Praxis-induced myoclonia: From the neurophysiologist to the patient perspective

To characterize semiology and EEG features of praxis-induced (PI) myoclonia and to describe the subjective perception of juvenile myoclonic epilepsy (JME) patients with this reflex trait.

Patients with JME who presented myoclonia during a Video-EEG Neuropsychological Protocol were selected. We analyzed the semiology of upper limbs myoclonia and the ictal EEG patterns on Video-EEG. We explored the subjective aspects of PI by performing a semi-structured interview to each patient.

15 patients experienced 59 upper limbs myoclonia. Jerks were more frequently asymmetric or unilateral (32/59); a bilaterally symmetric pattern of all myoclonia was observed in only five patients. Ictal pattern was polyspike-wave (PSW) in 31/59 myoclonic seizures and spike-and-wave (SW) in 28/59. Six patients started perceiving myoclonia while learning a new skill or practicing a previously learned skill in a more stressful context. For most patients, PI-myoclonia were a source of anxiety. PI persisted despite antiepileptic medications in 10 patients.

Electroclinical features of PI-myoclonia were more heterogeneous than traditionally described. Ictal pattern of SW was almost as frequent as classical PSW. Patients described the influence of learning new skills and anxiety on PI. Their subjective perception let us understand the impact of this reflex trait.