Neuroepidemiology of West syndrome and early infantile epileptic encephalopathy in Miyagi Prefecture, Japan.

To compare the incidence of West syndrome (WS) and early infantile epileptic encephalopathy (EIEE) in Miyagi Prefecture, Japan, we studied retrospectively the medical records of cases involving WS or EIEE for the period 2000-2005. During this period, 45 children developed WS and one child was diagnosed with EIEE. The estimated incidence rates of WS and EIEE were 4.2 per 10,000 live births (95% CI, 3.0-5.5) and 0.1 per 10,000 live births (95% CI, 0-0.3), respectively. The occurrence of EIEE was one-fortieth that of WS.