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Background: Functional dystonia (FD) is a common subtype of functional movement disorder. FD can be readily diagnosed based on positive signs and is potentially treatable with rehabilitation. Despite this, clinical outcomes remain variable and a gold standard approach to treatment is lacking., Cases: Here we present four cases of axial and limb functional dystonia who were treated with integrated rehabilitation and improved. The therapy approach and clinical outcomes are described, including videos., Literature Review: A literature review evaluated the published treatment strategies for the treatment of functional dystonia. Out of 338 articles, 25 were eligible for review and included mainly case reports and case series. Most patients received more than one treatment modality. Non-invasive therapies, commonly physiotherapy and psychological approaches were mostly associated with positive outcomes. Multiple treatments commonly used in dystonia were used, including botulinum toxin injections, pharmacotherapy and surgery, leading to variable outcomes., Conclusion: Therapy should be personalized to the clinical presentation. In challenging cases, initiation of a multidisciplinary approach may provide benefit regardless of etiology. Pharmacotherapy should be used judiciously, and surgical therapy should be avoided., (© 2024 The Author(s). Movement Disorders Clinical Practice published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Purpose: To describe the therapy approaches and clinical outcomes of an integrated care model for patients with functional movement disorder (FMD)., Materials and Methods: A retrospective chart review was conducted for all treated individuals with a primary diagnosis of FMD between January 2020 and July 2022. Patients received time-limited integrated therapy ( n  = 21) (i.e., simultaneous therapy delivered by psychiatry, neurology and physiotherapy), physiotherapy ( n  = 18) or virtual physiotherapy alone ( n  = 9). Primary outcomes included the Simplified-Functional Movement Disorders Rating Scale (S-FMDRS) and Clinical Global Impression-Improvement scale (CGI-I) collected at baseline and post-intervention., Results: Forty-eight patients completed treatment (42% male; mean age, 48.5 ± 16.6 years, median symptom duration 30 months). The most common presentations were gait disorder, tremor and mixed hyperkinetic FMD. Common comorbidities included pain and fatigue. Three-quarters of patients had a comorbid psychiatric diagnosis. There was a significant reduction in S-FMDRS score following therapy (71%, p  < 0.0001) and 69% had "much" or "very much" improved on the CGI-I. There was no difference between therapy groups. Attendance rates were high for both in-person (94%) and virtual (97%) visits., Conclusions: These findings support that a time-limited integrated model of care is feasible and effective in treating patients with FMD.

Background: Treatment of functional movement disorder (FMD) should be individualized, yet factors determining rehabilitation engagement have not been evaluated. Subspecialty FMD clinics are uniquely poised to explore factors influencing treatment suitability and triage., Objectives: To describe our approach and explore factors associated with triage to FMD rehabilitation., Methods: We conducted a retrospective chart review of 158 consecutive patients with FMD seen for integrated assessment by movement disorders neurology and psychiatry, with the purpose of triage to rehabilitation. Demographic and clinical variables were compared between patients triaged to therapy versus no therapy, and logistic regression was used to explore factors predictive of triage outcome. Change in primary outcome scores were analyzed., Results: Sixty-six patients (42%) were triaged to FMD therapy from July 2019 to December 2021. Patients triaged to therapy were more likely to have a constant movement disorder, gait disorder and/or tremor, hyperarousal, readiness for change, and people pleasing traits. Patients triaged to no therapy demonstrated persistent diagnostic disagreement, an inability to appreciate motor symptom inconsistency, low self-agency, a propensity to dissociate, and cluster B traits. 90% of patients triaged to rehabilitation had improved outcomes., Conclusions: The ability to "opt-in" to FMD rehabilitation relies on different factors than those relevant to establishing a diagnosis. Unlike many other neurological disorders, a triage and treatment planning step is recommended to identify those likely to meaningfully engage at that time. Holistic assessment through a transdisciplinary lens, and working collaboratively with the patient is essential to prioritize symptoms, determine engagement, and identify treatment targets., (© 2024 The Authors. Movement Disorders Clinical Practice published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Objective: Functional movement disorder (FMD), the motor-dominant subtype of functional neurological disorder, is a complex neuropsychiatric condition. Patients with FMD also manifest non-motor symptoms. Given that patients with FMD are diagnosed based on motor phenotype, the contribution of non-motor features to the neuropsychiatric syndrome is not well characterized. The objective of this hypothesis-generating study was to explore potential novel, neuropsychiatric FMD phenotypes by combining movement disorder presentations with non-motor comorbidities including somatic symptoms, psychiatric diagnoses, and psychological traits., Methods: This retrospective chart review evaluated 158 consecutive patients with a diagnosis of FMD who underwent deep phenotyping across neurological and psychiatric domains. Demographic, clinical, and self-report features were analyzed. A data-driven approach using cluster analysis was performed to detect patterns when combining the movement disorder presentation with somatic symptoms, psychiatric diagnoses, and psychological factors. These new neuropsychiatric FMD phenotypes were then tested using logistic regression models., Results: Distinct neuropsychiatric FMD phenotypes emerged when stratifying by episodic vs. constant motor symptoms. Episodic FMD was associated with hyperkinetic movements, hyperarousal, anxiety, and history of trauma. In contrast, constant FMD was associated with weakness, gait disorders, fixed dystonia, activity avoidance, and low self-agency. Pain, fatigue, somatic preoccupation, and health anxiety were common across all phenotypes., Conclusion: This study found patterns spanning the neurological-psychiatric interface that indicate that FMD is part of a broader neuropsychiatric syndrome. Adopting a transdisciplinary view of illness reveals readily identifiable clinical factors that are relevant for the development and maintenance of FMD.

