Perceptual Learning in Detoxified Alcoholic Men: Contributions From Explicit Memory, Executive Function, and Age

Alcohol-related amnesia and dementia: animal models have revealed the contributions of different etiological factors on neuropathology, neurochemical dysfunction and cognitive impairment

Chronic alcoholism is associated with impaired cognitive functioning. Over 75% of autopsied chronic alcoholics have significant brain damage and over 50% of detoxified alcoholics display some degree of learning and memory impairment. However, the relative contributions of different etiological factors to the development of alcohol-related neuropathology and cognitive impairment are questioned. One reason for this quandary is that both alcohol toxicity and thiamine deficiency result in brain damage and cognitive problems. Two alcohol-related neurological disorders, alcohol-associated dementia and Wernicke-Korsakoff syndrome have been modeled in rodents. These pre-clinical models have elucidated the relative contributions of ethanol toxicity and thiamine deficiency to the development of dementia and amnesia. What is observed in these models--from repeated and chronic ethanol exposure to thiamine deficiency--is a progression of both neural and cognitive dysregulation. Repeated binge exposure to ethanol leads to changes in neural plasticity by reducing GABAergic inhibition and facilitating glutamatergic excitation, long-term chronic ethanol exposure results in hippocampal and cortical cell loss as well as reduced hippocampal neurotrophin protein content critical for neural survival, and thiamine deficiency results in gross pathological lesions in the diencephalon, reduced neurotrophic protein levels, and neurotransmitters levels in the hippocampus and cortex. Behaviorally, after recovery from repeated or chronic ethanol exposure there is impairment in working or episodic memory that can recover with prolonged abstinence. In contrast, after thiamine deficiency there is severe and persistent spatial memory impairments and increased perseverative behavior. The interaction between ethanol and thiamine deficiency does not produce more behavioral or neural pathology, with the exception of reduction of white matter, than long-term thiamine deficiency alone.

Molecular and behavioral aspects of the actions of alcohol on the adult and developing brain

The brain is one of the major target organs of alcohol actions. Alcohol abuse can lead to alterations in brain structure and functions and, in some cases, to neurodegeneration. Cognitive deficits and alcohol dependence are highly damaging consequences of alcohol abuse. Clinical and experimental studies have demonstrated that the developing brain is particularly vulnerable to alcohol, and that drinking during gestation can lead to a range of physical, learning and behavioral defects (fetal alcohol spectrum disorders), with the most dramatic presentation corresponding to fetal alcohol syndrome. Recent findings also indicate that adolescence is a stage of brain maturation and that heavy drinking at this stage can have a negative impact on brain structure and functions causing important short- and long-term cognitive and behavioral consequences. The effects of alcohol on the brain are not uniform; some brain areas or cell populations are more vulnerable than others. The prefrontal cortex, the hippocampus, the cerebellum, the white matter and glial cells are particularly susceptible to the effects of ethanol. The molecular actions of alcohol on the brain are complex and involve numerous mechanisms and signaling pathways. Some of the mechanisms involved are common for the adult brain and for the developing brain, while others depend on the developmental stage. During brain ontogeny, alcohol causes irreversible alterations to the brain structure. It also impairs several molecular, neurochemical and cellular events taking place during normal brain development, including alterations in both gene expression regulation and the molecules involved in cell-cell interactions, interference with the mitogenic and growth factor response, enhancement of free radical formation and derangements of glial cell functions. However, in both adult and adolescent brains, alcohol damages specific brain areas through mechanisms involving excitotoxicity, free radical formation and neuroinflammatory damage resulting from activation of the innate immune system mediated by TLR4 receptors. Alcohol also acts on specific membrane proteins, such as neurotransmitter receptors (e.g. NMDA, GABA-A), ion channels (e.g. L-type Ca²⁺ channels, GIRKs), and signaling pathways (e.g. PKA and PKC signaling). These effects might underlie the wide variety of behavioral effects induced by ethanol drinking. The neuroadaptive changes affecting neurotransmission systems which are more sensitive to the acute effects of alcohol occur after long-term alcohol consumption. Alcohol-induced maladaptations in the dopaminergic mesolimbic system, abnormal plastic changes in the reward-related brain areas and genetic and epigenetic factors may all contribute to alcohol reinforcement and alcohol addiction. This manuscript reviews the mechanisms by which ethanol impacts the adult and the developing brain, and causes both neural impairments and cognitive and behavioral dysfunctions. The identification and the understanding of the cellular and molecular mechanisms involved in ethanol toxicity might contribute to the development of treatments and/or therapeutic agents that could reduce or eliminate the deleterious effects of alcohol on the brain.

