March 9, 2020
Functional neurological disorder (FND), also known as conversion disorder, is receiving renewed attention now that certain physical signs have been validated as being specific for the diagnosis. The improved diagnostic specificity has encouraged clinician-scientists to study the neurobiology of FND with the hope of developing better treatments.
David L. Perez, MD, MMSc, senior author and faculty member in the Department of Neurology and Department of Psychiatry, Ibai Diez, PhD, first author and research fellow in the Department of Neurology at Massachusetts General Hospital, and colleagues recently became the first group to use diffusion tensor imaging to examine white matter integrity across the various motor subtypes of FND. They found microstructural differences in limbic and associative tracts that are implicated in salience, defensive behaviors and emotion regulation.
Between 2014 and 2018, the research team recruited 32 patients from the Mass General FND Clinic, directed by Dr. Perez, with an average illness duration of 3.5 years. The cohort included 17 patients with a functional movement disorder (tremor, gait disorder, jerky movements, paroxysmal truncal/head movements or mixed disorder), 13 with functional weakness and 14 with psychogenic nonepileptic seizures. Eleven patients had mixed phenotypes. Comorbid psychiatric diagnoses were present in 29 patients.
Patients completed three questionnaires related to symptom severity and physical disability: