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Biomedical subjects

S Scarr-Salapatek

Publications and source records attributed to S Scarr-Salapatek.

7 recordsLinked to original sources
PubMed1976

Left-handedness in twins: incidence and patterns of performance in an adolescent sample.

Data on handedness and cognitive performance in an adolescent sample of same-sex twins were collected, and questions about incidence of left-handedness in twins and the relation between handedness and cognitive performance were considered. Same-sex twins have been found to have a higher incidence of left-handedness than that usually reported in the general population. There is a high incidence of handedness discordance (one twin right-handed and his cotwin left-handed) in both monozygotic and dizygotic twin pairs. In this sample, males and Blacks had particularly high rates of left-handedness. Among the monozygotic and dizygotic discordant pairs, quite different patterns of cognitive performance were found. On the Raven Progressive Matrices, the Columbia Test of Mental Maturity, and the Peabody Picture Vocabulary Test, the left-handers did better than their right-handed cotwins in the monozygotic pairs and the right-handers did better than their left-handed cotwins in the dizygotic pairs. Within subjects, no signficant differences were found for superiority of spatial or verbal abilities for either right-handers or left-handers. No general statements can be made about the performance of left-handed twins, since performance differs according to zygosity and handedness of cotwin configurations.

Adolescent↗
PubMed1975

A comparison of the physical and intellectual development of black children with and without sickle-cell trait.

Sickle-cell trait, a condition present in 7% to 9% of the United States Black population, is usually considered to be a clinically benign condition. However, there is increasing evidence to indicate the contrary, that is, the clinical pathophysiology is variable, ranging from a benign condition in most cases to a relatively few cases of severe pathological involvement. Physical and intellectual growth measures were taken on 19 children with sickle-cell trait (12 boys and 7 girls) from a large study of Black same-sex twin pairs from Philadelphia, Pennsylvania, and compared to measures taken of a sample of normal Black children from 155 monozygotic and dizygotic same-sex twin pairs. Sickle-cell trait carriers were found to weigh less, have smaller upper arm circumference lesser skinfold thickness, and showed less mature skeletal age, differing significantly from normal children. Sickle-cell carriers tended to score lower on four of five intellectual measures, scoring one fifth to one third of a standard deviation lower than normal children.

Adolescent↗