairment, as demonstrated by neuropsychological testing, evoked potentials, and brain morphometric analysis, which was correlated with the lifetime dose of ethanol consumed.

Reduction in cortical IMP-SPET tracer uptake with recent cigarette consumption in a young group of healthy males. San Diego HIV Neurobehavioral Research Center

Functional brain imaging techniques are being used increasingly to infer disturbances in brain function in various neuropsychiatric disorders, but the specificity of such findings is not always clear. We retrospectively examined the effects of one possible confound - cigarette smoking - on cortical uptake of iodine-123 iodoamphetamine (IMP) using single-photon emission tomographic imaging in a young (mean age=35 years) healthy group of male controls divided according to their smoking history. Subjects who had never smoked (n=17), or those with a history of smoking but no recent smoking (n=8), had equivalent and significantly higher mean cortical uptake of IMP than subjects with a history of smoking and who were current smokers (n=8). There were no differences in the cortical distribution of IMP. Our results indicate that cigarette smoking has an acute effect on global cerebral blood flow. This potential confound must be considered before abnormalities in cortical tracer uptake are attributed to some neuropsychiatric disorder of interest.

Single photon emission computerised tomography in chronic alcoholism. Antisocial personality disorder may be associated with decreased frontal perfusion

BACKGROUND

We examined the functional and structural cerebral changes in chronic alcoholics, analysing their association with personality features and alcohol drinking habits.

METHOD

Forty patients with alcohol dependency, including 15 with antisocial personality disorder (ASP) as defined in DSM-III-R and 10 age and sex matched healthy controls were studied after termination of withdrawal symptoms, using high resolution single photon emission tomography (SPECT), cranial computerised tomography (CT) and brainstem auditory evoked potentials (BAEP).

RESULTS

We found significant reductions in regional cerebral blood flow (rCBF) measurements of alcoholic patients. Low flow in frontal regions encountered in 67.5% of the patients was associated with the duration of alcohol consumption, while no such relation existed with the amount of daily intake. Patients with ASP exhibited more marked frontal hypoperfusion. Significant brain atrophy detected by CT was present in 40% of the patients and did not correlate with frontal hypoperfusion.

CONCLUSIONS

Patients with ASP are more sensitive to toxic effects of alcohol. Alternatively chronic alcoholism leads to frontal lobe dysfunction recognised as ASP in the clinical setting.

Single photon emission computed tomography with iodoamphetamine-123 and neuropsychological studies in long-term abstinent alcoholics

Ten long-term abstinent alcoholics (mean abstinence = 7.7 years) were compared with 13 recently detoxified substance-dependent inpatients (mean abstinence = 25 days) and 8 nonalcoholic control subjects on global end regional measures of cortical cerebral blood flow (CBF), and on neuropsychological measures. CBF was assessed using 123iodoamphetamine (IMP) single photon emission computed tomography (SPECT) under conditions of behavioral challenge (Raven's Progressive Matrices). CBF and neuropsychological test performance were worse in the recently detoxified inpatients. Of greater interest, there was a dissociation in the long-term abstinent group, which, while neuropsychologically indistinguishable from controls, showed significantly decreased mean cortical IMP uptake. We conclude that there may be persistent physiologic abnormalities in long-term abstinent alcoholics who have achieved full behavioral recovery. Smoking on the day of SPECT scanning was also identified to be a significant confound to understanding CBF changes in alcoholism.

Alzheimer's disease risk factors as related to cerebral blood flow

Inconsistencies within results of case-control studies on Alzheimer's disease risk factors led to a search of the literature for a potential cofactor. Reduced cerebral blood flow was selected and literature was surveyed for evidence of a cerebral blood flow linkage with the more than 40 putative risks. Alcohol abuse, depression, head trauma, underactivity, old age, sleep disturbance, glucose utilization, Down's syndrome, and Parkinson's disease are risk factors where an association with reduced cerebral blood flow is documented. Studies were cited showing that improved cerebral blood flow is associated with factors thought to be helpful in Alzheimer's disease, such as education or occupational attainment, exercise, headache, smoking, and arthritis/anti-inflammatory drugs to the extent that aspirin is used. Sugar consumption is identified as a potential risk factor with glucose management in Alzheimer's disease also shown to involve reduced cerebral blood flow. An hypothesis is developed showing how compromised regional cerebral blood flow could fit as a cofactor for genetic, autoimmune, and neurotoxic aspects of Alzheimer's disease.

Alcohol abuse and HIV infection have additive effects on frontal cortex function as measured by auditory evoked potential P3A latency

Both alcohol and human immunodeficiency virus (HIV) infection have been shown to produce central nervous system (CNS) morbidity in frontal brain regions. The degree to which the CNS morbidity in HIV infection, as it affects frontal cortex function, may be preferentially increased by alcohol abuse was examined using the auditory P3A evoked potential. The P3A indexes an orienting response, maximal over frontal cortex that occurs when novel nontarget stimuli are presented in the midst of a target detection paradigm. Four groups of subjects were compared: HIV+ alcohol abusers, HIV+ light/nondrinkers, HIV- alcohol abusers, and HIV- light/nondrinkers. The alcohol abuser and light/nondrinker HIV+ groups were matched on percent CD4 lymphocytes, insuring that the results reflected specific CNS effects and were not a result of differences between the groups in the degree of systemic immune suppression. Alcohol abuse and HIV infection had at least additive effects on P3A latency, consistent with alcohol abuse worsening the effect of HIV disease on frontal cortex function. Post-hoc analyses suggested that concomitant alcohol abuse results in the effects of HIV infection on P3A latency becoming manifest earlier in the HIV disease process.

The pattern of regional cerebral blood flow during alcohol withdrawal--a single photon emission tomography study with 99mTc-HMPAO

Cerebral blood flow was investigated during alcohol withdrawal in 15 male alcoholics by single photon emission computerized tomography with 99mTc-HMPAO and compared with the results of a second study 3 weeks later when all symptoms of withdrawal had disappeared and when the patients had been free of medication for at least 1 week. Slice images were reconstructed parallel to the orbitomeatal plane, and tracer activity was analyzed in 8 regions of interest per hemisphere. During alcohol withdrawal a special pattern of cerebral blood flow distribution could be observed. Relative perfusion was elevated in both inferior temporal regions, whereas it was reduced in the superior temporal region of both hemispheres. The changes of cerebral blood flow distribution did not correlate with neuropsychological findings nor with the severity of withdrawal syndrome.