Association of frontal and posterior cortical gray matter volume with time to alcohol relapse: a prospective study

OBJECTIVE

Alcoholism is associated with gray matter volume deficits in frontal and other brain regions. Whether persistent brain volume deficits in abstinence are predictive of subsequent time to alcohol relapse has not been established. The authors measured gray matter volumes in healthy volunteers and in a sample of treatment-engaged, alcohol-dependent patients after 1 month of abstinence and assessed whether smaller frontal gray matter volume was predictive of subsequent alcohol relapse outcomes.

METHOD

Forty-five abstinent alcohol-dependent patients in treatment and 50 healthy comparison subjects were scanned once using high-resolution (T(1)-weighted) structural MRI, and voxel-based morphometry was used to assess regional brain volume differences between the groups. A prospective study design was used to assess alcohol relapse in the alcohol-dependent group for 90 days after discharge from 6 weeks of inpatient treatment.

RESULTS

Significantly smaller gray matter volume in alcohol-dependent patients relative to comparison subjects was seen in three regions: the medial frontal cortex, the right lateral prefrontal cortex, and a posterior region surrounding the parietal-occipital sulcus. Smaller medial frontal and parietal-occipital gray matter volumes were each predictive of shorter time to any alcohol use and to heavy drinking relapse.

CONCLUSIONS

These findings are the first to demonstrate that gray matter volume deficits in specific medial frontal and posterior parietal-occipital brain regions are predictive of an earlier return to alcohol use and relapse risk, suggesting a significant role for gray matter atrophy in poor clinical outcomes in alcoholism. Extent of gray matter volume deficits in these regions could serve as useful neural markers of relapse risk and alcoholism treatment outcome.

Remote semantic memory for public figures in HIV infection, alcoholism, and their comorbidity

BACKGROUND

Impairments in component processes of working and episodic memory mark both HIV infection and chronic alcoholism, with compounded deficits often observed in individuals comorbid for these conditions. Remote semantic memory processes, however, have only seldom been studied in these diagnostic groups. Examination of remote semantic memory could provide insight into the underlying processes associated with storage and retrieval of learned information over extended time periods while elucidating spared and impaired cognitive functions in these clinical groups.

METHODS

We examined component processes of remote semantic memory in HIV infection and chronic alcoholism in 4 subject groups (HIV, ALC, HIV + ALC, and age-matched healthy adults) using a modified version of the Presidents Test. Free recall, recognition, and sequencing of presidential candidates and election dates were assessed. In addition, component processes of working, episodic, and semantic memory were assessed with ancillary cognitive tests.

RESULTS

The comorbid group (HIV + ALC) was significantly impaired on sequencing of remote semantic information compared with age-matched healthy adults. Free recall of remote semantic information was also modestly impaired in the HIV + ALC group, but normal performance for recognition of this information was observed. Few differences were observed between the single diagnosis groups (HIV, ALC) and healthy adults, although examination of the component processes underlying remote semantic memory scores elicited differences between the HIV and ALC groups. Selective remote memory processes were related to lifetime alcohol consumption in the ALC group and to viral load and depression level in the HIV group. Hepatitis C diagnosis was associated with lower remote semantic memory scores in all 3 clinical groups. Education level did not account for group differences reported.

CONCLUSIONS

This study provides behavioral support for the existence of adverse effects associated with the comorbidity of HIV infection and chronic alcoholism on selective component processes of memory function, with untoward effects exacerbated by Hepatitis C infection. The pattern of remote semantic memory function in HIV + ALC is consistent with those observed in neurological conditions primarily affecting frontostriatal pathways and suggests that remote memory dysfunction in HIV + ALC may be a result of impaired retrieval processes rather than loss of remote semantic information per se.

Low effective organizational strategies in visual memory performance of unmedicated alcoholics during early abstinence

OBJECTIVE

Alcohol-dependent patients in early abstinence show an impairment of cognitive functions which can be seen in poor implementation of newly learned skills for avoiding relapse. Executive dysfunction may persist during abstinence in alcohol-dependent persons, thus mitigating long-term abstinence. This study assessed visual memory function and choice of organizational strategies in alcoholics, as these are major factors necessary to implement ongoing behavior changes which are required for maintaining abstinence.

METHODS

We investigated 25 severely alcohol-dependent male patients between days 7 to 10 of abstinence, immediately after clinical withdrawal symptoms have ceased, compared to 15 healthy age, sex, and education matched controls. Pharmacological therapy had been terminated at least four half-lifes before inclusion into the study. Visual perceptual learning and organizational strategies were assessed with the Rey-Osterrieth Complex Figure Test (R-OCF).

RESULTS

There were no group differences in copying or recalling the figure, but time differences occurred. Alcoholics and healthy controls performed worse in recalling than in copying. But, alcoholics used less effective organizational strategies.

CONCLUSIONS

There was a deficit in choice of organizational strategy in newly abstinent and unmedicated alcohol-dependent patients. Due to the imperfect organizational strategies, alcoholics might need auxiliary therapeutic care to strengthen their cognitive ability.

Study of metamemory in patients with chronic alcoholism using a feeling-of-knowing episodic memory task

BACKGROUND

Alcoholism affects various cognitive processes, including components of memory. Metamemory, though of particular interest for patient treatment, has not yet been extensively investigated.

METHODS

 A feeling-of-knowing (FOK) measure of metamemory was administered to 28 alcoholic patients and 28 healthy controls during an episodic memory task including the learning of 20 pairs of items, followed by a 20-minute delayed recall and a recognition task. Prior to recognition, participants rated their ability to recognize each nonrecalled word among 4 items. This episodic FOK measure served to compare predictions of future recognition performance and actual recognition performance. Furthermore, a subjective measure of metamemory, the Metamemory In Adulthood (MIA) questionnaire, was completed by patients and controls. This assessment of alcoholic patients' metamemory profile was accompanied by an evaluation of episodic memory and executive functioning.

RESULTS

FOK results revealed deficits in accuracy, with the alcoholic patients providing overestimations. There were also links between FOK inaccuracy, executive decline, and episodic memory impairment in patients. MIA results showed that although alcoholics did display memory difficulties, they did not differ from controls on questions about memory capacity.

CONCLUSIONS

Chronic alcoholism affects both episodic memory and metamemory for novel information. Patients were relatively unaware of their memory deficits and believed that their memory was as good as that of the healthy controls. The monitoring measure (FOK) and the subjective measure of metamemory (MIA) showed that patients with chronic alcoholism overestimated their memory capacities. Episodic memory deficit and executive dysfunction would explain metamemory decline in this clinical population.

Mechanisms of postural control in alcoholic men and women: biomechanical analysis of musculoskeletal coordination during quiet standing

BACKGROUND

Excessive sway during quiet standing is a common sequela of chronic alcoholism even with prolonged sobriety. Whether alcoholic men and women who have remained abstinent from alcohol for weeks to months differ from each other in the degree of residual postural instability and biomechanical control mechanisms has not been directly tested.

METHOD

We used a force platform to characterize center-of-pressure biomechanical features of postural sway, with and without stabilizing conditions from touch, vision, and stance, in 34 alcoholic men, 15 alcoholic women, 22 control men, and 29 control women. Groups were matched in age (49.4 years), general intelligence, socioeconomic status, and handedness. Each alcoholic group was sober for an average of 75 days.

RESULTS

Analysis of postural sway when using all 3 stabilizing conditions versus none revealed diagnosis and sex differences in ability to balance. Alcoholics had significantly longer sway paths, especially in the anterior-posterior direction, than controls when maintaining erect posture without balance aids. With stabilizing conditions the sway paths of all groups shortened significantly, especially those of alcoholic men, who demonstrated a 3.1-fold improvement in sway path difference between the easiest and most challenging conditions; the remaining 3 groups, each showed a approximately 2.4-fold improvement. Application of a mechanical model to partition sway paths into open-loop and closed-loop postural control systems revealed that the sway paths of the alcoholic men but not alcoholic women were characterized by greater short-term (open-loop) diffusion coefficients without aids, often associated with muscle stiffening response. With stabilizing factors, all 4 groups showed similar long-term (closed loop) postural control. Correlations between cognitive abilities and closed-loop sway indices were more robust in alcoholic men than alcoholic women.

CONCLUSIONS

Reduction in sway and closed-loop activity during quiet standing with stabilizing factors shows some differential expression in men and women with histories of alcohol dependence. Nonetheless, enduring deficits in postural instability of both alcoholic men and alcoholic women suggest persisting liability for falling.

Contribution of Regional White Matter Integrity to Visuospatial Construction Accuracy, Organizational Strategy, and Memory for a Complex Figure in Abstinent Alcoholics

Visuospatial construction ability as used in drawing complex figures is commonly impaired in chronic alcoholics, but memory for such information can be enhanced by use of a holistic drawing strategy during encoding. We administered the Rey-Osterrieth Complex Figure Test (ROCFT) to 41 alcoholic and 38 control men and women and assessed the contribution of diffusion tensor imaging (DTI) measures of integrity of selected white matter tracts to ROCFT copy accuracy, copy strategy, and recall accuracy. Although alcoholics copied the figure less accurately than controls, a more holistic strategy at copy was associated with better recall in both groups. Greater radial diffusivity, reflecting compromised myelin integrity, in occipital forceps and external capsule was associated with poorer copy accuracy in both groups. Lower FA, reflecting compromised fiber microstructure in the inferior cingulate bundle, which links frontal and medial temporal episodic memory systems, was associated with piecemeal copy strategy and poorer immediate recall in the alcoholics. The correlations were generally modest and should be considered exploratory. To the extent that the inferior cingulate was relatively spared in alcoholics, it may have provided an alternative pathway to the compromised frontal system for successful copy strategy and, by extension, aided recall.

