Cognitive Complaints in Motor Functional Neurological (Conversion) Disorders: A Focused Review and Clinical Perspective

Neurocognitive performance in functional neurological disorder: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Cognitive complaints are common in functional neurological disorder (FND), but it is unclear whether objective neurocognitive deficits are present. This systematic review summarized validated/standardized cognitive test performance in FND samples across cognitive domains.

METHODS

Embase, PsycInfo and MEDLINE were searched from inception to 15 May 2023, combining terms for FND and cognitive domains (e.g., attention, memory, executive functioning). Studies included a range of FND phenotypes (seizures, motor, cognitive disorder, mixed), compared to healthy or clinical controls. Risk of bias was assessed with the modified Newcastle-Ottawa Scale and a qualitative synthesis/narrative review of cognitive performance in FND was conducted. Test performance scores were extracted, and random effects meta-analyses were run where appropriate. This review was registered on PROSPERO, CRD42023423139.

RESULTS

Fifty-six studies including 2260 individuals with FND were eligible. Although evidence for some impairments emerged across domains of executive functioning, attention, memory and psychomotor/processing speed, this was inconsistent across studies and FND phenotypes. Common confounds included group differences in demographics, medication and intellectual functioning. Only 24% of studies objectively assessed performance validity. Meta-analyses revealed higher scores on tests of naming (g = 0.67, 95% confidence interval [CI] 0.50, 0.84) and long-term memory (g = 0.43, 95% CI 0.13, 0.74) in functional seizures versus epilepsy, but no significant differences in working (g = -0.08, 95% CI -0.44, 0.29) or immediate (g = 0.25, 95% CI -0.02, 0.53) memory and cognitive flexibility (g = -0.01, 95% CI -0.29, 0.28).

CONCLUSIONS

There is mixed evidence for objective cognitive deficits in FND. Future research should control for confounds, include tests of performance validity, and assess relationships between objective and subjective neurocognitive functioning.

Protective effects of early exercise on neuroinflammation, and neurotoxicity associated by traumatic brain injury: a behavioral and neurochemical approach

OBJECTIVE

The benefits of exercise in TBI have been proven. However, the time-dependent effects of exercise initiation and the involved mechanisms are controversial. We investigated the effects of preconditioning, continuous, early, and delayed treadmill exercise on motor behavior, brain edema, inflammation, and oxidative stress in experimental traumatic brain injury (TBI).

MATERIALS AND METHODS

48 male rats were assigned into two groups: sedentary control (Sham and TBI) and exercise groups: 1MB (preconditioning, initiation beginning at 1 month before trauma), 1MBA (continuous, initiation beginning at 1 month before and continuing 1 month after trauma), 24hA (early, initiation beginning at 24 h after trauma), and 1WA (delay, initiation beginning at 1 week after trauma). The rats in exercise groups were forced to run on a treadmill five days a week for 30 min per day. Rotarod and open file were used to assess motor behavior. ELISA was also used to measure total antioxidant capacity (TAC), tumor necrosis factor-alpha (TNF-α), and malondialdehyde (MDA) in serum and CSF.

RESULTS

Exercise significantly decreased neurological impairments, motor deficits, and apoptosis compared with the sedentary group. Early (within 24 h) and ongoing (1 MBA) exercise significantly improved motor behavior after TBI. In addition, these exercise programs inhibited brain edema and the number of apoptotic cells. MDA and TNF-α levels increased in all exercise groups, but the effects were greater after early exercise than after delayed exercise, resulting in a significant decrease in TAC levels in serum and CSF. We discovered a positive correlation between MDA, TAC, and TNF-α concentration in serum and CSF.

CONCLUSION

Our finding suggests that early exercise (24hA) and 1MBA groups afford neuroprotection and reduce the second injury consequence, probably by reducing neuronal apoptosis and oxidative stress.

Sensory Processing Difficulties and Occupational Therapy Outcomes for Functional Neurological Disorder: A Retrospective Cohort Study

Background and Objectives

Occupational therapy (OT) consensus recommendations and articles outlining a sensory-based OT intervention for functional neurological disorder (FND) have been published. However, limited research has been conducted to examine the efficacy of OT interventions for FND. We performed a retrospective cohort study aimed at independently replicating preliminarily characterized sensory processing difficulties in patients with FND and reporting on clinical outcomes of a sensory-based OT treatment in this population. We hypothesized that (1) a history of functional seizures, anxiety, and/or post-traumatic stress disorder would be associated with increased sensory processing difficulties and (2) the number of OT treatment sessions received would positively relate to clinical improvement.

