Neurostimulation for Functional Neurological Disorder: Evaluating Longitudinal Neurophysiology.
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ABSTRACT:
SUBMITTER: Burke MJ
PROVIDER: S-EPMC6207130 | biostudies-literature | 2018 Sep-Oct
REPOSITORIES: biostudies-literature
Publications
Neurostimulation for Functional Neurological Disorder: Evaluating Longitudinal Neurophysiology.
Burke Matthew J MJ Isayama Reina R Jegatheeswaran Gaayathiri G Gunraj Carolyn C Feinstein Anthony A Lang Anthony E AE Chen Robert R
Movement disorders clinical practice 20180901 5
Similar Datasets
Project description:Functional Neurological Disorder (FND), also known as conversion disorder, is characterized by neurological symptoms that are incompatible with any known structural disorder and best explained by a biopsychosocial model. Evidence-based treatments for FND are limited, with cognitive behavioral therapy (CBT) and physiotherapy being the most effective interventions [1]. In recent years, functional neuroimaging studies have provided robust evidence of alterations in activity and connectivity in multiple brain networks in FND. This body of evidence suggests that neurocircuitry-based interventions, such as non-invasive brain stimulation techniques (NIBS), may also represent an effective therapeutic option for patients with FND. In this systematic review, we outline the current state of knowledge of NIBS in FND, and discuss limitations and future directions that may help establish the efficacy of NIBS as a therapeutic option for FND.
| S-EPMC8671519 | biostudies-literature
Project description: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.
| S-EPMC7320922 | biostudies-literature
Project description:Emotions have traditionally been considered crucial in the development of functional neurological disorder, but the evidence underpinning this association is not clear. We aimed to summarize evidence for association between functional neurological disorder and emotions as formulated by Breuer and Freud in their conception of hysterical conversion. Based on a systematic literature search, we identified 34 controlled studies and categorized them into four groups: (i) autonomic arousal, (ii) emotion-motion interactions, (iii) social modulation of symptoms, and (iv) bodily awareness in FND. We found evidence for autonomic dysregulation in FND; convergent neuroimaging findings implicate abnormal limbic-motor interactions in response to emotional stimuli in FND. Our results do not provide enough empirical evidence for social modulation of the symptoms, but there is a clinical support for the role of suggestion and placebo in FND. Our results provide evidence for abnormal bodily awareness in FND. Based on these findings, we propose that functional neurological symptoms are forms of emotional reactions shaped into symptoms by previous experience with illness and possibly reinforced by actual social contexts. Additional research should investigate the effect of social context on the intensity of functional neurological symptoms and associated brain regions.
| S-EPMC6182079 | biostudies-other
Project description:BackgroundMotor functional neurological disorder (mFND) is a clinical diagnosis with reliable features; however, patients are reluctant to accept the diagnosis and physicians themselves bear doubts on potential misdiagnoses. The identification of a positive biomarker could help limiting unnecessary costs of multiple referrals and investigations, thus promoting early diagnosis and allowing early engagement in appropriate therapy.ObjectivesTo test whether resting-state (RS) functional magnetic resonance imaging could discriminate patients suffering from mFND from healthy controls.MethodsWe classified 23 mFND patients and 25 age- and gender-matched healthy controls based on whole-brain RS functional connectivity (FC) data, using a support vector machine classifier and the standard Automated Anatomic Labeling (AAL) atlas, as well as two additional atlases for validation.ResultsAccuracy, specificity and sensitivity were over 68% (p = 0.004) to discriminate between mFND patients and controls, with consistent findings between the three tested atlases. The most discriminative connections comprised the right caudate, amygdala, prefrontal and sensorimotor regions. Post-hoc seed connectivity analyses showed that these regions were hyperconnected in patients compared to controls.ConclusionsThe good accuracy to discriminate patients from controls suggests that RS FC could be used as a biomarker with high diagnostic value in future clinical practice to identify mFND patients at the individual level.
