Dysfunctional Networks in Functional Dystonia

Functional dystonia, the second most common functional movement disorder, is characterized by acute or subacute onset of fixed limb, truncal, or facial posturing, incongruent with the action-induced, position-sensitive, and task-specific manifestations of dystonia. We review neurophysiological and neuroimaging data as the basis for a dysfunctional networks in functional dystonia. Reduced intracortical and spinal inhibition contributes to abnormal muscle activation, which may be perpetuated by abnormal sensorimotor processing, impaired selection of movements, and hypoactive sense of agency in the setting of normal movement preparation but abnormal connectivity between the limbic and motor networks. Phenotypic variability may be related to as-yet undefined interactions between abnormal top-down motor regulation and overactivation of areas implicated in self-awareness, self-monitoring, and active motor inhibition such as the cingulate and insular cortices. While there remain many gaps in knowledge, further combined neurophysiological and neuroimaging assessments stand to inform the neurobiological subtypes of functional dystonia and the potential therapeutic applications.

Use of non-invasive neurostimulation for rehabilitation in functional movement disorders

Functional movement disorders (FMD) are a subtype of functional neurological disorders which involve abnormal movements and include multiple phenomenologies. There is a growing interest in the mechanism, diagnosis, and treatment of these disorders. Most of the current therapeutic approaches rely on psychotherapy and physiotherapy conducted by a multidisciplinary team. Although this approach has shown good results in some cases, FMD cause a great burden on the health system and other treatment strategies are urgently needed. In this review, we summarize past studies that have applied non-invasive neurostimulation techniques, such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and peripheral nerve stimulation as a treatment for FMD. There is an increasing number of studies related to TMS including randomized controlled trials; however, the protocols amongst studies are not standardized. There is only preliminary evidence for the efficacy of non-invasive neuromodulation in reducing FMD symptoms, and further studies are needed. There is insufficient evidence to allow implementation of these techniques in clinical practice.

Organic Neuroelectronics: From Neural Interfaces to Neuroprosthetics

Requirements and recent advances in research on organic neuroelectronics are outlined herein. Neuroelectronics such as neural interfaces and neuroprosthetics provide a promising approach to diagnose and treat neurological diseases. However, the current neural interfaces are rigid and not biocompatible, so they induce an immune response and deterioration of neural signal transmission. Organic materials are promising candidates for neural interfaces, due to their mechanical softness, excellent electrochemical properties, and biocompatibility. Also, organic nervetronics, which mimics functional properties of the biological nerve system, is being developed to overcome the limitations of the complex and energy-consuming conventional neuroprosthetics that limit long-term implantation and daily-life usage. Examples of organic materials for neural interfaces and neural signal recordings are reviewed, recent advances of organic nervetronics that use organic artificial synapses are highlighted, and then further requirements for neuroprosthetics are discussed. Finally, the future challenges that must be overcome to achieve ideal organic neuroelectronics for next-generation neuroprosthetics are discussed.

Repetitive transcranial magnetic stimulation for patients with functional paralysis: a randomized controlled study

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been proposed to treat functional neurological disorders. Here, we aim to assess the efficacy of rTMS to treat functional paralysis in a controlled randomized trial.

METHODS

Patients received 2 sessions of active or sham 0.25 Hz rTMS (60 stimuli each), with a one-day interval, applied over the motor cortex contralateral to the paralysis. The primary outcome was the number of patients with an increase in motor score between baseline and after the second rTMS session, rated by two investigators blinded to the treatment allocation. Secondary outcomes were changes in global and fine motor scores between groups after rTMS, and occurrence of adverse events.

RESULTS

Sixty-two patients (46 female; mean [SD] age, 35.2 [13.9] years) were enrolled and randomized. Thirteen out of 32 (41%) and 11/30 (37%) patients had increased motor strength after active or sham rTMS, respectively (p=0.80). Changes in both global and fine motor scores after rTMS relative to baseline were also not significantly different between treatment groups (median difference in the global motor score 0.62 [0.83] and 0.37 [0.61], and fine motor scores 0.12 [0.18] and 0.08 [0.11], in active and sham rTMS groups, respectively, p=0.14). We observed six serious adverse events, consisting of 3 cephalalgia in the active group and 2 cephalalgia and 1 asthenia in the sham group.

CONCLUSIONS

Two sessions of sham or active low frequency rTMS were effective to improve functional paralysis, suggesting a placebo effect of this non-invasive brain stimulation technique.

