ETIOLOGY OF MENTAL RETARDATION IN INSTITUTIONALIZED PATIENTS

Abstract

We studied 225, non-selected, institutionalized individuals with mental retardation (MR). Profound MR was present in 176 (78%), severe in 34 (15%), moderate in 5 and mild MR in one; in 4 young children IQ scores were not available. Ninety patients (40%) were non-ambulatory. Cerebral palsy was noted in 134 or 59% of the individuals (spastic in 116, choreoathetoid in 2 and mixed in 16), epilepsy in 120 (53%), blindness in 41 (18%) and deafness in 22 patients (10%). There were 147 males and 78 females; 197 were 19 years old or younger. The patients were classified in 5 categories:1. Recognizable conditions of known etiology, 128 patients, (19 patients with mendelian and 9 with polygenic / multifactorial inheritance, 21 with chromosome aberrations and 79 with environmental injuries).2. Recognizable conditions of undetermined etiology, 15 patients.3. Presumed etiology, 28 patients.4. Unknown conditions with MCA/MR, 7 patients.5. Unknown conditions with MR without MCA, 47 patients.Only 18 patients (8%) had Down syndrome; combining categories 1 and 3, postnatal brain injury was found in 32 patients (14%) and perinatal brain injury in 51 (23%). Recognizable conditions were found in 142 or 62.8% of the patients.