Orthostatic myoclonus after brain tumor radiation: Insights from two lesional cases.

•In orthostatic myoclonus, lower limb myoclonus occurs only in upright posture.•OM is most often associated with diffuse neurodegenerative disease.•Two patients with frontal lobe tumors developed OM after resection and radiation.•Lesional cases suggest OM may be due to disruption of frontal lobe motor circuits.