An analysis of the conceptual framework underlying definitions of learning disabilities

Various theoretical perspectives have contributed to the different types of definitions of learning disabilities (LD) that have been developed since the category was first established. To date, there has been little consensus on the definition of learning disabilities. In the present study, three kinds of definitions, ability-achievement discrepancy, low achievement, and scatter, were examined to determine the extent to which there was common variance. The subject were 48 school-identified LD children and 96 non-LD children. Both samples had previously been administered a battery of psychoeducational tests. These data were used to classify each child as LD or non-LD according to each of 14 operational definitions. A factor analysis resulted in two distinct groupings of LD students; low achievement accounted for over four times as much variance as ability-achievement discrepancy. Scatter did not contribute independently to classification. The implications for LD-identification practices are discussed.     

Income inequality and risk of suicide in New York City neighborhoods: a multilevel case-control study

Evidence on the relationship between income inequality and suicide is inconsistent. Data from the New York City Office of the Chief Medical Examiner for all fatal injuries was collected to conduct a multilevel case-control study. In multilevel models, suicide decedents (n=374) were more likely than accident controls (n=453) to reside in neighborhoods with greater income inequality even after controlling for individual characteristics; this relation was modified by age with an effect overall and among decedents aged 15-34 but not among decedents 35-64. These data suggest that income inequality may contribute to the risk of suicide in younger adults.     

Instructions for Authors

Instructions for Authors

Instructions for Authors     

The Genetic and Environmental Relationship Between General and Specific Cognitive Abilities in Twins Age 80 and Older

In the first twin study of the old-old, individuals 80 years old and older, we examined the relationship between general and specific cognitive abilities from a genetic perspective. That is, we examined the extent to which genetic and environmental factors influence major group factors of cognitive abilities, independent of general cognitive ability. As part of the OctoTwin project in Sweden, general and specific cognitive abilities were assessed in 52 monozygotic and 65 same-sex dizygotic twin pairs 80 years old and older using a battery of seven tests that assess verbal, spatial, speed-of-processing, and memory performance. Results suggest that genetic effects associated with general cognitive ability ( g ) account for the correlation between g and verbal, spatial, and speed-of-processing abilities. No genetic influences were found for these specific cognitive abilities separate from g . In contrast, memory ability appears to be more distinct genetically from g than are other cognitive abilities. Comparison with younger samples suggests that cognitive abilities relating to speed of processing may be genetically dedifferentiated in the old-old.     

Escape from deficits in sodium intake after thalamic lesions as a function of preoperative experience

Saline and water intakes in response to treatments with a natriuretic agent and a mineralocorticoid were studied in intact rats and in rats with lesions centered in the taste delay of the thalamus. Intact rats responded to the treatments by increasing both saline and water intake. Rats with thalamic lesions that had never drunk saline prior to induction of the lesions generally did not increase their saline intake in response to the treatments but showed normal increases in water intake. In contrast, rats with thalamic lesions that had drunk saline prior to induction of the lesions showed normal increases in both saline and water intake. Preoperative experience of sodium need did not protect rats against the lesion-induced deficit.