[Cognitive impairments in alcohol dependence: From screening to treatment improvements]. / Troubles cognitifs dans l'alcoolodépendance : intérêt du dépistage dans l'optimisation des prises en charge.

Alcohol-related cognitive impairments are largely underestimated in clinical practice, even though they could limit the benefit of alcohol treatment and hamper the patient's ability to remain abstinent or to respect his/her therapeutic contract. These neuropsychological deficits can impact the management of patients well before the development of the well-known Korsakoff's syndrome. Indeed, even in the absence of ostensible neurological complications, excessive and chronic alcohol consumption results in damage of brain structure and function. The frontocerebellar circuit and the circuit of Papez, respectively involved in motor and executive abilities and episodic memory, are mainly affected. Those brain dysfunctions are associated with neuropsychological deficits, including deficits of executive functions, episodic memory, social cognition, as well as visuospatial and motor abilities. Such cognitive disorders can interfere with the motivation process to abandon maladjusted drinking behavior in favor of a healthier lifestyle (such as abstinence or controlled alcohol consumption). They can also limit the patient's capacity to fully benefit from treatment (notably psychoeducation and cognitive-behavioural treatments) currently widely proposed in French Addiction departments. In addition, they may contribute to relapse which is multi-determinated. A neuropsychological assessment appears therefore crucial to take relevant clinical decisions. However, very few addiction departments have the human and financial resources to conduct an extensive neuropsychological examination of all patients with alcohol dependence. Some brief screening tools can be used, notably the MOntreal Cognitive Assessment and the Brief Evaluation of Alcohol-Related Neuropsychological Impairments, which has been especially designed to assess cognitive and motor deficits in alcoholism. These tools can be used by non-psychologist clinicians to detect alcohol-related cognitive deficits, which require an extensive cognitive examination conducted by a neuropsychologist. The presence of cognitive dysfunctions in patients early in abstinence should encourage clinicians to adjust the modalities of the treatment. The fact to favor recovery of cognitive functions and brain volumes with abstinence or drastic reduction of alcohol consumption could be a first way to make it possible for patients to be cognitively able to benefit from treatment. Further studies are required to determine whether specifically designed cognitive remediation could boost (accelerate or increase) the recovery of brain functioning. Additionally, a potential effect of thiamine to limit alcohol-related cognitive deficits before the development of neurological complications remains to be determined. In this review, we presented the pattern of structural brain damage and the associated cognitive and motor impairments in alcohol-dependent patients. We then emphasized the harmful effects of neuropsychological deficits in the management of these patients. We also pointed how relevant it is to screen patients with neuropsychological impairments and we focused on the presentation of two brief screening tools for cognitive impairments, especially designed for alcohol-related deficits or not. Finally, we reported how these neuropsychological impairments could be taken into consideration the treatment of alcohol addiction by adjusting its timing and modalities.

Impaired decision-making and brain shrinkage in alcoholism.

Alcohol-dependent individuals usually favor instant gratification of alcohol use and ignore its long-term negative consequences, reflecting impaired decision-making. According to the somatic marker hypothesis, decision-making abilities are subtended by an extended brain network. As chronic alcohol consumption is known to be associated with brain shrinkage in this network, the present study investigated relationships between brain shrinkage and decision-making impairments in alcohol-dependent individuals early in abstinence using voxel-based morphometry. Thirty patients performed the Iowa Gambling Task and underwent a magnetic resonance imaging investigation (1.5T). Decision-making performances and brain data were compared with those of age-matched healthy controls. In the alcoholic group, a multiple regression analysis was conducted with two predictors (gray matter [GM] volume and decision-making measure) and two covariates (number of withdrawals and duration of alcoholism). Compared with controls, alcoholics had impaired decision-making and widespread reduced gray matter volume, especially in regions involved in decision-making. The regression analysis revealed links between high GM volume in the ventromedial prefrontal cortex, dorsal anterior cingulate cortex and right hippocampal formation, and high decision-making scores (P<0.001, uncorrected). Decision-making deficits in alcoholism may result from impairment of both emotional and cognitive networks.

Neuropsychological assessment and cerebral vascular disease: the new standards.

Vascular cognitive impairment (VCI) includes vascular dementia (VaD), vascular mild cognitive impairment (VaMCI) and mixed dementia. In clinical practice, VCI concerns patients referred for clinical stroke or cognitive complaint. To improve the characterization of VCI and to refine its diagnostic criteria, an international group has elaborated a new standardized evaluation battery of clinical, cognitive, behavioral and neuroradiological data which now constitutes the reference battery. The adaption of the battery for French-speaking subjects is reported as well as preliminary results of the on-going validation study of the GRECOG-VASC group [Clinical Trial NCT01339195]. The diagnostic accuracy of various screening tests is reviewed and showed an overall sub-optimal sensitivity (<0.8). Thus, the general recommendation is to perform systematically a comprehensive assessment in stroke patients at risk of VCI. Furthermore,the use of a structured interview has been shown to increase the detection of dementia. In addition to the well known NINDS-AIREN criteria of VaD, criteria of VCI have been recently proposed which are based on the demonstration of a cognitive disorder by neuropsychological testing and either history of clinical stroke or presence of vascular lesion by neuroimaging suggestive of a link between cognitive impairment and vascular disease. A memory deficit is no longer required for the diagnosis of VaD as it is based on the cognitive decline concerning two or more domains that affect activities of daily living. Both VaMCI and VaD are classified as probable or possible. These new criteria have yet to be validated. Considerable uncertainties remain regarding the determinant of VCI, and especially the lesion amount inducing VCI and VaD. The interaction between lesion amount and its location is currently re-examined using recent techniques for the analysis of MRI data. The high frequency of associated Alzheimer pathology is now assessable in vivo using amyloid imaging. The first studies showed that about a third of patients with VaD due to small vessel disease or with poststroke dementia have amyloid PET imaging suggestive of AD. These new techniques will examine the interaction between vascular lesions and promotion of amyloid deposition. Although results of these on-going studies will be available in few years, these data indicate that efforts should be done in clinical practice to reduce underdiagnosis of VCI; VCI should be examined using a specific protocol which will be fully normalized soon for French-speaking patients; the sub-optimal sensitivity of screening tests prompts to use a structured interview to grade Rankin scale and to perform systematically a comprehensive assessment in stroke patients at risk of VCI; poststroke dementia occurring after 3 months poststroke may be preventable by treatment of modifiable vascular risk factors and secondary prevention of stroke recurrence according to recent recommendations.

