A case report of rigidity and recurrent lower limb myoclonus: progressive encephalomyelitis rigidity and myoclonus syndrome, a chameleon

Background Progressive encephalomyelitis with rigidity and myoclonus (PERM) syndrome is a rare neurological condition. Its clinical characteristics include axial and limb muscle rigidity, myoclonus, painful spasms and hyperekplexia. Diagnosis of this disease can be very challenging and optimal long-term treatment is unclear.