Transcranial and muscular single-pulse magnetic stimulation is efficient on motor functional neurological disorders by the feedback of induced muscle contractions - A retrospective case series

Objective

Motor functional neurological disorders (mFNDs) are improved by repetitive transcranial magnetic stimulation (rTMS), which is thought to involve cortical modulation. We examined the outcome of a rapid TMS procedure.

Methods

Single-center retrospective case series including 41 consecutive patients suffering from mFNDs and receiving a combination of motor-evoked potentials (MEP), TMS and/or muscle stimulation.

Results

MEP and additional TMS were administered in 35 patients, sometimes with rescue by muscle stimulation. Magnetic muscle stimulation was given in 6 patients, sometimes with rescue by TMS. Complete immediate recovery was obtained in 65.9 % of the 41 patients, but the outcome of mFNDs after one year was poor. Treatment by TMS (n = 19) or by muscle stimulation (n = 4) given alone were associated with 78.9 % and 75 % of complete immediate recovery, respectively.

Conclusions

A rapid easy-to-perform TMS procedure obtained a high rate of immediate complete recovery in mFND. Clinical recovery was improved but was also obtained by direct magnetic stimulation of the paralyzed muscles.

Significance

TMS-induced recovery of mFND may not involve cortical modulation but could rather occur through reinforcement of the suggestion. Magnetic-induced muscle twitches may facilitate the self-expectation of motor recovery and could unlock the motor symptoms of mFND.

Neurostimulation for the treatment of functional neurological disorder: A systematic review

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.

A historical review of functional neurological disorder and comparison to contemporary models

Over the centuries, various etiologies have been proposed to explain functional neurological disorders (FND), including functional seizures. These have included models relying on supernatural influences upon the body, emphasis on consequences of malfunctioning reproductive organs, the bodily expression of painful emotions involving traumatic memories, or cognitive distortions through attention and predictive biases. Many theorists, especially since the 19th century, have had overlapping themes that continue to be relevant in modern clinical use. Treatments developed in accordance with different conceptual mechanisms. Given the heterogeneity of the disorder and the variable response to individual treatments obtained through history, physicians must consider symptom expression of an FND as an overestimation. An appreciation of multiple theories allows flexible development of unique treatment plans for individual patients.

Triggers and Clinical Presentations of Functional Neurological Disorders: Lessons from World War 1

INTRODUCTION

The psychological contribution to functional neurological and somatic symptom disorders is a major topic in current medical debate.

OBJECTIVE

For an understanding of the processes leading to functional somatic symptoms, it is paramount to explore their relationship with stress and life events and to elucidate the contribution of cultural factors.

METHODS

A total of 937 case records of civilian and military patients with functional somatic disorders treated in London during World War 1 were analysed. Group differences in symptom profiles and contemporaneous diagnoses were tested with χ2 tests.

RESULTS

Paralyses and speech disturbances were significantly more common in soldiers (43.3 and 17.2% of cases) than in civilian male (28.1 and 6.5%) and female patients (32.4 and 7.5%), whereas female patients had the highest rates of pain (48.6%) and somatic symptoms (67%). Triggers were identified in around two-thirds of cases and included accidents, physical illness, and work stress, in addition to the combat experience of the soldier patients. The nature of the trigger influenced symptom expression, with acute (combat and noncombat) events being particularly prone to trigger loss of motor function. Symptom profiles showed a great deal of multi-morbidity and overlap, although some symptom clusters were more (motor and speech disturbance) or less common (pain and loss of energy) in soldiers than civilians. Triggering life events in civilians were similar to those reported by patients with somatic symptom disorders today, with an important role of physical factors. Patterns of multi-morbidity and symptom clusters also resembled those of modern cohorts.

CONCLUSIONS

Analysis of historical records, illness trajectories, and treatments can enhance the understanding of the presentation, mechanisms, and course of functional neurological and related disorders and their consistency over time.

As good as it gets: an empirical study on mentally-ill patients and their stay at a general hospital in Sweden, 1896-1905

General hospital care and treatment of mentally ill patients in a Swedish town was studied in records for 503 patients, 1896-1905. Restraint was extremely rare; 65% left the hospital as healthy or improved. Non-psychotic and alcoholic patients spent fewer days in hospital than patients with psychosis or dementia. There was no evidence of a social status bias. For 36% of the patients a certificate for mental hospital care was issued, with additional information. The cause of illness was stated as unknown for 42% of these patients; adverse circumstances were recorded for 18%. Heredity for mental illness was found in 50% of the patients, particularly in those with mania. Patients with a higher social status were underrepresented.

