Table 1.

Clinical clues for different functional movement disorders in children.

Functional movement disorders	Clinical characteristics
Functional tremor	Entrainment Distractibility Co-activation or co-contraction sign Pause of tremor during contralateral ballistic movements Variability in tremor frequency, burst duration, axis, and/or topographical distribution Whack-a-mole sign@
Functional Dystonia	Rapid onset Fixed posturing at rest from the outset Variable resistance to passive manipulation Distractibility or absence of dystonia when unobserved Presence of pain Lack of sensory trick or overflow
Functional myoclonus	Variability in duration and/or distribution of jerks or of their latency (if stimulus sensitive) Fully suppressible Entrainable into rhythmic oscillations upon repetitive tapping tasks Predominance of axial or facial jerks
Functional gait	Fluctuation of impairment Excessive slowness of movements, hesitation “Tightrope” walking with exaggerated truncal sway while maintaining a narrow base Truncal instability with good targeting of nearby objects Continuous flexion of the toes Improvement with distraction Worsening with suggestion, Tripping propulsion with falls
Functional Tics	Not fully stereotypical Interference with speech or voluntary actions Lack of premonitory urge Inability to voluntarily suppress tics
Features common in functional movements disorders in children	The dominant side is more affected Functional dystonia may not be always fixed Myoclonus is relatively more common Distractibility, variability, suggestibility, and entrainment are easily demonstrable

^@Emergence and worsening of tremor in a separate body part when an initially affected body part is suppressed by someone holding it down.