Background: Pain is common in Parkinson's disease (PD), but effective therapies are limited., Objectives: To determine the maximum tolerated dose (MTD) and safety of formulations of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) for pain in PD., Methods: In this phase 1b, double-blind, randomized, single-center study, participants were randomized to three formulations of THC/CBD (18:0, 10:10, and 1:20). The MTD, adverse events (AE), and tolerability are described for each formulation., Results: Eight participants were randomized. The MTD was similar among groups (0.8-0.9 mL/daily), and there were no serious AE or study drop-outs. The most common AE were drowsiness and dizziness (three participants). Epworth sleepiness scale scores were higher in the high CBD formulation (1:20)., Conclusions: In patients with pain and PD, mixed formulations of THC/CBD were tolerated with no serious AE. Considering the safety profile, future phase II studies should be considered., (© 2023 International Parkinson and Movement Disorder Society.)

Functional movement disorder (FMD) is a complex neuropsychiatric syndrome, encompassing abnormal movements and weakness, and is a common cause of potentially disabling neurological symptoms. It is vital to recognize that FMD is a syndrome, with nonmotor manifestations negatively affecting a patient's quality of life. This review highlights a diagnostic algorithm, where a history suggestive of FMD is combined with the presence of positive signs on examination and appropriate investigations to make the diagnosis. Positive signs indicate internal inconsistency such as variability and distractibility, and clinical findings that are incongruent with other known neurological disease. Importantly, the clinical assessment acts as the first opportunity to allow patients to understand FMD as the cause for their symptoms. Accurate and early diagnosis of FMD is necessary given that it is a treatable and potentially reversible cause of disability, with significant risk of iatrogenic harm associated with misdiagnosis., Competing Interests: None declared., (Thieme. All rights reserved.)

Introduction: Essential tremor (ET) is a tremor syndrome characterized by bilateral, upper limb action tremor. Essential tremor-plus (ET-plus) describes ET patients with additional neurologic signs. It is unknown whether there is a difference in response to treatment with ventralis intermedius nucleus deep brain stimulation (VIM DBS) in patients with ET and ET-plus. Due to potential variability in underlying etiology in ET-plus, there is a concern that ET-plus patients may have worse outcomes. The aim of this study was to identify whether patients with ET-plus have worse tremor outcomes after VIM DBS than patients with ET. Methods: This is a retrospective chart and video review evaluating VIM DBS outcomes by comparing changes from baseline in the Fahn-Tolosa-Marin Tremor Rating Scale Part B (FTM-B) for the treated limb between patients with ET and ET-plus at follow-up examinations. Patients were re-classified as having ET or ET-plus using pre-operative examination videos by two independent movement disorders neurologists blinded to patient characteristics. As a secondary outcome, we evaluated for correlations and potential predictors of treatment response. Results: Twenty-six patients were included: 13 with ET, 13 with ET-plus. There were no significant differences in the change in FTM-B scores between the ET and ET-plus patients at each follow-up examination. None of the included patients developed new symptoms compatible with dystonia, parkinsonism or gait disturbances. Conclusions: Patients with ET-plus had tremor improvement from VIM DBS, with no differences when compared to those with ET, without emergence of postoperative neurological issues. Patients with ET-plus should still be considered good candidates for VIM DBS for treatment of tremor., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Gilmour, Martino, Hunka, Lawrence, Kiss and Bruno.)

