Spontaneous confabulations and behavioral and cognitive dysexecutive syndrome

Assessment of Executive Function in Patients with Traumatic Brain Injury with the Wisconsin Card-Sorting Test

This review aimed at providing a brief and comprehensive summary of recent research regarding the use of the Wisconsin Card-Sorting Test (WCST) to assess executive function in patients with traumatic brain injury (TBI). A bibliographical search, performed in PubMed, Web of Science, Scopus, Cochrane Library, and PsycInfo, targeted publications from 2010 to 2020, in English or Spanish. Information regarding the studies’ designs, sample features and use of the WCST scores was recorded. An initial search eliciting 387 citations was reduced to 47 relevant papers. The highest proportion of publications came from the United States of America (34.0%) and included adult patients (95.7%). Observational designs were the most frequent (85.1%), the highest proportion being cross-sectional or case series studies. The average time after the occurrence of the TBI ranged from 4 to 62 years in single case studies, and from 6 weeks up to 23.5 years in the studies with more than one patient. Four studies compared groups of patients with TBI according to the severity (mild, moderate and/or severe), and in two cases, the studies compared TBI patients with healthy controls. Randomized control trials were seven in total. The noncomputerized WCST version including 128 cards was the most frequently used (78.7%). Characterization of the clinical profile of participants was the most frequent purpose (34.0%). The WCST is a common measure of executive function in patients with TBI. Although shorter and/or computerized versions are available, the original WCST with 128 cards is still used most often. The WCST is a useful tool for research and clinical purposes, yet a common practice is to report only one or a few of the possible scores, which prevents further valid comparisons across studies. Results might be useful to professionals in the clinical and research fields to guide them in assessment planning and proper interpretation of the WCST scores.

Confabulation Resilience of the Developing Brain: A Brief Review

OBJECTIVES

To investigate a possible confabulation resilience of the developing brain.

METHODS

We performed a literature search on confabulation in PubMed and identified all empirical studies of children and adolescents under the age of 18.

RESULTS

The analysis identified only three case studies of confabulation in children under the age of 18 of 286 empirical studies of confabulation. This reveals a striking discrepancy in the number of reported cases caused by brain injury between children and adults. We hypothesize that there may be a resilience toward confabulation in the developing brain and present three tentative explanations regarding the possible underlying mechanisms.

CONCLUSIONS

Additional awareness on the scarcity of reported cases of confabulation in children could lead to important insights on the nature of confabulation and greater understanding of the resilience and plasticity of the developing brain. (JINS, 2019, 25, 426-431).

Memory, Decision-Making, and the Ventromedial Prefrontal Cortex (vmPFC): The Roles of Subcallosal and Posterior Orbitofrontal Cortices in Monitoring and Control Processes

The ventromedial prefrontal cortex (vmPFC) prominently and separately features in neurobiological models of decision-making (e.g., value-encoding) and of memory (e.g., automatic veracity-monitoring). Recent decision-making models propose value judgments that inherently comprise of second-order confidence estimates. These demonstrate quadratic relationships with first-order judgments and are automatically encoded in vmPFC activity. Memory studies use Quantity-Accuracy Profiles to capture similar first-order and second-order meta-mnemonic processes, suggesting convergence across domains. Patients with PFC damage answered general knowledge questionnaires under 2 conditions. During forced report, they chose an answer and rated the probability of it being correct (first-order "monitoring"). During free report, they could choose to volunteer or withhold their previous answers (second-order "control") to maximize performance. We found quadratic relationships between first-order and second-order meta-mnemonic processes; voxel-based lesion-symptom mapping demonstrated that vmPFC damage diminished that relationship. Furthermore, damage to subcallosal vmPFC was specifically associated with impaired monitoring and additional damage to posterior orbitofrontal cortex led to deficient control. In decision-making, these regions typically support valuation and choice, respectively. Persistent spontaneous confabulation (false memory production) confirmed the clinical relevance of these dissociations. Compared with patients with no confabulation history, patients who currently confabulate were impaired on both monitoring and control, whereas former confabulators demonstrated impaired monitoring but intact control.