| S-EPMC5651543 | biostudies-literature
Project description:With the creation of the Somatic Symptom and Related Disorders category of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition in 2013, the functional neurological (symptom) disorder diagnostic criteria underwent transformative changes. These included an emphasis on 'rule-in' physical examination signs/semiological features guiding diagnosis and the removal of a required proximal psychological stressor to be linked to symptoms. In addition, the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition somatization disorder, somatoform pain disorder and undifferentiated somatoform disorder conditions were eliminated and collapsed into the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition somatic symptom disorder diagnosis. With somatic symptom disorder, emphasis was placed on a cognitive-behavioural (psychological) formulation as the basis for diagnosis in individuals reporting distressing bodily symptoms such as pain and/or fatigue; the need for bodily symptoms to be 'medically unexplained' was removed, and the overall utility of this diagnostic criteria remains debated. A consequence of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition restructuring is that the diagnosis of somatization disorder that encompassed individuals with functional neurological (sensorimotor) symptoms and prominent other bodily symptoms, including pain, was eliminated. This change negatively impacts clinical and research efforts because many patients with functional neurological disorder experience pain, supporting that the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition would benefit from an integrated diagnosis at this intersection. We seek to revisit this with modifications, particularly since pain (and a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition somatization disorder comorbidity, more specifically) is associated with poor clinical prognosis in functional neurological disorder. As a first step, we systematically reviewed the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition somatization disorder literature to detail epidemiologic, healthcare utilization, demographic, diagnostic, medical and psychiatric comorbidity, psychosocial, neurobiological and treatment data. Thereafter, we propose a preliminary revision to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition allowing for the specifier functional neurological disorder 'with prominent pain'. To meet this criterion, core functional neurological symptoms (e.g. limb weakness, gait difficulties, seizures, non-dermatomal sensory loss and/or blindness) would have 'rule-in' signs and pain (>6 months) impairing social and/or occupational functioning would also be present. Two optional secondary specifiers assist in characterizing individuals with cognitive-behavioural (psychological) features recognized to amplify or perpetuate pain and documenting if there is a pain-related comorbidity. The specifier of 'with prominent pain' is etiologically neutral, while secondary specifiers provide additional clarification. We advocate for a similar approach to contextualize fatigue and mixed somatic symptoms in functional neurological disorder. While this preliminary proposal requires prospective data and additional discussion, these revisions offer the potential benefit to readily identify important functional neurological disorder subgroups-resulting in diagnostic, treatment and pathophysiology implications.
| S-EPMC7784044 | biostudies-literature
Project description:Functional neurological disorder is common in neurological practice. A new approach to the positive diagnosis of this disorder focuses on recognisable patterns of genuinely experienced symptoms and signs that show variability within the same task and between different tasks over time. Psychological stressors are common risk factors for functional neurological disorder, but are often absent. Four entities-functional seizures, functional movement disorders, persistent perceptual postural dizziness, and functional cognitive disorder-show similarities in aetiology and pathophysiology and are variants of a disorder at the interface between neurology and psychiatry. All four entities have distinctive features and can be diagnosed with the support of clinical neurophysiological studies and other biomarkers. The pathophysiology of functional neurological disorder includes overactivity of the limbic system, the development of an internal symptom model as part of a predictive coding framework, and dysfunction of brain networks that gives movement the sense of voluntariness. Evidence supports tailored multidisciplinary treatment that can involve physical and psychological therapy approaches.
| S-EPMC9107510 | biostudies-literature
Project description:BackgroundFunctional neurological disorder (FND) is a condition at the intersection of neurology and psychiatry. Individuals with FND exhibit corticolimbic abnormalities, yet little is known about the role of white matter tracts in the pathophysiology of FND. This study characterized between-group differences in microstructural integrity, and correlated fiber bundle integrity with symptom severity, physical disability, and illness duration.MethodsA diffusion tensor imaging (DTI) study was performed in 32 patients with mixed FND compared to 36 healthy controls. Diffusion-weighted magnetic resonance images were collected along with patient-reported symptom severity, physical disability (Short Form Health Survey-36), and illness duration data. Weighted-degree and link-level graph theory and probabilistic tractography analyses characterized fractional anisotropy (FA) values across cortico-subcortical connections. Results were corrected for multiple comparisons.ResultsCompared to controls, FND patients showed reduced FA in the stria terminalis/fornix, medial forebrain bundle, extreme capsule, uncinate fasciculus, cingulum bundle, corpus callosum, and striatal-postcentral gyrus projections. Except for the stria terminalis/fornix, these differences remained significant adjusting for depression and anxiety. In within-group analyses, physical disability inversely correlated with stria terminalis/fornix and medial forebrain bundle FA values; illness duration negatively correlated with stria terminalis/fornix white matter integrity. A FND symptom severity composite score did not correlate with FA in patients.ConclusionsIn this first DTI study of mixed FND, microstructural differences were observed in limbic and associative tracts implicated in salience, defensive behaviors, and emotion regulation. These findings advance our understanding of neurocircuit pathways in the pathophysiology of FND.