Macrostructural abnormalities in Korsakoff syndrome compared with uncomplicated alcoholism.

OBJECTIVE: To distinguish, in patients with Korsakoff syndrome (KS), the structural brain abnormalities shared with alcoholic patients without KS (AL), from those specific to KS. METHODS: MRI data were collected in 11 alcoholic patients with KS, 34 alcoholic patients without KS, and 25 healthy control subjects (CS). Gray and white matter volumes were compared in the 3 groups using a voxel-based approach. RESULTS: A conjunction analysis indicated a large pattern of shared gray and white matter volume deficits in AL and KS. There were graded effects of volume deficits (KS < AL < CS) in the medial portion of the thalami, hypothalamus (mammillary bodies), left insula, and genu of the corpus callosum. Abnormalities in the left thalamic radiation were observed only in KS. CONCLUSIONS: Our results indicate considerable similarities in the pattern of gray and white matter damage in AL and KS. This finding confirms the widespread neurotoxic effect of chronic alcohol consumption. Only a few cerebral regions, including the medial thalami, mammillary bodies, and corpus callosum, were more severely damaged in KS than in AL. The continuum of macrostructural damage from AL to KS is therefore restricted to key brain structures. Longitudinal investigations are required to determine whether alcoholic patients with medial thalamic volumes that are comparable to those of patients with KS are at increased risk of developing KS.

Cognitive procedural learning in early Alzheimer's disease: impaired processes and compensatory mechanisms.

INTRODUCTION: The aim of this study was to study cognitive procedural learning in early Alzheimer's disease (AD). METHODS: Cognitive procedural learning was assessed using the Tower of Hanoi (TH) task. In order to take account of possible interactions between different systems during cognitive procedural learning, we also measured non-verbal intellectual functions, working memory, and declarative memory. RESULTS: Our results showed an apparent preservation of cognitive procedural learning in AD and a deleterious effect of the disease on verbal intelligence and declarative memory. Correlational analyses revealed a difference between AD patients and control participants in the type of processing they applied to the task. CONCLUSION: The non-involvement of declarative memory would appear to be partly responsible for a slowdown in the cognitive procedural dynamics of AD patients. As the AD patients were unable to use their declarative memory, they were still in a problem-solving mode at the end of the learning protocol and had to implement higher order cognitive processes (i.e., compensatory mechanisms) to perform the procedural task.

The advantage of errorless learning for the acquisition of new concepts' labels in alcoholics.

BACKGROUND: Previous findings revealed that the acquisition of new semantic concepts' labels was impaired in uncomplicated alcoholic patients. The use of errorless learning may therefore allow them to improve learning performance. However, the flexibility of the new knowledge and the memory processes involved in errorless learning remain unclear. METHOD: New concepts' labels acquisition was examined in 15 alcoholic patients and 15 control participants in an errorless learning condition compared with 19 alcoholic patients and 19 control subjects in a trial-and-error learning condition. The flexibility of the new information was evaluated using different photographs from those used in the learning sessions but representing the same concepts. All of the participants carried out an additional explicit memory task and an implicit memory task was also performed by subjects in the errorless learning condition. RESULTS: The alcoholic group in the errorless condition differed significantly from the alcoholic group in the trial-and-error condition but did not differ from the two control groups. There was no significant difference between results in the learning test and the flexibility task. Finally, in the alcoholic group, the naming score in the learning test was correlated with the explicit memory score but not with the implicit memory score. CONCLUSIONS: Using errorless learning, alcoholics improved their abilities to learn new concepts' labels. Moreover, new knowledge acquired with errorless learning was flexible. The errorless learning advantage may rely on explicit rather than implicit memory processes in these alcohol-dependent patients presenting only mild to moderate deficits of explicit memory capacities.

Preservation of cognitive procedural memory in a case of Korsakoff's syndrome: methodological and theoretical insights.

Using the Tower of Hanoï puzzle, Butters, et al. in 1985 illustrated the difficulties in learning the procedure and questioned the suitability of this task for assessment of the cognitive procedural memory in Korsakoff's syndrome. Our objective, in the light of these criticisms, was to show preservation of cognitive procedure capacities with the Tower of Hanoï for a man (P.F.) who was suffering from alcoholic Korsakoff's syndrome. For this procedural task, some aids helped to compensate in part for the difficulties with declarative memory and with working memory. In this condition, P.F. was able to learn the cognitive procedure. This study suggests that cognitive procedure memory may be preserved in some patients suffering from Korsakoff's syndrome and that this may be shown when a suitable task is used. The result makes it possible to discuss the interaction between declarative and procedural knowledge in the solving of the Tower of Hanoï.