Background: Psychogenic nonepileptic attacks (PNEA) are events of altered behavior that resemble epileptic seizures (ES) but are not caused by abnormal electrical cortical activity. Understanding which clinical signs and symptoms are associated with PNEA may allow better triaging for video-electroencephalogram monitoring (VEM) and for a more accurate prediction when such testing is unavailable., Methods: We performed a systematic review searching Medline, Embase, and Cochrane Central from inception to March 29, 2019. We included original research that reported at least one clinical sign or symptom, included distinct groups of adult ES and PNEA with no overlap, and used VEM for the reference standard. Two authors independently assessed quality of the studies using the Quality Assessment of Diagnostic Accuracy Studies tool. Pooled estimates of sensitivity and specificity of studies were evaluated using a bivariate random effects model., Results: We identified 4028 articles, of which 33 were included. There was a female sex predominance in the PNEA population (n = 22). From our meta-analysis, pooled sensitivities (0.27-0.72) and specificities (0.51-0.89) for PNEA were modest for individual signs. History of sexual abuse had the highest pooled specificity (89%), while the most sensitive feature was female sex (72%). Individual studies (n = 4) reported high levels of accuracy for ictal eye closure (sensitivity 64-73.7% and specificity 76.9-100%) and post-traumatic stress disorder (no reported sensitivity or specificity). Assuming the pre-test probability for PNEA in a tertiary care epilepsy center is 14%, even the strongest meta-analyzed features only exert modest diagnostic value, increasing post-test probabilities to a maximum of 33%., Conclusions: This review reflects the limited certainty afforded by individual clinical features to distinguish between PNEA and ES. Specific demographic and comorbid features, even despite moderately high specificities, impart minimal impact on diagnostic decision making. This emphasizes the need for the development of multisource predictive tools to optimize diagnostic likelihood ratios., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: The aim of this scoping review is to describe the characteristics of patients requiring admission to hospital for functional neurological disorder (FND), assess interventions provided, and evaluate outcomes in the context of acute hospital presentation or elective admission with chronic symptoms (>3 months)., Methods: A scoping review was performed. Included articles described adult patients admitted with FND to an inpatient care setting. Articles focusing on psychogenic non-epileptic attacks (PNEA) were excluded., Results: The search strategy identified 1963 citations. A total of 34 articles met inclusion criteria, with 458 patients (66% female) described. The pooled mean age of patients in all studies was 40.6 years. Eleven studies described patients with acute presentation, and 16 studies described patients with chronic FND symptoms admitted to the hospital. Motor symptoms were most common. Interventions were most commonly physiotherapy and psychotherapy. Most studies reported partial or complete resolution of symptoms., Conclusions: This scoping review summarizes the literature on the characteristics of patients admitted to the hospital, both with acute and chronic symptoms, for inpatient treatment of FND. When comparing patients with acute to those with chronic symptoms, we found that acute presentations were older (46.9 vs. 43.7 years) and had a higher representation of men (33% vs. 30%). Those presenting with chronic symptoms were more likely to not improve or relapse. We postulate that early diagnosis and inpatient rehabilitation could have a positive impact on outcomes for patients with FND.

Functional neurological disorder (FND) is a common cause of persistent and disabling neurological symptoms. These symptoms are varied and include abnormal control of movement, episodes of altered awareness resembling epileptic seizures and abnormal sensation and are often comorbid with chronic pain, fatigue and cognitive symptoms. There is increasing evidence for the role of neurologists in both the assessment and management of FND. The aim of this review is to discuss strategies for the management of FND by focusing on the diagnostic discussion and general principles, as well as specific treatment strategies for various FND symptoms, highlighting the role of the neurologist and proposing a structure for an interdisciplinary FND service.

