Social cognition in Alzheimer's disease: A separate construct contributing to dependence

Abstract

The extent to which social cognitive changes reflect a discrete constellation of symptoms dissociable from general cognitive changes in Alzheimer’s disease (AD) is unclear. Moreover, whether social cognitive symptoms contribute to disease severity and progression is unknown. The current multicenter study investigated cross-sectional and longitudinal associations between social cognition, general cognition, and dependence in 517 participants with Probable AD. Participants were followed every 6-months for 5.5 years. Results from multivariate latent growth curve models adjusted for sex, age, education, depression, and recruitment site revealed that social cognition and general cognition were unrelated cross-sectionally and over time. However, baseline levels of each were independently related to dependence, and change values of each were independently related to change in dependence. These findings highlight the separability of social and general cognition in AD. Results underscore the relevance of considering social cognition when modeling disease and estimating clinical outcomes related to patient disability.

Determinants of theory of mind performance in Alzheimer's disease: A data-mining study

“…ToM in AD 14 on EF in AD, directly contradicting a recent study that highlighted the independence of ToM impairment and general cognition performance in AD (Cosentino et al, 2014).…”

“…These deficits persist over time and also rapidly worsen in bvFTD patients with marked mPFC atrophy compared to those with limited mPFC atrophy (Kumfor et al, 2014). By contrast, the evidence for ToM impairment in AD has lacked general consensus on whether deficits on ToM tasks are a result of an authentic impairment of ToM (Cosentino et al, 2014;Freedman et al, 2013;Moreau et al, 2016), or due to deteriorating general cognition in the disease, an approach that is compatible with the interactive models of ToM (Dodich et al, 2016;Stone et al, 2006). Few studies in support of a stand-alone ToM deficit in AD have shown that AD patients could fail on basic ToM tasks like gaze-processing (Laisney et al, 2013) and inferring someone's (first-order false) beliefs (Freedman et al, 2013;Le Bouc et al, 2012).…”

“…One possible reason for such differences is that (Cosentino et al, 2014) measured social cognition using a carer-reported deficit scale that may be affected strongly by caregiver bias and reflect less accurate patient-centred ToM deficits while our study used a performance-based, objective measure of ToM processing. Moreover, the confirmation of our results in a subgroup of patients with biological evidence of diagnosis and replication of our findings in an independent group of AD patients strengthened our findings.…”

“…In particular, the dependency of social cognition on processes such as executive functioning (EF) and episodic memory in AD remains unclear, as past studies examining these interactions have reported inconsistent findings (Castelli et al, 2011;Cosentino et al, 2014;El Haj, Gely-Nargeot, & Raffard, 2015;Moreau et al, 2016). Though differences between studies and viewpoints can be attributed to methodological, test-choice, and sample differences, it remains important to reconcile these opposing perspectives.…”

Alzheimer's disease research in the context of the national plan to address Alzheimer's disease

“…In order to conduct trials on new therapeutics with enough statistical power to gain approval, thousands of participants need to be enrolled and tracked over many months or even years for prevention trials. Participation in clinical studies can also be challenging for individuals affected by Alzheimer's causing slower enrollment rates and greater drop-out rates (Cerami et al, 2014;Cosentino et al, 2014;Stephens et al, 2014). Many participants also have co-existing conditions that may prevent their participation or may be exclusion criteria for the study.…”