Neuropsychology of Alcoholism. In: Galanter M, Begleiter H, Cicero T, Deitrich R, Goodwin DW, Gottheil E, Paredes A, Rothschild M, Mason J, editors. Genetics Behavioral Treatment Social Mediators and Prevention Current Concepts in Diagnosis. Boston: Springer US; 1983. pp. 449-69. [DOI: 10.1007/978-1-4613-3617-4_23]

Differentiating Individuals with and without Alcohol Use Disorder Using Resting-State fMRI Functional Connectivity of Reward Network, Neuropsychological Performance, and Impulsivity Measures

Individuals with alcohol use disorder (AUD) may manifest an array of neural and behavioral abnormalities, including altered brain networks, impaired neurocognitive functioning, and heightened impulsivity. Using multidomain measures, the current study aimed to identify specific features that can differentiate individuals with AUD from healthy controls (CTL), utilizing a random forests (RF) classification model. Features included fMRI-based resting-state functional connectivity (rsFC) across the reward network, neuropsychological task performance, and behavioral impulsivity scores, collected from thirty abstinent adult males with prior history of AUD and thirty CTL individuals without a history of AUD. It was found that the RF model achieved a classification accuracy of 86.67% (AUC = 93%) and identified key features of FC and impulsivity that significantly contributed to classifying AUD from CTL individuals. Impulsivity scores were the topmost predictors, followed by twelve rsFC features involving seventeen key reward regions in the brain, such as the ventral tegmental area, nucleus accumbens, anterior insula, anterior cingulate cortex, and other cortical and subcortical structures. Individuals with AUD manifested significant differences in impulsivity and alterations in functional connectivity relative to controls. Specifically, AUD showed heightened impulsivity and hypoconnectivity in nine connections across 13 regions and hyperconnectivity in three connections involving six regions. Relative to controls, visuo-spatial short-term working memory was also found to be impaired in AUD. In conclusion, specific multidomain features of brain connectivity, impulsivity, and neuropsychological performance can be used in a machine learning framework to effectively classify AUD individuals from healthy controls.

Random Forest Classification of Alcohol Use Disorder Using EEG Source Functional Connectivity, Neuropsychological Functioning, and Impulsivity Measures

: Individuals with alcohol use disorder (AUD) manifest a variety of impairments that can be attributed to alterations in specific brain networks. The current study aims to identify features of EEG-based functional connectivity, neuropsychological performance, and impulsivity that can classify individuals with AUD (N = 30) from unaffected controls (CTL, N = 30) using random forest classification. The features included were: (i) EEG source functional connectivity (FC) of the default mode network (DMN) derived using eLORETA algorithm, (ii) neuropsychological scores from the Tower of London test (TOLT) and the visual span test (VST), and (iii) impulsivity factors from the Barratt impulsiveness scale (BIS). The random forest model achieved a classification accuracy of 80% and identified 29 FC connections (among 66 connections per frequency band), 3 neuropsychological variables from VST (total number of correctly performed trials in forward and backward sequences and average time for correct trials in forward sequence) and all four impulsivity scores (motor, non-planning, attentional, and total) as significantly contributing to classifying individuals as either AUD or CTL. Although there was a significant age difference between the groups, most of the top variables that contributed to the classification were not significantly correlated with age. The AUD group showed a predominant pattern of hyperconnectivity among 25 of 29 significant connections, indicating aberrant network functioning during resting state suggestive of neural hyperexcitability and impulsivity. Further, parahippocampal hyperconnectivity with other DMN regions was identified as a major hub region dysregulated in AUD (13 connections overall), possibly due to neural damage from chronic drinking, which may give rise to cognitive impairments, including memory deficits and blackouts. Furthermore, hypoconnectivity observed in four connections (prefrontal nodes connecting posterior right-hemispheric regions) may indicate a weaker or fractured prefrontal connectivity with other regions, which may be related to impaired higher cognitive functions. The AUD group also showed poorer memory performance on the VST task and increased impulsivity in all factors compared to controls. Features from all three domains had significant associations with one another. These results indicate that dysregulated neural connectivity across the DMN regions, especially relating to hyperconnected parahippocampal hub as well as hypoconnected prefrontal hub, may potentially represent neurophysiological biomarkers of AUD, while poor visual memory performance and heightened impulsivity may serve as cognitive-behavioral indices of AUD.

Random Forest Classification of Alcohol Use Disorder Using fMRI Functional Connectivity, Neuropsychological Functioning, and Impulsivity Measures

Individuals with alcohol use disorder (AUD) are known to manifest a variety of neurocognitive impairments that can be attributed to alterations in specific brain networks. The current study aims to identify specific features of brain connectivity, neuropsychological performance, and impulsivity traits that can classify adult males with AUD (n = 30) from healthy controls (CTL, n = 30) using the Random Forest (RF) classification method. The predictor variables were: (i) fMRI-based within-network functional connectivity (FC) of the Default Mode Network (DMN), (ii) neuropsychological scores from the Tower of London Test (TOLT), and the Visual Span Test (VST), and (iii) impulsivity factors from the Barratt Impulsiveness Scale (BIS). The RF model, with a classification accuracy of 76.67%, identified fourteen DMN connections, two neuropsychological variables (memory span and total correct scores of the forward condition of the VST), and all impulsivity factors as significantly important for classifying participants into either the AUD or CTL group. Specifically, the AUD group manifested hyperconnectivity across the bilateral anterior cingulate cortex and the prefrontal cortex as well as between the bilateral posterior cingulate cortex and the left inferior parietal lobule, while showing hypoconnectivity in long-range anterior-posterior and interhemispheric long-range connections. Individuals with AUD also showed poorer memory performance and increased impulsivity compared to CTL individuals. Furthermore, there were significant associations among FC, impulsivity, neuropsychological performance, and AUD status. These results confirm the previous findings that alterations in specific brain networks coupled with poor neuropsychological functioning and heightened impulsivity may characterize individuals with AUD, who can be efficiently identified using classification algorithms such as Random Forest.

Impaired fear recognition and attentional set-shifting is associated with brain structural changes in alcoholic patients

Alcoholic patients with multiple detoxifications/relapses show cognitive and emotional deficits. We performed structural magnetic resonance imaging and examined performance on a cognitive flexibility task (intra-extradimensional set shift and reversal; IED). We also presented subjects with fearful, disgust and anger facial emotional expressions. Participants were abstaining, multiply detoxified (MDTx; n = 12) or singly detoxified patients (SDTx; n = 17) and social drinker controls (n = 31). Alcoholic patients were less able than controls to change their behavior in accordance with the changing of the rules in the IED and they were less accurate in recognizing fearful expressions in particular. They also showed lower gray matter volume compared with controls in frontal brain areas, including inferior frontal cortex (IFC) and insula that mediate emotional processing, inferior parietal lobule and medial frontal cortex that mediate attentional and motor planning processes, respectively. Impairments in performance and some of the regional decreases in gray matter were greater in MDTx. Gray matter volume in IFC in patients was negatively correlated with the number of detoxifications, whereas inferior parietal lobule was negatively correlated with the control over drinking score (impaired control over drinking questionnaire). Performance in IED was also negatively correlated with gray matter volume in IFC/BA47, whereas recognition of fearful faces was positively correlated with the IFC gray matter. Repeated episodes of detoxification from alcohol, related to severity of dependency, are coupled with altered brain structure in areas of emotional regulation, attention and motor planning. Such changes may confer increased inability to switch behavior according to environmental demands and social incompetence, contributing to relapse.

Reduced resource optimization in male alcoholics: N400 in a lexical decision paradigm

BACKGROUND

Event Related Potential (ERP) studies have highlighted some measures, notably P3 amplitude, that are associated with both state and trait deficits in alcoholism, while studies examining N400 amplitude in alcoholism are few. The present study aims to examine differences in the N400 component, an electrophysiological correlate of semantic priming, in event-related potentials from a lexical decision task in 87 alcohol dependent subjects and 57 community controls.

METHODS

 Each subject was presented with 300 stimuli sequentially in a quasi-randomized design, where 150 stimuli were words and 150 were non-words. The subjects made a lexical decision indicating the word/non-word status with a button press. Among the words, 50 words (primed) were always preceded by their antonyms (prime, n=50), whereas the remaining 50 words were unrelated. N400 amplitude and latency measures were compiled from ERPs to the primed and unprimed words. Corresponding reaction time (RT) and response characteristics were also analyzed.

RESULTS

Control subjects revealed a significant attenuation of the N400 response to the primed word when compared to the unprimed word. Significantly less attenuation was observed in alcohol dependent subjects. No significant group differences were seen for latency and behavioral measures. All subjects had slower RT for unprimed words compared to primed words; however significantly less RT savings between the unprimed and primed condition was noted for alcoholics.

CONCLUSIONS

 These results suggest a reduced flexibility in the cognitive networks and a lack of resource optimization in alcoholics. The reduced attenuation of N400 during the primed condition in the alcohol dependent subjects may reflect an inability to engage similar neuronal substrates associated with semantic relatedness as seen in the controls. As diminished N400 attenuation during priming is observed in both alcoholics and high risk subjects, it may be a marker of risk and a good endophenotype for alcoholism.

White matter integrity in adolescents with histories of marijuana use and binge drinking

Structural brain abnormalities have been observed in adolescents with alcohol use disorders but less is known about neuropathological brain characteristics of teens with sub-diagnostic binge drinking or the common pattern of binge drinking combined with marijuana use. The goal of this study was to examine white matter integrity in adolescents with histories of binge drinking and marijuana use. Diffusion tensor imaging (DTI) was conducted with 42 adolescents (ages 16-19) classified as controls, binge drinkers, or binge drinkers who are also heavy marijuana users. Tract based spatial analysis identified shared fiber structure across individuals and facilitated voxelwise comparisons of fractional anisotropy (FA) and mean diffusivity (MD) between groups. Significant between group differences were found in FA in eight white matter regions (ps < or = .016) between the binge drink-only group and controls, including superior corona radiata, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and superior longitudinal fasciculus. Interestingly, in 4 of these same regions, binge drinkers who are also heavy marijuana users had higher FA than binge drinkers who did not use marijuana (ps<.05). MD did not differ between groups. Findings are largely consistent with research suggesting less neuropathology in adolescents without histories of substance use. However, binge drinkers who also use marijuana did not show as consistent a divergence from non-users as did the binge drink-only group. Detection of white matter alterations may have implications in identifying early cognitive dysfunction in substance using adolescents.

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.

Sleep electroencephalographic spectral power after withdrawal from alcohol in alcohol-dependent patients

BACKGROUND

Dysfunctional hyperarousal is suspected to be a neurophysiological determinant of relapse in abstinent alcohol-dependent patients. In the present study, we used spectral power analysis of the sleep electroencephalographic (EEG) to quantify brain activity during sleep in patients during subacute withdrawal as well as in control subjects. Our hypothesis was that the subgroup of patients who relapsed within the 3 months to follow-up would exhibit-increased dysfunctional arousal manifested by higher-frequency (beta) EEG power during sleep.

METHODS

Twenty-six alcohol-dependent in-patients were examined with polysomnography over 2 nights 2 to 3 weeks after withdrawal. At the 3-month clinical follow-up assessment, 12 of them had relapsed and 14 abstained. The control group consisted of 23 healthy subjects similar to the patients with alcohol dependence in age and gender distribution. Spectral sleep EEG analysis was performed on both nights (adaptation and baseline) of all subjects. Logarithmic artifact-controlled spectral band power of sleep stage 2 and rapid eye movement (REM) sleep was analyzed for Group, Gender, and Age effects using multiple analyses of covariance. Three groups were compared with the Group factor: relapsers, abstainers, and controls.

RESULTS

Generally, both Group and Age effects were significant for the second, baseline night for the visually scored sleep parameters, while spectral EEG parameters showed significant differences in the adaptation night. In the adaptation night, a significant enhancement in the beta2 band (24-32 Hz) was seen in REM sleep in relapsers relative to both abstainers and controls.

CONCLUSIONS

The beta2 increase could be interpreted as a sign of dysfunctional arousal during REM sleep "unmasked" by the additional stressor of sleep environment adaptation. Its determinants are likely to be both premorbid and drinking history related.

Assessing cerebral dysfunction with probe-evoked potentials in a CNV task -- a study in alcoholics

OBJECTIVES

Contrary to event-related potential (ERP) components N1, N2 and P3, slow ERPs have rarely been used in assessing cerebral dysfunction in mental disorders. Focussing on slow waves (SWs) and on patients with mild cerebral dysfunction, we recorded ERPs in alcoholics using a dual task design.

