Effects of material deprivation on neurological functioning

Socioeconomic status, a forgotten variable in lateralization development

Socioeconomic status (SES), a variable combining income, education, and occupation, is correlated with a variety of social health outcomes including school dropout rates, early parenthood, delinquency, and mental illness. Several studies conducted in the 1970s and 1980s largely failed to report a relationship between SES and hemispheric asymmetry as measured by lateral differences in dichotic listening, tactile dot enumeration, and visual emotion and word recognition. However, none of the studies used asymmetry measures correcting for both ceiling and floor effects in accuracy, raising the question of whether lower and higher SES groups were comparable. Here the published data are reanalyzed using a laterality coefficient that corrects for such effects. The results are consistent across studies in revealing reduced lateralization in lower SES groups. Developmentally, this finding is consistent with either maturation delay or reduced functional specialization, or both. Suggestions are made for further research that include the use of behavioral asymmetry measures to screen tasks for structural and functional brain imaging.

Prevalence of attention-deficit/hyperactivity disorder symptoms in 4- to 17-year-old children in the general population

The purposes of this study were (a) to estimate the prevalence of Attention-Deficit/Hyperactivity Disorder (AD/HD) symptoms in the general preschool and school population; and (b) to analyze the influence of gender, age, and socioeconomic status (SES) variables on AD/HD symptoms. Out of the 80,000 preschool and schoolchildren living in Manizales, Colombia, a random sample of 540 children was selected. Two gender, three age (4- to 5-year olds, 6- to 11-year olds, and 12- to 17-year olds), and three SES (low, middle, and high) groups were used. The 18 DSM-IV symptoms corresponding to AD/HD Criterion A were assessed on a scale of 0 (never) to 3 (almost always). All three demographic variables established statistically significant differences: AD/HD symptoms were more frequent in 6- to 11-year-old, low-SES, male participants. DSM-IV Criterion A for AD/HD was fulfilled by 19.8% of the boys and 12.3% of the girls. However, this difference was marginally significant only in the AD/HD Subtype I: Combined. It was concluded that demographic variables are significant correlates of the AD/HD diagnosis. The prevalence found in this study was higher than usually reported, even though only the symptomatic DSM-IV AD/HD criterion was analyzed. We failed to confirm the assumed AD/HD gender ratio.

Differences in postural hypotension and ankle jerks in the elderly from two contrasting socio-economic levels

Subjects in low socio-economic strata in underdeveloped countries are subjected to considerable adverse influences which may enhance age-related changes in the nervous system. We therefore assessed the presence of ankle jerks and the degree of postural hypotension in two groups, one from the upper socio-economic level (58 subjects) and the other from the lower socio-economic level (56 subjects). All subjects were over 65 years of age. Only 6% had bilateral loss of ankle jerks, with no difference between the groups. Postural hypotension of 30 mmHg or greater was more frequent in the upper socio-economic group, nine out of 58 versus two out of 56 in the lower group. We conclude that there is no relationship in the elderly between social deprivation and certain markers of neurological dysfunction, such as the absence of ankle jerks and postural hypotension. The reasons for a greater frequency of postural hypotension in the higher socio-economic group are unclear.

Sociocultural effects in neuropsychological assessment

The group selected for this evaluation consisted of 109 normal people with an average age of 25, coming from two different sociocultural levels (high and low) of Mexico City. All were completely evaluated by Luria's battery for neuropsychological assessment, adapted by Ardila, Ostrosky, and Canseco, 1981. This group of tests measures nine different areas: Motor Functions, Somatosensory Knowledge, Auditory Knowledge, Visuospatial Knowledge, Cognitive Processes, Language, Reading, Writing and Basic Calculations. For all of these, the higher performance standards were achieved by the subjects from the high sociocultural level. A significant interaction between sociocultural level and sex was observed. The differences between sexes appear only in subjects from the low sociocultural level. Factor analysis of the battery revealed that the most sensitive items to sociocultural level were those related on one hand, to the handling of complex structural and conceptual aspects of language and on the other hand, to the organization of motor sequences and in general motor programming. Research related to the differences found is reviewed and implications for clinical assessment are discussed.