Epilepsy in Children with Mental Retardation: A Cohort Study

Summary: The cumulative risk of seizures and epilepsy was investigated in a prospectively identified cohort of 221 children with mental retardation (MR) born between 1951 and 1955 in Aberdeen, Scotland. By age 22 years, 33 (15%) had epilepsy. An additional 16 (7%) had had at least one seizure, but did not meet the criteria for epilepsy. The cumulative risk of epilepsy was 9, 11, 13, and 15% at 5, 10, 15, and 22 years, respectively. In children with MR and no associated disabilities, the cumulative risk of epilepsy was only 2.6, 3.2, 3.9, and 5.2% at 5, 10, 15, and 22 years. In children with MR and cerebral palsy (CP), the cumulative risk was 28, 31, and 38% at 5, 10, and 22 years. Children with a postnatal injury associated with MR had a cumulative risk of epilepsy of 53, 66, and 66% at 5, 10, and 15 years after the injury. By age 22 years, 39% had achieved 5‐year seizure‐free remission, including 56% of children with MR without associated disability, 47% of children with MR and CP, and 11% of children with a postnatal injury. We conclude that, in the absence of associated disability or postnatal injury, the risk of epilepsy in the retarded population is low. Epilepsy in this population also will frequently enter remission in later life.

[1]  P. Kellaway,et al.  Proposal for Revised Clinical and Electroencephalographic Classification of Epileptic Seizures , 1981, Epilepsia.

[2]  S. A. Richardson,et al.  A functional classification of seizures and its distribution in a mentally retarded population. , 1981, American journal of mental deficiency.

[3]  D. Hirtz,et al.  Do seizures in children cause intellectual deterioration? , 1986, The New England journal of medicine.

[4]  G. Hagberg,et al.  SEVERE MENTAL RETARDATION IN A SWEDISH COUNTY I. Epidemiology, Gestational Age, Birth Weight and Associated CNS Handicaps in Children Born 1959–70 , 1977, Acta paediatrica Scandinavica.

[5]  S. A. Richardson,et al.  Seizures and epilepsy in a mentally retarded population over the first 22 years of life. , 1980, Applied research in mental retardation.

[6]  M. Reunanen,et al.  Lymphocyte blast transformation responses to mitogens and specific antigens in different clinical phases of multiple sclerosis: a follow‐up study , 1983, Acta neurologica Scandinavica.

[7]  A. Børresen,et al.  Effect of haptoglobin subtypes on serum lipid levels. , 1987, Human heredity.

[8]  J. Ellenberg,et al.  Predictors of epilepsy in children who have experienced febrile seizures. , 1976, The New England journal of medicine.

[9]  W. Hauser,et al.  The risk of epilepsy following febrile convulsions , 1979, Neurology.

[10]  J. Kalbfleisch,et al.  The Statistical Analysis of Failure Time Data , 1980 .

[11]  W. Hauser,et al.  The Epidemiology of Epilepsy in Rochester, Minnesota, 1935 Through 1967 , 1975, Epilepsia.

[12]  J. Peto,et al.  Asymptotically Efficient Rank Invariant Test Procedures , 1972 .

[13]  A. Sadovnick,et al.  Mental retardation in over half-a-million consecutive livebirths: an epidemiological study. , 1985, American journal of mental deficiency.

[14]  M. Sillanpää.  Social functioning and seizure status of young adults with onset of epilepsy in childhood. , 1983, Acta neurologica Scandinavica. Supplementum.

[15]  L. Kurland,et al.  Cerebral palsy , 1985, Neurology.

[16]  W. Hauser,et al.  Remission of Seizures and Relapse in Patients with Epilepsy , 1979, Epilepsia.

[17]  C. Drillien,et al.  Studies in Mental Handicap Part I: Prevalence and distribution by clinical type and severity of defect , 2007 .

[18]  H. Birch,et al.  Book Reviews , 2006 .

[19]  S. Bryson,et al.  Review of recent epidemiological studies of mental retardation: prevalence, associated disorders, and etiology. , 1987, American journal of mental retardation : AJMR.

[20]  G. Holmgren,et al.  Mild mental retardation in children in a northern Swedish county. , 1981, Journal of mental deficiency research.

[21]  W. Hauser,et al.  Factors prognostic of unprovoked seizures after febrile convulsions. , 1987, The New England journal of medicine.

[22]  Jordan Grafman,et al.  Epilepsy after penetrating head injury. I. Clinical correlates , 1985, Neurology.

[23]  A. Leviton,et al.  Methodological issues in the epidemiology of seizure disorders in children. , 1981, Epidemiologic reviews.

[24]  J. Opitz,et al.  An etiological survey of the severely retarded Hertfordshire children who were born between January 1, 1965 and December 31, 1967. , 1977, American journal of medical genetics.

[25]  E. Kaplan,et al.  Nonparametric Estimation from Incomplete Observations , 1958 .

[26]  G. Hagberg,et al.  Severe Mental Retardation in a Swedish County – II. Etiologic and Pathogenetic Aspects of Children Born 1959–1970 , 1977, Neuropadiatrie.

[27]  G. Hagberg,et al.  MILD MENTAL RETARDATION IN SWEDISH SCHOOL CHILDREN , 1981, Acta paediatrica Scandinavica.

[28]  J. Lagergren.  Children with motor handicaps. Epidemiological, medical and socio-paediatric aspects of motor handicapped children in a Swedish county. , 1981, Acta paediatrica Scandinavica. Supplement.