Psychogenic axial myoclonus: report on two cases.

ABSTRACT

Axial myoclonus (AM) is characterized by sudden muscle jerks involving axial and proximal muscles. It includes propriospinal myoclonus (PSM) which consists of trunk flexion or extension jerking with activity arising in axial muscles and spreading to caudal and rostral muscles at low velocity along propriospinal pathways. We report on two patients displaying flexion AM jerks in the absence of structural lesion of the central nervous system or electrophysiological evidence of organic origin. A conversion disorder was diagnosed. The jerks disappeared after psychoeducation with the patients remaining symptom free in 6-year long follow-up. The diagnoses of psychogenic axial (propriospinal-like) myoclonus were established. The literature on psychogenic axial (propriospinal-like myoclonus) is limited to a case report. Our cases demonstrate a good response to psychotropic medication and psychoeducation and fulfill the psychogenic movement disorder criteria. The phenomenology of psychogenic abnormal movements is diverse and PSM-like clinical picture may be a novel presentation.