Source monitoring in Korsakoff's syndrome: “Did I touch the toothbrush or did I imagine doing so?”

"Do not take that medication": negative prospective memory in Korsakoff's syndrome

BACKGROUND

While prospective memory (i.e., the ability to execute a future plan) has been extensively researched, little is known about negative prospective memory (i.e., the ability to remember not to execute a future plan) in Korsakoff's syndrome (KS). We thus evaluated both prospective memory and negative prospective memory in KS, as well as the relationship between both types of prospective memory and inhibition.

METHODS

Patients with KS and control participants were invited to press a button on the keyboard (i.e., prospective memory) or not to press a button when a cue word (e.g., negative prospective memory) was encountered.

RESULTS

The analysis demonstrated that patients with KS had more prospective memory errors (i.e., forgetting to click the keyboard when the instruction was to do so) than control participants. The analysis also demonstrated that patients with KS had more negative prospective memory errors (i.e., clicking the keyboard when the instruction was not to do so) than control participants. Similar levels of commissions and omissions were observed in patients with KS than in control participants. Interestingly, prospective and negative prospective performances were significantly correlated with performance on an inhibition assessment task.

DISCUSSION

Our study demonstrates that KS is characterized by not only difficulty in remembering to execute a future intention but also by difficulty in remembering not to execute a future intention. A decline in negative prospective memory in KS can be associated with difficulty in inhibiting no longer appropriate previously learned intentions.

Prevalences and Indications of Psychotropic Drug Prescriptions in Nursing Home Residents with Korsakoff Syndrome

Psychotropic drugs (PD) are often prescribed to nursing home residents with Korsakoff syndrome (KS). It is unknown whether these drugs are prescribed correctly or whether they are prescribed off-label, for example, to treat behavioral symptoms. To get more insight into PD prescriptions, a descriptive study was performed. The type, category and indications of PD prescriptions of 285 participants were analyzed using medication charts and questionnaires. Behavioral symptoms were investigated with the Neuropsychiatric Inventory-Questionnaire. The results showed that atypical antipsychotics (57.1%) were prescribed more frequently than typical antipsychotics (49.3%). Of the antidepressants, selective serotonin/norepinephrine reuptake inhibitors (63.1%) were most frequently prescribed, followed by tricyclic antidepressants (23.4%). Of the benzodiazepines, anxiolytics (85.7%) were more prescribed than hypnotics (24.5%). Besides psychiatric disorders, PD were also prescribed to treat behavioral symptoms varying from 29.9% (antipsycho-tics) to 26.3% (benzodiazepines) and 9.3% (antidepressants). Furthermore, prescriptions were high if behavioral symptoms were present. To conclude, PD are often prescribed to residents with KS for an unapproved indication, namely behavioral symptoms. Additional research is needed to obtain further insight into the current prescribing culture and the effectiveness of PD. The insights thus obtained may, ultimately, contribute to the appropriate prescription of PD for people with KS.

"Ten dollars today or 50 dollars after one month?" Temporal discounting in Korsakoff syndrome

OBJECTIVE

Little research has investigated decision making in patients with Korsakoff syndrome (KS). Specifically, to our knowledge, there is a lack of research investigating whether patients with KS may tend to prefer immediate over future rewards (i.e., temporal discounting). Further, we investigated the relationship between temporal discounting and inhibition.

METHODS

We, for the first time, invited patients with KS and control participants to perform a temporal discounting task, in which they answered questions probing preferences between an immediate, but smaller amount of money, and a delayed, but larger amount of money (e.g., "would you prefer 10 dollars today or 50 dollars after one month?"). Furthermore, inhibition was measured using the Stroop Colour Word Test.

RESULTS

Analysis demonstrated higher temporal discounting in patients with KS than in control participants. Temporal discounting in both populations was significantly correlated with inhibition.

CONCLUSIONS

Patients with KS may have difficulties to suppress the temptation of smaller, but immediate, rewards.

"What Did I Tell This Sad Person?": Memory for Emotional Destinations in Korsakoff's Syndrome

We investigated destination memory, defined as the ability to remember to whom a piece of information was previously transmitted, for emotional destinations (i.e., a happy or sad person) in Korsakoff's syndrome (KS). We asked patients with KS and control participants to tell facts to neutral, positive, or negative faces. On a subsequent recognition task, participants had to decide to whom they told each fact. Compared with control participants, patients with KS demonstrated lower recognition of neutral, emotionally positive, and emotionally negative destinations. Patients with KS demonstrated lower recognition of emotionally negative than for emotionally positive or neutral destinations, but there were no significant differences between recognition of neutral and emotionally positive destinations. Our study demonstrates a compromised ability to process negative destinations in KS. Our study highlights the relationship between memory decline and impaired emotional processing in KS.

