The importance of screening for functional neurological disorders in patients with persistent post-concussion symptoms

Changes in Resting-State Functional Connectivity and Cognitive-Affective Symptoms in Patients With Post-Concussion Syndrome Treated With N-Acetyl Cysteine

OBJECTIVE

Concussion accounts for more than 80% of people experiencing traumatic brain injury. Acute concussion is associated with characteristic cognitive and functional deficits that may persist for weeks to months. A subgroup of these patients (from 10% to 50%) have persistent symptoms referred to as chronic post-concussion syndrome (PCS). There are limited treatment options for these patients and the pathophysiology is poorly understood, though oxidative stress is thought to be a contributing factor. The purpose of this study was to evaluate whether an antioxidant, N-acetylcysteine (NAC), might be beneficial in patients with PCS.

SETTING

Outpatient medicine center.

PARTICIPANTS

Fifty patients with chronic PCS for at least 3 months post injury.

DESIGN

The patients with PCS were enrolled in this randomized unblinded clinical trial to receive the antioxidant NAC as a combination of daily oral and weekly intravenous infusions, or assigned to a waitlist control group where they would continue to receive standard of care.

MAIN MEASURES

Resting-state functional connectivity (FC) magnetic resonance imaging (rsFC-MRI) was performed pre and post either NAC or the waitlist period along with cognitive, emotional, and sensory symptom assessments.

RESULTS

The results demonstrated significant (P < .05) improvements in symptoms as determined by the Rivermead Post-Concussion Symptoms Questionnaire, Spielberger State-Trait Anxiety Inventory, and Profile of Mood Scale in the PCS group receiving NAC as compared to patients receiving ongoing standard care. Importantly, there were significant (P< .01) changes in FC in the NAC group, particularly in networks such as the default mode network, salience network, and executive control network. These changes in FC also correlated with improvements in symptoms.

CONCLUSIONS

In patients with chronic PCS, NAC treatment was associated with significant changes in resting state FC and improvement in a variety of symptoms, particularly cognitive and affective symptoms.

Prevalence of autoimmune diseases in functional neurological disorder: influence of psychiatric comorbidities and biological sex

BACKGROUND

Functional neurological disorder (FND) is a common and disabling neuropsychiatric condition, which disproportionally affects women compared with men. While the etiopathogenesis of this disorder remains elusive, immune dysregulation is emerging as one potential mechanism. To begin to understand the role of immune dysfunctions in FND, we assessed the prevalence of several common autoimmune diseases (ADs) in a large cohort of patients with FND and examined the influence of psychiatric comorbidities and biological sex.

METHODS

Using a large biorepository database (Mass General Brigham Biobank), we obtained demographic and clinical data of a cohort of 643 patients diagnosed with FND between January 2015 and December 2021. The proportion of ADs was calculated overall, by sex and by the presence of psychiatric comorbidities.

RESULTS

The overall prevalence of ADs in our sample was 41.9%, with connective tissue and autoimmune endocrine diseases being the most commonly observed ADs. Among patients with FND and ADs, 27.7% had ≥2 ADs and 8% met criteria for multiple autoimmune syndrome. Rates of ADs were significantly higher in subjects with comorbid major depressive disorder and post-traumatic stress disorder (p= 0.02). Women represented the largest proportion of patients with concurrent ADs, both in the overall sample and in the subgroups of interest (p's < 0.05).

CONCLUSIONS

This study is unique in providing evidence of an association between FND and ADs. Future studies are needed to investigate the mechanisms underlying this association and to understand whether FND is characterised by distinct dysregulations in immune response.

Functional Neurological Disorder Presenting After Concussion: A Retrospective Case Series

OBJECTIVE

Although a majority of individuals recover from a concussion within weeks of the index injury, a substantial minority of patients report persistent postconcussion symptoms. Some of these symptoms may reflect a diagnosis of functional neurological disorder (FND). The authors evaluated the relationship between persistent postconcussion symptoms and FND symptoms.

METHODS

In this retrospective chart review, the authors characterized demographic and clinical information from 50 patients with a confirmed diagnosis of FND whose functional neurological symptoms started after a concussion.

RESULTS

Patients who developed FND after a concussion had high rates of baseline risk factors for both persistent postconcussion symptoms and FND. After the concussive event, functional neurological symptoms presented abruptly or developed insidiously over time. Functional neurological symptoms ranged widely and included gait symptoms, seizures, speech and language symptoms, weakness, sensory symptoms, tremors, and vision and oculomotor symptoms.

CONCLUSIONS

Functional neurological symptoms can arise after a concussion. FND should be considered in the differential diagnosis of individuals presenting with neurological symptoms beginning after a concussion. By failing to recognize functional symptoms, clinicians may inadvertently reinforce negative health-related beliefs regarding a patient's injured brain.