Methods

Medical records were reviewed for 77 consecutive adults with FND who received outpatient, sensory-based OT care. Data from the Adolescent/Adult Sensory Profile characterized self-reported sensory processing patterns across 4 quadrants (low registration, sensory sensitivity, sensory seeking, and sensory avoidance) in this population. Following univariate screenings, multivariate linear regression analyses were performed to identify neuropsychiatric characteristics associated with discrete sensory processing patterns. Clinical improvement was quantified using an estimated, clinician-determined improvement rating ("improved" vs "not improved"), and relationships between clinical participation, baseline neuropsychiatric factors, and outcomes were investigated.

Results

Patients with FND reported sensory processing patterns with elevated scores in low registration, sensory sensitivity, and sensation avoidance compared with normative values; differences in sensory processing scores were not observed across FND subtypes (i.e., motor, seizure, and speech variants). In linear regression analyses, lifetime history of an anxiety disorder, history of migraine headaches, current cognitive complaints, and a comorbid major neurologic condition independently predicted individual differences in sensory processing scores. Following a sensory-based OT intervention, 62% of individuals with FND were clinician determined as "improved." In a multivariate logistic regression analysis controlling for baseline characteristics associated with improvement ratings, number of treatment sessions positively correlated with clinical improvement.

Discussion

These findings support the presence of sensory processing difficulties in patients with FND and provide Class IV evidence for the efficacy of an outpatient, sensory-based OT intervention in this population. Controlled prospective trials are warranted.

The role of neuropsychology in the care of patients with functional neurological symptom disorder

OBJECTIVE

Functional neurological symptom disorder (FNSD) is a neuropsychiatric condition characterized by signs/symptoms associated with brain network dysfunction. FNSDs are common and are associated with high healthcare costs. FNSDs are relevant to neuropsychologists, as they frequently present with chronic neuropsychiatric symptoms, subjective cognitive concerns, and/or low neuropsychological test scores, with associated disability and reduced quality of life. However, neuropsychologists in some settings are not involved in care of patients with FNSDs. This review summarizes relevant FNSD literature with a focus on the role of neuropsychologists.

METHODS

A brief review of the literature is provided with respect to epidemiology, public health impact, symptomatology, pathophysiology, and treatment.

RESULTS

Two primary areas of focus for this review are the following: (1) increasing neuropsychologists' training in FNSDs, and (2) increasing neuropsychologists' role in assessment and treatment of FNSD patients.

CONCLUSIONS

Patients with FNSD would benefit from increased involvement of neuropsychologists in their care.

Reduced Subjective Cognitive Concerns With Neurobehavioral Therapy in Functional Seizures and Traumatic Brain Injury

OBJECTIVE

Functional seizures are common among people with traumatic brain injury (TBI). Subjective cognitive concerns refer to a person's own perception of problems with cognitive functioning in everyday life. The authors investigated the presence and correlates of subjective cognitive concerns and the response to neurobehavioral therapy among adults with TBI and functional seizures (TBI+FS group).

METHODS

In this observational study, participants in the TBI+FS group (N=47) completed a 12-session neurobehavioral therapy protocol for seizures, while participants in the comparison group (TBI without seizures) (N=50) received usual treatment. Subjective cognitive concerns, objective cognition, mental health, and quality of life were assessed before and after treatment. Data collection occurred from 2018 to 2022.

RESULTS

Baseline subjective cognitive concerns were reported for 37 (79%) participants in the TBI+FS group and 20 (40%) participants in the comparison group. In a multivariable regression model in the TBI+FS group, baseline global mental health (β=-0.97) and obsessive-compulsive symptoms (β=-1.01) were associated with subjective cognitive concerns at baseline. The TBI+FS group had fewer subjective cognitive concerns after treatment (η2=0.09), whereas the TBI comparison group showed a nonsignificant increase in subjective cognitive concerns.

CONCLUSIONS

Subjective cognitive concerns are common among people with TBI and functional seizures and may be related to general mental health and obsessive-compulsive symptoms. Evidence-based neurobehavioral therapy for functional seizures is a reasonable treatment option to address such concerns in this population, although additional studies in culturally diverse samples are needed. In addition, people with functional seizures would likely benefit from rehabilitation specifically targeted toward cognitive functioning.

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.

