The causes of mental retardation (MR) were studied as part of a multidisciplinary epidemiological case-control study in 151 mentally retarded patients identified by screening four age cohorts (12,882 children) at 8-9 years of age in the province of Kuopio, Finland. The causes of MR in 77 severely retarded (SD < or = -3 SD) and 74 mildly retarded (-2 > SD > -3) children were divided into pre-, peri-, postnatal and unknown groups according to the probable time of onset. The causes were pre-, peri-, postnatal and unknown in 60%, 9%, 8% and 23%, and 22%, 1%, 3% and 74%, in the two populations, respectively. Genetic causes were found in 28% of all 151 cases; the three most common subgroups were trisomy 21, fragile X syndrome and aspartylglycosaminuria (13%, 4% and 2% respectively). The study design used provided reliable information on the causes of MR and also demonstrated those forms of genetic metabolic diseases typical of Finnish inheritance.

Seventy-five epilepsy patients with at least two complex partial seizures/month were treated with gamma-vinyl GABA (GVG) 3 g/day for 3 months. Forty-one patients (54%) showed a reduction of greater than or equal to 50% in seizures. The median monthly seizure frequency decreased from 11.5 to 4 seizures/month. Twenty percent of patients had an improvement in general performance without a significant reduction in seizures. The responders entered the second phase of the study, in which 28 patients were randomly allocated to 3 g/day and 25 patients to 1.5 g/day GVG under double-blind conditions. The dosage of 3 g/day appeared to be clearly more effective than 1.5 g/day. However, even with 1.5 g/day GVG the seizure frequency was significantly reduced as compared to baseline. Drowsiness was the most commonly observed side effect, and it diminished with continued treatment. In three cases side effects led to the withdrawal of GVG therapy.

Intrauterine growth retardation (IUGR) in pre-term infants 13(1985) 171

Summary:Purpose: This study presents data on cumulative risk of seizures, cause, comorbidity, and remission of epilepsy among mentally retarded (MR) children followed until the age of 22 years.Methods: A total of 151 MR children were identified at the age of 8 or 9 years by screening four birth cohorts of 12,882 children born from 1969 to 1972 in the Finnish province of Kuopio. Information about epilepsy was gathered longitudinally when children were 9 to 10, 17, and 22 years old. The guidelines for epidemiological studies on epilepsy proposed by the International League Against Epilepsy were followed.Results: By the age of 10 years, 29 of the 151 MR children (19%) had epilepsy. The cumulative risk for epilepsy at 22 years was 21%. The probability of developing epilepsy was increased fivefold in severely MR children compared with mildly MR children, i.e., in 27 of the 77 severely MR children (35%) versus 5 of the 74 mildly MR children (7%). Postnatal causes of mental retardation or association with cerebral palsy increased the risk for epilepsy, especially in the mildly MR children. When these risk factors were not present, the mildly MR children exhibited only a 3% risk for epilepsy, whereas the respective risk was about 10-fold in severe mental retardation. The cumulative probability of epilepsy being in remission for 5 years by the age of 22 was 32%.Conclusions: The cumulative risk of epilepsy varies according to the severity and the cause of the retardation as well as the presence of additional disabilities. The cumulative probability of epilepsy remission tended to increase with age.

We studied the antiepileptic potency of vigabatrin (gamma-vinyl GABA, GVG) as an open trial in a group of 36 mentally handicapped patients with drug-resistant epilepsy (30 had seizures of partial onset and 6 had primary generalized [PG] tonic-clonic convulsions). With this treatment, 13 (43%) of the patients with seizures of partial onset and 2 (33%) with PG had more than 50% reduction in seizure frequency. The antiepileptic effect appeared during the first month of therapy and continued throughout the 7-month study. The side effects were mild: tiredness, aggressiveness, and ataxia. Other antiepileptic drugs remained at baseline levels during GVG therapy. GVG did not alter EEG recordings. Our results suggest that GVG is effective for treatment of intractable epilepsy, especially the partial type, in mentally retarded patients. Longer follow-up is needed, however, to determine that the clinical effect is maintained and that no severe side effects appear.