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Comment & Response
July 1, 2019

Dancing Dorsal Quadrilaterals—Organic or Functional?—Reply

Author Affiliations
  • 1The Edmond J. Safra Program in Parkinson’s Disease and the Morton and Gloria Shulman Movement Disorders Clinic, Division of Neurology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
  • 2Department of Medicine, University of Adelaide, Adelaide, South Australia
JAMA Neurol. 2019;76(8):985-986. doi:10.1001/jamaneurol.2019.1720

In Reply We thank Chouksey et al for their interest and the opportunity to further discuss the similarities and differences between functional movement disorders (FMD) and peripherally induced movement disorders (PIMD), particularly the dancing dorsal quadrilaterals (DDQ) syndrome that we described.1 As they indicate, the diagnostic criteria for PIMD have not been validated. Indeed, many potential examples of PIMD are eventually considered to represent FMD, and the concept of posttraumatic abnormal movements remains controversial.2,3 Nonetheless, FMD tend to occur immediately or shortly after minor peripheral trauma in a nonanatomical pattern, in contrast to the delayed onset of segmentally appropriate movements after significant injury evidenced in the DDQ. Furthermore, some well-recognized organic movement disorders of central origin, such as “delayed-onset dystonia” and symptomatic palatal tremor, may evolve over several months after a considerably long latency from the time of the inciting lesion4,5; this is typical of the classical PIMD painful legs and moving toes.

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