Several copy number variants have been associated with neuropsychiatric disorders and these variants have been shown to also influence cognitive abilities in carriers unaffected by psychiatric disorders. Previously, we associated the 15q11.2(BP1-BP2) deletion with specific learning disabilities and a larger corpus callosum. Here we investigate, in a much larger sample, the effect of the 15q11.2(BP1-BP2) deletion on cognitive, structural and functional correlates of dyslexia and dyscalculia. We report that the deletion confers greatest risk of the combined phenotype of dyslexia and dyscalculia. We also show that the deletion associates with a smaller left fusiform gyrus. Moreover, tailored functional magnetic resonance imaging experiments using phonological lexical decision and multiplication verification tasks demonstrate altered activation in the left fusiform and the left angular gyri in carriers. Thus, by using convergent evidence from neuropsychological testing, and structural and functional neuroimaging, we show that the 15q11.2(BP1-BP2) deletion affects cognitive, structural and functional correlates of both dyslexia and dyscalculia.
Testosterone is an important hormone in the sexual differentiation of the brain, contributing to differences in cognitive abilities between males and females. For instance, studies in clinical populations such as females with congenital adrenal hyperplasia (CAH) who are exposed to high levels of androgens in utero support arguments for prenatal testosterone effects on characteristics such as visuospatial cognition and behaviour. The comparison of opposite-sex (OS) and same-sex (SS) twin pairs can be used to help establish the role of prenatal testosterone. However, although some twin studies confirm a masculinizing effect of a male co-twin regarding for instance perception and cognition it remains unclear whether intra-uterine hormone transfer exists in humans. Our aim was to test the potential influences of testosterone on academic performance in OS twins. We compared ninth-grade test scores and teacher ratings of OS (n=1812) and SS (n=4054) twins as well as of twins and singletons (n=13,900) in mathematics, physics/chemistry, Danish, and English. We found that males had significantly higher test scores in mathematics than females (.06-.15 SD), whereas females performed better in Danish (.33-.49 SD), English (.20 SD), and neatness (.45-.64 SD). However, we did not find that OS females performed better in mathematics than SS and singleton females, nor did they perform worse either in Danish or English. Scores for OS and SS males were similar in all topics. In conclusion, this study did not provide evidence for a masculinization of female twins with male co-twins with regard to academic performance in adolescence.
Cites: Behav Genet. 1993 Jul;23(4):323-98240211
Cites: Proc Natl Acad Sci U S A. 1993 Dec 15;90(24):11900-48265645
Three studies that examined the links between affective personality, as constructed from responses to the Positive Affect (PA) and Negative Affect (NA) Scale (PANAS), and individuals' self-report of self-esteem, intrinsic motivation and Beck's Depression Inventory (BDI) depression in high school students and persons in working occupations are described. Self-report estimations of several other neuropsychiatric and psychosocial variables including, the Uppsala Sleep Inventory (USI), the Hospital Anxiety and Depression (HAD) test, Dispositional optimism, Locus of control, the Subjective Stress Experience test (SSE) and the Stress-Energy (SE) test, were also derived. Marked effects due to affective personality type upon somatic and psychological stress, anxiety and depression, self-esteem, internal and external locus of control, optimism, stress and energy, intrinsic motivation, external regulation, identified regulation, major sleep problems, problems falling asleep, and psychophysiological problems were observed; levels of self-esteem, self-motivation and BDI-depression all produced substantial effects on health and well-being. Regression analyses indicated PA was predicted by dispositional optimism (thrice), energy (thrice), and intrinsic motivation, and counter predicted by depression (twice) and stress (twice); and NA by anxiety (twice), stress (twice), psychological stress, identified regulation, BDI depression and psychophysiological problems, and counter predicted by internal locus of control and self-esteem. BDI-depression was predicted by negative affect, major sleep problems and psychophysiological problems (Study III), self-esteem by dispositional optimism and energy, and counter predicted by anxiety, depression and stress (Study I), and intrinsic motivation by dispositional optimism, energy, PA and self-esteem (Study II). These convergent findings are interpreted from a perspective of the cognitive-emotional expressions underlying behavioural or presymptomatic profiles presenting predispositions for health or ill health.
Performance of reaction time (RT) tasks was investigated in young children and adults to test the hypothesis that age-related differences in processing speed supersede a "global" mechanism and are a function of specific differences in task demands and processing requirements. The sample consisted of 54 4-year-olds, 53 5-year-olds, 59 6-year-olds, and 35 adults from Russia. Using the regression approach pioneered by Brinley and the transformation method proposed by Madden and colleagues and Ridderinkhoff and van der Molen, age-related differences in processing speed differed among RT tasks with varying demands. In particular, RTs differed between children and adults on tasks that required response suppression, discrimination of color or spatial orientation, reversal of contingencies of previously learned stimulus-response rules, and greater stimulus-response complexity. Relative costs of these RT task differences were larger than predicted by the global difference hypothesis except for response suppression. Among young children, age-related differences larger than predicted by the global difference hypothesis were evident when tasks required color or spatial orientation discrimination and stimulus-response rule complexity, but not for response suppression or reversal of stimulus-response contingencies. Process-specific, age-related differences in processing speed that support heterochronicity of brain development during childhood were revealed.
This paper sought to provide normative values for grip strength among older adults across different age groups in northwest Russia and to investigate their predictive value for adverse events.
A population-based prospective cohort study of 611 community-dwelling individuals 65+. Grip strength was measured using the standard protocol applied in the Groningen Elderly Tests. The cut-off thresholds for grip strength were defined separately for men and women of different ages using a weighted polynomial regression. A Cox regression analysis, the c-statistic, a risk reclassification analysis, and bootstrapping techniques were used to analyze the data. The outcomes were the 5-year mortality rate, the loss of autonomy and mental decline.
We determined the age-related reference intervals of grip strength for older adults. The 5(th) and 10(th) percentiles of grip strength were associated with a higher risk for malnutrition, low autonomy, physical and mental functioning and 5-year mortality. The 5(th) percentile of grip strength was associated with a decline in autonomy.
This study presents age- and sex-specific reference values for grip strength in the 65+ Russian population derived from a prospective cohort study. The norms can be used in clinical practice to identify patients at increased risk for adverse outcomes.
Cites: J Hand Surg Eur Vol. 2009 Feb;34(1):76-8419129352
This article reports the results of 3 studies that attempted to alter the mode of cognitive representation by training with nonsocial targets and then examined subsequent intergroup perception. In each study, participants examined an array of drinking glasses while receiving training in exemplar or prototype cognitive representation. Participants then responded to written trait descriptions of people (Experiment 1), photographs of the faces of members of European ethnic groups (Experiment 2), and full-body photographs of indigenous people (Experiment 3). Compared with prototype training, exemplar training with the nonsocial targets resulted in more complex cognitive representations of the social targets and written descriptions of the social targets that were more individuated. Discussion considers the implications of these results for the study of intergroup perception.
