Functional sensory symptoms

Characterizing Acute-Onset Small Fiber Neuropathy

BACKGROUND AND OBJECTIVES

Immune-mediated small fiber neuropathy (SFN) is increasingly recognized. Acute-onset SFN (AOSFN) remains poorly described. Herein, we report a series of AOSFN cases in which immune origins are debatable.

METHODS

We included consecutive patients with probable or definite AOSFN. Diagnosis of SFN was based on the NEURODIAB criteria. Acute onset was considered when the maximum intensity and extension of both symptoms and signs were reached within 28 days. We performed the following investigations: clinical examination, neurophysiologic assessment encompassing a nerve conduction study to rule out large fiber neuropathy, laser-evoked potentials (LEPs), warm detection thresholds (WDTs), electrochemical skin conductance (ESC), epidermal nerve fiber density (ENF), and patient serum reactivity against mouse sciatic nerve teased fibers, mouse dorsal root ganglion (DRG) sections, and cultured DRG. The serum reactivity of healthy subjects (n = 10) and diseased controls (n = 12) was also analyzed. Data on baseline characteristics, biological investigations, and disease course were collected.

RESULTS

Twenty patients presenting AOSFN were identified (60% women; median age: 44.2 years [interquartile range: 35.7-56.2]). SFN was definite in 18 patients (90%) and probable in 2 patients. A precipitating event was present in 16 patients (80%). The median duration of the progression phase was 14 days [5-28]. Pain was present in 17 patients (85%). Twelve patients (60%) reported autonomic involvement. The clinical pattern was predominantly non-length-dependent (85%). Diagnosis was confirmed by abnormal LEPs (60%), ENF (55%), WDT (39%), or ESC (31%). CSF analysis was normal in 5 of 5 patients. Antifibroblast growth factor 3 antibodies were positive in 4 of 18 patients (22%) and anticontactin-associated protein-2 antibodies in one patient. In vitro studies showed IgG immunoreactivity against nerve tissue in 14 patients (70%), but not in healthy subjects or diseased controls. Patient serum antibodies bound to unmyelinated fibers, Schwann cells, juxtaparanodes, paranodes, or DRG. Patients' condition improved after a short course of oral corticosteroids (3/3). Thirteen patients (65%) showed partial or complete recovery. Others displayed relapses or a chronic course.

DISCUSSION

AOSFN primarily presents as an acute, non-length-dependent, symmetric painful neuropathy with a variable disease course. An immune-mediated origin has been suggested based on in vitro immunohistochemical studies.

[Borderline regions between neurology and psychiatry, focusing particularly on the functional neurological disorders]

Neurology in Japan did not develop from the separation of neuropsychiatry into neurology and psychiatry, which casts a shadow on the present situation of Japanese neurology. Functional neurological disorder (FND; hysteria) is a typical link between neurology and psychiatry. FND is a common disorder, which has been described from the ancient times and has also been the headstream of neurology. FND is not diagnosed by exclusion or by psychiatric causes, but should be actively diagnosed based on the neurological signs themselves (= positive signs of FND) as early as possible, with minimal ancillary tests. This opinion has been supported by the newest Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). Many positive signs have been described. Assessment by a neurologist also becomes a treatment.

Functional neurological disorder and placebo and nocebo effects: shared mechanisms

Functional neurological disorder (FND) is characterized by neurological symptoms that cannot be explained by a structural neurological cause. Among the different aetiological models that have been proposed for FND, of note is the Bayesian predictive coding model, which posits that perception relies on top-down cortical predictions (priors) to infer the source of incoming sensory information. This model can also apply to non-pathological experiences, such as placebo and nocebo effects, wherein sensory information is shaped by prior expectations and learning. To date, most studies of the relationship between placebo and nocebo effects and FND have focused on the use of placebos for diagnosis and treatment of FND. Here, we propose that this relationship might go beyond diagnosis and therapy. We develop a framework in which shared cognitive, personality and neuroanatomical factors justify the consideration of a deeper link between FND and placebo and nocebo effects. This new perspective might offer guidance for clarification of the pathogenesis of FND and for the identification of potential biomarkers and therapeutic targets.

