Functional cognitive disorders: identification and management

Self-reported anterograde memory loss in older persons that is not validated on neuropsychological assessment: Considerations for a dissociative diagnosis

The past decade has witnessed amplified public awareness of age-related dementias. This has resulted in a dramatic rise in the number of older persons referred to memory clinics with a primary complaint of self-reported memory loss without an antecedent neurological event (e.g., stroke) who produce neuropsychological test profiles that lack evidence of such impairment. Since the latter part of the 19th century, a confusing array of changing terminology, criteria, and perceived causation have been ascribed to patients with unverified medical symptoms to implicate psychological causation. Such terms are often misperceived by laypersons as reflecting character flaws or malingering. Of import for clinical neuropsychologists, the 11th edition of the International Classification of Diseases added cognitive to symptoms eligible for a diagnosis of the modern formulation, dissociative neurological symptom disorder. One dissociative option for referrals with self-reported neurocognitive symptoms not validated on neuropsychological testing is functional memory disorder, conceived as a psychological disorder where emotional distress is plausibly related to the perceived memory loss but is of less severity than would warrant a major depressive or anxiety diagnosis. If evidence of psychological distress or behavioral impairment is not present the referral likely reflects the increased public awareness of age-related dementias interacting with the high base rate of self-perceived memory loss in the general population. In such cases, a dissociative diagnosis should be avoided as there is evidence of neither a medical nor a psychological disorder. A summary statement of not dementia or similar is likely sufficient to help the patient.

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.

Feasibility randomised controlled trial of online group Acceptance and Commitment Therapy for Functional Cognitive Disorder (ACT4FCD)

INTRODUCTION

Functional cognitive disorder (FCD) is seen increasingly in clinics commissioned to assess cognitive disorders. Patients report frequent cognitive, especially memory, failures. The diagnosis can be made clinically, and unnecessary investigations avoided. While there is some evidence that psychological treatments can be helpful, they are not routinely available. Therefore, we have developed a brief psychological intervention using the principles of acceptance and commitment therapy (ACT) that can be delivered in groups and online. We are conducting a feasibility study to assess whether the intervention can be delivered within a randomised controlled trial. We aim to study the feasibility of recruitment, willingness to be randomised to intervention or control condition, adherence to the intervention, completion of outcome measures and acceptability of treatment.

METHODS AND ANALYSIS

We aim to recruit 48 participants randomised 50:50 to either the ACT intervention and treatment as usual (TAU), or TAU alone. ACT will be provided to participants in the treatment arm following completion of baseline outcome measures. Completion of these outcome measures will be repeated at 8, 16 and 26 weeks. The measures will assess several domains including psychological flexibility, subjective cognitive symptoms, mood and anxiety, health-related quality of life and functioning, healthcare utilisation, and satisfaction with care and participant-rated improvement. Fifteen participants will be selected for in-depth qualitative interviews about their experiences of living with FCD and of the ACT intervention.

ETHICS AND DISSEMINATION

The study received a favourable opinion from the South East Scotland Research Ethics Committee 02 on 30 September 2022 (REC reference: 22/SS/0059). HRA approval was received on 1 November 2022 (IRAS 313730). The results will be published in full in an open-access journal.

TRIAL REGISTRATION NUMBER

ISRCTN12939037.

Differences in care between younger and older patients in the 2019 English national memory service audit

AIMS AND METHOD

This paper analyses how practice varied between patients aged <65 and ≥65 years in the 2019 UK national memory service audit.

RESULTS

Data on 3959 patients were analysed. Those aged <65 (7% of the sample) were less likely than those aged ≥65 to be diagnosed with dementia (23 v. 67%) and more likely to receive a functional, psychiatric or no diagnosis. Younger patients were more likely to have magnetic resonance imaging; use of dementia biomarkers was low in both groups. Frontotemporal dementia and functional cognitive disorder were diagnosed infrequently. Use of dementia navigators/advisors and carer psychoeducation was similar between groups; younger patients were less likely to be offered but more likely to accept cognitive stimulation therapy.

CLINICAL IMPLICATIONS

Memory services seeing younger people need expertise in functional cognitive disorder, alongside clinical skills and technologies to diagnose rarer forms of dementia. Further work is needed to understand why cognitive stimulation therapy is less frequently offered to younger people.

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.

Improving Diagnosis of Functional Cognitive Impairment in Younger Adults in Primary Care: Validation of Cognitive Screening Tools and the 4-Item Geriatric Depression Scale

Background: Cognitive decline is classically attributed to organic causes such as dementia; however, depression can play a role in cognitive decline. Objective: To evaluate cognitive screening tools and the 4-item Geriatric Depression Scale (GDS-4) for use in primary care to distinguish cognitive decline secondary to depression. Method: Clinical data collected over 2.5 years for assessed patients in a secondary clinical service for younger adults. Cognitive screening tools (General Practitioner Assessment of Cognition, Addenbrooke’s Cognitive Examination-III, Rowland Universal Dementia Assessment Scale, Salzburg Dementia Test Prediction) and GDS-4 were analyzed for their accuracy to differentiate patients with cognitive decline due to depression from those with subjective cognitive complaints. Results: 180 young adults seen in a memory clinic setting (<  65 years) were included. These individuals either had a diagnosis of depression (n = 46) or no cognitive impairment on assessment (n = 134) despite having subjective cognitive complaints. All used cognitive tools had poor accuracy in differentiating cognitive decline secondary to depression from subjective cognitive complaints. The GDS-4 alone, however, was able to differentiate with high accuracy (AUC = 0.818) individuals who had cognitive problems secondary to depression. Conclusion: Cognitive screening tools used alone are ineffective in discriminating cognitive decline secondary to depression. Incorporating the GDS-4 into the screening process by primary practitioners could facilitate early identification and treatment of depression in younger people, avoiding unnecessary referrals memory services.