Initiating moderate to heavy alcohol use predicts changes in neuropsychological functioning for adolescent girls and boys

This study prospectively examines the influence of alcohol on neuropsychological functioning in boys and girls characterized prior to initiating drinking (N = 76, ages 12-14). Adolescents who transitioned into heavy (n = 25; 11 girls, 14 boys) or moderate (n = 11; 2 girls, 9 boys) drinking were compared with matched controls who remained nonusers throughout the approximately 3-year follow-up period (N = 40; 16 girls, 24 boys). For girls, more past year drinking days predicted a greater reduction in visuospatial task performance from baseline to follow-up, above and beyond performance on equivalent measures at baseline (R2Delta = 10%, p < .05), particularly on tests of visuospatial memory (R2Delta = 8%, p < .05). For boys, a tendency was seen for more past year hangover symptoms to predict worsened sustained attention (R2Delta = 7%, p < .05). These preliminary longitudinal findings suggest that initiating moderately heavy alcohol use and incurring hangover during adolescence may adversely influence neurocognitive functioning. Neurocognitive deficits linked to heavy drinking during this critical developmental period may lead to direct and indirect changes in neuromaturational course, with effects that would extend into adulthood.

Working and episodic memory in HIV infection, alcoholism, and their comorbidity: baseline and 1-year follow-up examinations

BACKGROUND

Selective memory deficits occur in individuals with human immunodeficiency virus (HIV) infection and those with chronic alcoholism, but the potential compounded effect of these conditions is seldom considered, despite the high prevalence of alcohol use disorders in HIV infection.

METHODS

Here, we examined component processes of working and episodic memory in HIV infection and chronic alcoholism (ALC) in 4 subject groups (HIV, ALC, HIV + ALC, and normal controls) at baseline and 1-year follow-up. Accuracy scores, response times, and rate of information processing were assessed with subtests of the computerized neuropsychological test battery, the MicroCog.

RESULTS

Although individuals with either HIV infection or alcoholism generally performed at normal levels, individuals comorbid with HIV infection and alcoholism were impaired relative to controls and to the single diagnosis groups on selective memory processes. Immediate episodic memory was impaired, whereas working memory remained intact. Ability to retain information over time was not impaired in the clinical groups. Little performance change between groups was detected over 1 year. Results could not be explained by amount of alcohol consumed over a lifetime, CD4 cell count, AIDS diagnosis, or HAART medication.

CONCLUSIONS

This study provides behavioral support for adverse synergism of HIV infection and chronic alcoholism on brain function and is consistent with neuroimaging reports of compromised hippocampal and associated memory structures related to episodic memory processes in these 2 conditions.

Effects of alcoholism severity and smoking on executive neurocognitive function

AIMS

Neurocognitive deficits in chronic alcoholic men are well documented. Impairments include memory, visual-spatial processing, problem solving and executive function. The cause of impairment could include direct effects of alcohol toxicity, pre-existing cognitive deficits that predispose towards substance abuse, comorbid psychiatric disorders and abuse of substances other than alcohol. Cigarette smoking occurs at higher rates in alcoholism and has been linked to poor cognitive performance, yet the effects of smoking on cognitive function in alcoholism are often ignored. We examined whether chronic alcoholism and chronic smoking have effects on executive function.

METHODS

Alcoholism and smoking were examined in a community-recruited sample of alcoholic and non-alcoholic men (n = 240) using standard neuropsychological and reaction-time measures of executive function. Alcoholism was measured as the average level of alcoholism diagnoses across the study duration (12 years). Smoking was measured in pack-years.

RESULTS

Both alcoholism and smoking were correlated negatively with a composite executive function score. For component measures, alcoholism was correlated negatively with a broad range of measures, whereas smoking was correlated negatively with measures that emphasize response speed. In regression analyses, both smoking and alcoholism were significant predictors of executive function composite. However, when IQ is included in the regression analyses, alcoholism severity is no longer significant.

CONCLUSIONS

Both smoking and alcoholism were related to executive function. However, the effect of alcoholism was not independent of IQ, suggesting a generalized effect, perhaps affecting a wide range of cognitive abilities of which executive function is a component. On the other hand, the effect of smoking on measures relying on response speed were independent of IQ, suggesting a more specific processing speed deficit associated with chronic smoking.

