Functional Cognitive Disorders (FCD): How Is Metacognition Involved?

Perspectives on the diagnosis and management of functional cognitive disorder: An international Delphi study

BACKGROUND

Current proposed criteria for functional cognitive disorder (FCD) have not been externally validated. We sought to analyse the current perspectives of cognitive specialists in the diagnosis and management of FCD in comparison with neurodegenerative conditions.

METHODS

International experts in cognitive disorders were invited to assess seven illustrative clinical vignettes containing history and bedside characteristics alone. Participants assigned a probable diagnosis and selected the appropriate investigation and treatment. Qualitative, quantitative and inter-rater agreement analyses were undertaken.

RESULTS

Eighteen diagnostic terminologies were assigned by 45 cognitive experts from 12 countries with a median of 13 years of experience, across the seven scenarios. Accurate discrimination between FCD and neurodegeneration was observed, independently of background and years of experience: 100% of the neurodegenerative vignettes were correctly classified and 75%-88% of the FCD diagnoses were attributed to non-neurodegenerative causes. There was <50% agreement in the terminology used for FCD, in comparison with 87%-92% agreement for neurodegenerative syndromes. Blood tests and neuropsychological evaluation were the leading diagnostic modalities for FCD. Diagnostic communication, psychotherapy and psychiatry referral were the main suggested management strategies in FCD.

CONCLUSIONS

Our study demonstrates the feasibility of distinguishing between FCD and neurodegeneration based on relevant patient characteristics and history details. These characteristics need further validation and operationalisation. Heterogeneous labelling and framing pose clinical and research challenges reflecting a lack of agreement in the field. Careful consideration of FCD diagnosis is advised, particularly in the presence of comorbidities. This study informs future research on diagnostic tools and evidence-based interventions.

Neuropsychological evaluation of functional cognitive disorder: A narrative review

Objective: To critically review contemporary theoretical models, diagnostic approaches, clinical features, and assessment findings in Functional Cognitive Disorder (FCD), and make recommendations for neuropsychological evaluation of this condition. Method: Narrative review. Results: FCD is common in neuropsychological practice. It is characterized by cognitive symptoms that are not better explained by another medical or psychiatric disorder. The cognitive symptoms are associated with distress and/or limitations in daily functioning, but are potentially reversible with appropriate identification and treatment. Historically, a variety of diagnostic frameworks have attempted to capture this condition. A contemporary conceptualization of FCD positions it as a subtype of Functional Neurological Disorder, with shared and unique etiological factors. Patients with FCD tend to perform normally on neuropsychological testing or demonstrate relatively weak memory acquisition (e.g. list learning trials) in comparison to strong attention and delayed recall performance. Careful history-taking and behavioral observations are essential to support the diagnosis of FCD. Areas of ongoing controversy include operationalizing "internal inconsistencies" and the role of performance validity testing. Evidence for targeted interventions remains scarce. Conclusions: Neuropsychologists familiar with FCD can uniquely contribute to the care of patients with this condition by improving diagnostic clarity, richening case formulation, communicating effectively with referrers, and leading clinical management. Further research is needed to refine diagnosis, prognosis, and treatment.

Factors perpetuating functional cognitive symptoms after mild traumatic brain injury

INTRODUCTION

Self-reported memory difficulties (forgetting familiar names, misplacing objects) often persist long after a mild traumatic brain injury (mTBI), despite normal neuropsychological test performance. This clinical presentation may be a manifestation of a functional cognitive disorder (FCD). Several mechanisms underlying FCD have been proposed, including metacognitive impairment, memory perfectionism, and misdirected attention, as well as depression or anxiety-related explanations. This study aims to explore these candidate perpetuating factors in mTBI, to advance our understanding of why memory symptoms frequently persist following mTBI.

METHODS

A cross-sectional study of 67 adults (n = 39 with mTBI mean = 25 months ago and n = 28 healthy controls). Participants completed standardized questionnaires (including the Functional Memory Disorder Inventory), a metacognitive task (to quantify discrepancies between their trial-by-trial accuracy and confidence), and a brief neuropsychological test battery. We assessed candidate mechanisms in two ways: (1) between-groups, comparing participants with mTBI to healthy controls, and (2) within-group, examining their associations with functional memory symptom severity (FMDI) in the mTBI group.

