Cerebral atrophy and hypoperfusion improve during treatment of Wernicke-Korsakoff syndrome

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.

Abnormal thiamine-dependent processes in Alzheimer's Disease. Lessons from diabetes

Reduced glucose metabolism is an invariant feature of Alzheimer's Disease (AD) and an outstanding biomarker of disease progression. Glucose metabolism may be an attractive therapeutic target, whether the decline initiates AD pathophysiology or is a critical component of a cascade. The cause of cerebral regional glucose hypometabolism remains unclear. Thiamine-dependent processes are critical in glucose metabolism and are diminished in brains of AD patients at autopsy. Further, the reductions in thiamine-dependent processes are highly correlated to the decline in clinical dementia rating scales. In animal models, thiamine deficiency exacerbates plaque formation, promotes phosphorylation of tau and impairs memory. In contrast, treatment of mouse models of AD with the thiamine derivative benfotiamine diminishes plaques, decreases phosphorylation of tau and reverses memory deficits. Diabetes predisposes to AD, which suggests they may share some common mechanisms. Benfotiamine diminishes peripheral neuropathy in diabetic humans and animals. In diabetes, benfotiamine induces key thiamine-dependent enzymes of the pentose shunt to reduce accumulation of toxic metabolites including advanced glycation end products (AGE). Related mechanisms may lead to reversal of plaque formation by benfotiamine in animals. If so, the use of benfotiamine could provide a safe intervention to reverse biological and clinical processes of AD progression. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.

Reduced sensory and motor nerve conduction velocities in moderate drinkers

The mechanism responsible for peripheral nerve dysfunction in chronic alcoholism has not been fully elucidated either in terms of its relationship to the quantity of alcohol consumed or to nutritional status. As part of a series of studies to address these issues, the effects of moderate drinking (60-90 g ethanol per day) or heavy drinking (> 100 g ethanol per day) on peripheral nervous function and thiamine status was measured in 73 patients admitted to a detoxification unit. Electromyographic evaluation revealed significant reductions in median and ulnar sensory and motor nerve conduction velocities in both moderate drinkers (n = 30) and heavy drinkers (n = 43) compared to age-matched controls. Twelve moderate drinkers and 25 heavy drinkers manifested clinical neurological signs of peripheral neuropathy. Thiamine deficiency, as revealed by erythrocyte transketolase activation assay, was detected in two moderate drinkers and seven heavy drinkers but was not significantly correlated with electromyographic alterations with the exception of ulnar nerves. These findings provide evidence for significant early peripheral nerve dysfunction in moderate drinkers and a possible contributory role of thiamine deficiency to the ulnar nerve conduction deficits. Whether deficits in other water-soluble vitamins or a direct neurotoxic effect of ethanol are implicated in alcoholic peripheral neuropathy awaits further studies.

Alcohol-thiamine interactions: an update on the pathogenesis of Wernicke encephalopathy

Wernicke encephalopathy is a neurological disorder commonly observed in chronic alcohol abuse, in patients with AIDS, and in other conditions of compromised nutritional status. The underlying cause of the disorder is thiamine deficiency. The present review highlights data focusing on alcohol-thiamine interactions and their relationship to the pathogenesis of Wernicke encephalopathy. Recent findings on the effects of alcohol on thiamine absorption and storage and on thiamine phosphorylation to the enzyme co-factor form (thiamine diphosphate) are discussed with regard to the postulated "biochemical lesion" of Wernicke encephalopathy. Also discussed are new findings on the molecular genetics of the thiamine-dependent enzyme transketolase in patients with Wernicke encephalopathy. A discussion of the hypotheses regarding the mechanisms underlying the phenomenon of selective neuronal cell death observed in this disorder including cerebral energy deficit, focal lactic acidosis, glutamate excitotoxicity, increased expression of immediate-early genes, free radicals and perturbations of the blood-brain barrier are presented. Finally, the possible role of thiamine deficiency in alcoholic peripheral neuropathy is reviewed.

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.

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.

Intravenous vitamins for alcoholics in the emergency department: a review

It is common practice for emergency physicians to provide i.v. vitamin replacements for alcoholics who present to the emergency department (ED). This article describes vitamin deficiencies in alcoholics and reviews the utility and utilization of vitamins in the emergency department. We conclude that the current data do not support the routine administration of i.v. vitamins to alcoholics who present to the ED and we do not recommend this practice.