Functional Neurological Disorders: Clinical Spectrum, Diagnosis, and Treatment

BACKGROUND

Functional neurological disorders (FNDs) are common but often misdiagnosed.

REVIEW SUMMARY

The incidence of FNDs is between 4 and 12 per 100,000, comparable to multiple sclerosis and amyotrophic lateral sclerosis, and it is the second most common diagnosis in neurology clinics. Some clues in the history are sudden onset, intermittent time course, variability of manifestation over time, childhood trauma, and history of other somatic symptoms. Anxiety and depression are common, but not necessarily more than in the general population. Although there are no tests currently capable of demonstrating whether symptoms are willfully produced, there may not be a clear categorical difference between voluntary and involuntary symptoms. The prognosis of an FND is linked to early diagnosis and symptom duration, but unfortunately, the majority of the patients are diagnosed after considerable delays.

CONCLUSIONS

A positive diagnosis of FNDs can be made on the basis of history and neurological signs without reliance on psychological stressors. Past sensitizing events and neurobiological abnormalities contribute to the pathogenesis of FNDs. Physical rehabilitation and psychological interventions alone or in combination are helpful in the treatment.

Functional neurological disorder: Extending the diagnosis to other disorders, and proposing an alternate disease term—Attentionally-modifiable disorder

BACKGROUND: The term “functional neurological disorder,” or “FND,” applies to disorders whose occurrence of neurological symptoms fluctuate with the patient’s attention to them. However, many other disorders that are not called “FND” nonetheless can also follow this pattern. Consequently, guidelines are unclear for diagnosing “FND.” OBJECTIVE: To review the neurological conditions that follow this pattern, but which have not so far been termed “FND,” to understand their overlap with conditions that have been termed “FND,” and to discuss the rationale for why FND has not been diagnosed for them. METHOD: A systematic review of the PubMed literature registry using the terms “fluctuation,” “inconsistency,” or “attention” did not yield much in the way of these candidate disorders. Consequently, this review instead relied on the author’s personal library of peer-reviewed studies of disorders that have resembled FND but which were not termed this way, due to his longstanding interest in this problem. Consequently, this approach was not systematic and was subjective regarding disease inclusion. RESULTS: This review identified numerous, diverse conditions that generally involve fluctuating neurological symptoms that can vary with the person’s attention to them, but which have not been called “FND.” The literature was unclear for reasons for not referring to “FND” in these instances. CONCLUSION: Most likely because of historical biases, the use of the term “FND” has been unnecessarily restricted. Because at its core FND is an attentionally-influenced disorder that can respond well to behavioral treatments, the field of neurological rehabilitation could benefit by extending the range of conditions that could be considered as “FND” and referred for similar behavioral treatments. Because the term “FND” has been viewed unfavorably by some patients and clinical practitioners and whose treatment is not implied, the alternative term attentionally-modifiable disorder is proposed.

Clinical Correlates of Functional Motor Disorders: An Italian Multicenter Study

Background

Functional motor disorders (FMDs) are abnormal movements that are significantly altered by distractive maneuvers and are incongruent with movement disorders seen in typical neurological diseases.

Objective

The objectives of this article are to (1) describe the clinical manifestations of FMDs, including nonmotor symptoms and occurrence of other functional neurological disorders (FND); and (2) to report the frequency of isolated and combined FMDs and their relationship with demographic and clinical variables.

Methods

For this multicenter, observational study, we enrolled consecutive outpatients with a definite diagnosis of FMDs attending 25 tertiary movement disorders centers in Italy. Each patient underwent a detailed clinical evaluation with a definition of the phenotype and number of FMDs (isolated, combined) and an assessment of associated neurological and psychiatric symptoms.

