Residual cognitive deficits 50 years after lead poisoning during childhood

The long term neurobehavioural consequences of childhood lead poisoning are not known. In this study adult subjects with a documented history of lead poisoning before age 4 and matched controls were examined with an abbreviated battery of neuropsychological tests including measures of attention, reasoning, memory, motor speed, and current mood. The subjects exposed to lead were inferior to controls on almost all of the cognitive tasks. This pattern of widespread deficits resembles that found in children evaluated at the time of acute exposure to lead rather than the more circumscribed pattern typically seen in adults exposed to lead. Despite having completed as many years of schooling as controls, the subjects exposed to lead were lower in lifetime occupational status. Within the exposed group, performance on the neuropsychological battery and occupational status were related, consistent with the presumed impact of limitations in neuropsychological functioning on everyday life. The results suggest that many subjects exposed to lead suffered acute encephalopathy in childhood which resolved into a chronic subclinical encephalopathy with associated cognitive dysfunction still evident in adulthood. These findings lend support to efforts to limit exposure to lead in childhood

Heritability of specific language impairment depends on diagnostic criteria

Heritability estimates for specific language impairment (SLI) have been inconsistent. Four twin studies reported heritability of 0.5 or more, but a recent report from the Twins Early Development Study found negligible genetic influence in 4-year-olds. We considered whether the method of ascertainment influenced results and found substantially higher heritability if SLI was defined in terms of referral to speech and language pathology services than if defined by language test scores. Further analysis showed that presence of speech difficulties played a major role in determining whether a child had contact with services. Childhood language disorders that are identified by population screening are likely to have a different phenotype and different etiology from clinically referred cases. Genetic studies are more likely to find high heritability if they focus on cases who have speech difficulties and who have been referred for intervention

Recognising social and non-social emotions in self and others: A study of autism

Studies of emotion processing in autism have produced mixed results, with fewer studies observing autism-specific deficits than might be imagined. In the current study, 21 individuals with autism and 21 age- and ability-matched, learning disabled comparison participants were tested for their ability to (a) recognise, in others, expressions of “social” emotions (e.g., embarrassment) and “non-social” emotions (e.g., happiness) and; (b) report their own previous experiences of each of these emotions. In line with predictions, amongst both groups of participants, social emotions were more difficult to recognise and report than non-social emotions. Also amongst both groups, the ability to report social emotion-experience was significantly associated with the ability to recognise social emotions in others, independent of age and verbal ability. However, contrary to predictions, there were no group differences in the levels or patterns of performance amongst participants with autism and comparison participants. In light of previous research, these results suggest either that emotion-processing is not as specifically impaired in autism as is traditionally thought to be the case, or that individuals with autism are implementing compensatory strategies to succeed on experimental tasks in the absence of emotion-processing competence