Normal human aging: factors contributing to cerebral atrophy

Factors that accelerate rates of 'normal' age-related cerebral atrophic and degenerative changes are important because they may predispose to cognitive declines. To determine characteristic patterns of normal aging, risk factors were correlated with serial neurological-neuropsychological examinations, CT measures of progressive cerebral atrophy, local tissue hypodensities, or perfusional declines. Both cross-sectional and longitudinal designs were utilized. Ninety-four cognitively and neurologically normal aging volunteers, 15 with a history of transient ischemic attacks (TIAs), were followed for mean intervals of 3.0+/-2.1 years. Results indicated that: (1) after age 60, cerebral atrophy, polio- and leuko-araiosis doubled and cerebral perfusion decreased, with marked individual variations; (2) risk factors independently accelerating cerebral atrophy and cortico-subcortical perfusional declines included TIAs, hypertension, smoking, hyperlipidemia, excessive alcohol consumption and male gender; (3) progressive leuko-araiosis correlated directly with cortical atrophy and cortical perfusional declines. We posit that: (1) cerebral atrophy and degenerative changes result from neuronal shrinkage and/or loss, which are accelerated by TIAs, hypertension, smoking, hyperlipidemia, excessive alcohol consumption and male gender; (2) accelerated cerebral atrophic and degenerative changes identified by neuroimaging should be considered as markers for depleted neuronal synaptic reserves, which predispose to cognitive declines. Interventions available for controlling some of these risk factors include control of TIAs, hypertension, and hyperlipidemia, as well as tobacco and alcohol withdrawal.

Functional EEG mapping and SPECT in detoxified male alcoholics

Fifteen alcoholics diagnosed according to DSM-III-R, who were detoxified for at least 2 weeks and showed no clinical withdrawal signs, were investigated with 16 channel EEG mapping during resting, manumotor and music perception conditions, and were compared with 13 control persons. Single photon emission computed tomography (SPECT) using hexa-methyl-propilene-amine-oxime (HMPAO) labeled with 99m-technetium (99mTc) as tracer was performed separately (in patients only) and submitted to semiquantitative region of interest (ROI) analysis in 2 slices, 6 and 10 cm above canthomeatal line, respectively. Resting EEG showed increased power values in fast beta frequency band for the detoxified alcoholics. On cortical stimulation, patients showed signs of pathological EEG reactivity. Correlations of EEG parameters to cerebral blood flow (CBF) values (patients only) yielded coefficients around zero for all frequency bands (signs of uncoupling). All findings point to organic brain dysfunctions in these patients which extend beyond the period of withdrawal.

Decreased cingulate and precuneate glucose utilization in alcoholic Korsakoff's syndrome

Localized cerebral glucose utilization was determined for nine abstinent alcoholic men with Korsakoff's syndrome and 10 age-matched normal men who underwent positron emission tomography with [18F]2-fluoro-2-deoxyglucose (FDG). Patients with Korsakoff's syndrome showed relatively decreased glucose utilization in cingulate and precuneate areas. These decreases persisted even after correction for group differences in ventricular and sulcal cerebrospinal fluid measured on computed tomography. Electroencephalographic recordings at the time of FDG uptake showed no group differences, a finding that demonstrates that the metabolic differences could not be explained by differences in physiological arousal at the time of scanning. It is concluded that the decreased glucose utilization in the patients reflects a disruption of memory circuitry, the Papez circuit, caused by diencephalic lesions induced by thiamine deficiency.

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.

Randomized clinical trial of daily aspirin therapy in multi-infarct dementia. A pilot study

Seventy multi-infarct dementia patients were randomized into an aspirin-treated group and an untreated control group for an exploratory investigation to determine any effects of 325 mg aspirin daily on cognitive performance. The control group did not receive placebo but evaluations were carried out in a blinded manner. The index group (N = 37, mean age 67.1 years) received 325 mg of aspirin by mouth once daily while the control group (N = 33, mean age 67.6 years) was followed and treated in a similar manner except that they received no aspirin. Both groups had comparable risk factors for stroke, which were treated similarly, as well as comparable initial cerebral blood flow values, as measured by the 133xenon inhalation method, and initial scores on Cognitive Capacity Screening Examination testing. Patients were evaluated at intervals of one year. Significant improvements were demonstrated for cerebral perfusion values (P less than .0001) and cognitive performance scores (P less than .0001) among aspirin-treated patients compared to untreated controls at each of three annual follow-up evaluations. Both men and women benefited from aspirin therapy and their quality of life and independence appeared to be improved, which was not apparent in the control group. Daily aspirin appears to improve or stabilize declines in cerebral perfusion and cognition among patients with multi-infarct dementia.