Results

Of 410 FMDs (71% females; mean age, 47 ± 16.1 years) the most common phenotypes were weakness and tremor. People with FMDs had higher educational levels than the general population and frequent nonmotor symptoms, especially anxiety, fatigue, and pain. Almost half of the patients with FMDs had other FNDs, such as sensory symptoms, nonepileptic seizures, and visual symptoms. Patients with combined FMDs showed a higher burden of nonmotor symptoms and more frequent FNDs. Multivariate regression analysis showed that a diagnosis of combined FMDs was more likely to be delivered by a movement disorders neurologist. Also, FMD duration, pain, insomnia, diagnosis of somatoform disease, and treatment with antipsychotics were all significantly associated with combined FMDs.

Conclusions

Our findings highlight the need for multidimensional assessments in patients with FMDs given the high frequency of nonmotor symptoms and other FNDs, especially in patients with combined FMDs.

Childhood sexual abuse predicts treatment outcome in conversion disorder/functional neurological disorder. An observational longitudinal study

OBJECTIVE

Explore trauma, stress, and other predictive factors for treatment outcome in conversion disorder/functional neurological disorder (CD/FND).

METHODS

Prospective observational design. Clinical cohort study among consecutive outpatients with DSM-IV CD/FND in a specialized mental health institution for somatic symptom disorders and related disorders (SSRD), presented between 1 February 2010 and 31 December 2017. Patient files were assessed for early childhood trauma, childhood sexual abuse, current stress, and other predictive factors. Patient-related routine outcome monitoring (PROM) data were evaluated for treatment outcome at physical (Patient Health Questionnaire [PHQ15], Physical Symptoms Questionnaire [PSQ]) level as primary outcome, and depression (Patient Health Questionnaire [PHQ9]), anxiety (General Anxiety Disorder [GAD7]), general functioning (Short Form 36 Health Survey [SF36]), and pain (Brief Pain Inventory [BPI]) as secondary outcome.

RESULTS

A total of 64 outpatients were included in the study. 70.3% of the sample reported childhood trauma and 64.1% a recent life event. Mean scores of patients proceeding to treatment improved. Sexual abuse in childhood (F(1, 28) = 30.068, β = 0.608 p < .001) was significantly associated with worse physical (PHQ15, PSQ) treatment outcome. 42.2% reported comorbid depression, and this was significantly associated with worse concomitant depressive (PHQ9) (F[1, 39] = 11.526, β = 0.478, p = .002) and anxiety (GAD7) (F[1,34] = 7.950, β = 0.435, p = .008) outcome.

CONCLUSION

Childhood sexual abuse is significantly associated with poor treatment outcome in CD/FND. Randomized clinical trials evaluating treatment models addressing childhood sexual abuse in CD are needed.

Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders

Importance

Functional neurological disorders (FND) are common sources of disability in medicine. Patients have often been misdiagnosed, correctly diagnosed after lengthy delays, and/or subjected to poorly delivered diagnoses that prevent diagnostic understanding and lead to inappropriate treatments, iatrogenic harm, unnecessary and costly evaluations, and poor outcomes.

Observations

Functional Neurological Symptom Disorder/Conversion Disorder was adopted by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, replacing the term psychogenic with functional and removing the criterion of psychological stress as a prerequisite for FND. A diagnosis can now be made in an inclusionary manner by identifying neurological signs that are specific to FNDs without reliance on presence or absence of psychological stressors or suggestive historical clues. The new model highlights a wider range of past sensitizing events, such as physical trauma, medical illness, or physiological/psychophysiological events. In this model, strong ideas and expectations about these events correlate with abnormal predictions of sensory data and body-focused attention. Neurobiological abnormalities include hypoactivation of the supplementary motor area and relative disconnection with areas that select or inhibit movements and are associated with a sense of agency. Promising evidence has accumulated for the benefit of specific physical rehabilitation and psychological interventions alone or in combination, but clinical trial evidence remains limited.

Conclusions and Relevance

Functional neurological disorders are a neglected but potentially reversible source of disability. Further research is needed to determine the dose and duration of various interventions, the value of combination treatments and multidisciplinary therapy, and the therapeutic modality best suited for each patient.

