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Differential of voluntary and involuntary movements
1  Johns Hopkins University School of Medicine
Academic Editor: Stephen Meriney (registering DOI)
  • Introduction: The differentiation of voluntary and involuntary movements represents a crucial challenge for observers, particularly providers who face the behaviors in an emergency.
  • Methods: An algorithm is developed to classify movements as voluntary or involuntary are identified. Red flags to identify movements that require treatment or restraint are presented.
  • Results and Discussion:

Involuntary movements include the broad class of movement disorders, including (A) movement disorders with identified pathophysiology and (B) functional movement disorders, a wide variety of movements that may or may not resemble movement disorders with identified pathophysiology.

Voluntary movements include (A) motions deliberately performed by persons to express exuberance such as applause and zaghrouta and (B) motions deliberately performed by persons to deceive others, such as (A) malingering, the fabrication of actions in order to avoid jail, work, school, and to obtain financial and other rewards, and (B) Münchausen syndrome, the fabrication of symptoms and signs to seek medical attention and treatment. Identification of functional movement disorders and fabricated voluntary movements is crucial to avoid providing inappropriate interventions, such as medications and surgeries with significant risks and no beneficial effects.

Electrophysiological and motion measurements may facilitate the identification of voluntary movements. For example, a Bereitschaftspotential, a surface-negative electrical brain potential identified on electroencephalograph (EGG), can identify self-initiated voluntary acts.

  • Conclusions

Neuroscientists can benefit from the proposed algorithm to differentiate voluntary and involuntary movements particularly in emergent situations to determine when interventions are required and contraindicated.

Keywords: applause; Bereitschaftspotential; conversion disorder; functional movement disorders; involuntary; malingering; movement disorders; Münchausen syndrome; ululation; voluntary