Treatment of Functional Movement Disorder

Functional movement disorder (FMD) may be the most common functional neurologic symptom disorder (FND), representing a significant therapeutic challenge for healthcare providers.^1-3 Accounting for 3% to 20% of clinical visits for movement disorders, FMD is characterized by sudden symptom onset, distractibility, and inconsistent or incongruent movements.^1-5 Recent progress has been made in understanding the physiologic underpinnings of functional disorders, with encouraging paths forward for care of the sizeable and vulnerable population of people with these conditions. Less emphasis on psychologic triggers and more focus on positively made diagnoses through neurologic examination improve the therapeutic alliance between patient and clinicians, foster research, potentially decrease healthcare expenditures, and improve patient safety.

Persons with FMD are often significantly disabled by their condition and best served by an interdisciplinary approach, with collaboration among neurology, rehabilitation, psychiatry, psychology, and social work professionals.^6,7 Many barriers to truly interdisciplinary care for FMD exist, including continued misconceptions and stigma around functional disorders and lack of reimbursement and incentives for integrated care. Current best practices can still be implemented effectively while we await and advocate for improved infrastructure.

Conveying the Diagnosis

Communicating a clear, unambiguous diagnosis of FMD to the patient is a key therapeutic step.⁸ Perceiving a clinician’s lack of interest, negative attitude, or use of inconsistent terminology impedes patient’s ability to receive an FMD diagnosis and thereby hinders effective treatment.⁹ Individuals may also find it difficult to accept an FMD diagnosis owing to a lack of public awareness, absence of supporting radiologic or laboratory findings, or strong beliefs regarding alternate diagnoses.⁹

With these barriers in mind, communication frameworks for diagnosis of FND have been developed (Box).^9,10 First, the clinician should be explicit in their belief of their patient’s symptoms. Simply stating “I believe you” or “this is familiar” will be helpful for patients who have likely felt dismissed in previous health care encounters. Next, clearly stating the diagnosis helps direct patients to information, resources, and appropriate treatment. It is unnecessary to emphasize conditions the patient does not have, because this deviates from the diagnosis of any other neurologic condition and can add to confusion.⁹

Metaphors may be helpful to explain the mind-body disconnect in FND, such as the difference between “hardware” and “software” problems in the brain, or likening neurologic symptoms to other involuntary reactions of the nervous system (eg, blushing or stage fright).¹¹ For FMD specifically, demonstrating positive movement exam features is a powerful tool to help build confidence in the diagnosis and underscore the potential for reversibility.¹² For example, sharing the distractibility of abnormal movements with clinical maneuvers such as tremor entrainment can lead to an honest explanation of a phenomenon that may already have been noticed without understanding of its meaning.¹² Incorporating the patient as part of the diagnostic team and respecting their experience and observations can also improve acceptance and thereby prognosis. A way of phrasing this is, “As your neurologist, I know a lot about the brain, but you know a lot about your brain, so we must work together.”

Persons with FMD should receive written information and supplemental resources on FMD. A follow-up neurology visit is recommended to reexamine the patient, reinforce the diagnosis, and answer any questions prior to referral to therapy. Whenever possible, referral to therapists with experience and comfort with FMD is preferred, ideally with a “warm handoff” between team members and ongoing involvement of the neurologist. All treatment team members must provide a unified message to improve the likelihood of treatment success.

Treatments

Physical Therapy

The core principle of physical therapy interventions for FMD is motor retraining or reprogramming.⁸ Rehabilitation therapists can further apply their expertise in movement mechanics to identify injuries and dysfunction secondary to the functional movement.⁸ A 2013 systematic review of physiotherapy interventions for FMD explored 29 studies with a total of 379 participants. The average duration of inpatient physical therapy treatments ranged from 5 days to 12 weeks, whereas nonprotocolized therapies lasted anywhere from 4 days to 6 months or longer.¹³ The main interventions included education about the disorder, retraining of movement patterns with gradual addition of more complex movements, distraction during motor tasks, facilitation of automatic postural and balance reactions, and strengthening or conditioning exercises.¹³ Several studies emphasized positive reinforcement for therapy-related gains while ignoring or minimizing reinforcement of maladaptive movements. These protocols also stressed the importance of removing or avoiding adaptive equipment, such as walkers, because this might further encourage secondary injuries and deconditioning.^1,5,13 Most studies demonstrated improvements in symptom severity, self-reported quality of life, and objective measures of motor function.

Patient adherence to recommended therapy is associated with clinical outcome, suggesting that appropriate patient selection and preparation for participation in motor reprogramming should be considered.¹⁴ Individuals with multiple other functional symptoms, severe pain, or untreated mood disorders may be too impaired by comorbid symptoms to fully engage in physiotherapy.¹ Although studies are supportive of the benefit of focused motor retraining programs in FMD overall,¹⁵ further work remains to reach consensus on the appropriate frequency and duration of physiotherapy, as well as the need for parallel, complementary treatment modalities.

Occupational Therapy

Like physical therapy, the goal of occupational therapy in FMD is retraining normal movement, focusing on improving function with activities of daily life, work, and recreation. Although dedicated occupational therapy clinical studies have not been done to date, consensus recommendations were released by a group of international therapists in 2020 summarizing the important components of successful intervention in patients with FMD.¹⁶ These recommendations highlight the importance of a biopsychosocial framework of FMD treatment, including building therapeutic rapport by listening to the patient’s story, educating the patient on diagnosis and symptoms, and identifying unhelpful thoughts, beliefs, or behaviors interfering with progress.¹⁶ Proposed interventions for functional tremor include the use of superimposed voluntary rhythms on top of existing tremor, handwriting retraining using gross rather than fine movements, discouraging cocontraction of other muscle groups as a compensatory method to suppress tremor, and using the unaffected limb to introduce a new rhythm (eg, tapping or opening/closing a hand) to entrain a unilateral functional tremor to stillness.¹⁶ For functional jerks, sensory grounding, relaxation techniques, and awareness of prejerk thoughts and emotions with development of compensatory movements were suggested as methods to regain control and direct attention away from the movement.¹⁶

Speech Therapy

Functional speech disorder (FSD) is a subcategory of FMD, with 25% to 50% of persons with FMD also having speech abnormalities including dysphonia, stuttering, prosodic abnormalities, and articulation abnormalities.¹⁷ This group of patients may find additional benefit from speech therapy. Clinical features indicative of FSD include inconsistent speech patterns (eg, irregular speed or variable severity depending on task), suggestibility, distractibility, and paradoxical fatigability (eg, strained voice).¹⁷ Speech interventions for FSD start with imitation of simple sounds or words with gradual increase in complexity to natural reading or conversational speech, similar to the approach for motor reprogramming of the extremities.¹⁷ Speech pathologists may also incorporate touch cues on a patient’s face (eg, jaw, lips, tongue) to identify the atypical movement and help support and shape functional movement.

Psychotherapies

The 2 types of psychotherapy most studied in FMD are cognitive behavioral therapy (CBT) and psychodynamic psychotherapy (PDP). CBT aims to change cognitive distortions to improve emotions and behaviors, whereas PDP attempts to explore the culprit psychopathology with an emphasis on resolving underlying conflicts.^8,18 A prospective cohort study of 15 persons with FMD analyzed the effect of CBT on functional tremor over 12 weeks using functional MRI (fMRI) and tremor severity scores as outcome measures.¹⁹ CBT significantly reduced tremor severity with remission or near remission occurring in 73.3% of the cohort. Results from fMRI imaging underscored this finding, showing significantly decreased activation of the anterior cingulate/paracingulate cortex during basic emotion processing compared with baseline, with the greatest change seen in those with severe baseline depression. Evidence for PDP for FMD is less clear; a retrospective study found symptomatic improvement in 60% of patients, although another found no difference between PDP and regular neurology clinic visits in a randomized crossover trial.¹⁸ Limitations of PDP include the time-consuming nature of this therapy and patient reluctance to delve into past trauma.

Interdisciplinary Approach

Interdisciplinary clinics have been shown to improve outcomes for other complex movement disorders and this approach lends itself well to functional disorders. Specialty clinics for FMD usually include an intake assessment by a team consisting of neurologists, physical therapist, occupational therapists, speech therapists, and psychologists, followed by development of individualized treatment plans.^7,8 In comparison to multidisciplinary clinics where each health professional practices independently, integrated FMD clinics allow for individualization of a therapeutic plan by combining a patient’s physical goals, movement phenomenology, and psychologic traits (Figure).⁷ This method helps validate the movement disorder as a disorder of the brain perpetuated by rather than caused by psychosocial stressors.⁷ The benefit of an integrated clinic extends beyond the individual’s experience and may allow individual practitioners to acquire new clinical skills to use in their practice. For example, a neurologist may learn to screen more effectively for psychiatric comorbidities and may use physical therapy strategies in the physical exam, whereas the psychiatrist could use positive exam findings as a physical marker to jumpstart psychotherapy.⁷

Although most FMD treatment is done on an outpatient basis, when there are severe symptoms or failures of outpatient therapies, inpatient multidisciplinary rehabilitation may be useful. In 2 observational studies of 4-week inpatient treatment programs, improvement in functional ability in the majority of participants was observed.^20,21 Improvement in mood and anxiety was noted in 1 of these studies,²⁰ although the other found no significant improvement in rates of return to work.²¹ A randomized, blinded, crossover study compared the effects of immediate vs delayed 3-week inpatient rehabilitation in 60 people with FMD and found significant improvement in functional mobility and independence, with sustained benefit at 1-month and 1-year follow-up and no differences between groups.²² Direct comparison of the various studied treatment programs is limited by differences in duration, frequency, outcome measures, and follow-up period; however, most did show significant improvements in functional measures.

