When the voice follows the jerk: Periodic vocalizations in subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis (SSPE) is a progressive neurological complication of measles infection and movement disorders are commonly seen in this condition. We describe an 11-year-old boy with SSPE, with mixed movement phenomenology, including dystonia, slow as well as brief myoclonus, repetitive behaviours, and peculiar periodic vocalizations, which followed the slow myoclonic jerks, and discuss possible mechanisms.