"Somewhere Between an Actual Disease and a Disease": A Grounded Theory Study on Diagnosing Functional Neurological Disorders From a Multi-Informant Perspective

Functional Neurological Disorders are characterized by sensory-motor or cognitive symptoms. Recent research has revealed their complex nature involving biological, psychological, and social factors. Care requires a multidisciplinary approach, which, to date, has yet to be considered. A Constructivist Grounded Theory study was conducted to understand the reasons behind this, exploring Functional Neurological Disorders diagnosis, communication, and understanding from multiple perspectives (patients and healthcare professionals). The core category was "negotiating Functional Neurological Disorders meanings and care amid a dissatisfying dichotomy," with sub-categories: i) seeking to "word" the disease, ii) exposing reductionism, and iii) a pluralist vision emerging. Diagnosing and communicating Functional Neurological Disorders is a process of negotiating meanings and care that hinges on participants' diverse ontological perspectives regarding the condition. Results highlight the difficulty in finding common ground and achieving mutual understanding among the various viewpoints, creating a challenge in establishing a unified approach to Functional Neurological Disorders care. In this context, only a few healthcare professionals emphasized the potential benefits of increased integration. A shift is required from a reductionist to an integrated biopsychosocial perspective to develop a more cohesive approach. Defining a medical paradigm through dialogue with teams and patients is essential in addressing Functional Neurological Disorders effectively. Furthermore, the required interdisciplinary approach holds the potential to mitigate the dissatisfaction arising from fragmented and compartmentalized care (the "dissatisfying dichotomy") experienced by our participants. It signifies a comprehensive strategy that could address the concerns of all involved parties and enhance the overall quality of care provided.

Neuropsychological performance and effort in patients diagnosed with psychogenic nonepileptic seizures - Descriptive study of a Czech sample

PURPOSE

The aim of the study was to examine the neuropsychological performance and effort in patients with a confirmed PNES diagnosis. The second aim of the study was to investigate the relationship between validity indicators from the cognitive battery with validity and clinical scales from a personality scale.

METHOD

Patients with PNES (N = 250; F:M 186:64; mean age 38.32 (13.23)) were assessed utilizing the RBANS (Czech Research version) to evaluate cognitive performance and to obtain the Effort Index. The MMPI-2 was used to evaluate personality and psychopathology.

RESULTS

Global cognitive performance was 0.92 SD below average (according to the Gaussian distribution) in patients with PNES. The lowest scores in the sample were in the Attention domain (-1.7SD). Insufficient effort was detected in 10% of patients. Education correlated negatively with the Effort index (rs = -0.25, p = 0.01). A mild significant correlation in Scale 7 (rs = 0.21, p = 0.01) and Scale 8 (rs = 0.24, p = 0.01), and a significant correlation between Effort Index and Back F Scale (rs = 0.23, p = 0.01) were noted.

CONCLUSIONS

Assessment of cognitive performance and effort is an essential part of the comprehensive evaluation of patients with PNES during their hospitalization at Epilepsy centers. Many aspects of the neuropsychological assessment can offer useful indications for reaching a differential diagnosis, including clinical history, behavioral observations, cognitive and symptom validity testing, and structured psychological inventories.

Neuropsychiatric Treatment Approaches for Functional Neurological Disorder: A How to Guide

There is a growing body of knowledge regarding management of functional neurological disorder (FND). The aim of this article is to guide the clinician through FND clinical management, from delivery of the diagnosis, to creation of a biopsychosocially-informed treatment plan, to troubleshooting common issues that arise throughout longitudinal care. We review the evidence and core principles of both rehabilitative therapies (physical therapy, occupational therapy, and speech and language therapy) and psychological therapies for the treatment of FND, and discuss the benefits of engaging a multidisciplinary and interdisciplinary team. The optimal timing of specific therapeutic interventions is also discussed, emphasizing a patient-centered perspective. Resources for further reading, for both patients and clinicians, are provided throughout. Additional research is needed to further optimize the therapeutic approach to patients with FND, including the need to develop novel treatments for those that do not positively respond to currently available interventions.

