Video 1
The video demonstrates orthostatic lower limb shaking and orthostatic negative myoclonus in a 14-year-old male with SSPE. On standing, shaking is evident in both lower limbs, transmitted to the trunk and upper body. Superimposed on this, episodic bilateral knee buckling with giving way is observed, consistent with orthostatic negative myoclonus. On walking, the shaking resolves; however, periodic episodes of negative myoclonus persist, manifesting as brief interruptions of gait with transient knee flexion.
Figure 1
Brain MRI showing bilateral frontal grey and white matter lesions with involvement of the genu of the corpus callosum.