Cognitive performance in long-term abstinent elderly alcoholics

BACKGROUND

To date, there is a wealth of literature describing the deleterious effects of active alcoholism on cognitive function. There is also a growing body of literature on the extent of cognitive recovery that can occur with abstinence. However, there is still a dearth of published findings on cognitive functioning in very long-term abstinence alcoholics, especially in the elderly population.

METHODS

The current study examines 91 elderly abstinent alcoholics (EAA) (49 men and 42 women) with an average age of 67.3 years, abstinent for an average of 14.8 years (range 0.5 to 45 years), and age and gender comparable light/nondrinking controls. The EAA group was divided into 3 subgroups: individuals that attained abstinence before age 50 years, between the ages 50 and 60 years, and after age 60 years. Attention, verbal fluency, abstraction/cognitive flexibility, psychomotor, immediate memory, delayed memory, reaction time, spatial processing, and auditory working memory were assessed. The AMNART and cranium size were used as estimates of brain reserve capacity, and the association of all variables with alcohol use measures was examined.

RESULTS

Overall, the EAA groups performed comparably to controls on the assessments of cognitive function. Only the abstinent in group before 50 years of age performed worse than controls, and this was only in the domain of auditory working memory. EAAs had larger craniums than their controls. This effect was strongest for those who drank the longest and had the shortest abstinence. Such individuals also performed better cognitively.

CONCLUSIONS

Our data showed that elderly alcoholics that drank late into life, but with at least 6 months abstinence can exhibit normal cognitive functioning. Selective survivorship and selection bias probably play a part in these findings. Cognitively healthier alcoholics, with more brain reserve capacity, may be more likely to live into their 60s, 70s, or 80s of age with relatively intact cognition, and to volunteer for studies such as this. Our results do not imply that all elderly alcoholics with long-term abstinence will attain normal cognition.

Improvement in memory and static balance with abstinence in alcoholic men and women: selective relations with change in brain structure

We investigated whether changes in memory or static balance in chronic alcoholics, occurring with abstinence or relapse, are associated with changes in lateral and fourth ventricular volume. Alcoholics meeting DSM-IV criteria for Alcohol Dependence (n=15) and non-alcoholic controls (n=26) were examined twice at a mean interval of 2 years with standard Wechsler Abbreviated Scale of Intelligence (WASI), Wechsler Memory Scale-Revised (WMS-R) tests, an ataxia battery, and structural MRI. At study entry, alcoholics had been abstinent on average for over 4 months and achieved lower scores than controls on WASI General IQ Index, WMS-R General Memory Index, and the ataxia battery. The 10 alcoholics who maintained sobriety at retest did not differ at study entry in socio-demographic measures, alcohol use, or WASI and WMS-R summary scores from the five relapsers. At follow-up, abstainers improved more than controls on the WMS-R General Memory Index. Ataxia tended to improve in abstainers relative to controls. Associations were observed between memory and lateral ventricular volume change and between ataxia and fourth ventricular volume change in alcoholics but not in the controls. Both memory and ataxia can improve with sustained sobriety, and brain-behavior associations suggest selective brain structural substrates for the changes observed.

An inverse relationship between typical alcohol consumption and facial symmetry detection ability in young women

The relationship between monthly alcohol consumption over the past 6 months and facial symmetry perception ability was examined in young sober women with typical college-age drinking patterns. Facial symmetry detection performance was inversely related to typical monthly alcohol consumption, r (41) = -0.57, p < 0.001. Other variables that were predictive of facial symmetry detection included alcohol-related hangover and blackout frequency over the past 6 months, number of alcoholic drinks over the past week, early adolescent alcohol consumption and frequency of drug use. The relationship between alcohol use and symmetry detection could not be explained by individual differences in personality, family alcoholism history or other drug use. These findings suggest the possibility of a neurotoxic effect of alcohol on facial symmetry perception ability in female undergraduate students. As similar results did not emerge for a test of dot symmetry detection, the findings appear specific to facial symmetry. No previous studies have examined the effect of alcohol history on symmetry detection. The findings add to a growing literature indicating negative visuospatial effects of early alcohol use, and suggest the importance of further research examining alcohol and drug effects on sober facial perception in non-alcoholic populations.

Genuine episodic memory deficits and executive dysfunctions in alcoholic subjects early in abstinence

BACKGROUND

Chronic alcoholism is known to impair episodic memory function, but the specific nature of this impairment is still unclear. Moreover, it has never been established whether episodic memory deficit in alcoholism is an intrinsic memory deficit or whether it has an executive origin. Thus, the objectives are to specify which episodic memory processes are impaired early in abstinence from alcohol and to determine whether they should be regarded as genuine memory deficits or rather as the indirect consequences of executive impairments.

