Interactive effects of APOE and CHRNA4 on attention and white matter volume in healthy middle-aged and older adults

In the present study, we investigated age-related changes in interactions between efficiency of neuronal repair mechanisms and efficiency of cholinergic neurotransmission in the context of attentional orienting. In addition, we explored white matter volume changes as possible neuronal underpinnings. A sample of 230 healthy middle-aged (53–64 years) and older (65–75 years) adults was genotyped for polymorphisms of APOE and CHRNA4, a nicotinic receptor subunit gene. Participants were administered a visuospatial attention task involving letter discrimination with location cues of varying validity. Genotype effects on white matter volume were also investigated in a subset of participants who received MRI scans. APOE interacted with CHRNA4, such that APOE-ε4 carriers who were also CHRNA4 TT homozygotes showed disproportionately slowed reaction time (RT) following invalid location cues. The interaction was stronger in the middle-aged participants than in the older participants. There was also a trend for individuals with combined APOE-ε4/CHRNA4 TT genotypes to show both lower white matter volume and slower overall RT on the attention task. The interaction of a neurotransmission gene (CHRNA4) and a susceptibility gene (APOE) suggests that the efficiency of neuronal repair mechanisms may modulate the cholinergic system to influence attentional function.     

Visual neglect in the first weeks after a stroke in the right hemisphere

The aim of the study was to characterize symptoms of visual neglect among patients who recently survived a stroke in the right hemisphere (RH), and to contribute to the understanding of change in symptoms during the first months after a RH stroke. Thirteen patients with a RH stroke and twenty controls were assessed by using standard neglect tests. Five patients were followed up by repetitive test sessions during the next four months. To assess more subtle symptoms, reaction-time (RT) measures derived from an experimental cue-target paradigm were included in the final test session. A high frequency of neglect symptoms was documented at the first test session. The changes in performance during the first weeks were characterized by a high inter-individual as well as a high intra-individual variability. Although the remission rate on standard tests was high in the follow-up study, the RT measures indicated sustained symptoms of visual extinction in all patients. The long-term implication of the changes of neglect symptoms during the first weeks after a stroke and signs of sustained symptoms of visual extinction calls for further longitudinal studies including a larger group of patients.     

Socioeconomic Status and Child Mental Health: The Role of Parental Emotional Well-Being and Parenting Practices

This study examined the role of parental emotional well-being and parenting practices as mediators of the association between familial socioeconomic status (SES) and child mental health problems. The sample included 2,043 5th-7th graders (50.7 % female) participating in the second wave of the Bergen Child Study. Children completed the Strengths and Difficulties Questionnaire, parents reported family economy and education level, emotional well-being (measured with the Everyday Feelings Questionnaire), and the use of negative disciplinary and affirmative parenting practices (measured using the Family Life Questionnaire). Path analyses were conducted to examine the associations between SES and externalizing and internalizing problems. Results supported a model where family economy was associated with externalizing problems through parental emotional well-being and parenting practices, whereas maternal education level was associated with externalizing problems through negative discipline. The direct association between paternal education level and externalizing problems was not mediated by parenting. For internalizing problems, we found both direct associations with family economy and indirect associations with family economy through parental emotional well-being and parenting. The results suggest that parental emotional well-being and parenting practices are two potential mechanisms through which low socioeconomic status is associated with child mental health problems.     

Conners’ continuous performance test (CCPT-II) in children with ADHD,ODD, or a combined ADHD/ODD diagnosis

The current study investigated if results on the Conners’ Continuous Performance Test (CCPT-II) could discriminate between children with ADHD (n = 59), ODD (n = 10), ADHD+ODD (n = 15), and normal controls (n =160), and how the results are associated with and explained by the intellectual function of the child. The sample was derived from the Bergen Child Study (BCS), a longitudinal, ongoing, population-based study of children’s development and mental health. CCPT-II performance did not differentiate between the three diagnostic groups (i.e., ADHD, ODD, and ADHD+ODD). Children with ODD (with or without comorbid ADHD) did not differ from children in the control group on any CCPT-II parameters. Children with ADHD made statistically significant more errors of omissions and showed a more variable response time to targets than the control group. The correlations between CCPT-II measures and IQ were mild to moderate, and there was a statistically significant group difference in IQ: Children with ADHD, and children with ADHD+ODD, obtained lower IQ scores than normal controls. A hierarchical multiple regression analysis showed that IQ, but not diagnostic group status, was significant predictors of CCPT-II performance. CCPT-II performance should be interpreted with caution when assessing ADHD and/or ODD in children.     

A dichotic listening study of attention control in older adults

The influence of age on attentional control of bottom-up processing was investigated with a dichotic-listening paradigm. The typical right-ear-advantage (REA) without specific attentional instructions was used as a measure of bottom-up processing (non-forced condition). Top-down attentional control was evaluated by instructing subjects to report only the right or left ear stimulus of the dichotic pair (forced-right, forced-left conditions). Both young and old participants showed a REA in the non-forced condition and an increased REA in the forced-right condition. The old group failed, however, to use attention to modulate the REA to the same degree as the younger participants in the forced-left condition. Only the young group showed a significant left ear advantage (LEA). The results are discussed in relation to cognitive decline in normal aging and in early stages of dementia.     

Familiarity,Cued and Free Odor Identification and Their Association with Cognitive Functioning in Middle Aged and Older Adults

ABSTRACT

The aim of the present study was to examine the association between familiarity of odors, cued and free odor identification performance and cognitive function in elderly adults. It was further investigated how age affects performance on the various odor tasks. A third aim was to investigate the role of familiarity in explaining performance on the free identification task. One hundred and thirty-six participants (aged 45–79 years) with normal olfactory sensitivity were assessed with the Scandinavian Odor Identification Test (SOIT) and standardized tests of cognitive function. Familiarity did not correlate with any measure of cognitive function, while verbal identification performance was associated with several cognitive measures, although correlations were modest. In this sample, free odor identification was affected by increasing age to a marginally larger extent than cued identification performance and familiarity ratings. The results suggest that the different olfactory tasks involve different levels of cognitive processing.     

Development of flexible visual recognition memory in human infants

Research using the visual paired comparison task has shown that visual recognition memory across changing contexts is dependent on the integrity of the hippocampal formation in human adults and in monkeys. The acquisition of contextual flexibility may contribute to the change in memory performance that occurs late in the first year of life. To assess this skill, the images are presented on a background of one colour during familiarization and on a different coloured background during the recognition test. Our research showed that recognition memory is impaired by a change in context at 6 and 12 months of age but is unaffected at 18 and 24 months of age. The findings are discussed in relation to hippocampal development and the proposed developmental step in memory at 9-10 months of age.