| S-EPMC7247956 | biostudies-literature
Project description:Closed-loop brain stimulation is increasingly used in level 4 epilepsy centers without an understanding of how the device behaves on a daily basis. This lack of insight is a barrier to improving closed-loop therapy and ultimately understanding why some patients never achieve seizure reduction. We aimed to quantify the accuracy of closed-loop seizure detection and stimulation on the RNS device through extrapolating information derived from manually reviewed ECoG recordings and comprehensive device logging information. RNS System event logging data were obtained, reviewed, and analyzed using a custom-built software package. A weighted-means methodology was developed to adjust for bias and incompleteness in event logs and evaluated using Bland-Altman plots and Wilcoxon signed-rank tests to compare adjusted and non-weighted (standard method) results. Twelve patients implanted for a mean of 21.5 (interquartile range 13.5-31) months were reviewed. The mean seizure frequency reduction post-RNS implantation was 40.1% (interquartile range 0-96.2%). Three primary levels of event logging granularity were identified (ECoG recordings: 3.0% complete (interquartile range 0.3-1.8%); Event Lists: 72.9% complete (interquartile range 44.7-99.8%); Activity Logs: 100% complete; completeness measured with respect to Activity Logs). Bland-Altman interpretation confirmed non-equivalence with unpredictable differences in both magnitude and direction. Wilcoxon signed rank tests demonstrated significant (p?<?10-6) differences in accuracy, sensitivity, and specificity at >5% absolute mean difference for extrapolated versus standard results. Device behavior logged by the RNS System should be used in conjunction with careful review of stored ECoG data to extrapolate metrics for detector performance and stimulation.
| S-EPMC7338816 | biostudies-literature
Project description:The use of noninvasive transcranial electrical stimulation (tES) has rapidly increased over the past two decades. Yet, tES continues to be largely implemented in laboratory and rehabilitation settings, thereby limiting accessibility to the broader population. We have previously demonstrated that transcranial alternating current stimulation (tACS) in the theta (4-7 Hz) band improves cognitive control, such as multitasking, in younger adults following a single tACS session, as well as in older adults following three tACS sessions. Here, the goal was to extend our in-lab results by (1) assessing the feasibility for at-home tACS and (2) evaluating whether five tACS sessions may yield continuing improvements in multitasking ability in young adults. Participants (aged 18 - 34 years) received bilateral prefrontal tACS while engaged in an adaptive multitasking training over five consecutive days in their home settings. Participants were randomly assigned to receive either 20-minutes of theta or delta tACS during daily multitasking training. Prior to and on the day immediately following five days of tACS, we assessed performance on single task, multitask, and sustained attention ability with analyses of variance statistics. 92.1% of participants were able to self-administer tACS at home without researcher assistance. However, we observed that both theta and delta tACS groups exhibited improvements in both single and multitask performance. Compared to previously collected data, five days of theta tACS was comparable to one day of theta tACS. However, theta tACS has continued benefits in older, but not younger adults as evidenced by previous research. Both groups similarly improved in sustained attention. These results demonstrate that laboratory paradigms utilizing neurostimulation can be effectively deployed in a home environment without direct support from research personnel. Moreover, these results suggest that while theta tACS may facilitate multitasking improvements over one session, multiple sessions of theta tACS results in diminishing returns in young adults. Additional research will be required to confirm if delta activity plays an important role in multitasking ability.
| S-EPMC9483846 | biostudies-literature
Project description:An increasing concern affecting a growing aging population is working memory (WM) decline. Consequently, there is great interest in improving or stabilizing WM, which drives expanded use of brain training exercises. Such regimens generally result in temporary WM benefits to the trained tasks but minimal transfer of benefit to untrained tasks. Pairing training with neurostimulation may stabilize or improve WM performance by enhancing plasticity and strengthening WM-related cortical networks. We tested this possibility in healthy older adults. Participants received 10 sessions of sham (control) or active (anodal, 1.5 mA) tDCS to the right prefrontal, parietal, or prefrontal/parietal (alternating) cortices. After ten minutes of sham or active tDCS, participants performed verbal and visual WM training tasks. On the first, tenth, and follow-up sessions, participants performed transfer WM tasks including the spatial 2-back, Stroop, and digit span tasks. The results demonstrated that all groups benefited from WM training, as expected. However, at follow-up 1-month after training ended, only the participants in the active tDCS groups maintained significant improvement. Importantly, this pattern was observed for both trained and transfer tasks. These results demonstrate that tDCS-linked WM training can provide long-term benefits in maintaining cognitive training benefits and extending them to untrained tasks.
| S-EPMC4388845 | biostudies-literature