Clinic-Based Assessment and Treatment Strategies for Functional Neurologic Disorders

Functional neurologic disorder (FND) is a common cause of disability and distress among people seen in outpatient neurology.¹ FND is the second most common reason for people to consult outpatient neurology services, after headaches.² Whereas evidence demonstrates the efficacy of interdisciplinary care in treating people with FND, access to programs remains limited, and the diagnosis and treatment process can be lengthy, ranging from months to years.^1,3 There is an urgent need for neurologists to provide effective diagnosis, screening, treatment, and referral for people with FND. In this article, we provide a framework for tangible FND screening, FND treatment strategies, and resources to use in outpatient clinical visits.

An FND evaluation begins by confirming the diagnosis through positive clinical signs that lend themselves directly to treatment. The diagnostic process also includes screening for comorbid conditions and identifying underlying and contributing factors. Contributing factors include motor control impairments, sensory processing differences, autonomic dysfunction, and lifestyle and psychosocial factors. By focusing on these contributing factors, neurologists can provide effective treatment within a clinical visit, and begin the referral process for additional rehabilitation support.

Clinical Diagnosis and Explanation

Despite growing pathophysiologic evidence that FND is a disorder attributable to nervous system dysfunction, some clinicians may perceive the symptoms as feigned, voluntary, or malingering.⁴ FND is a distinct disorder with several subtypes including functional seizures and functional movement disorders, and it is inaccurate to diagnose FND on the basis of exclusion of other medical findings.⁴ There are positive clinically diagnostic features of FND (not to be mistaken for diagnostic tests, such as imaging or laboratory work) with sensitive and specific signs,^1,5 including the Hoover sign, tremor entrainment test, and “whack-a-mole” sign.⁵ Performance of clinical tests, such as the Hoover sign test, hip abductor test, and tremor entrainment test, provides validation of the diagnosis and demonstration that voluntary movement control can occur.⁵ Having a good understanding of one’s diagnosis is a prognostic indicator for recovery in individuals with FND, which improves with positive clinical diagnostic testing and proper explanation of the diagnosis.⁶

In addition to confirmation of the diagnosis, screening for comorbidities in individuals with suspected FND improves the process of treatment selection and patient referral. Important comorbid conditions to consider include migraine; hypermobility syndromes, such as Ehlers-Danlos syndrome; postural orthostatic tachycardia syndrome; dysautonomia; and autism spectrum disorder.^7-9

As part of the clinical examination, we propose a decision-making framework to guide screening, treatment, and referral. The Figure demonstrates this decision-making process within the context of a clinical visit that includes treatment suggestions based on positive clinical findings and screening for contributing factors.

Testing and Screening Leading to Treatment

Motor Contributory Factors: Hoover Sign, Hip Abduction Sign, and Entrainment Test

When impaired movement is the main concern (ie, functional movement disorder [FMD]), the assessment priority is to demonstrate that automatic movement is possible. This can be done by performing clinical tests.^4,10 One positive motor sign of FMD is that attentional focus on the body part causes worsened or altered movement capability. The Hoover sign, hip abductor test, and tremor entrainment test serve a diagnostic purpose by demonstrating attention-driven dysfunction, but these tests can also function as a form of treatment.¹⁰ For example, if a person has difficulty walking due to unilateral functional weakness, the principles of the Hoover sign (ie, attentional focus and automatic hip extension) can be turned into treatment.^5,10 After demonstrating that automatic hip extension occurs during testing of the Hoover sign, the neurologist may trial an external focus of attention during gait, such as stepping over lines to elicit automatic hip flexion and contralateral hip extension. There are different ways in which the principles of the Hoover sign can be used in treatment, including the use of dual-task movements and external focus interventions to promote automatic movement. Use of dual-task movements and external focus interventions elicit automatic movement because there is a shift in focus away from the impaired motor output. Other examples of external focus interventions include catching a ball and painting.⁶

Shifting attention focus away from the body region also can include the use of cognitive dual tasks. Examples of cognitive dual tasks include solving mathematics problems, listing items in a category of the person’s choosing, or alphabetizing categories. Another option to shift attention focus away from the body region includes eliciting automatic movement. Eliciting automatic movement during examinations allows the individual to experience access to voluntary movement and anticipate a mechanism of improvement and supports referral to neurologic physical therapy.⁶ Screening for automatic movements and variability of movement can also be done by changing the movement task.⁶ Examples of changing the task for gait include trials of increasing and decreasing speed, skipping, jogging, walking backward, and bear crawling.⁶ The video available at www.practicalneurology.com provides examples of externally focused tasks.

Sensory Contributory Factors

People with FND may describe functional sensory signs, such as numbness in a nondermatomal pattern, splitting midline sensory changes, or global, widespread pain.¹¹ These sensory changes can be a barrier to production of motor output.¹¹ In these cases, the first step in the clinical visit should include confirming sensory impairment through standard sensory testing and sensory integration testing, such as graphesthesia, stereognosis, 2-point discrimination, or visual motion sensitivity (for dizziness). Positive functional sensory findings include variable sensory loss or sensory loss that is not consistent with dermatomal, peripheral nerve, or cortical patterns.¹¹ A person may describe sensory symptoms they have experienced since childhood (eg, sensitivity to sound, touch, taste; visual or motion-related symptoms), indicating a sensory processing or integration difference that might be contributing to FND symptoms.¹²

Treatments for sensory symptoms, such as holding or wearing a weighted object (eg, weighted vest, ankle weights) during functional movement, may be trialed to determine whether the motor output improves. Additional treatment strategies include compression wear to the affected area, use of fidgets, or use of a weighted blanket. Recommended equipment to have in the clinic includes a small ball, abdominal binder, compression wraps, bubbles, fidgets, ankle weights, weighted vest, and weighted blanket. The Table describes sensory strategies based on presenting symptoms. Individuals with sensory dysfunction should be referred to occupational therapy or physical therapy.