Seeing again: treatment of functional visual loss

There is very little published literature on treatment strategies for functional visual loss. We present two people with long duration of functional visual loss who achieved complete recovery with a novel combination of therapeutic approaches. These included: (1) the clinician being transparent regarding positive signs such as optokinetic nystagmus, in order to persuade family members of the diagnosis, (2) regularly positively acknowledging everyday events that indicated visual ability, (3) using occipital transcranial magnetic stimulation to induce phosphenes as an artificial temporary visual experience and (4) using hypnotherapy to promote visual recovery. We discuss these individual therapeutic approaches in further detail including their background and rationale and include patients' reflection on their treatment experiences.

Impact of Transcranial Magnetic Stimulation on Functional Movement Disorders: Cortical Modulation or a Behavioral Effect?

Introduction

Recent studies suggest that repeated transcranial magnetic stimulation (TMS) improves functional movement disorders (FMDs), but the underlying mechanisms are unclear. The objective was to determine whether the beneficial action of TMS in patients with FMDs is due to cortical neuromodulation or rather to a cognitive-behavioral effect.

Method

Consecutive patients with FMDs underwent repeated low-frequency (0.25 Hz) magnetic stimulation over the cortex contralateral to the symptoms or over the spinal roots [root magnetic stimulation (RMS)] homolateral to the symptoms. The patients were randomized into two groups: group 1 received RMS on day 1 and TMS on day 2, while group 2 received the same treatments in reverse order. We blindly assessed the severity of movement disorders before and after each stimulation session.

Results

We studied 33 patients with FMDs (dystonia, tremor, myoclonus, Parkinsonism, or stereotypies). The median symptom duration was 2.9 years. The magnetic stimulation sessions led to a significant improvement (>50%) in 22 patients (66%). We found no difference between TMS and RMS.

Conclusion

We suggest that the therapeutic benefit of TMS in patients with FMDs is due more to a cognitive-behavioral effect than to cortical neuromodulation.

Neurologic approaches to hysteria, psychogenic and functional disorders from the late 19th century onwards

The history of functional neurologic disorders in the 20th century from the point of view of the neurologist is U-shaped. A flurry of interest between the 1880s and early 1920s gave way to lack of interest, skepticism, and concern about misdiagnosis. This was mirrored by increasing professional and geographic divisions between neurology and psychiatry after the First World War. In the 1990s the advent of imaging and other technology highlighted the positive nature of a functional diagnosis. Having been closer in the early 20th century but later more separate, these disorders are now once again the subject of academic and clinical interest, although arguably still very much on the fringes of neurology and neuropsychiatry. Revisiting older material provides a rich source of ideas and data for today's clinical researcher, but also offers cautionary tales of theories and treatments that led to stagnation rather than advancement of the field. Patterns of treatment do have a habit of repeating themselves, for example, the current enthusiasm for transcranial magnetic stimulation compared to the excitement about electrotherapy in the 19th century. For these reasons, an understanding of the history of functional disorders in neurology is arguably more important than it is for other areas of neurologic practice.

Transcranial magnetic stimulation as a treatment for functional (psychogenic) upper limb weakness

OBJECTIVE

There has been a recent resurgence of interest in physical treatments for functional motor disorders (FMD) including Transcranial Magnetic Stimulation (TMS). This pilot study aimed to test the effectiveness of a single session of motor cortex TMS as a treatment for functional upper limb weakness.

METHODS

Ten subjects with a diagnosis of functional upper limb weakness were randomised to immediate (n=7) or delayed (3months) (n=3) TMS treatment. Median age was 35 (range 23-52) and median symptom duration was 2.3years (range 5months - 20years). 46-70 single pulses were applied to the motor cortex at 120-150% motor threshold. We used a verbal protocol designed to standardized the effects of suggestion. Primary outcome measures were self-reported symptom severity, grip strength and tapping frequency immediately after treatment, and symptom severity and disability (SF-12 and Modified Rankin Scale (MRS)) after 3months.

RESULTS

There was a small significant reduction in symptom severity immediately after treatment, but no improvement in grip strength or tapping frequency and no change in symptom severity, SF-12 or MRS 3months after treatment. Small numbers precluded comparison of immediate treatment with delayed treatment. Four of eight subjects responding to three-month follow-up reported late-onset adverse effects.

CONCLUSION

This pilot study suggests limited benefits for TMS as a one-off non-neuromodulatory treatment for stable chronic outpatients. TMS may still have a role alongside more intensive multidisciplinary therapy input, or in patients with severe deficits where the possibility of normal movement can be hard to demonstrate.

TRIAL REGISTRATION

NCT02102906.

Non-Invasive Brain Stimulation in Conversion (Functional) Weakness and Paralysis: A Systematic Review and Future Perspectives

Conversion (functional) limb weakness or paralysis (FW) can be a debilitating condition, and often causes significant distress or impairment in social, occupational, or other important areas of functioning. Most treatment concepts are multi-disciplinary, containing a behavioral approach combined with a motor learning program. Non-invasive brain stimulation (NIBS) methods, such as electroconvulsive therapy (ECT), and transcranial magnetic stimulation (TMS) have been used in the past few decades to treat FW. In order to identify all published studies that used NIBS methods such as ECT, TMS and transcranial direct current stimulation (tDCS) for treating FW patients a systematic review of the literature was conducted in PubMed and Web of Science. In a second step, narratives were used to retrospectively determine nominal CGI-I (Clinical Global Impression scale–Improvement) scores to describe approximate changes of FW symptoms. We identified two articles (case reports) with ECT used for treatment of FW, five with TMS with a total of 86 patients, and none with tDCS. In 75 out of 86 patients treated with repetitive (r)TMS a nominal CGI-I score could be estimated, showing a satisfactory short-term improvement. Fifty-four out of seventy-five identified patients (72%) had a CGI-I score of 1 (very much improved), 13 (17%) a score of 2 (much improved), 5 (7%) a score of 3 (minimally improved), and 3 (5%) remained unchanged (CGI-I = 4). In no case did patients worsen after rTMS treatment, and no severe adverse effects were reported. At follow-up, symptom improvement was not quantifiable in terms of CGI-I for the majority of the cases. Patients treated with ECT showed a satisfactory short-term response (CGI-I = 2), but deterioration of FW symptoms at follow-up. Despite the predominantly positive results presented in the identified studies and satisfactory levels of efficacy measured with retrospectively calculated nominal CGI-I scores, any assumption of a beneficial effect of NIBS in FW has to be seen with caution, as only few articles could be retrieved and their quality was mostly poor. This article elucidates how NIBS might help in FW and gives recommendations for future study designs using NIBS in this condition.

Cranial functional (psychogenic) movement disorders

Functional (psychogenic) neurological symptoms are frequently encountered in neurological practice. Cranial movement disorders--affecting the eyes, face, jaw, tongue, or palate--are an under-recognised feature of patients with functional symptoms. They can present in isolation or in the context of other functional symptoms; in particular, for functional eye movements, positive clinical signs such as convergence spasms can be triggered by the clinical examination. Although the specialty of functional neurological disorders has expanded, appreciation of cranial functional movement disorders is still insufficient. Identification of the positive features of cranial functional movement disorders such as convergence and unilateral platysmal spasm might lend diagnostic weight to a suspected functional neurological disorder. Understanding of the differential diagnosis, which is broad and includes many organic causes (eg, stroke), is essential to make an early and accurate diagnosis to prevent complications and initiate appropriate management. Increased understanding of these disorders is also crucial to drive clinical trials and studies of individually tailored therapies.

Transcranial magnetic stimulation and sedation as treatment for functional neurologic disorders

Functional neurologic disorder (FND), also known as conversion disorder, is common and often associated with a poor prognosis. It has been relatively neglected by research and as such there is a conspicuous lack of evidence-based treatments. Physical and psychologic therapies are the main treatment modalities, over and above reassurance and sensitive explanation of the diagnosis. However there are two other historic treatments that have seen a recent resurgence of interest and use. The first is electric stimulation, which was initially pioneered with direct stimulation of nerves but now used indirectly (and therefore noninvasively) in the form of transcranial magnetic stimulation (TMS). The second is (therapeutic) sedation, previously known as "abreaction," where it was mostly used in the context of psychologic investigation and treatment, but now increasingly advocated during rehabilitation as a way to therapeutically demonstrate reversibility of symptoms. This chapter introduces the background of these treatment modalities, their evolution into their current applications before critically evaluating their current evidence base and exploring possible mechanisms of action. It also tentatively suggests when they should be considered in current practice and briefly considers their future potential. In summary there is encouraging preliminary evidence to suggest that both TMS and sedation may be effective treatments for FNDs.