Background: We describe a case of convulsive status epilepticus caused by intracranial hypotension, a complication of spinal surgery. Intracranial hypotension (IH) is typically characterized by an orthostatic headache. There have been limited case reports describing surgery-associated IH presenting with seizures., Methods: Case report and review of the literature., Results: A 71-year-old woman with chronic back pain developed convulsive status epilepticus, characterized by generalized clonic seizures, immediately following scoliosis surgery. She had no history of seizures or other seizure risk factors. Despite treatment with intravenous midazolam, phenytoin, and lacosamide, seizures recurred five times over three hours. Thus, propofol and midazolam infusions were initiated. An electroencephalogram revealed burst suppression and bilateral hemispheric epileptiform discharges. Magnetic resonance imaging of the brain was consistent with IH without cortical vein thrombosis. Fluid from the surgical drains was positive for Beta-2 transferrin, consistent with cerebral spinal fluid. Her IH was likely due to an intraoperative dural tear causing status epilepticus. Over two weeks, she remained on bed rest, sedation was weaned, and phenytoin and lacosamide were tapered and discontinued. She had no further seizures., Conclusions: IH is an under-recognized cause of seizure following the spinal or cranial surgery, lumbar puncture, or spinal anesthesia. Proposed mechanisms include traction on cortical structures, increased cerebral blood flow, and cortical irritation secondary to subdural hygromas.

We evaluated the full field electroretinogram (ERG) to assess age-related changes in retina function in humans. ERG recordings were performed on healthy subjects with normal fundus appearance, lack of cataract and 20/20 acuity, aged 20-39 years (n = 27; mean age 25 ± 5, standard deviation), 40-59 years (n = 20; mean 53 ± 5), and 60-82 years (n = 18; mean 69 ± 5). Multiple ERG tests were applied, including light and dark-adapted stimulus-response function, dark adaptation and dynamic of recovery from a single bright flash under dark-adapted conditions. Changes in ERG properties were found in the oldest age group when compared with the two younger age groups. (1) The photopic hill effect was less pronounced. (2) Both photopic a-wave and b-wave amplitudes and implicit times were increased at high stimulus strengths. (3) Dark adaptation time was delayed for pure rod and L/M cone-driven responses, respectively. (4) Dark-adapted a-wave but not b-wave amplitudes were reduced, yielding higher B/A ratios. (5) Dark-adapted a- and b-waves implicit times were prolonged: there was a direct proportional correlation between minimal a-wave implicit times and age. (6) The dynamic of dark current recovery from a bright flash, under dark-adapted conditions, was transiently faster at intervals between 0.9 and 2 s. These results denote that aging of the healthy retina is accompanied by specific functional changes, which must be taken into account to optimally diagnose potential pathologies.

Unlike laboratory rats and mice, muridae of the Arvicanthis family (A. ansorgei and A. niloticus) are adapted to functioning best in daylight. To date, they have been used as experimental models mainly in studies of circadian rhythms. However, recent work aimed at optimizing photoreceptor-directed gene delivery vectors (Khani et al. [2007] Invest Ophthalmol Vis Sci 48:3954-3961) suggests their potential usefulness for studying retinal pathologies and therapies. In the present study we analyzed the retinal anatomy and visual performance of the Nile grass rat (A. niloticus) using immunohistofluorescence and the optokinetic response (OKR). We found that approximately 35-40% of photoreceptors are cones; that many neural features of the inner retina are similar to those in other diurnal mammals; and that spatial acuity, measured by the OKR, is more than two times that of the usual laboratory rodents. These observations are consistent with the known diurnal habits of this animal, and further support its pertinence as a complementary model for studies of structure, function, and pathology in cone-rich mammalian retinae.

Background: Vision is initiated by phototransduction in the outer retina by photoreceptors, whose high metabolic rate generates large CO2 loads. Inner retina cells then process the visual signal and CO2. The anion exchanger 3 gene (AE3/Slc4a3) encodes full-length AE3 (AE3fl) and cardiac AE3 (AE3c) isoforms, catalyzing plasma membrane Cl-/HCO3- exchange in Müller (AE3fl) and horizontal (AE3c) cells. AE3 thus maintains acid-balance by removing photoreceptor-generated CO2 waste., Methodology/principal Findings: We report that Slc4a3-/- null mice have inner retina defects (electroretinogram b-wave reduction, optic nerve and retinal vessel anomalies). These pathologic features are common to most human vitreoretinal degenerations. Immunobloting analysis revealed that Na+/HCO3- co-transporter (NBC1), and carbonic anhydrase II and CAXIV, protein expression were elevated in Slc4a3-/- mouse retinas, suggesting compensation for loss of AE3. TUNEL staining showed increased numbers of apoptotic nuclei from 4-6 months of age, in Slc4a3-/- mice, indicating late onset photoreceptor death., Conclusions/significance: Identification of Slc4a3 as underlying a previously unrecognized cause of blindness suggests this gene as a new candidate for a subset of hereditary vitreoretinal retinal degeneration.