Application of Intelligent Exercise Training Equipment in Clinical Nursing of Neurology Department

To investigate the effect of intelligent exercise training equipment on lower limb function and standing stability of stroke patients with hemiplegia in clinical nursing of neurology department. Forty-eight stroke patients with a course of 1 to 3 months were randomly divided into treatment group and control group, with 24 cases in each group. The control group was treated with conventional rehabilitation training, and the treatment group was treated with intelligent training system, twice a day, 20 min each time. Lower extremity motor function (using the FMA-L scale) and walking function (using the functional walking scale FAC) were assessed before treatment and 4 weeks after treatment. The results showed that there was no statistical difference between the control group and the treatment group in the t-test of lower limb motor function scores before rehabilitation treatment (P > 0.05). After treatment, the lower extremity motor function scores of the two groups were tested by group design T-test, and the results showed that there was a significant difference between the two groups (P < 0.05); The effect of the treatment group was significantly better than that of the control group (P < 0.05). Intelligent exercise training equipment combined with routine rehabilitation therapy in clinical nursing of neurology department could improve the lower extremity motor function and walking ability of patients with convalescence stroke hemiplegia, and the effect was better than that of routine rehabilitation therapy alone.

Five shades of gray: Conceptual and methodological issues around multivariate models of performance validity

OBJECTIVE

This study was designed to empirically investigate the signal detection profile of various multivariate models of performance validity tests (MV-PVTs) and explore several contested assumptions underlying validity assessment in general and MV-PVTs specifically.

METHOD

Archival data were collected from 167 patients (52.4%male; MAge = 39.7) clinicially evaluated subsequent to a TBI. Performance validity was psychometrically defined using two free-standing PVTs and five composite measures, each based on five embedded PVTs.

RESULTS

MV-PVTs had superior classification accuracy compared to univariate cutoffs. The similarity between predictor and criterion PVTs influenced signal detection profiles. False positive rates (FPR) in MV-PVTs can be effectively controlled using more stringent multivariate cutoffs. In addition to Pass and Fail, Borderline is a legitimate third outcome of performance validity assessment. Failing memory-based PVTs was associated with elevated self-reported psychiatric symptoms.

CONCLUSIONS

Concerns about elevated FPR in MV-PVTs are unsubstantiated. In fact, MV-PVTs are psychometrically superior to individual components. Instrumentation artifacts are endemic to PVTs, and represent both a threat and an opportunity during the interpretation of a given neurocognitive profile. There is no such thing as too much information in performance validity assessment. Psychometric issues should be evaluated based on empirical, not theoretical models. As the number/severity of embedded PVT failures accumulates, assessors must consider the possibility of non-credible presentation and its clinical implications to neurorehabilitation.

Differentiating Functional Cognitive Disorder from Early Neurodegeneration: A Clinic-Based Study

Functional cognitive disorder (FCD) is a relatively common cause of cognitive symptoms, characterised by inconsistency between symptoms and observed or self-reported cognitive functioning. We aimed to improve the clinical characterisation of FCD, in particular its differentiation from early neurodegeneration. Two patient cohorts were recruited from a UK-based tertiary cognitive clinic, diagnosed following clinical assessment, investigation and expert multidisciplinary team review: FCD, (n = 21), and neurodegenerative Mild Cognitive Impairment (nMCI, n = 17). We separately recruited a healthy control group (n = 25). All participants completed an assessment battery including: Hopkins Verbal Learning Test-Revised (HVLT-R), Trail Making Test Part B (TMT-B); Depression Anxiety and Stress Scale (DASS) and Minnesota Multiphasic Personality Inventory (MMPI-2RF). In comparison to healthy controls, the FCD and nMCI groups were equally impaired on trail making, immediate recall, and recognition tasks; had equally elevated mood symptoms; showed similar aberration on a range of personality measures; and had similar difficulties on inbuilt performance validity tests. However, participants with FCD performed significantly better than nMCI on HVLT-R delayed free recall and retention (regression coefficient −10.34, p = 0.01). Mood, personality and certain cognitive abilities were similarly altered across nMCI and FCD groups. However, those with FCD displayed spared delayed recall and retention, in comparison to impaired immediate recall and recognition. This pattern, which is distinct from that seen in prodromal neurodegeneration, is a marker of internal inconsistency. Differentiating FCD from nMCI is challenging, and the identification of positive neuropsychometric features of FCD is an important contribution to this emerging area of cognitive neurology.

Social aspects of life in patients with functional seizures: Closing the gap in the biopsychosocial formulation

The human, as a biological system, is an open system embedded within larger systems -including the family, culture, and socio-political environment. In this context, a patient with functional seizures (FS) is embedded in relationships, educational/professional institutions, culture, and society. Both connection to these broader systems and the quality of these connections, as well as the soundness of each system in and of itself, influence the health and well-being of patients in positive or negative ways. The social aspects of life are important determinants of health and quality of life across the lifespan. The current narrative review brings out several overarching themes in patients with FS. Sections on attachment, marriage, social networking, and stigma highlight the central roles of supportive and affirmative relationships across the lifespan. The section on education underscores the importance of keeping children and youth with FS connected within their school environments, as well as managing any barriers - learning difficulties, school response to FS events, stigma, etc.-that can diminish this connection. Finally, the sections on employment and driving highlight the value of being an active participant in one's society. In summary, FS impacts patients across most social aspects of life domains regardless of age - factors that are important when developing biopsychosocial formulations. This review concludes that the multidisciplinary management of FS requires careful assessment of social aspects of life in patients which can then be targeted for treatment, to improve their quality of life, facilitating recovery, and reducing the risk of relapse.