METHODS

Forty recently detoxified alcoholic inpatients at alcohol entry treatment and 55 group-matched controls underwent a neuropsychological assessment of episodic memory and executive functions. The episodic memory evaluation consisted of 3 tasks complementing each other designed to measure the different episodic memory components (learning, storage, encoding and retrieval, contextual memory, and autonoetic consciousness) and 5 executive tasks testing capacities of organization, inhibition, flexibility, updating, and integration.

RESULTS

Compared with control subjects, alcoholic patients presented impaired learning abilities, encoding processes, retrieval processes, contextual memory and autonoetic consciousness. However, there was no difference between the 2 groups regarding the storage capacities assessed by the rate of forgetting. Concerning executive functions, alcoholic subjects displayed deficits in each executive task used. Nevertheless, stepwise regression analyses showed that only performances on fluency tasks were significantly predictive of some of the episodic memory disorders (learning abilities for 40%, encoding processes for 20%, temporal memory for 21%, and state of consciousness associated with memories for 26%) in the alcoholic group.

DISCUSSION

At alcohol treatment entry, alcoholic patients present genuine episodic memory deficits that cannot be regarded solely as the consequences of executive dysfunctions. These results are in accordance with neuroimaging findings showing hippocampal atrophy. Moreover, given the involvement of episodic memory and executive functions in alcohol treatment, these data could have clinical implications.

Chronic Smoking Is Associated With Differential Neurocognitive Recovery in Abstinent Alcoholic Patients: A Preliminary Investigation

BACKGROUND

Approximately 50 to 90% of individuals in North America seeking treatment for alcoholism are chronic smokers. A growing body of evidence suggests that chronic cigarette smokers show a pattern of neurocognitive dysfunction similar to that observed in alcoholic patients. However, previous studies investigating neurocognitive recovery in abstinent alcoholic patients did not specifically consider the potential effects of chronic cigarette smoking.

METHODS

This study comprehensively compared longitudinal neurocognitive changes over 6 to 9 months of abstinence among 13 nonsmoking recovering alcoholic patients (ALC) and 12 actively smoking ALC. The neurocognitive performance of the alcoholic groups was compared with nonsmoking light-drinking controls (nonsmoking LD).

RESULTS

Nonsmoking ALC exhibited a significantly greater magnitude of longitudinal improvement than smoking ALC on measures of cognitive efficiency, executive skills, visuospatial skills, and working memory. Both nonsmoking ALC and smoking ALC demonstrated equivalent improvement on auditory-verbal learning, auditory-verbal memory, and processing speed. Nonsmoking LD showed no significant changes in neurocognition over time. In cross-sectional comparisons at 6 to 9 months of abstinence, nonsmoking ALC were superior to smoking ALC on measures of auditory-verbal learning, auditory-verbal memory, cognitive efficiency, executive skills, processing speed, and working memory. The longitudinal and cross-sectional neurocognitive differences observed between nonsmoking and smoking ALC remained significant after covarying for group differences in education, estimated premorbid intelligence alcohol consumption, and other potentially confounding variables. In smoking ALC, greater smoking severity was inversely related to longitudinal improvement on multiple neurocognitive measures.

CONCLUSIONS

These preliminary results suggest that chronic smoking may modulate neurocognitive recovery in abstinent alcoholic patients. More generally, chronic smoking may impact neurocognition in other conditions where is it a prevalent behavior.

Component cognitive and motor processes of the digit symbol test: differential deficits in alcoholism, HIV infection, and their comorbidity

BACKGROUND

Alcoholism (ALC) is highly prevalent in patients with human immunodeficiency virus (HIV) infection (HIV), and those with comorbidity (ALC+HIV) may suffer compounded deficits in cognitive and motor functions affected by both conditions. Given that each disease can adversely affect motor, visuospatial, and executive functions, we used an expanded version of the Digit Symbol (DS) test to assess the separate and combined effects of ALC and HIV infection on these cognitive and motor components.

METHODS

Participants were 44 ALC, 43 HIV, 55 ALC+HIV, and 49 normal controls (NC). We modified DS test administration to assess sustained attention (grid completion speed), associative learning (number of boxes completed in 15-second epochs), and incidental learning (total number-symbol pairs correctly recalled) and also used ancillary tests of fine motor, visuospatial, and executive functions to assess their relationship with the different components of DS performance. All scores were corrected for age and education based on NC performance.