Treatment of chronic organic mental disorders associated with alcoholism

Considering the magnitude of the problem, the treatment of alcoholism-associated chronic organic mental disorders has not been extensively studied. Alcoholic organic brain disease is heuristically viewed as the admixture of clinical syndromes of impairment [alcoholic amnestic disorder or Korsakoff's psychosis (KP) and dementia associated with alcoholism (DAA)], each with its distinguishing cognitive, neuropathological, and neurochemical characteristics. Differences between KP and DAA are highlighted by studies that compare KP patients with those having Alzheimer's disease or depression. Furthermore, treatment of cognitive deficits in KP and DAA may be modeled after strategies that have proved effective for these other neuropsychiatric disorders. Although abstinence and proper nutrition remain the cornerstones of treatment, pharmacological modification of neurotransmitter function and/or enhancement of cerebral metabolism combined with behavioral methods may also be beneficial. Serotonergic approaches to improve memory in detoxified alcoholics may also reduce alcohol intake, and this has implication for treatment of less impaired alcoholics.

Alcohol and brain damage

1. The safe limits of alcohol intake are difficult to define because of individual variations in susceptibility to damage. The present recommendations are based largely on epidemiological studies of liver damage. 2. Recent investigations indicate that alcoholic brain damage is much more common than previously suspected. More information is required about its natural history and the characteristics of individuals most likely to suffer damage. 3. Thiamin (vitamin B1) deficiency has long been associated with brain damage and may result from a number of additive causes in the alcoholic patient. New information indicating damage to the protein moeity of some of the thiamin-using enzymes has been reviewed, as have possible mechanisms of brain cell necrosis.

Computerized history and self-assessment questionnaire for diagnostic screening among patients with dementia

In order to standardize and quantify diagnostic information derived from medical histories and case reports given by demented patients, their families or care-providers, a questionnaire has been developed containing 94 questions. The output is categorized by computer into graphic clinical scales which correlate and weigh information relating to seven of the most common causes of dementia. The present investigation assesses the validity of predictive diagnostic classifications derived from the clinical scales tested on admission by correlating them later with final diagnoses determined independently by thorough clinical evaluation including standard diagnostic tests, computed tomography and nuclear magnetic resonance scans. Results of 101 healthy, neurologically normal, age-matched volunteers and 140 patients representative of the more common forms of dementia indicate that correct diagnostic identification was: 75% for dementia secondary to Parkinson's disease, 100% for Huntington's disease, 90.2% for Alzheimer's disease, 82.4% for multi-infarct dementia, 90.0% for posttraumatic dementia, 77.8% for normal-pressure hydrocephalus and 85.7% for Wernicke-Korsakoff dementia. Correct diagnostic assignment was highly significant (P less than .0005). The screening questionnaire may prove to be a useful and standard diagnostic tool for clinicians and investigators concerned with epidemiology, prevention and treatment of dementia.

Three-dimensional mapping of local cerebral perfusion in alcoholic encephalopathy with and without Wernicke-Korsakoff syndrome

Seventeen severe chronic alcoholic patients with and without Wernicke-Korsakoff syndrome (WKS) were examined prospectively after being treated by withdrawal from alcohol. The WKS patients also received thiamine supplements. Three-dimensional measurements of local cerebral blood flow (LCBF) and local partition coefficients (L lambda) were made utilizing xenon contrast computed tomography (Xe CT-CBF). Results were displayed as color-coded brain maps before and after treatment and these were correlated with neurological and cognitive examinations. Before treatment chronic alcoholics without WKS (n = 10) showed diffuse reductions of LCBF values throughout all gray matter including hypothalamus, vicinity of nucleus basalis of Meynert, thalamus, and basal ganglia. Similar, but more severe, reductions were seen in patients with WKS (n = 7), however, white matter perfusion was also reduced. In WKS, most prominent reductions of LCBF were also seen in hypothalamus and basal forebrain nuclei but thalamus, basal ganglia, and limbic systems were severely reduced. After treatment, both groups with alcoholic encephalopathy showed marked clinical improvement and cerebral perfusion was restored toward normal. Chronic alcohol abuse, in the absence of thiamine deficiency, reduces CBF by direct neurotoxic effects. If thiamine deficiency is also present, more severe and localized hemodynamic reductions are superimposed.

Abstinence improves cerebral perfusion and brain volume in alcoholic neurotoxicity without Wernicke-Korsakoff syndrome

Twenty severe chronic alcoholic patients with signs of neurotoxicity but without Wernicke-Korsakoff syndrome were treated by abstinence from alcohol and examined prospectively at intervals thereafter. Serial examinations included detailed medical histories, neurological examinations, cognitive capacity screening examinations, computed tomography scans with measurements of sulcal and ventricular volume, and measurements of regional CBF. All sedatives were withdrawn before CBF measurements were made. Before treatment, gray matter blood flow values were significantly reduced compared with those of age-matched normal volunteers, but white matter blood flow values were normal and the ventricles were enlarged. After abstinence from alcohol, mean gray matter blood flow values and brain volume both increased significantly.