Positive clinical signs in neurological diseases - An observational study

Many patients with organic neurological disease have symptoms and signs that are unexplained by their disease condition. We attempted to explore the prevalence of positive clinical signs in patients with various organic neurological diseases. We performed a prospective uncontrolled observational study on the presence of 7 positive signs in adults with various organic neurological diseases that were admitted to our tertiary care hospital. This observation was performed during their neurological examination in those who provided consent, could comprehend and lacked terminal illness or profound weakness that limited their ability to perform these tasks. We dichotomized them into two groups based on the presence of these signs. Out of 190 patients that were evaluated between 2014 and 2015, 37 patients had at least one positive sign. On univariate analysis: young age, female gender, prior anxiety, history of childhood abuse, identification of sensory deficits on examination and lack of imaging correlation with clinical localization were identified as risk factors for these positive signs. On multivariate analysis, anxiety (OR 2.88, 95% CI 1.11-7.49, p = 0.03) and presence of sensory deficits on examination (OR 5.81, 95% CI 2.36-14.32, p ≤ 0.001) were associated with these positive signs. Positive signs are common in patients with organic neurological diseases that have anxiety or sensory deficits and may imply a component of functional overlay. Large studies are required to understand its pathophysiology and impact on future outcomes.

Prevalence of functional (psychogenic) parkinsonism in two Swiss movement disorders clinics and review of the literature

BACKGROUND

Functional parkinsonism (FP) is considered rare but no studies have looked at its frequency. Case series have described high rates of comorbidity with Parkinson's disease (PD), suggesting a possible association between these conditions.

OBJECTIVES

To study the prevalence, epidemiology and clinical features of FP and its association with PD.

METHODS

We conducted a cross-sectional population-based prevalence study as well as a chart review of cases who received a diagnosis of FP over a 10-year-period in two movement disorder clinics in Switzerland. Epidemiological data regarding FP features were collected. The co-occurrence of PD, psychiatric disorders and other functional disorders were recorded. Clinical differences between FP and FP+PD groups are presented and discussed in light of a literature review.

RESULTS

The crude prevalence of FP was 0.64 per 100,000 in our population. FP represented 0.24% of patients with parkinsonism. Among 12 FP cases, female gender predominance (87%), mean age of onset of 45.5(±13.3 Standard deviation SD) years and prolonged diagnostic delay (mean 59±75 SD months) was found. Six patients had an additional diagnosis of PD, 83% of depression and 66% of other functional neurological disorder. In four patients with FP+PD, FP preceded PD by 6 to 56months.

CONCLUSIONS

These results suggest that FP should be considered in the differential diagnosis of patients presenting with parkinsonism. The high rate of co-occurrence with PD emphasizes the importance of long-term follow up of these patients. The observation that FP often precedes PD should be verified in prospective studies.

Dissociative sensibility disorders - A retrospective case series and systematic literature review

CONTEXT

Dissociative disorders present a huge challenge in clinical settings. In contrast to other dissociative symptoms, dissociative sensibility disorders are rarely focused on.

OBJECTIVE

To identify the clinical characteristics and outcomes of dissociative sensibility disorders in children and adolescents, and to review the use of diagnostic procedures.

DATA SOURCES

For the review, a literature search used Pubmed, Embase, Web of Science, and PubPsych (to 02/2015) and the reference lists of the studies identified.

STUDY SELECTION

Screening of titles and abstracts; full-text assessment by two reviewers.

DATA SELECTION

The original case series was identified by using the local data register.

DATA EXTRACTION

Two reviewers independently reviewed the data and, if they agreed on the relevance, extracted the data. In the original case series, data were extracted retrospectively from the records.

RESULTS

Sixteen studies and seven case reports were identified, including 931 cases with dissociative disorders. In 210 cases the patient suffered either from a single sensibility disorder or predominantly from sensibility disorders. We identified thirteen further cases in our cohort. In both groups there was female predominance; the mean age of manifestation was early adolescence. The timing of admissions was variable. In approximately 50% of cases a premorbid stressful life event could be identified. Over 75% of cases had a good prognosis with complete resolution.

LIMITATIONS

Retrospective character of our own data collection, partially missing differentiation between the subgroups of dissociative disorders in the reviewed studies.

CONCLUSIONS

There is no uniform procedure for diagnostic work-up. The overall short-term prognosis is good.