Functional Neurological Disorders: Exploring Unmet Needs

A specialist in functional neurological disorders calls for greater attention to these common neuropsychiatric conditions.

Despite accounting for the second-most common reason someone visits a neurology clinic, behind only headaches, functional neurological disorders (FNDs) have been largely neglected by the medical community until recently. Previously known as a “conversion disorder” prior to the fifth edition of the DSM, an FND is a brain-based disorder that impacts emotion and cognition, as well as motor and sensory processes.

Two of the most frequently encountered clinical presentations of FNDs are functional seizures (also called dissociative or psychogenic nonepileptic seizures) and functional movement disorders (FMDs). Other subtypes of FNDs include functional cognitive disorder, functional speech disorder, and functional dizziness, now known as persistent postural-perceptual dizziness (PPPD).

“Neuropsychiatry, a field of medicine committed to understanding brain-behavior relationships, is well positioned to advance our understanding of contributing risk factors and the neural mechanisms underlying FNDs,” says Chadrick Lane, M.D., Assistant Professor of Psychiatry and the inaugural Clinical Neuroscience Scholar within the Peter O’Donnell Jr. Brain Institute at UT Southwestern Medical Center. “Due to various reasons, including a need for more training in FNDs, clinicians often feel ill-equipped to debrief patients about their diagnosis. This can be remedied with multidisciplinary clinical programs and curricular development in medical education.”

Dr. Lane's clinical and research efforts are focused on neuropsychiatry. He co-directs the Department of Psychiatry's FND Multidisciplinary Clinic, is part of the UT Southwestern Epilepsy Team, and is an active member of both the American Neuropsychiatric Association and Functional Neurological Disorder Society. 

High Unmet Need

For effective treatment, neurologists, psychiatrists, psychotherapists, and rehabilitative therapists must all collaborate closely in the care of patients, Dr. Lane explains, adding that currently there is a dearth of FND-focused specialty care across the Unites States. 

“FNDs are one of the most common reasons for new outpatient neurological consultations,” Dr. Lane says. “Studies suggest an incidence of 10 to 15 per 100,000, translating to an estimated prevalence of 250,000 to 300,000 people in the United States alone.”

Dr. Lane notes that neuroimaging studies have illustrated differences in those living with an FND compared to those without an FND. Networks in the brain responsible for emotional regulation, allocation of attention, and the perception of volitional control over movements may be working less effectively in those with an FND. 

“FNDs have a high association with a history of prior trauma, as well as medical comorbidities, such as mild traumatic brain injury, fibromyalgia, chronic fatigue syndrome, and chronic pain syndrome,” Dr. Lane explains.

Establishing the Diagnosis

In years past, an FND was regarded as a diagnosis of exclusion. A patient seeking care would receive a neurological workup, and when nothing returned consistent with a structural neurological condition, the patient would receive a diagnosis of FND. In the past decade, important progress has been made in making FND a diagnosis of inclusion, based on positive exam and history findings as well incongruity with other neurological disorders.

The gold standard in the diagnosis of functional seizures is the use of video EEG (vEEG). This procedure records brain wave activity while the patient is observed in the hospital. If a typical seizure is captured on video, presents with functional characteristics, and epileptic activity is present on the EEG, a reliable diagnosis can be made. Common signs of functional seizures are fluctuating asynchronous limb or side-to-side head movements, long duration of events, ictal eye closure and crying, pelvic thrusting, peri-ictal responsiveness, and post-ictal memory recall.

“vEEG results require experienced interpretation by epileptologists,” Dr. Lane says. “Many patients lack access to specialized monitoring units or have an ‘indeterminate’ diagnosis due to equivocal or uneventful monitoring.”

The International League Against Epilepsy (ILAE) published methods of diagnosing functional seizures based on levels of certainty. While vEEG is the highest level of certainty, this system allows for patients to receive a workup when they may not have access to an epilepsy monitoring unit for vEEG evaluation. 

While research on biomarkers to differentiate epileptic from functional seizures is ongoing, at present, clinical history, individual risk factors, and vEEG are the standard of care. Dr. Lane explains that neuropsychiatry is an essential part of the treatment picture given the high rates of psychiatric comorbidity. 

For an FMD, establishing a proper diagnosis rests on key elements of clinical history and characteristic signs on examination (e.g., specific movement patterns). In addition, clinical tests such as imaging and labs can play an important role.  

Initiating Evidence-Based Therapy

Importantly, prompt diagnosis allows for more rapid implementation of appropriate evidence-based interventions. The mainstay of treatment, Dr. Lane notes, is psychotherapy and rehabilitative therapies, including physical, occupational, and speech therapies. Medications can have a role in the management of co-occurring conditions, including depression, trauma-related disorders, and anxiety.  

“Multidisciplinary treatment teams are fundamental to the successful care of patients with an FND,” Dr. Lane says. “As is often noted in the literature, treatment begins with diagnosis.  Assuring patients that their symptoms are real and brain-based, providing a helpful metaphor such as FND being a ‘software’ rather than a ‘hardware’ problem, and delivering the diagnosis with compassion, empathy, and confidence are all critical to setting a patient on the right treatment trajectory.” 

A Unique Clinical Approach

The Peter O’Donnell Jr. Brain Institute Functional Neurological Disorder Clinic is made up of neurologists, psychotherapists, psychiatrists, rehabilitative therapists, and speech-language pathologists. It is funded in part by an award from the OBI’s Clinical Neuroscience Scholars Program and is one of only a handful of centers in the nation to take a comprehensive approach to managing FNDs, with staff working together to address the physical, psychological, and social aspects of these disorders.

Upon initial presentation, patients are evaluated by both a psychiatrist and psychotherapist, who then formulate a treatment plan. Subsequently, most patients are referred to the clinic’s eight-week, evidence-based group therapy program, designed specifically for the treatment of FNDs.

“Only a few centers can provide this particular type of therapeutic intervention,” Dr. Lane says. “We bring together a collaborative team of neurologists, psychiatrists, psychotherapists, and rehabilitative therapists, each actively participating in the patient’s care.”

While it’s too early to draw conclusions, Dr. Lane says he and his colleagues are excited to analyze the clinic’s outcomes in the coming months and years. If research based on similar programs at other institutions is any indication, the OBI Functional Neurological Disorder Clinic will prove beneficial to the region.

Future Directions and Conclusions

The fundamental pathophysiology of all FNDs remains incomplete. Current understanding includes overactivity of the limbic system, symptom modeling as part of a predictive coding framework, and dysfunction of self-agency networks. Studies have demonstrated brain anatomical differences (gray matter volume and cortical thickness) and connectivity differences using fMRI between patients with an FND compared to those without. 

“These early studies, though in their infancy, note alterations in brain function that may provide clues to the neural underpinnings of FNDs – however, longitudinal studies are still needed to address the question of causality,” Dr. Lane says.

As to optimal treatment strategies, commonalities have begun to emerge, including the benefit of therapy, with evidence increasingly supporting tailored multidisciplinary approaches. Neuromodulation, particularly transcranial magnetic stimulation, may hold promise. 

“Our understanding of FNDs and their treatments has advanced, but we have far to go.  Importantly, there is hope, and people can experience improved functionality, quality of life, and – possibly – symptom control,” Dr. Lane says.

He adds that further research is needed to determine the optimal dose and duration of various approaches and to assess the value of combination strategies, stressing that therapeutic success hinges on a diagnostic approach that validates the patient’s symptoms and disability, allowing for full understanding and acceptance by the patient.

“FNDs are real conditions that arise from extraordinarily complex biological, psychological, and social interactions. Recovery is possible,” he concludes.