A dual-process exploration of binge drinking: Evidence through behavioral and electrophysiological findings.

The dual-process model, describing addictive disorders as resulting from an imbalance between increased automatic approach behaviors towards the substance and reduced abilities to control these behaviors, constitutes a sound theoretical framework to understand alcohol-use disorders. The present study aimed at exploring this imbalance at behavioral and cerebral levels in binge drinking, a pattern of excessive alcohol consumption frequently observed in youth, by assessing both reflective control abilities and automatic processing of alcohol-related stimuli. For this purpose, 25 binge drinkers and 25 comparison participants performed a Go/No-Go task during electrophysiological recording. Inhibition abilities were investigated during explicit (ie, distinguishing alcoholic versus nonalcoholic drinks) and implicit (ie, distinguishing sparkling versus nonsparkling drinks, independently of their alcohol content) processing of beverage cues. Binge drinkers presented poorer inhibition for the explicit processing of beverage cues, as well as reduced N200 amplitude for the specific processing of alcohol-related stimuli. As a whole, these findings indicated inhibition impairments in binge drinkers, particularly for alcohol cues processing and at the attentional stage of the cognitive stream. In line with the dual-process model, these results support that binge drinking is already characterized by an underactivation of the reflective system combined with an overactivation of the automatic system. Results also underlined the influence of explicit processing compared with implicit ones. At the clinical level, our findings reinforce the need to develop intervention methods focusing on the inhibition of approach behaviors towards alcohol-related stimuli.

A Patient-Tailored Evidence-Based Approach for Developing Early Neuropsychological Training Programs in Addiction Settings.

Substance use disorders (SUDs) are associated with impairments of cognitive functions, and cognitive training programs are thus rapidly developing in SUD treatment. However, neuropsychological impairments observed early after withdrawal (i.e., early impairments), that is, approximately in the first six months, may be widespread. Consequently, it might not be possible to train all the identified early impairments. In these situations, we propose that the priority of cognitive training should be given to the early impairments found to be associated with early dropout or relapse (i.e., relapse-related impairments). However, substance-specific relapse-related impairments have not been singled out among all early impairments so far. Using a systematic literature search, we identified the types of established early impairments for all SUDs, and we assessed the extent to which these early impairments were found to be associated with relapse-related impairments. All cognitive functions were investigated according to a classification based on current neuropsychological models, distinguishing classical cognitive, substance-bias, and social cognition systems. According to the current evidence, demonstrated relapse-related impairments in alcohol use disorder comprised impulsivity, long-term memory, and higher-order executive functions. For cannabis use disorder, the identified relapse-related impairments were impulsivity and working memory. For stimulant use disorder, the identified relapse-related impairments were attentional abilities and higher-order executive functions. For opioid use disorder, the only identified relapse-related impairments were higher executive functions. However, many early impairments were not explored with respect to dropout/relapse, particularly for stimulant and opioid use disorders. The current literature reveals substance-specific relapse-related impairments, which supports a pragmatic patient-tailored approach for defining which early impairments should be prioritized in terms of training among patients with SUDs.

Electrophysiological correlates of emotional crossmodal processing in binge drinking.

Emotional crossmodal integration (i.e., multisensorial decoding of emotions) is a crucial process that ensures adaptive social behaviors and responses to the environment. Recent evidence suggests that in binge drinking-an excessive alcohol consumption pattern associated with psychological and cerebral deficits-crossmodal integration is preserved at the behavioral level. Although some studies have suggested brain modifications during affective processing in binge drinking, nothing is known about the cerebral correlates of crossmodal integration. In the current study, we asked 53 university students (17 binge drinkers, 17 moderate drinkers, 19 nondrinkers) to perform an emotional crossmodal task while their behavioral and neurophysiological responses were recorded. Participants had to identify happiness and anger in three conditions (unimodal, crossmodal congruent, crossmodal incongruent) and two modalities (face and/or voice). Binge drinkers did not significantly differ from moderate drinkers and nondrinkers at the behavioral level. However, widespread cerebral modifications were found at perceptual (N100) and mainly at decisional (P3b) stages in binge drinkers, indexed by slower brain processing and stronger activity. These cerebral modifications were mostly related to anger processing and crossmodal integration. This study highlights higher electrophysiological activity in the absence of behavioral deficits, which could index a potential compensation process in binge drinkers. In line with results found in severe alcohol-use disorders, these electrophysiological findings show modified anger processing, which might have a deleterious impact on social functioning. Moreover, this study suggests impaired crossmodal integration at early stages of alcohol-related disorders.

Impaired affective prosody decoding in severe alcohol use disorder and Korsakoff syndrome.