Are Functional (Psychogenic Nonepileptic) Seizures the Sole Expression of Psychological Processes?

Functional [psychogenic nonepileptic/dissociative] seizures (FND-seiz) and related functional neurological disorder subtypes were of immense interest to early founders of modern-day neurology and psychiatry. Unfortunately, the divide that occurred between the both specialties throughout the mid-twentieth century placed FND-seiz at the borderland between the two disciplines. In the process, a false Cartesian dualism emerged that labeled psychiatric conditions as impairments of the mind and neurological conditions as disturbances in structural neuroanatomy. Excitingly, modern-day neuropsychiatric perspectives now consider neurologic and psychiatric conditions as disorders of both brain and mind. In this article, we aim to integrate neurologic and psychiatric perspectives in the conceptual framing of FND-seiz. In doing so, we explore emerging relationships between symptoms, neuropsychological constructs, brain networks, and neuroendocrine/autonomic biomarkers of disease. Evidence suggests that the neuropsychological constructs of emotion processing, attention, interoception, and self-agency are important in the pathophysiology of FND-seiz. Furthermore, FND-seiz is a multi-network brain disorder, with evidence supporting roles for disturbances within and across the salience, limbic, attentional, multimodal integration, and sensorimotor networks. Risk factors, including the magnitude of previously experienced adverse life events, relate to individual differences in network architecture and neuroendocrine profiles. The time has come to use an integrated neuropsychiatric approach that embraces the closely intertwined relationship between physical health and mental health to conceptualize FND-seiz and related functional neurological disorder subtypes.

Towards an Outpatient Model of Care for Motor Functional Neurological Disorders: A Neuropsychiatric Perspective

Functional neurological disorder (FND), a condition at the intersection of neurology and psychiatry, is a common and disabling outpatient referral to neurology and neuropsychiatry clinics. In this perspective article, we focus on the motor spectrum of FND (mFND), including individuals with functional movement disorders (FND-movt), functional limb weakness/paresis (FND-par) and functional [psychogenic non-epileptic/dissociative] seizures (FND-seiz). Over the past several decades, there have been dedicated efforts within the neurologic and psychiatric communities to create "rule-in" diagnostic criteria, as well as thoughtful approaches to the clinical interview, delivery of the diagnosis and the development of a patient-centered treatment plan. These advances allow the promotion of good clinical practices in the outpatient assessment and management of mFND. Informed by the literature and our prior clinical experiences, we provide suggestions on how to evaluate individuals with suspected functional motor symptoms - including conducting sensitive psychiatric and psychosocial screenings. Additional sections discuss common "rule-in" neurological examination and semiologic signs of motor FND, as well as approaches to deliver the diagnosis and formulate a treatment plan based on individual patient needs. To aid the development of shared (partially overlapping) expertise that catalyzes an interdisciplinary approach to mFND, the use of physiotherapy for therapeutic motor retraining and cognitive behavioral therapy to examine relationships between symptoms, thoughts, behaviors and emotions are also discussed. Additional clinical research is needed to further refine and operationalize the assessment and management of mFND, across clinics, healthcare settings and countries.

A framework for understanding the pathophysiology of functional neurological disorder

The symptoms of functional neurological disorder (FND) are a product of its pathophysiology. The pathophysiology of FND is reflective of dysfunction within and across different brain circuits that, in turn, affects specific constructs. In this perspective article, we briefly review five constructs that are affected in FND: emotion processing (including salience), agency, attention, interoception, and predictive processing/inference. Examples of underlying neural circuits include salience, multimodal integration, and attention networks. The symptoms of each patient can be described as a combination of dysfunction in several of these networks and related processes. While we have gained a considerable understanding of FND, there is more work to be done, including determining how pathophysiological abnormalities arise as a consequence of etiologic biopsychosocial factors. To facilitate advances in this underserved and important area, we propose a pathophysiology-focused research agenda to engage government-sponsored funding agencies and foundations.