RESULTS

Neither single diagnosis group-ALC nor HIV-was impaired on DS score or grid completion speed compared with the NC group, but the dual-diagnosis ALC+HIV group was impaired. Greater lifetime alcohol consumption was associated with longer grid completion time in both ALC and ALC+HIV. The HIV group demonstrated associative learning on DS but ALC+HIV and ALC did not. All groups performed similarly on incidental learning. Multiple regression analyses demonstrated that executive functions, assessed by Color Trails 2, predicted traditional DS performance in all groups. Fine Finger Movement additionally predicted traditional DS performance and grid completion speed in HIV. Visuospatial function, assessed by ability to copy the Rey-Osterrieth complex figure, did not contribute independently to DS performance in either alcohol group.

CONCLUSIONS

Alcoholism combined with HIV infection resulted in deficits in visuospatial psychomotor function, as assessed by the DS test, although deficits were not observed in either disease condition alone. Neither alcohol group showed associative learning, and both had compromised sustained attention. Combined cognitive and motor adverse effects of alcoholism and HIV infection were manifest in psychomotor speed, sustained attention, and associative learning of visuospatial material and are testimony to the dangers of alcohol abuse even in relatively healthy patients with HIV infection.

Gender Differences in Neurocognitive Functioning Among Alcohol-Dependent Russian Patients

BACKGROUND

There are a limited number of studies that have examined gender differences in the neurocognitive test performances of alcohol-dependent individuals. Those that have been conducted reported that compared with men, women's visuospatial skills, psychomotor speed, and working memory are more profoundly affected by chronic alcohol abuse despite a shorter duration of drinking and a lesser quantity of alcohol consumed.

METHODS

The performances of Russian male and female alcoholic and nonalcoholic control subjects were compared on a series of neurocognitive tasks that assess motor speed, visuoperceptual processing, visuospatial processing, decision making, and cognitive flexibility.

RESULTS

Group and gender differences emerged on specific components of each task administered. Female compared with male alcoholic subjects exhibited poorer performances on tests of visual working memory, spatial planning and problem solving, and cognitive flexibility.

CONCLUSION

The data support and extend prior research demonstrating a more deleterious impact of alcohol dependence on female alcoholic subjects' cognitive functioning compared with male alcoholic subjects. Several theories are offered to account for gender differences in neurocognitive performance.

Effect of Episodic and Working Memory Impairments on Semantic and Cognitive Procedural Learning at Alcohol Treatment Entry

BACKGROUND

Chronic alcoholism is known to impair the functioning of episodic and working memory, which may consequently reduce the ability to learn complex novel information. Nevertheless, semantic and cognitive procedural learning have not been properly explored at alcohol treatment entry, despite its potential clinical relevance. The goal of the present study was therefore to determine whether alcoholic patients, immediately after the weaning phase, are cognitively able to acquire complex new knowledge, given their episodic and working memory deficits.

METHODS

Twenty alcoholic inpatients with episodic memory and working memory deficits at alcohol treatment entry and a control group of 20 healthy subjects underwent a protocol of semantic acquisition and cognitive procedural learning. The semantic learning task consisted of the acquisition of 10 novel concepts, while subjects were administered the Tower of Toronto task to measure cognitive procedural learning.

RESULTS

Analyses showed that although alcoholic subjects were able to acquire the category and features of the semantic concepts, albeit slowly, they presented impaired label learning. In the control group, executive functions and episodic memory predicted semantic learning in the first and second halves of the protocol, respectively. In addition to the cognitive processes involved in the learning strategies invoked by controls, alcoholic subjects seem to attempt to compensate for their impaired cognitive functions, invoking capacities of short-term passive storage. Regarding cognitive procedural learning, although the patients eventually achieved the same results as the controls, they failed to automate the procedure. Contrary to the control group, the alcoholic groups' learning performance was predicted by controlled cognitive functions throughout the protocol.

CONCLUSION

At alcohol treatment entry, alcoholic patients with neuropsychological deficits have difficulty acquiring novel semantic and cognitive procedural knowledge. Compared with controls, they seem to use more costly learning strategies, which are nonetheless less efficient. These learning disabilities need to be considered when treatment requiring the acquisition of complex novel information is envisaged.

Is the P300 deficit in alcoholism associated with early visual impairments (P100, N170)? An oddball paradigm

OBJECTIVE

Studies exploring chronic alcoholism with event-related potentials (ERPs) have shown delayed latency and reduced amplitude of the P300, a long-lasting positive potential reflecting decisional processing. This P300 deficit in alcoholism is generally interpreted as a disturbance in central nervous system inhibition or in memory/attention. The present study aimed at identifying if this electrophysiological deficit is already present on earlier components, and advances a new hypothesis concerning the interpretation of the P300 alteration.

METHODS

Patients suffering from alcoholism and matched healthy controls had to detect, in an oddball paradigm, emotional faces among a succession of neutral faces. Behavioral performance and ERP data (recorded from 32 electrodes) were analyzed.