Recognizing others' emotions is a fundamental social skill, widely impaired in psychiatric populations. These emotional dysfunctions are involved in the development and maintenance of alcohol-related disorders, but their differential intensity across emotions and their modifications during disease evolution remain underexplored. Affective prosody decoding was assessed through a vocalization task using six emotions, among 17 patients with severe alcohol use disorder, 16 Korsakoff syndrome patients (diagnosed following DSM-V criteria) and 19 controls. Significant disturbances in emotional decoding, particularly for negative emotions, were found in alcohol-related disorders. These impairments, identical for both experimental groups, constitute a core deficit in excessive alcohol use.

Imbalance between cognitive systems in alcohol-dependence and Korsakoff syndrome: An exploration using the Alcohol Flanker Task.

BACKGROUND: Alcohol-dependent individuals (ALC) simultaneously present decreased inhibitory control and increased attention towards alcohol-related cues. The dual-process models have proposed that these symptoms reflect an imbalance between prefrontal/reflective and limbic/automatic systems, respectively leading to cognitive dysfunctions in executive processes and to alcohol-related bias. However, most previous research has focused on a separate exploration of these systems among ALC, and the direct measure of their interactions remains to be conducted. Moreover, no study has explored the evolution of this imbalance across the successive stages of alcohol-related disorders, and particularly in Korsakoff syndrome (KS), the most frequent neurological complication of alcohol-dependence. METHOD: Ten KS, 14 ALC, and 14 matched control participants performed a modified Flanker task, the "Alcohol Flanker Task," based on congruent, incongruent, and neutral conditions with alcohol-related stimuli. This task required inhibitory processing on alcohol-related stimuli and evaluated, through a behavioral approach, the interaction between reflective and automatic systems, as well as its evolution between ALC and KS. RESULTS: ALC and KS both presented high reactivity towards alcohol-related stimuli, confirming the presence of alcohol-related bias. KS showed increased omission rates (related to distractor interference) while ALC showed higher false-alarm rates (related to prepotent response inhibition). These results suggest that different inhibitory subcomponents might be altered at the successive stages of the pathology, and experimentally confirms the crucial role of the interaction between reflective and automatic processes in alcohol-use disorders. CONCLUSION: The present results reinforce the proposal that alcohol-related cues significantly impact inhibitory control in alcohol-related disorders. However, ALC and KS present different patterns of deficits depending on task complexity (i.e., executive load), thus suggesting a dissociation in inhibitory functions when processing alcohol-related cues.

Affective impairments in binge drinking: Investigation through emotional facial expression decoding.

OBJECTIVE: Binge drinking, an excessive alcohol consumption pattern frequently observed in young people, is known to be associated with psychological and cerebral deficits. While cognitive dysfunctions have been widely investigated, emotional abilities have scarcely been explored. Such an exploration would however offer a more exhaustive understanding of the deficits associated with binge drinking, as well as of the possible transition towards alcohol-dependence. METHODS: 46 young adults (23 binge drinkers, 12 women; 23 control participants, 12 women) were recruited among university students. They performed an emotional recognition task consisting of the visual decoding of six basic emotions (i.e. anger, contempt, disgust, fear, happiness, and sadness). Accuracy scores and detection thresholds were collected for each emotion. RESULTS: Binge drinkers showed lower performance than control participants for the decoding of all emotions and increased detection threshold, this later reflecting less ability to capture an emotion. Binge drinking is thus associated with a need for higher emotional intensity to perform correct detection. Moreover, these emotional difficulties appear specifically related to alcohol consumption. CONCLUSION: These findings reinforce previous experimental evidence of altered emotional processing among binge drinkers, and extend these results for various emotional contents. They support the hypothesis of a continuum between binge drinking and alcohol-dependence, in which massive emotional impairments have been documented. Indeed, these impairments could be involved in the onset and maintenance of excessive alcohol consumption, notably through the established relationship between emotional deficits and social distress.

Crossmodal processing of emotions in alcohol-dependence and Korsakoff syndrome.

