C Padgett

Exploring the effect of the apolipoprotein E (APOE) gene on executive function, working memory, and processing speed during the early recovery period following traumatic brain injury

ABSTRACT Introduction: There is evidence that the e4 allele of the apolipoprotein E (APOE) gene is detrimental to cognitive function, but results from traumatic brain injury (TBI) populations are mixed. A possible explanation is that APOEe2 carriers have routinely been incorporated into APOEe4 and non-e4 groups, despite APOEe2 being proposed to have an ameliorative effect. Our primary aim was to investigate the influence of APOEe4 on cognitive impairment during early recovery following TBI, excluding the potential confound of APOEe2 possession. A secondary objective was to explore whether APOEe4 displays more pronounced effects in moderate to severe TBI and to consider the potential postinjury protective influence of the APOEe2 allele. Method: Participants who recently sustained a TBI (posttraumatic amnesia > 5 minutes) were assessed on measures of information processing speed, executive function, and working memory upon remission of posttraumatic amnesia. APOE genotype was determined by buccal saliva DNA extraction (APOEe4 n = 37, APOEe3 n = 92, APOEe2 n = 13). Results: Stepwise multiple regressions were performed to compare APOEe4 carriers to APOEe3 homozygotes, with injury severity, age, and estimated premorbid IQ included in the first step. This model was found to significantly predict performance on all tasks, accounting for 17.3–24.3% of the variance. When APOEe4 status was added for the second step, there were no significant changes on any tasks (additional variance <1%). The effect of APOEe4 in moderate to severe TBI and the effect of APOEe2 were explored by analysis of covariance (ANCOVA), with no significant effects revealed. Conclusions: It is unlikely that APOE genotype influences cognitive function in the initial recovery period following TBI, regardless of injury severity. However, a more nuanced and long-term exploration of the effect of APOE genotype in the TBI population is warranted.

Is APOE ε4 associated with poorer cognitive outcome following traumatic brain injury? A meta-analysis.

OBJECTIVE Cognitive impairment is a common sequelae of traumatic brain injury (TBI); however, predicting who will experience poorer outcomes remains challenging. A potential risk factor that has gained attention is the APOE gene, with the ε4 allele hypothesized to have a detrimental effect on post-TBI cognitive outcome. The aim of this meta-analysis was to evaluate the effect of APOE ε4 both in terms of general cognitive function and within specific domains known to be prone to impairment following TBI (executive function, working memory, verbal memory and visual memory). METHOD A literature search was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA), resulting in the inclusion of 10 studies (ε4-carriers n = 143, noncarriers n = 510). Neuropsychological tasks were identified, and Cohens d was calculated and pooled. Meta-analyses were conducted on general cognitive functioning and for the specific cognitive domains of interest. RESULTS No significant differences were found between APOE ε4-carriers or noncarriers, either in general cognitive function or in the cognitive domains of executive function, working memory, verbal memory, or visual memory. CONCLUSIONS This meta-analysis indicates that APOE ε4 does not have a detrimental effect on cognitive performance following TBI. We propose that the relationship between APOE and cognitive function following TBI is complex, and a more-nuanced exploration of APOE genotypes is needed. (PsycINFO Database Record

Normal adult and adolescent performance on TASIT-S, a short version of The Assessment of Social Inference Test

Abstract There is a need for short, reliable, sensitive assessment tools to measure social cognition. The Awareness of Social Inference Test (TASIT) is an ecologically valid instrument that uses videos of actors engaged in everyday conversations to assess emotion perception, the ability to detect lies, sarcasm and sincerity, and the ability to judge what others are thinking, intending, feeling, and saying. A recently developed short version of TASIT retains the structure of the original test and its clinical sensitivity. In this paper, we compare TASIT-S performance in healthy adolescents, adults, and older adults as well as the effects of country (U.S.A. and Australia), English familiarity and gender. In this study 616 Australians including 226 adolescents (13–19) and 390 adults aged 20–75 + along with 180 U.S. residents (aged 20–74) completed one, two, or three parts of TASIT-S either face to face (Australians) or on-line (US residents). Results indicated that there were minor differences in TASIT-S performance (Part 3 only) based on country of residence and no significant effects for English familiarity in adolescents (not examined in adults). There were no gender effects. Young and middle aged adults (20–59) tended to perform better than adolescents and older adults on most parts of TASIT-S. In general, TASIT-S scores decreased moderately with advancing age. In conclusion, TASIT-S is a useful screen for social cognitive impairment in English speakers that is appropriate for use from adolescence through to older age. It produces comparable scores in the U.S.A. and Australia.

Push or pull? Unpacking the social compensation hypothesis of Internet use in an educational context

Individual differences such as social anxiety and extraversion have been shown to influence education outcomes. However, there has been limited investigation of the relationship between individual differences and attitudes towards online and offline learning. This study aimed to investigate for the first time how social anxiety and extraversion influence student attitudes to online and offline learning, specifically in relation to tertiary level practical activities. Based on the social compensation hypothesis, it was predicted that students with higher levels of extraversion and lower levels of social anxiety would report more favourable attitudes to face-to-face learning activities. It was further predicted that less extraverted and more socially anxious students would have more favourable attitudes to online learning activities. Undergraduate students (N=322, 67% female) completed the HEXACO-60 personality inventory, the Mini Social Phobia Inventory, and measures of attitudes towards online and offline activities. Two hierarchical multiple regressions were conducted. The first revealed that neither extraversion nor social anxiety contributed significantly to preference for online practical activities. The second regression revealed that greater emotionality, greater extraversion, greater conscientiousness, and lower levels of social anxiety were associated with more favourable attitudes towards face-to-face practical activities. In contrast to predictions, extraversion and social anxiety did not significantly contribute to attitudes to online learning activities. However, in line with predictions, greater extraversion and lower levels of social anxiety were associated with more favourable attitudes towards face-to-face practical activities. These findings indicate that online learning activities have limited compensatory effects for students who experience social discomfort, and that the social compensation hypothesis may apply within an educational framework, but in unexpected ways. Applies the social compensation hypothesis of Internet use as a theoretical paradigm.Examines role of social anxiety (SA) and extraversion in online and offline learning.Extraversion and SA not associated with attitudes to online activities.Extraversion and low SA positively predict face-to-face activity attitudes.Online learning has limited compensatory effects for socially anxious students.