The fabricated past: intentionally fabricated autobiographical memories in Alzheimer's disease

OBJECTIVE

We investigated intentionally fabricated autobiographical memories in Alzheimer's Disease (AD).

METHOD

We invited AD patients and control participants to construct real events as well as fabricated events describing fictitious personal events that occurred in the past.

RESULTS

Results demonstrated slower retrieval time for intentionally fabricated memories than for real ones in both AD patients and control participants. The analysis also showed similar vividness for intentionally fabricated memories and real ones in AD patients but lower vividness for intentionally fabricated memories than for real ones in control participants.

CONCLUSIONS

The slow retrieval time of intentionally fabricated memories may be attributed to the cognitive effort required to retrieve elements from autobiographical memory and edit them to construct a new memory. We suggest that the vividness of intentionally fabricated memories observed in AD may induce confusion with real memories. In addition to the experimental approach of our study, we offer a theoretical rationale for intentionally fabricated autobiographical memories by situating them in the wider context of different facets of false memories in AD (e.g. confabulations, source monitoring errors).

Autobiographical memory in Korsakoff syndrome: A review

Autobiographical memory (AM) (i.e., memory for personal information) is a unique form of memory that goes beyond recalling information such as what, where and when of an event, to include what that event means and why it is important to our life story. This paper therefore reviews the available literature on AM in Korsakoff syndrome (KS). It summarizes the characteristics of AM disorders in KS patients. These disorders are mainly characterized by the difficulties that patients with KS have in retrieving and reliving specific AMs and in retrieving recent and remote memories. Another core characteristic of AM disorders in KS is confabulations. This paper hypothesizes that patients with KS may produce autobiographical confabulations to support their objectives and beliefs or even to answer a social demand or simply to share personal experiences with others. Although the current evidence demonstrates disorders of AM in KS, there is a need for more research about the characteristics of these disorders. This review thus proposes several perspectives for theoretical and clinical research.

Personality and social memory: High source and destination memory in extroverts

We evaluated relationship between personality and memory for social interactions. More specifically, we investigated the relationship between extraversion and the ability to remember who told us some information (i.e., source memory) and the ability to remember to whom we told that information (i.e., destination memory). On a source memory task, participants received information from pictures of celebrities; a subsequent recognition test required them to identify the celebrities from whom they had received that information. On a destination memory task, participants were invited to tell information to celebrities; a later recognition task instructed them to identify the celebrity to whom they had previously told that information. Besides the assessment of source and destination memory, participants answered a questionnaire regarding extraversion. Results demonstrated significant positive correlation between extraversion and source memory, as well as significant positive correlation between extraversion and destination memory. In other words, the more participants described themselves as extraverts, the higher their source and destination memory. During social communications (e.g., in a conversation), extraverts may demonstrate high source and destination memory as these individuals typically value social communication, public sharing, and processing of social information.

High emotional experience during autobiographical retrieval in women with Korsakoff syndrome

INTRODUCTION

In this exploratory study, we investigated gender differences regarding autobiographical memory in KS.

METHOD

We invited 33 patients with KS and 35 matched control participants to retrieve autobiographical memories and, afterward, to rate mental time travel during retrieval, emotional value and importance of memories.

RESULTS

Analysis demonstrated lower specificity (i.e., lower ability to retrieve memories situated in a specific time and space), mental time travel, and importance in patients with KS compared to control participants. Analysis also demonstrated no significant difference between patients with KS and control participants regarding emotion. Critically, analysis demonstrated no significant differences neither women and men with KS, nor between women and men in the control group, regarding autobiographical specificity, mental time travel, or importance. However, women with KS attributed higher emotional value for memories compared to men with KS, and the same results were observed in the control group.

DISCUSSION

These findings demonstrate that the higher emotional experience during autobiographical retrieval, as observed in the general population, can also be observed in KS.

Confabulations in Alcoholic Korsakoff's Syndrome: A Factor Analysis of the Nijmegen-Venray Confabulation List

Confabulations generally refer to the emergence of memories of experiences and events that, in reality, never took place, and which are unintentionally produced. They are frequently observed in alcoholic Korsakoff's syndrome. The aim of the current study was to validate the Nijmegen-Venray Confabulation List (NVCL), an observation scale for quantifying both spontaneous and provoked confabulations. The NVCL was completed for 252 patients with alcoholic Korsakoff's syndrome. Exploratory and confirmatory factor analyses were conducted to test three- and four-factor models of the NVCL structure. A four-factor model (provoked confabulations, spontaneous confabulations, severity of spontaneous confabulations, and distorted sense of reality) fitted the data better than the initially proposed three-factor model (provoked confabulations, spontaneous confabulations, memory, and orientation). The new instrument is therefore referred to as the NVCL-R. We encourage clinicians to include the assessment of confabulations in the neuropsychological examination, and to do so with validated instruments such as the NVCL-R.