METHODS

ERPs to auditory probes presented either 1s before the warning or 1s before the imperative stimulus of a visual contingent negative variation (CNV) paradigm were recorded from 33 scalp electrodes in 27 alcoholics following detoxification and 12 healthy controls. Independent component analysis (ICA) was used to separate potentially overlapping spatial components.

RESULTS

In alcoholics compared to controls, probe ERPs showed increased N2, decreased P3 and increased negative SWs of two types appearing pre- and post-P3, respectively. Both negative SWs significantly correlated with neuropsychological indices reflecting verbal intelligence and memory functions. The increase in probe-evoked N1 and P3 potentials during CNV, putatively associated with enhanced cortical excitability, significantly correlated with clinical features of protracted alcohol withdrawal syndrome in alcoholics.

CONCLUSIONS

Our experimental approach revealed two types of negative SWs which strongly correlated with neuropsychological deficits of mildly impaired patients. It is suggested that our methods might enhance diagnostic efficiency of ERPs. An electrophysiological measure of protracted alcohol withdrawal might be useful for managing central nervous system dysfunction in alcoholics.

Clinical significance of alcohol intake parameters at initiation of drinking

A considerable effort is now being focused upon the identification in young adulthood of predictive variables that can be used to detect individuals at risk for developing future alcohol problems. One goal is that such individuals may be targeted for early intervention efforts aimed at preventing the development of serious alcohol-related problems. Another goal is to extend the understanding of the etiology of alcoholism by identifying physiological and behavioral mechanisms underlying the addictive process. Reviewed below are efforts focused upon the importance and predictive value of the response to early exposures to ethanol, including alcohol intake variables at onset of drinking.

Rotation, locomotor activity and individual differences in voluntary ethanol consumption

Spontaneous turning behavior and locomotor activity were evaluated for their ability to predict differences in the voluntary consumption of ethanol in male Long-Evans rats. Animals were assessed for their preferred direction of turning behavior and for high vs. low levels of spontaneous locomotor activity, as determined during nocturnal testing in a rotometer. Subsequently, preference for a 10% ethanol solution vs. water was determined in a 24-h two-bottle home-cage free-choice paradigm. Rats exhibiting a right-turning preference consumed more ethanol than rats showing a left-turning preference. While locomotor activity alone did not predict differences in drinking, turning and locomotor activity together predicted differences in ethanol consumption. Low-activity right-turning rats consumed more ethanol than all the other groups of rats. Previous studies from this laboratory have shown that individual differences in turning behavior are accompanied by different asymmetries in dopamine (DA) function in the medial prefrontal cortex (mPFC). Individual differences in locomotor activity are associated with differences in nucleus accumbens (NAS) DA function. The present data suggest that variations in mPFC DA asymmetry and NAS DA function may underlie differences in the voluntary consumption of ethanol.

Neuropsychological function and psychosocial status of alcohol rehabilitation program residents

This investigation examined the relationship between changes in psychosocial status and changes in neuropsychological function of clients undergoing treatment for substance use. A sample of 74 adults enrolled at a rehabilitation program for substance use were randomly assigned to two groups (one serving as a comparison group for practice effects). Participants were tested three times over 60 days on self-esteem, motivation, depression, and neuropsychological function. Consistent with other studies, participants demonstrated impaired baseline neuropsychological function that improved with alcoholic abstinence; however, changes in motivation and depression were associated with positive changes on few tests of neuropsychological function. The more common predictor of improved motor function test scores was low baseline function. Participants who remained in treatment were more likely to be Black, homeless, report less alcohol consumption, and score lower on a motivational scale than those who left treatment.

Perceptuomotor function of homeless males in alcohol rehabilitation

In a sample of 76 alcohol rehabilitation program (ARP) residents, homeless men demonstrated significantly poorer perceptuomotor function than nonhomeless men. This difference persisted despite similarities in several factors associated with neurobehavioral test scores including demographic characteristics; frequency, quantity, and duration of alcohol and other substance use; psychosocial factors, including motivation and social support; health, including history of head trauma; and neurotoxic occupational exposure.

Alcohol and adolescence

Alcohol is the drug of choice for most substance-abusing adolescents and is the drug most often associated with teenage deaths. This article summarizes what is known about the inheritance of alcohol abuse, as well as the physical, developmental, psychosocial, and behavioral factors related to adolescent alcohol use.