INTRODUCTION: Decoding emotional information from faces and voices is crucial for efficient interpersonal communication. Emotional decoding deficits have been found in alcohol-dependence (ALC), particularly in crossmodal situations (with simultaneous stimulations from different modalities), but are still underexplored in Korsakoff syndrome (KS). The aim of this study is to determine whether the continuity hypothesis, postulating a gradual worsening of cognitive and brain impairments from ALC to KS, is valid for emotional crossmodal processing. METHODS: Sixteen KS, 17 ALC and 19 matched healthy controls (CP) had to detect the emotion (anger or happiness) displayed by auditory, visual or crossmodal auditory-visual stimuli. Crossmodal stimuli were either emotionally congruent (leading to a facilitation effect, i.e. enhanced performance for crossmodal condition compared to unimodal ones) or incongruent (leading to an interference effect, i.e. decreased performance for crossmodal condition due to discordant information across modalities). Reaction times and accuracy were recorded. RESULTS: Crossmodal integration for congruent information was dampened only in ALC, while both ALC and KS demonstrated, compared to CP, decreased performance for decoding emotional facial expressions in the incongruent condition. CONCLUSIONS: The crossmodal integration appears impaired in ALC but preserved in KS. Both alcohol-related disorders present an increased interference effect. These results show the interest of more ecological designs, using crossmodal stimuli, to explore emotional decoding in alcohol-related disorders. They also suggest that the continuum hypothesis cannot be generalised to emotional decoding abilities.

Preserved Crossmodal Integration of Emotional Signals in Binge Drinking.

Binge drinking is an alcohol consumption pattern with various psychological and cognitive consequences. As binge drinking showed qualitatively comparable cognitive impairments to those reported in alcohol-dependence, a continuum hypothesis suggests that this habit would be a first step toward alcohol-related disorders. Besides these cognitive impairments, alcohol-dependence is also characterized by large-scale deficits in emotional processing, particularly in crossmodal contexts, and these abilities have scarcely been explored in binge drinking. Emotional decoding, most often based on multiple modalities (e.g., facial expression, prosody or gesture), yet represents a crucial ability for efficient interpersonal communication and social integration. The present study is the first exploration of crossmodal emotional processing in binge drinking, in order to test whether binge drinkers already present the emotional impairments described among alcohol-dependent patients, in line with the continuum hypothesis. Twenty binge drinkers and 20 matched controls performed an experimental task requiring the identification of two emotions (happiness or anger) presented in two modalities (visual or auditory) within three conditions (unimodal, crossmodal congruent or crossmodal incongruent). In accordance with previous research in binge drinking and alcohol-dependence, this study was based on two main hypotheses. First, binge drinkers would present a reduced facilitation effect (i.e., classically indexed in healthy populations by faster reaction times when two congruent modalities are presented simultaneously). Second, binge drinkers would have higher difficulties to inhibit interference in incongruent modalities. Results showed no significant difference between groups in emotional decoding ability, whatever the modality or condition. Control participants, however, appeared slower than binge drinkers in recognizing facial expressions, also leading to a stronger facilitation effect when the two modalities were presented simultaneously. However, findings did not show a disrupted facilitation effect in binge drinkers, whom also presented preserved performance to inhibit incongruence during emotional decoding. The current results thus suggest that binge drinkers do not demonstrate a deficit for emotional processing, both in unimodal and crossmodal contexts. These results imply that binge drinking might not be characterized by impairments for the identification of primary emotions, which could also indicate that these emotional processing abilities are well-preserved at early stages of excessive alcohol consumption.

Executive functions in alcohol-dependence: A theoretically grounded and integrative exploration.

BACKGROUND: Alcohol-dependence is related to large-scale cognitive impairments, particularly for executive functions (EF). These deficits persist even after long-term abstinence and have a major impact on patients' everyday life and relapse risk. Earlier studies, based on multi-determined tasks, mostly focused on inhibition and did not offer a theoretically-grounded and exhaustive view of the differential deficit across EF. The present paper proposes a model-based exploration of EF in alcohol-dependent individuals (ALC), to precisely compare the specific deficit related to each executive subcomponent. METHODS: Forty-seven recently detoxified ALC were compared to 47 matched healthy participants on a nine-tasks validated neuropsychological battery, simultaneously exploring and comparing the three main executive subcomponents (shifting, updating, and inhibition). Psychopathological comorbidities were also controlled for. RESULTS: Reaction time indexes revealed a global slowing down among ALC, whatever the EF explored. Accuracy indexes revealed a moderate deficit for inhibition tasks but a massive impairment for shifting and updating ones. Complementary analyses indicated that the executive deficits observed were centrally related to alcohol-dependence, while comorbid depressive symptoms appeared to intensify the deficits observed. CONCLUSIONS: By offering a direct comparison between the three major EF, these results showed that alcohol-related executive deficits extend beyond the classically described inhibition impairment. This impairment encompasses each EF subcomponent, as ALC actually presented stronger deficits for updating and shifting abilities. This first observation of a multifaceted EF deficit stresses the need for an individualized evaluation and rehabilitation of EF during and/or after the detoxification process.

Source Memory in Korsakoff Syndrome: Disentangling the Mechanisms of Temporal Confusion.

