Park JE. J Clin Neurol. 2017 Oct;13(4):317-324. https://doi.org/10.3988/jcn.2017.13.4.317

Functional movement disorder (FMD) is a type of functional neurological disorder that is common but often difficult to diagnose or manage. FMD can present as various phenotypes, including tremor, dystonia, myoclonus, gait disorders, and parkinsonism. Conducting a clinical examination appropriate for assessing a patient with suspected FMD is important, and various diagnostic testing maneuvers may also be helpful. Treatment involving a multidisciplinary team, either outpatient or inpatient, has been found to be most effective. Examples of such treatment protocols are also discussed in this review. While recognition and understanding of the disorder has improved over the past few decades, as well as the development of treatments, it is not uncommon for patients and physicians to continue to experience various difficulties when dealing with this disorder. In this review, I provide a practical overview of FMD and discuss how the clinical encounter itself can play a role in patients’ acceptance of the diagnosis. Recent neuroimaging studies that aid in understanding the pathophysiology are also discussed.

Background: Functional movement disorders are recognized as a "crisis'' in neurology. We aimed to determine the rate of incidence of functional movement disorder patients at a university outpatient neurology clinic in South Korea, and highlight the clinical and phenomenological characteristics. Methods: Patients who were assessed by a movement disorders neurologist at a university hospital between March 2016 and May 2017 were screened for functional movement disorders. Demographic and clinical data were reviewed, and the phenomenology of movements was studied. Results: Of 321 patients evaluated for the chief complaint of a movement abnormality, approximately 10% (31 patients) were diagnosed with a functional movement disorder. The female to male ratio was 7: 1 (27 females to four males). The mean age at presentation was 53 years (standard error 3.6 years), and the mean disease duration was 5 years (standard error 1.4 years). Sixty-one percent (19 out of 31 patients) had a past medical history of depression, anxiety, or other psychiatric illnesses. Tremor and speech abnormalities were most prevalent (19 and 12 patients, respectively). Onset was reported to be abrupt in 14 patients (45%). Thirteen (42%) patients were found to have improvement at a follow-up visit, 10 (32%) had no improvement, and eight (26%) were lost to follow-up. Discussion: Functional movement disorders are not uncommon in the outpatient neurology clinic. Our results confirm that tremor is the most frequent movement occurring in functional movement disorders, and the most commonly affected body parts were found to be the upper and lower extremities. Speech was also found to be frequently involved (39%). Patients with no improvement at follow-up had longer mean disease duration (6.2 years), consistent with previous observations that prolonged symptom duration is associated with poor clinical outcome. Our study results obtained from a Korean population suggest that previous observations on functional movement disorders from other regions hold true in Eastern Asia.

Background: Functional movement disorder (FMD), a conversion disorder characterized by involuntary movements, is difficult to treat. Methods: We aimed to assess the effects of anodal transcranial direct current stimulation (tDCS) and yoga in FMD patients (n=5). TDCS of the right temporoparietal junction, a brain region relevant in the sense of self-agency, was conducted. Subjects underwent both sham and anodal tDCS with a washout period of 3 weeks. Yoga was used as a mode of exercise, as well as in conjunction with stimulation to sustain potential changes in neural plasticity. Results: A total of 5 subjects completed the study [mean age: 52 (SE: 4) y, disease duration: 5 (SE: 1.6) y], undergoing both sham and anodal tDCS. Anodal tDCS does not appear to be superior to sham tDCS in alleviating symptoms and disability, but combining tDCS and yoga appears to lead to mild improvement noted on clinical observation, based on the change in the efficacy index of Clinical Global Impression found in 4 subjects. Conclusion: Our study results suggest that anodal tDCS is not superior to sham tDCS in alleviating subjective symptoms and disability in FMD. However, interpretation of these results is limited due to the small number of stimulation sessions and number of subjects. Future studies using more frequent stimulation sessions are needed to further determine whether anodal tDCS may have a therapeutic effect in this patient group compared with sham tDCS.