Summary
Epilepsy-mental deterioration, Finnish type, is a very rare form of childhood epilepsy occurring in northern Finland. Inheritance is recessive. The patients are normal at birth and develop normally until school age. Age at onset is 5 to 10 years, the patients presenting with generalized tonic-clonic seizures. These seizures increase in frequency reaching a maximum of approximately 1 or 2 seizures per week at puberty. After puberty, frequency begins to decline unrelated to changes in medication. After 35 years of age many patients are virtually seizure-free. In the electroencephalogram, focal and nonfocal initiation of paroxysms is seen. Among several antiepileptic drugs tried, clonazepam appeared to be the most efficacious drug. Mental development, which is originally normal, begins to deteriorate 2 to 5 years after the onset of epilepsy, and the deterioration continues during adulthood in spite of good epilepsy control, leading to mental retardation by middle age. *Author: Orphanet editorial team (September 2002)*.