RESULTS

In line with previous studies, data showed that alcoholism led to a P300 deficit. Moreover, we observed for the first time that this deficit begins at earlier visual (P100) and face-processing (N170) stages, and we found high positive correlations between P100, N170 and P300 for amplitude and latency values, suggesting cumulative deficits on the cognitive continuum.

CONCLUSIONS

We suggest that the P300 deficit observed in chronic alcoholism could be linked to earlier visuo-spatial deficits rather than being an impairment of the specific processes linked to the P300.

SIGNIFICANCE

These results call for reconsidering the interpretation of P300 impairments at a fundamental and clinical level, and shows that earlier ERP components must be taken into account in future studies.

Neuropsychological functioning in posttraumatic stress disorder and alcohol abuse

Studies have shown differences in neuropsychological functioning between groups with posttraumatic stress disorder (PTSD) and control participants. Because individuals with PTSD often have a history of comorbid alcohol abuse, the extent to which an alcohol confound is responsible for these differences remains a concern. The current study compares neuropsychological testing scores in 4 groups of veterans with and without PTSD (PTSD+ and PTSD-, respectively) and with and without a history of alcohol abuse (ETOH+ and ETOH-, respectively): n for PTSD+/ETOH- = 30, n for PTSD+/ETOH- = 37, n for PTSD-/ETOH+ = 30, and n for PTSD-/ETOH- = 31. Results showed that PTSD, when alcohol, educational level, vocabulary, and depression are controlled for, was associated with decreased verbal memory, attention, and processing speed performance. Alcohol abuse history was associated with decreased visual memory performance. By controlling for alcohol and depression, the authors can more conclusively demonstrate that verbal memory and attention differences are associated with PTSD.

Visuoperceptual learning in alcoholic Korsakoff syndrome

Relative to the characteristically profound deficits of explicit memory, components of implicit memory remain largely intact in patients with alcohol-induced Korsakoff syndrome (KS). Perceptual priming occurs in KS and transfer of learning has been consistently observed on mirror reading, a perceptual reversal task. Although priming also occurs with fragmented pictures, a perceptual closure task, it is unclear whether transfer of learning can occur. This study examined visuoperceptual learning in 4 men with alcoholic KS, 9 recently detoxified alcoholic men (ALC), 21 healthy age-matched normal control men (NC), and 6 young normal control men (YNC). Subjects were tested with the Gollin Incomplete Pictures Test at initial and 1-hour and 1-day retest sessions. Both alcoholic groups (KS, ALC) were impaired in visuoperceptual ability. All subject groups showed visuoperceptual learning. The KS group showed additional learning after continued exposure to the stimuli, despite their nonmnemonic visuospatial deficits and profound explicit memory impairment for the test stimuli. Transfer of learning to similar but new stimuli was not evident in either the KS or young healthy control subjects; learning occurred only for the specific items presented. The persistence of learning beyond the life of the percept, which was independent of declarative features (such as item recall), suggests that perceptual learning and memory reflects an intact cognitive memory process in KS. This process is likely mediated by posterior cortical networks relatively unaffected in KS and that are independent of the hippocampal-diencephalic declarative memory system.

Neuropsychological functioning and alcohol dependence

PURPOSE OF REVIEW

Alcohol dependence is a significant challenge to society and health-care services. The associated cognitive deficits are thought to affect behavioral control, therapy and liability to relapse. The present review demonstrates important new findings.

RECENT FINDINGS

Recent interest focused on compensatory functional circuits, components of executive functioning, externally induced attentional biases and the relevance of the cognitive deficits for therapy and rehabilitation.

SUMMARY

Recent studies found widespread compromised fronto-cortico-cerebellar circuits to underlie cognitive deficits. The inclusion of cerebellar structures to support functions traditionally associated with cortical and even prefrontal structures is important. However, most importantly, alcohol-dependent patients use additional and generally higher-order executive functions to compensate for deficient task performance. The compensatory mechanisms might help to explain close to normal functioning in basic cognitive domains enabled by support of executive components. But deficits in executive functions themselves might emerge more directly. New approaches concerning executive functioning, analyzing functional components of executive tasks, found response inhibition and decision-making to be impaired but normal performance in simple working memory tasks. Multiple withdrawals have been shown to lead to a higher degree of executive deficit. The causing mechanism underlying the attentional bias induced by alcohol-related words (stroop effect) is still under debate. Correlation of cognitive deficits with therapy outcome turned out to be weak. However, important interactions of cognitive deficits with personality, therapy-setting and successful coping, together with the finding that cognitive performance of alcohol-dependent patients could be enhanced by motivating instructions, might open new strategies in treatment planning and cognitive rehabilitation.