BACKGROUND: Korsakoff syndrome (KS), most frequently resulting from alcohol dependence (ALC), is characterized by severe anterograde amnesia. It has been suggested that these deficits may extend to other memory components, and notably source memory deficits involved in the disorientation and temporal confusion frequently observed in KS. However, the extent of this source memory impairment in KS and its usefulness for the differential diagnosis between ALC and KS remain unexplored. METHODS: Nineteen patients with KS were compared with 19 alcohol-dependent individuals and 19 controls in a source memory test exploring temporal context confusions ("continuous recognition task"). Episodic memory and psychopathological comorbidities were controlled for. RESULTS: While no source memory deficit was observed in ALC, KS was associated with a significant presence of temporal context confusion, even when the influence of comorbidities was taken into account. This source memory impairment did not appear to be related to performances on episodic memory or executive functions. CONCLUSIONS: Patients with KS displayed source memory deficits, as indexed by temporal context confusions. The absence of a relationship with episodic memory performances seems to indicate that source memory impairment is not a mere by-product of amnesia. As ALC was associated with preserved source memory, the presence of temporal context confusion may serve as a complementary tool for the differential diagnosis between ALC and KS.

New Perspectives in the Exploration of Korsakoff's Syndrome: The Usefulness of Neurophysiological Markers.

This perspective aims at underlining the usefulness of event-related potentials (ERP) to better understand the brain correlates of Korsakoff's syndrome (KS), a neuropsychiatric disease characterized by severe memory impairment and most frequently resulting as a neurological complication of alcohol-dependence (AD). While ERP have been broadly used in AD, it has up to now been very little applied in KS or in the comparison of KS and AD. Within the framework of dual-process models, an influential theory postulating that addictive states result from an imbalance between under-activated reflective system and over-activated automatic-affective one, this paper proposes: (1) a brief synthesis of the main results of ERP studies in AD and KS, and (2) new research avenues using ERP to identify the electrophysiological correlates of cognitive and emotional dysfunction in KS. These experimental perspectives aim at exploring the continuity hypothesis, which postulates a gradient of impairments from AD to KS. We conclude on the possibility of developing neuropsychological strategies with electrophysiological follow-up to ensure KS diagnosis and test the efficacy of patient's neurocognitive rehabilitation.

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

Chemosensory (olfaction-taste) dysfunctions are considered as reliable biomarkers in many neurological and psychiatric states. However, experimental measures of chemosensory abilities are lacking in alcohol-dependence (AD) and Korsakoff Syndrome (KS, a neurological complication of AD), despite the role played by alcohol-related odors and taste in the emergence and maintenance of AD. This study thus investigated chemosensory impairments in AD and KS. Olfactory-gustatory measures were taken among 20 KS, 20 AD, and 20 control participants. Olfaction (odor detection-discrimination-identification) was assessed using the "Sniffin Sticks" battery and taste was measured using the "Taste Strips" task. Impairments were found for high-level olfaction in AD (odor discrimination) and KS (odor discrimination-identification), even after controlling for psychopathological comorbidities. Gustatory deficits were also observed in both groups, indexing a global deficit for chemosensory perception. Finally, the gradient of impairment between the successive disease stages for odor identification suggests that the hypothesis of a continuum between AD and KS regarding cognitive deficits can be generalized to chemosensory perception. AD and KS are thus characterized by deficits in chemosensory abilities, which could constitute a marker of the AD-KS transition. In view of its deleterious influence on everyday life, chemosensory dysfunction should also be taken into account in clinical settings.

Revisiting the continuum hypothesis: toward an in-depth exploration of executive functions in korsakoff syndrome.

Korsakoff syndrome (KS) is a neurological state mostly caused by alcohol-dependence and leading to disproportionate episodic memory deficits. KS patients present more severe anterograde amnesia than Alcohol-Dependent Subjects (ADS), which led to the continuum hypothesis postulating a progressive increase in brain and cognitive damages during the evolution from ADS to KS. This hypothesis has been extensively examined for memory but is still debated for other abilities, notably executive functions (EF). EF have up to now been explored by unspecific tasks in KS, and few studies explored their interactions with memory. Exploring EF in KS by specific tasks based on current EF models could thus renew the exploration of the continuum hypothesis. This paper will propose a research program aiming at: (1) clarifying the extent of executive dysfunctions in KS by tasks focusing on specific EF subcomponents; (2) determining the differential EF deficits in ADS and KS; (3) exploring EF-memory interactions in KS with innovative tasks. At the fundamental level, this exploration will test the continuum hypothesis beyond memory. At the clinical level, it will propose new rehabilitation tools focusing on the EF specifically impaired in KS.