Autonomic Contributory Factors

Autonomic nervous system screening is indicated for individuals with suspected autonomic dysfunction (eg, reports of fainting, rapid heart rate, dizziness, sweating, bowel or bladder issues). An active stand test for screening and referral to cardiology is indicated for individuals with suspected postural orthostatic tachycardia syndrome.¹³ People with FND have been found to have a decrease in parasympathetic activity compared with healthy participants. If a heightened sympathetic response (decreased parasympathetic response) over a long period is suspected to contribute to symptoms, a wrist or chest-worn monitor can provide objective data and is a useful tool for monitoring heart rate variability.¹⁴

Grounding, or nervous system regulation, describes a simple clinical tool that can be used in the clinic to promote parasympathetic nervous system activation.¹⁵ A simple grounding exercise is the “5-4-3-2-1” exercise, in which the person lists 5 things they see, 4 things they hear, 3 things they feel, 2 things they smell, and 1 thing they taste. Having patients perform a prolonged exhale with an external focus of attention can be an especially helpful grounding exercise.¹⁵ Examples include blowing bubbles or breathing through a straw. Performance of grounding techniques at the onset of autonomic dysfunction symptoms can reduce symptom severity and prevent symptoms from escalating.¹⁵ The Table provides suggestions to consider in the clinical visit based on symptom presentation. Referral to occupational therapy or neurologic physical therapy is indicated for individuals with autonomic dysfunction.

Lifestyle, Psychosocial, and Cognitive Contributory Factors

In the past, diagnosis of FND was based on “medically unexplained symptoms,” or FND was believed to be attributable to mental health concerns, such as anxiety or trauma.³ Although a trauma subtype of FND has been identified, FND is better understood as a complex condition with biologic, lifestyle, psychologic, and social factors.^16,17 Trauma and anxiety may be comorbid factors, but they are not positive diagnostic criteria for FND.^5,17 Many people with FND consider stress and anxiety to be perpetuating factors more than causes of FND, or they do not consider the relevance of stress and anxiety to their individual situation.¹⁸ Therefore, to explain FND as only psychologic in nature can be invalidating as well as untrue. FND is a chronic, confusing, and disabling condition, and people with FND can benefit from psychologic support. Screening for anxiety and depression within the context of FND evaluation is important to support referral of individuals with anxiety and depression to psychologic care. It is also vital that individuals with FND who have experienced trauma be referred to trauma-informed psychologic services.

People with FND may demonstrate decreased parasympathetic activity not correlated with anxiety or depression.¹⁴ This lowered parasympathetic regulation is an important lifestyle factor to address. Other lifestyle factors include sleep, diet, exercise, and energy management. By screening for contributory lifestyle factors during subjective examination, with questions about impaired pacing (boom or bust activity pattern), sleep dysregulation, and excessive sympathetic activity, referral can be made to a lifestyle occupational therapist to reduce ongoing perpetuating factors.

Health Care Referrals and Resources

Referrals

Neurologists can provide screening and initial treatment resources, but most people with FND need rehabilitation to meet their functional and life participation goals. Referrals to physical therapy, occupational therapy, speech therapy, and clinical psychology differ based on symptoms and goals of the person with FND.¹⁹ Helpful allied health professionals include neurologic physical therapists, lifestyle occupational therapists, and speech therapists specializing in functional communication and cognitive disorders. In neurologic physical therapy, the goal is to retrain movement using sensory systems and autonomic nervous system regulation, and unlock automatic movement through motor control.⁵ Speech therapy is helpful for functional communication or functional cognitive disorders by producing automatic movement, regaining control over initiation of speech, and understanding cognitive load.²⁰ Lifestyle occupational therapy focuses on health education and behavioral change, including physical functioning, mental health, and social functioning.²¹ A persisting barrier to care for people with FND is access to specialists, but resources continue to grow, and specialty care should be recommended at clinic visits.³

Resources

FND Hope (https://fndhope.org) is a global charity dedicated to assisting individuals with FND, with international support from the United States, United Kingdom, Canada, and Australia. The Academy of Neurologic Physical Therapy (www.neuropt.org) is an American organization that helps individuals locate neurologic physical therapists. Dysautonomia International (www.dysautonomiainternational.org) is a nonprofit geared toward helping people with dysautonomia live with chronic illness. The international Ehlers-Danlos Society (www.ehlers-danlos.com) promotes research and provides education on Ehlers-Danlos syndrome and hypermobility spectrum disorders.

Conclusion

Neurologists play an important role in the diagnosis and management of FND. Providing clear diagnosis, treatment, and referral in the clinic visit will help expedite care and reduce disability for people with FND. An evidence-based framework for screening, treatment, and referral will assist neurologists as they seek to provide diagnostic clarity, identify and address comorbid conditions, and provide appropriate referrals and resources.