RESULTS

Participants with mTBI performed similarly to controls on objective measures of memory ability but reported experiencing much more frequent memory lapses in daily life. Contrary to expectations, metacognitive efficiency did not differentiate the mTBI and control groups and was not associated with functional memory symptoms. Memory perfectionism was strongly associated with greater functional memory symptoms among participants with mTBI but did not differ between groups when accounting for age. Depression and checking behaviors produced consistent results across between-groups and within-group analyses: these factors were greater in the mTBI group compared to the control group and were associated with greater functional memory symptoms within the mTBI group.

CONCLUSIONS

This study highlights promising (e.g., depression, checking behaviors) and unlikely (e.g., metacognitive impairment) mechanisms underlying functional memory symptoms after mTBI, to guide future research and treatment.

Functional Cognitive Disorder: Diagnosis, Treatment, and Differentiation from Secondary Causes of Cognitive Difficulties

Functional cognitive disorder is an increasingly common cause of referral to the memory clinic. As a substantial source of disability, clinicians involved in the management of patients with cognitive complaints need to familiarize themselves with this important differential diagnosis. Our approach focuses on the identification of positive features of internal inconsistency (historical and clinical clues alongside patterns of performance) instead of an exclusionary approach. Although effective treatments are desperately needed, promising therapies include metacognitive retraining and cognitive-behavioral therapy modalities. Future research should focus on a better understanding of disease trajectories and outcomes as well as the development of evidence-based interventions.

Cognitive profile in functional disorders

INTRODUCTION

Patients with functional disorders (FD) often experience cognitive problems such as forgetfulness and distractibility alongside physical symptoms that cannot be attributed to a known somatic disease.

METHOD

Test scores of cognitive tests and psychiatric rating scales of 100 outpatients diagnosed with a functional disorder were compared to a control group (n = 300) of patients with other diagnoses and to test norms for the general population.

RESULTS

Out of the 100 patients with functional disorders, 59 reported significant subjective cognitive symptoms. A moderate difference (d = 0.5-0.7) was found between the FD group mean and the population mean in processing speed tests, as well as in four psychiatric rating scales (depression, anxiety, phobias, somatisation) but there were no statistically significant differences in verbal and nonverbal reasoning or in logical memory. Somatisation and logical verbal memory scores were higher in the FD group compared to the control group.

CONCLUSION

The findings of the study suggest that a decline in processing speed is a central feature in the cognitive profile of patients with functional disorders.

Interoception in functional motor symptoms and functional seizures: Preliminary evidence of intact accuracy alongside reduced insight and altered sensibility

Altered interoception may be a pathophysiological mechanism in functional neurological disorder (FND). However, findings have been inconsistent across interoceptive dimensions in FND including functional motor symptoms (FMS) and seizures (FS). Here, individuals with FMS/FS (n = 17) and healthy controls (HC, n = 17) completed measures of interoceptive accuracy and insight (adapted heartbeat tracking task [HTT] with confidence ratings), a time estimation control task (TET) and the Multidimensional Assessment of Interoceptive Awareness-2 (MAIA-2) to assess interoceptive sensibility. The groups did not differ in interoceptive accuracy (p = 1.00, g = 0.00) or confidence (p = .99, g = 0.004), although the FMS/FS group displayed lower scores on the "Not-Distracting" (p < .001, g = 1.42) and "Trusting" (p = .005, g = 1.17) MAIA-2 subscales, relative to HCs. The groups did not differ in TET performance (p = .82, g = 0.08). There was a positive relationship between HTT accuracy and confidence (insight) in HCs (r = .61, p = .016) but not in FMS/FS (r = 0.11, p = .69). HTT confidence was positively correlated with MAIA-2 "Self-Regulation" (r = 0.77, p = .002) and negatively correlated with FND symptom severity (r = -0.84, p < .001) and impact (r = -0.86, p < .001) in FMS/FS. Impaired interoceptive accuracy may not be a core feature in FMS/FS, but reduced insight and altered sensibility may be relevant. Reduced certainty in self-evaluations of bodily experiences may contribute to the pathogenesis of FND symptoms.

