8 Computational Modeling of Memory Processes in non-CNS Cancer Survivors

Objective:Cognitive impairment is an often-overlooked issue that non-CNS cancer survivors face. Our current understanding of their issues is lacking, as traditional memory sum scores grant us little insight into the underlying cognitive processes of memory and its impairment. We can improve the informativity of memory impairment studies by isolating which cognitive processes are impaired.Participants and Methods:Participants were breast cancer survivors who received chemotherapy (n=68), and women controls (n=157). The participants completed the Amsterdam Cognition Scan (ACS), in which classical neuropsychological tests are digitally recreated for online at-home administration. Online administration reduces the burden on patients and allows for recording measurements with greater precision. The specific test used to illustrate the effectiveness of our computational modeling approach was the ACS equivalent of the Rey Auditory Verbal Learning Test, in which participants are tasked with recalling a list of 15 words five times. We formulated a Hierarchical Bayesian Cognitive Model to replace traditional sum scores and disentangle performance into the more theoretically meaningful concepts of 'memory storage’ and 'memory retrieval'.Results:A traditional analysis of the sum of trials 1-5 indicated no significant difference between patients and controls (t(223)=-0.99, p = 0.323), with a small effect size (Cohen’s d = -0.14).For the newly isolated cognitive process “memory storage”, a non-significant difference was found between patients and controls (d=0.10, 95% credible interval on Cohen’s d: [0.25, 0.43]). On the “memory retrieval” process, a medium significant difference was found between patients and controls (d = -0.57, 95% credible interval on Cohen’s d: [-1.00, -0.19]).Conclusions:The results indicate that the impaired memory processes in cancer patients are not a general impairment across all memory functions, but rather a selective impairment of memory retrieval. Our method of analysis revealed information that would have been left unnoticed had we relied on traditional sum over trials 1-5.