Future Thinking in Korsakoff Syndrome

Aims

Prior research has been mainly concerned with the ability of patients with Korsakoff syndrome (KS) to project themselves into the past. Little is known about the patients’ ability to project themselves into the future. We therefore compared past and future thinking in patients with KS.

Methods

We invited patients with KS and control participants to retrieve past events and reconstruct future events. Participants were also invited to rate subjective characteristics (i.e. time travel, emotional feeling, and visual imagery) of the past and future events.

Results

Patients with KS demonstrated low specificity, time travel, and emotional experience during past and future thinking. However, while lower emotional experience was observed in patients with KS than in the control participants during future thinking, no significant differences were observed between the two populations during past thinking. Regarding within-group comparisons, patients with KS demonstrated no significant differences between past and future thinking in terms of specificity, time travel, and visual imagery; however, they demonstrated higher emotional experience during past than during future thinking. Regarding control participants, they demonstrated no significant differences between past and future thinking in terms of specificity, time travel, emotional experience, and visual imagery.

Conclusion

Our findings demonstrate a diminished ability to construct specific future scenarios as well as a diminished subjective experience during future thinking in KS.

Executive Dysfunction in Patients With Korsakoff's Syndrome: A Theory-Driven Approach

Aims

In addition to amnesia, executive deficits are prominent in Korsakoff's syndrome (KS), yet poorly studied. This study investigates the degree of executive dysfunction in patients with KS for the three main executive subcomponents shifting, updating and inhibition using novel, theory-driven paradigms.

Short summary

Compared to healthy controls, patients with KS show impairments on the executive subcomponents shifting and updating, but not on inhibition.

Methods

Executive functions were measured with six carefully designed tasks in 36 abstinent patients with KS (mean age 62.3; 28% woman) and compared with 30 healthy non-alcoholic controls (mean age 61.8; 40% woman). ANOVAs were conducted to examine group differences and effect sizes were calculated.

Results

Compared to healthy controls, patients with KS were impaired on the executive subcomponents shifting and updating. No statistically significant group difference was found on the factor inhibition.

Conclusions

Executive dysfunction in long-abstinent patients with alcoholic KS shows a profile in which shifting and updating ability are affected most. It also highlights that executive dysfunction is an important feature of KS and requires more attention in scientific and clinical practice, as these deficits may also affect daily functioning.

Tell about yourself to improve your autobiographical memory: A study of Korsakoff's syndrome

Korsakoff's syndrome (KS) has been associated with a difficulty to retrieve specific autobiographical memories. We investigated whether this difficulty can be alleviated after the retrieval of statements describing self-images. KS patients and control participants were recruited and asked to retrieve autobiographical memories after providing statements to the question "Who am I?" and after a control condition consisting of verbal fluency. Analysis showed higher autobiographical specificity in the "Who am I?" than in verbal fluency condition in both patients with KS and control participants. At a theoretical level, our findings demonstrate how retrieval of information related to conceptual self may influence autobiographical memory in KS. At a clinical level, our procedures are important as they demonstrate how a simple task (i.e., "Who am I?" statements) may serve as a tool to cue specific autobiographical memories in patients with KS.

Beneficial Effect of Minimal Interference on Item Memory But Not on Source Memory in Alzheimer's Disease

OBJECTIVES

Research suggests beneficial effects of minimal interference on item memory in mild Alzheimer's disease (AD). We conducted a study to test whether these beneficial effects extend to source memory, i.e., the ability to remember the episodic context in which an information was previously acquired.

METHOD

Twenty-six mild AD participants and 28 controls manipulated six objects or watched the experimenter manipulating six other objects. After immediate item recall ("what were the items?") and source recall ("by whom the items were previously manipulated?"), an interference or a minimal interference condition was administrated. In the interference condition, participants were assessed with neuropsychological tests for 10 min. In the minimal interference condition, they rested alone in a dark and quiet room for 10 minutes. Both interference and minimal interference conditions were followed by the delayed recall, on which participants were asked to remember the previously-presented objects and their source.

RESULTS

Higher item memory was observed following minimal interference than following interference in AD participants (p < .01) and controls (p < .01). Also, AD participants demonstrated higher item memory on immediate recall than following interference (p < .001) or minimal interference (p < .001); controls also demonstrated higher item memory on immediate recall than following interference (p < .001) or minimal interference (p < .001). Considering source memory, similar source memory was observed following interference and minimal interference in AD participants (p > .1) and controls (p > .1). Also, AD participants demonstrated higher source memory on immediate recall than following interference (p < .001) or minimal interference (p < .001); controls also demonstrated higher source memory on immediate recall than following interference (p < .001) or minimal interference (p < .001).

CONCLUSION

Failures of hippocampus-dependent associative or consolidation processes in AD may preclude benefits of minimal interference for source memory. Nevertheless, AD patients may show some capacity to retain simple material, should the material presentation be followed by short delays that are free of further stimuli.