Alzheimer s & Dementia | 2019
INDEPENDENT EFFECTS OF COGNITIVE RESERVE ON COGNITION IN ALS: PRELIMINARY RESULTS FROM A MULTIDISCIPLINARY ALS CLINIC
Abstract
Our economic decision-making task (adapted from Chung et al 2015) consists of Solo trials (no social influence) and Info trials (with risk-enhanced, risk-reduced, or mixed social influence). Task 2: Go-Nogo task tests inhibitory control. It contains 60% ‘go’ trials, 20% ‘rarego’ trials and 20% ‘nogo’ trials. Participants respond to ‘go’ and ‘rarego’ cues as quickly as possible, while withholding responses to ‘nogo’ cues. We measured behavioral and EEG responses during both Tasks. Results: In Task 1, individuals with lower amyloid (higher risk of AD) had higher risk preference (model parameter RA) in SOLO trials (R 1⁄4 -0.36, p<0.01). PAT risk preference changed after social influence, even though the social peers’ opinions debate with each other: change of RA (Info_ Mix – Solo) is below zero in PATs (z1⁄4-2.16, p1⁄40.03), while NATs did not change (z1⁄41.13, p1⁄40.18) (Wilcoxon rank tes). In Task 2, amyloid positively correlated with the accuracy (for go, r1⁄40.41, p1⁄40.0028; for rarego, r1⁄40.27, p1⁄40.0496), and negatively correlated with reaction time (for go, r1⁄4-0.29, p1⁄40.0394). Tau did not correlate with accuracy or RT. The nogo ERP was significantly different between PAT and NAT in 400-600ms time window in frontal lobe. Combining Tasks 1 and 2, we found that the Go and rarego accuracy negatively correlated with the RA in SOLO trials: for Go accuracy and RA, R1⁄4-0.24, p 1⁄40.08; for rarego accuracy and RA, R1⁄4-0.27, p1⁄40.05, suggesting executive inhibitory control is relevant to risk preference: better executive control, the lower risk taking. Conclusions: Pre-symptomatic Alzheimer’s individuals are vulnerable to social influence during economic decision making, related to altered inhibitory control ability.