Korsakoff’s syndrome: a critical review

Nicolaas JM Arts,1,2 Serge JW Walvoort,1 Roy PC Kessels1,3,4 1Centre of Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, Vincent van Gogh Institute for Psychiatry, Venray, 2Neuropsychiatry Center Thalamus, Institution for Integrated Mental Health Care Pro Persona, Wolfheze, 3Department of Neuropsychology and Rehabilitation Psychology, Donders Institute for Brain, Cognition and Behaviour, Radboud University, 4Department of Medical Psychology, Radboud University Medical Center, Nijmegen, the Netherlands Abstract: In this review, we present a survey on Korsakoff’s syndrome (KS), a residual syndrome in patients who suffered from a Wernicke encephalopathy (WE) that is predominantly characterized by global amnesia, and in more severe cases also by cognitive and behavioral dysfunction. We describe the history of KS and its definition, its epidemiology, and the lack of consensus criteria for its diagnosis. The cognitive and behavioral symptoms of KS, which include anterograde and retrograde amnesia, executive dysfunction, confabulation, apathy, as well as affective and social-cognitive impairments, are discussed. Moreover, recent insights into the underlying neurocognitive mechanisms of these symptoms are presented. In addition, the evidence so far on the etiology of KS is examined, highlighting the role of thiamine and alcohol and discussing the continuity hypothesis. Furthermore, the neuropathology of KS is reviewed, focusing on abnormalities in the diencephalon, including the mammillary bodies and thalamic nuclei. Pharmacological treatment options and nonpharmacological interventions, such as those based on cognitive rehabilitation, are discussed. Our review shows that thiamine deficiency (TD) is a crucial factor in the etiology of KS. Although alcohol abuse is by far the most important context in which TD occurs, there is no convincing evidence for an essential contribution of ethanol neurotoxicity (EN) to the development of WE or to the progression of WE to KS. Future research on the postmortem histopathological analysis of brain tissues of KS patients is crucial for the advancement of our knowledge of KS, especially for associating its symptoms with lesions in various thalamic nuclei. A necessary requirement for the advancement of studies on KS is the broad acceptance of a comprehensive definition and definite diagnostic criteria. Therefore, in this review, we propose such a definition of KS and draft outlines for prospective diagnostic criteria. Keywords: Korsakoff’s syndrome, alcohol amnestic disorder, Wernicke encephalopathy, thiamine deficiency, ethanol neurotoxicity, thalamus, memory, executive function, histor

Measuring illness insight in patients with alcohol-related cognitive dysfunction using the Q8 questionnaire: a validation study

Serge JW Walvoort,1–3 Paul T van der Heijden,3,4 Roy PC Kessels,1,2,5 Jos IM Egger1–3,6 1Centre of Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, Vincent van Gogh Institute for Psychiatry, Venray, 2Donders Institute for Brain, Cognition and Behaviour, 3Behavioural Science Institute, Radboud University, Nijmegen, 4Reinier van Arkel Mental Health Institute, ‘s-Hertogenbosch, 5Department of Medical Psychology, Radboud University Medical Center, Nijmegen, 6Centre of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands Aim: Impaired illness insight may hamper treatment outcome in patients with alcohol-related cognitive deficits. In this study, a short questionnaire for the assessment of illness insight (eg, the Q8) was investigated in patients with Korsakoff’s syndrome (KS) and in alcohol use disorder (AUD) patients with mild neurocognitive deficits. Methods: First, reliability coefficients were computed and internal structure was investigated. Then, comparisons were made between patients with KS and patients with AUD. Furthermore, correlations with the Dysexecutive Questionnaire (DEX) were investigated. Finally, Q8 total scores were correlated with neuropsychological tests for processing speed, memory, and executive function. Results: Internal consistency of the Q8 was acceptable (ie, Cronbach’s α =0.73). The Q8 items represent one factor, and scores differ significantly between AUD and KS patients. The Q8 total score, related to the DEX discrepancy score and scores on neuropsychological tests as was hypothesized, indicates that a higher degree of illness insight is associated with a higher level of cognitive functioning. Conclusion: The Q8 is a short, valid, and easy-to-administer questionnaire to reliably assess illness insight in patients with moderate-to-severe alcohol-related cognitive dysfunction. Keywords: illness insight, anosognosia, alcohol use disorder, Korsakoff’s syndrome, cognition, neuropsychological assessmen

The effect of errorless learning on quality of life in patients with Korsakoff’s syndrome

Yvonne CM Rensen,1 Jos IM Egger,2,3 Josette Westhoff,1 Serge JW Walvoort,1 Roy PC Kessels1,3,4 1Center of Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands; 2Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands; 3Donders Institute for Brain, Cognition, and Behavior, Radboud University, Nijmegen, 4Department of Medical Psychology, Radboud University Medical Center, Nijmegen, the Netherlands Background: Errorless learning (EL) is a promising rehabilitation principle for (re)learning instrumental activities in patients with amnesia, including patients with Korsakoff’s syndrome (KS). Successfully (re)learning tasks might improve the sense of competence and independence, and subsequently the quality of life. Quality of life in patients with KS has received limited attention, and no studies have been conducted to experimentally examine the effect of EL on quality of life in patients in this patient group. Materials and methods: The QUALIDEM, an observation scale for quality of life, was completed by professional nurses before and after EL training in a group of fifty-one patients with KS. This scale was also completed for a group of thirty-one control patients receiving care as usual but no EL training. Results: Quality of life was significantly increased on eight of the nine subscales in the Korsakoff group who participated in an EL training. There was a trend toward a significant increase in “positive affect” (ie, the ninth subscale). In contrast, no changes over time were found on any of the subscales in the control group that did not participate in any EL training. Conclusion: Despite severe memory impairments, patients with KS still have the potential to (partially) (re)learn tasks using EL. This potential should be exploited, as the successes of (re)-learning might improve the quality of life of Korsakoff patients in nursing homes. Keywords: Korsakoff’s syndrome, errorless learning, quality of life, memor