Towards a neural network hypothesis for functional cognitive disorders: an extension of the Overfitted Brain Hypothesis

Introduction: Whilst the empirical understanding of functional cognitive disorders (FCD) has advanced in recent years, theoretical and conceptual models have evolved more slowly. Existing frameworks for FCD are based on models of other functional neurological disorders or of metacognitive processes and are recognised to lack mechanistic precision.Methods: In this article, a novel application to FCD of Hoel's Overfitted Brain Hypothesis of the evolved function of dreaming is attempted.Results: This posits that the empirically observed sleep disturbance in FCD entails impaired dreaming which causes the brain to be overfitted and hence unable to generalise appropriately, producing mismatch between memory expectations and memory performance.Conclusions: This formulation of FCD is based on considerations derived from the study of neural networks and shares commonalities with Bayesian models of functional neurological disorders. Additionally, it has implications for future hypothesis-driven research in FCD and suggests a pragmatic basis for management strategies.

Memory for forgetting in adults with persistent symptoms following concussion

INTRODUCTION

Persistent memory complaints following concussion often do not coincide with evidence of objective memory impairment. To the extent this clinical presentation represents Functional Cognitive Disorder (FCD), we would expect preservation or even enhancement of memory for instances of forgetting, based on two lines of prior evidence. First, emotional arousal enhances autobiographical memory. People who experience memory lapses as worrisome may better remember them. Second, individuals with FCD can paradoxically provide detailed accounts of memory lapses compared to patients with neurodegenerative disease, who tend to provide vague examples. The current study aimed to better characterize the recall of forgetting events in people with subjective memory problems following concussion.

METHODS

The study sample consisted of adults with chronic post-concussion symptoms (N = 37, M = 42.7 years old; 70.27% women; M = 24.9 months post-injury) and normal-range performance on conventional neuropsychological tests. Participants completed a measure of memory complaint severity and the Autobiographical Interview (AI). The AI was used to quantify the richness of narrative recollections of recent instances when they forgot something and (control) personal events that did not involve forgetting. Linear regression modeling assessed the relationship between memory complaint severity and AI variables, including narrative details, valence, arousal, and rehearsal of memories.

RESULTS

There was no association between memory complaint severity and memory for forgetting vs. control events. We further found no association between memory complaint severity and AI performance overall (collapsing across forgetting and control events). Participants with greater memory complaints experienced past memory lapses as more negative than control memories, but did not consistently differ on other AI phenomenological variables.

CONCLUSION

Autobiographical recall of memory lapses appears preserved but not selectively heightened in people who report experiencing severe memory problems long after concussion. This inconsistency supports conceptualization of persistent memory complaints after concussion as FCD.

OUP accepted manuscript

OBJECTIVE

The etiology of persistent memory complaints after concussion is poorly understood. Memory perfectionism (highly valuing memory ability and intolerance of minor memory lapses) may help explain why some people report persistent subjective memory problems in the absence of corresponding objective memory impairment. This study investigated the relationship between memory perfectionism and persistent memory complaints after concussion.

METHODS

Secondary analysis of baseline data from a randomized controlled trial. Adults (N = 77; 61% women) with persistent symptoms following concussion were recruited from outpatient specialty clinics. Participants completed the National Institutes of Health Toolbox Cognition Battery, Test of Memory Malingering-Trial 1, and questionnaires measuring memory perfectionism (Metamemory in Adulthood-Achievement subscale), forgetfulness and other postconcussion symptoms (Rivermead Postconcussion Symptoms Questionnaire; RPQ), and depression (Patient Health Questionnaire-2) at M = 17.8 weeks postinjury. Patients with versus without severe memory complaints (based on the RPQ) were compared.

RESULTS

Memory perfectionism was associated cross-sectionally with severe memory complaint, after controlling for objective memory ability, overall cognitive ability, and depression (95% confidence interval for odds ratio = 1.11-1.40). Sensitivity analyses showed that this relationship did not depend on use of specific objective memory tests nor on inclusion of participants who failed performance validity testing. In a control comparison to test the specificity of identified relationships, memory perfectionism was not associated with severe fatigue (95% confidence interval for odds ratio = 0.91-1.07).

CONCLUSIONS

Memory perfectionism may be a risk factor for persistent memory symptoms after concussion, with potential relevance to the spectrum of functional cognitive disorders more broadly.