The Association Between Familial Risk and Brain Abnormalities Is Disease Specific: An ENIGMA-Relatives Study of Schizophrenia and Bipolar Disorder

Background: Schizophrenia and bipolar disorder share genetic liability, and some structural brain abnormalities are common to both conditions. First-degree relatives of patients with schizophrenia (FDRs-SZ) show similar brain abnormalities to patients, albeit with smaller effect sizes. Imaging findings in first-degree relatives of patients with bipolar disorder (FDRs-BD) have been inconsistent in the past, but recent studies report regionally greater volumes compared with control subjects. Methods: We performed a meta-analysis of global and subcortical brain measures of 6008 individuals (1228 FDRs-SZ, 852 FDRs-BD, 2246 control subjects, 1016 patients with schizophrenia, 666 patients with bipolar disorder) from 34 schizophrenia and/or bipolar disorder family cohorts with standardized methods. Analyses were repeated with a correction for intracranial volume (ICV) and for the presence of any psychopathology in the relatives and control subjects. Results: FDRs-BD had significantly larger ICV (d = +0.16, q <.05 corrected), whereas FDRs-SZ showed smaller thalamic volumes than control subjects (d = −0.12, q <.05 corrected). ICV explained the enlargements in the brain measures in FDRs-BD. In FDRs-SZ, after correction for ICV, total brain, cortical gray matter, cerebral white matter, cerebellar gray and white matter, and thalamus volumes were significantly smaller; the cortex was thinner (d < −0.09, q <.05 corrected); and third ventricle was larger (d = +0.15, q <.05 corrected). The findings were not explained by psychopathology in the relatives or control subjects. Conclusions: Despite shared genetic liability, FDRs-SZ and FDRs-BD show a differential pattern of structural brain abnormalities, specifically a divergent effect in ICV. This may imply that the neurodevelopmental trajectories leading to brain anomalies in schizophrenia or bipolar disorder are distinct

Self-Perceived Benefits of Cognitive Training in Healthy Older Adults

The idea that individualized, computer-based cognitive training improves cognitive functioning in non-trained domains is highly contested. An understudied area is whether cognitive training improves one’s own perception of cognitive and day-to-day functioning. Furthermore, no studies have compared working memory training to programs that train higher-level processes themselves, namely logic and planning, in improving perception of cognitive abilities. We investigated self-reported changes in: (a) cognitive errors relevant to daily life; (b) expectations regarding training; and (c) impact of training on daily life, in healthy older adults who completed working memory training or logic and planning training. Ninety-seven healthy older adults completed 8-weeks of computerized cognitive training that targeted either working memory or logic and planning. Findings were compared to a no-training control group. Participants reported fewer cognitive failures relevant to daily life after training compared to the no-training control group, with a greater reduction in errors reported by the logic and planning training group compared to the working memory training group. Trainees’ perception of training efficacy decreased over time. Nonetheless, approximately half of the participants in both training groups endorsed “some improvement” or more in self-perceived day-to-day functioning at post-testing. These results support the conclusion that individualized computerized cognitive training may enhance subjective perceptions of change and that higher level cognitive training may confer additional benefits. Findings suggest that cognitive training can enhance cognitive self-efficacy in healthy seniors

Measuring Fluid Intelligence in Healthy Older Adults

The present study evaluated subjective and objective cognitive measures as predictors of fluid intelligence in healthy older adults. We hypothesized that objective cognitive measures would predict fluid intelligence to a greater degree than self-reported cognitive functioning. Ninety-three healthy older (>65 years old) community-dwelling adults participated. Raven’s Advanced Progressive Matrices (RAPM) were used to measure fluid intelligence, Digit Span Sequencing (DSS) was used to measure working memory, Trail Making Test (TMT) was used to measure cognitive flexibility, Design Fluency Test (DFT) was used to measure creativity, and Tower Test (TT) was used to measure planning. The Cognitive Failures Questionnaire (CFQ) was used to measure subjective perceptions of cognitive functioning. RAPM was correlated with DSS, TT, and DFT. When CFQ was the only predictor, the regression model predicting fluid intelligence was not significant. When DSS, TMT, DFT, and TT were included in the model, there was a significant change in the model and the final model was also significant, with DFT as the only significant predictor. The model accounted for approximately 20% of the variability in fluid intelligence. Our findings suggest that the most reliable means of assessing fluid intelligence is to assess it directly.Peer Reviewe

Dual N-Back Working Memory Training in Healthy Adults: A Randomized Comparison to Processing Speed Training.

UNLABELLED:Enhancing cognitive ability is an attractive concept, particularly for middle-aged adults interested in maintaining cognitive functioning and preventing age-related declines. Computerized working memory training has been investigated as a safe method of cognitive enhancement in younger and older adults, although few studies have considered the potential impact of working memory training on middle-aged adults. This study investigated dual n-back working memory training in healthy adults aged 30-60. Fifty-seven adults completed measures of working memory, processing speed, and fluid intelligence before and after a 5-week web-based dual n-back or active control (processing speed) training program. RESULTS:Repeated measures multivariate analysis of variance failed to identify improvements across the three cognitive composites, working memory, processing speed, and fluid intelligence, after training. Follow-up Bayesian analyses supported null findings for training effects for each individual composite. Findings suggest that dual n-back working memory training may not benefit working memory or fluid intelligence in healthy adults. Further investigation is necessary to clarify if other forms of working memory training may be beneficial, and what factors impact training-related benefits, should they occur, in this population

Cognitive and Affective Theory of Mind and Relations With Executive Functioning in Middle Childhood

Theory of mind (ToM) refers to the ability to make inferences about mental states. Thus far, little research has examined ToM development in middle childhood. Importantly, recent studies have distinguished between making inferences about beliefs (cognitive ToM) and emotions (affective ToM). ToM has also been associated with executive functioning, though research on the differential relations between cognitive ToM and affective ToM and specific components of executive functioning is scarce. The current study examined advanced cognitive and affective ToM in 8- to 11-year-olds (N = 168). Working memory, inhibition, and set-shifting abilities were also assessed. Results showed that, in this age group, cognitive ToM increased significantly with age, and combined cognitive and affective ToM trendwise increased with age. All three domains of executive functioning (EF) showed age-related improvement. Inhibitory control and verbal IQ significantly predicted cognitive ToM, whereas verbal IQ predicted affective ToM. These results suggest that cognitive and affective components of ToM are distinguishable and may be differentially related to EF

Participant characteristics at baseline.

<p>Participant characteristics at baseline.</p

Correlations among outcome measures at baseline.

<p>Correlations among outcome measures at baseline.</p