Pharmacotherapy

Pharmacotherapy for FMD is typically aimed at treating comorbidities (eg, depression, anxiety, or chronic pain). A retrospective cohort study showed that over two-thirds of people with FMD had an anxiety disorder, nearly a third had depression, and a third had a trauma-related disorder.²³ Those with untreated comorbidities are less likely to be successful with physical rehabilitation efforts, making it imperative that screening and treatment of these conditions is considered during initial evaluations.¹ With pharmacologic treatment of mood disorders, it is difficult to conclude whether any functional improvement could be attributed to a medication alone (eg, antidepressants) or if FMD symptoms improve as a result of treated mood disorder. Previous studies attempting to address this question have significant limitations, including small cohort size, lack of randomization, and selection bias.²⁴

Botulinum Toxin

Thus far, no studies have shown any significant benefit of botulinum toxin for people with FMD. A double-blind, randomized, controlled trial for functional jerks found no difference in motor symptoms compared with placebo.²⁵ There was, however, a reported 60% subjective improvement in both groups suggesting a potential role for placebo therapies, although the ethics of this approach remains controversial.²⁵ Another randomized, controlled study compared botulinum toxin administration vs placebo prior to CBT in participants with functional dystonia, and, again, no difference was found between groups with both improving independent of intervention.²⁶

Other Treatments

Hypnosis in the treatment of functional disorders dates to the nineteenth century, although studies have reported variable outcomes. At baseline, persons with FND have higher hypnotizability scores compared with people without FND, suggesting a possible benefit of hypnosis therapy.²⁷ A small randomized controlled trial with 44 participants who had FMD studied the effect of 10 weekly sessions of hypnosis and found significant reduction of symptoms and improvement in quality-of-life measures.²⁷ The treatment protocol consisted of “direct and indirect suggestions designed to alter cue-conditionings relevant to motor symptoms.” For example, for a person with hand contractures, the therapist might emphasize relaxation techniques in addition to a hypnotic suggestion of a balloon being blown up thereby encouraging a hand to open up.²⁷ Although hypnosis alone may not be enough to treat FMD, there is evidence to suggest it can play an adjunctive role.

Virtual reality (VR) technology is of increased interest in neurology, with prior studies of mirror visual feedback (MVF) proving successful in cases of phantom limb, pain-disuse syndromes, and poststroke hemiparesis using visual limb-swapping illusions in which “perceived movement is controlled by the contralateral unaffected limb.”²⁸ MVF leads to increased activation of the ipsilateral motor cortex and subsequent increased control of the affected limb.²⁸ Additional studies have also hinted at the possibility of long-lasting cortical reorganization after intervention, which further underscores the proposed mechanism of FMD.²⁸ The VR4FND^a trial is investigating the feasibility and safety of VR technology in persons with FMD; study completion was estimated by January 2024 but may be delayed because the trial was suspended due to COVID-19 precautions.

Prognosis

Several variables have been identified as possible factors in clinical outcomes in FMD. A large epidemiologic study in a tertiary care center found that good physical health, positive social life, perceived effectiveness of treatment by their physician, and comorbid anxiety were associated with a good prognosis; whereas smoking history, long duration of illness, and dissatisfaction with their physician were poor prognostic indicators.²⁹ A systematic review of 24 studies found mixed conclusions regarding age, although younger onset was more often noted to be favorable.³⁰ The presence of psychiatric comorbidities tended towards negative outcomes, with the exception of anxiety disorders, as did longer duration of neurologic symptoms prior to diagnosis and treatment.

Summary

FMD is a common neuropsychiatric disorder with potential for reversibility. A clearly and empathetically explained diagnosis is a critical therapeutic step that can increase the likelihood of patient acceptance and subsequent participation in prescribed therapies. Limited randomized, controlled trials compare treatment modalities, although observational studies increasingly support the value of interdisciplinary care that includes neurology, physical therapy, occupational therapy, speech therapy, and psychologic interventions. Further work is needed to determine the appropriate duration of these treatments and address the multiple barriers to optimal care for FMD.