Sara A. Finkelstein’s research while affiliated with Harvard Medical School and other places

Background Robust epidemiological data regarding population incidence and prevalence of functional neurological disorder (FND) would be helpful with regards to resource allocation and planning for this disorder, particularly given high symptom burden and high healthcare utilisation. We therefore aimed to systematically review and synthesise available data on FND incidence and prevalence. Methods PubMed was searched to identify original research articles that reported on the incidence or prevalence of FND. Risk of bias assessment for each study was conducted. Incidence and prevalence rates of FND were additionally estimated by extrapolating data from low risk of bias studies on functional seizures alone. Results Thirty-nine articles were included. Nineteen reported on FND incidence, 21 reported on prevalence. Comparison between studies was difficult due to methodological differences and significant heterogeneity of incidence and prevalence estimates was found. The incidence of FND was estimated at 10–22/100 00, while minimum prevalence of FND was estimated at 80–140/100 000, with a possible range of 50–1600/100 000. Incidence of paediatric FND was estimated to be between 1 and 18/100 000. Conclusions The range of incidence and prevalence varies widely across studies, with significant heterogeneity among studies and most studies likely provide underestimates due to methodological challenges. However, using our best method as a conservative estimate, there are likely a minimum of 50–100 000 people with FND in the UK, as an example country. Given that FND appears to be more prevalent than many other well-known and well-funded neurological disorders, incidence and prevalence data suggested here indicate the need for greater research and clinical funding allocation to FND programmes.

Background Brain imaging studies investigating grey matter in functional neurological disorder (FND) have used univariate approaches to report group-level differences compared with healthy controls (HCs). However, these findings have limited translatability because they do not differentiate patients from controls at the individual-level. Methods 183 participants were prospectively recruited across three groups: 61 patients with mixed FND (FND-mixed), 61 age-matched and sex-matched HCs and 61 age, sex, depression and anxiety-matched psychiatric controls (PCs). Radial basis function support vector machine classifiers with cross-validation were used to distinguish individuals with FND from HCs and PCs using 134 FreeSurfer -derived grey matter MRI features. Results Patients with FND-mixed were differentiated from HCs with an accuracy of 0.66 (p=0.005; area under the receiving operating characteristic (AUROC)=0.74); this sample was also distinguished from PCs with an accuracy of 0.60 (p=0.038; AUROC=0.56). When focusing on the functional motor disorder subtype (FND-motor, n=46), a classifier robustly differentiated these patients from HCs (accuracy=0.72; p=0.002; AUROC=0.80). FND-motor could not be distinguished from PCs, and the functional seizures subtype (n=23) could not be classified against either control group. Important regions contributing to statistically significant multivariate classifications included the cingulate gyrus, hippocampal subfields and amygdalar nuclei. Correctly versus incorrectly classified participants did not differ across a range of tested psychometric variables. Conclusions These findings underscore the interconnection of brain structure and function in the pathophysiology of FND and demonstrate the feasibility of using structural MRI to classify the disorder. Out-of-sample replication and larger-scale classifier efforts incorporating psychiatric and neurological controls are needed.

Background: While expert consensus recommendations support the use of speech and language therapy (SLT) for patients with functional speech disorder (FND-speech), there is limited published data on clinical outcomes. Objective: To retrospectively report the treatment outcomes and clinical characteristics of patients with FND-speech that attended outpatient SLT as part of a multidisciplinary program for functional neurological disorder (FND). Methods: In this case series, we included adult patients with FND-speech that consecutively participated in outpatient SLT at our institution between October 2014 and September 2021. Baseline demographic and neuropsychiatric characteristics were extracted from the medical records, along with data on FND-speech phenotypes, number of treatment sessions received, and clinician-determined outcomes. Only descriptive statistics were used to report findings. Results: Twenty patients met inclusion criteria; ages ranged from 21-77, with a mean of 51.6±16.2 years. 85% of the cohort presented with mixed FND-speech symptoms. Patients attended a range of 2-37 visits, with an average of 9.2±8.0 visits over 4.4±3.5 months. At the last treatment session, 3 patients were asymptomatic, 15 had improved, and 2 had not improved; 8 individuals that improved received video telehealth interventions. Conclusion: This case series lends additional support for outpatient SLT in the assessment and management of individuals with FND-speech, and may help clarify patient and provider treatment expectations. Additional prospective research is needed to investigate baseline predictors of treatment response and further define the optimal frequency, intensity, duration, and clinical setting for SLT delivery in this population.

Functional neurological disorder (FND) is a common and disabling disorder, often misunderstood by clinicians. Although viewed sceptically by some, FND is a diagnosis that can be made accurately, based on positive clinical signs, with clinical features that have remained stable for over 100 years. Despite some progress in the last decade, people with FND continue to suffer subtle and overt forms of discrimination by clinicians, researchers and the public. There is abundant evidence that disorders perceived as primarily affecting women are neglected in healthcare and medical research, and the course of FND mirrors this neglect. We outline the reasons why FND is a feminist issue, incorporating historical and contemporary clinical, research and social perspectives. We call for parity for FND in medical education, research and clinical service development so that people affected by FND can receive the care they need.