The purpose of this paper is to review the anthropological evidence relating to the cultural determinants of the right-hand first postaulted by Hertz in his classic study. Also a genetic/cultural conformity model of handedness is presented that postulates that the incidence of handedness in a society is held to result both from the genetic expression of handedness interacting with cultural pressures towards conformity. The evolutionary basis for the hemispheric functional organization into cognitive and perceptual hemispheric functions is discussed in terms of "right-handed dominant homozygotes, DD," "heterozygotes, DR," mixed-handers, and "left-handed recessive homozygotes, RR." The cross-cultural distribution of handedness provides support for this model since the more conforming agriculturalists as measured by the Asch Test have a significantly lower incidence of left-handedness (0.59%, 1.5% and 3.4%), while the more permissively socialized Eskimo and Arunta hunters, who are seen to be more independent on the Asch Test, have 11.3% and 10.5% left-handers, respectively. Also, due to the greater pressures for females to conform in agricultural societies, the incidence of female left-handedness in agricultural societies is 0% out of 330 female Ss, with 3.8%, 0.79%, and 2.5% in agricultural males, as contrasted with the Eskimo hunters who have 12.5% left-handed males and 10.3% left-handed females, showing no significant sex difference. A further Hong Kong-English study also supports the genetic/cultural conformity model with a significantly lower incidence of Hong Kong Chinese left-handers (RR: male = 2.7%, and female = 4.2%). The next section, concerned with the neonatal sex-hormone differentiation and lateralization processes, provides a neuropsychologic theory relating to spatial and linguistic skills that is relevant to the following section, which deals with relationships between laterality and cognitive style. The results are also presented for the Alaskan Eskimo in relation to hand, eye, auditory dominance and cognitive style. The analysis of Eskimo fixed-versus mixed-laterality data also confirms, as predicted, that both within and across a modality (e.g., right hand/right eye/right ear) fixed right-dominance Eskimo Ss are more field-independent than mixed-dominance Ss, while the fixed left-dominance Ss are the most field-dependent and have lower spatial skills. The discussion section reviews the papers relating to the genetic/conformity model of handedness, as well as laterality and cognitive style. The evolutionary adaptive significance of sex differences in gonadal differentiation and lateralization of the brain on spatial and linguistic skills are also reviewed. The conclusions are concerned with the implications for biosocial theory and the rapidly changing incidence of left-handedness due to accompanying changes in cultural pressures both within and across cultures.
To explore nursing home patients' oral hygiene and their nurses' assessments of barriers to improvement.
In nursing homes, nurses are responsible for patients' oral hygiene.
This study assessed the oral hygiene of 358 patients in 11 Norwegian nursing homes. 494 nurses in the same nursing homes participated in a questionnaire study.
More than 40% of patients had unacceptable oral hygiene. 'More than 10 teeth' gave OR = 2, 1 (p = 0.013) and 'resist being helped' OR = 2.5 (p = 0.018) for unacceptable oral hygiene. Eighty percent of the nurses believed knowledge of oral health was important, and 9.1% often considered taking care of patients' teeth unpleasant. Half of the nurses reported lack of time to give regular oral care, and 97% experienced resistant behaviour in patients. Resistant behaviour often left oral care undone. Twenty-one percent of the nurses had considered making legal decisions about use of force or restraints to overcome resistance to teeth cleaning.
Oral hygiene in the nursing homes needed to be improved. Resistant behaviour is a major barrier. To overcome this barrier nurses' education, organisational strategies to provide more time for oral care, and coping with resistant behaviour in patients are important factors.
The British Stroke Driver Screening Assessment (SDSA) is a set of four simple cognitive tests to evaluate driving fitness in stroke patients. To evaluate its usefulness in a Scandinavian context, we adapted the tests and assessed a group of 97 stroke patients from Sweden and Norway, using a driving test as the criterion. When results were calculated according to the original method, based on a discriminant function, less than 70% of the participants were correctly classified. To improve the predictive potential, a new discriminant analysis was performed, using the scores of a subsample of 49 patients, and validated on the remaining 48 participants. In total, 78% of the patients were correctly classified, but specificity was superior to sensitivity. We conclude that the Nordic version of the SDSA is a useful instrument, provided that test scores are interpreted in a balanced manner, taking into account the possibility of compensatory traffic behavior.
Infections and activated immune responses can affect the brain through several pathways that might also affect cognition. However, no large-scale study has previously investigated the effect of infections on the general cognitive ability in the general population.
Danish nationwide registers were linked to establish a cohort of all 161,696 male conscripts during the years 2006-2012 who were tested for cognitive ability, which was based on logical, verbal, numerical and spatial reasoning at a mean age of 19.4 years. Test scores were converted to a mean of 100.00 and with a standard deviation (SD) of 15. Data were analyzed as a cohort study with severe infections requiring hospitalization as exposure using linear regression.
Adjusted effect sizes were calculated with non-exposure to severe infections as reference, ranging from 0.12 SD to 0.63 SD on general cognitive ability. A prior infection was associated with significantly lower cognitive ability by a mean of 1.76 (95%CI: -1.92 to -1.61; corresponding to 0.12 SD). The cognitive ability was affected the most by the temporal proximity of the last infection (P
Cites: J Neurosci. 2012 Jan 11;32(2):436-5122238080