Epidemiological study on the etiology of mental retardation
Mimaki, T.; Yabuuchi, H.
No to Hattatsu 16(4): 271-278
1984
ISSN/ISBN: 0029-0831 PMID: 6237661 Document Number: 234006
A survey of 1854 handicapped children born during 1977-1980 in Osaka [Japan] was undertaken. They included 234 severely handicapped (12.6%), 65 severely retarded (3.5%), 319 moderately retarded (17.2%) and 441 mildly retarded children (23.8%). Of these, 1081 were males and 704 were females. Mild mental retardation was associated in 66.4% of the children with psychotic disorders, 35.5% of the physically handicapped, 25% of the children with severely impaired vision, and in 10.4% of the children with severe hearing impairment. Seizure disorders were found in 64.1% of severely handicapped, 36.9% of severely retarded, 16% of moderately retarded and in 14.3% of mildly retarded children. Infantile spasms was the most common seizure disorder among severely handicapped, severely retarded and moderately retarded children. As the etiology of mental retardation for 400 subjects (48.5) were of unknown causes, 171 (20.7%) had Down's syndrome, 29 (3.5%) had infantile spasms, 26 (3.2%) had malformation syndromes and 23 (2.8%) had hydrocephalus.