Progression of myoclonus subtypes in subacute sclerosing panencephalitis

Periodic Jaw-Opening Myoclonus in Subacute Sclerosing Panencephalitis

“…4 One electrophysiological study demonstrated that the origin of myoclonus varies with the stage of disease progression, with cortical and cortical-subcortical origins in the earlier stages and progression to the caudal brainstem occurring in more advanced disease. 5 Brainstem involvement has been observed previously on radiology 6 and pathology. 7 In our patient, jaw myoclonus probably represents the extension of the disease from the cortical/subcortical origin to the brainstem, with consequent myoclonus affecting the trigeminal-innervated jaw muscles, occurring in association with axial myoclonus.…”

Myoclonus: Differential diagnosis and current management

“…Hepatic encephalopathy shows a typical EEG pattern with diffuse triphasic waves, often associated with negative myoclonus. Among infectious diseases, subacute sclerosing panencephalitis displays a typical EEG pattern with symmetrical periodic delta wave complexes at long intervals, associated with generalized jerks 31 . In Herpes simplex virus encephalitis, lateralized periodic discharges can be related to myoclonus.…”

Jaw Opening Myoclonus in Subacute Sclerosing Panencephalitis

“…Myoclonus in SSPE may be generalized, multifocal, segmental, hemi-or focal. 2 The myoclonus in SSPE has been described as slow myoclonus, hung myoclonus, epileptic spasm, or periodic dystonic myoclonus. 3 Jaw-opening myoclonus is a rare phenomenon in SSPE, and the exact site of origin of myoclonus in SSPE is unknown.…”

“…Abnormal jaw movements can include jaw dystonia (opening or closing), drug‐induced dyskinesia, jaw tremor, tics, chorea, and rarely jaw myoclonus, many of which are also encountered in SSPE. Myoclonus in SSPE may be generalized, multifocal, segmental, hemi‐ or focal 2 . The myoclonus in SSPE has been described as slow myoclonus, hung myoclonus, epileptic spasm, or periodic dystonic myoclonus 3 .…”