Using serial position effects to investigate memory dysfunction in homeless and precariously housed persons

Abstract

Background: Homeless and precariously housed persons exhibit significant memory impairment, but the component processes underlying memory dysfunction have not been explored. We examined the serial position profile (i.e., primacy and recency effects) of verbal memory and its neuroanatomical correlates to identify the nature of memory difficulties in a large cohort of homeless and precariously housed adults. Method: The sample included 227 community-dwelling homeless and precariously housed adults. Serial position scores (primacy, middle, recency) were computed using the Hopkins Verbal Learning Test-Revised. Paired sample t-tests were used to compare percent recall from each word list region. Age-adjusted correlations assessed associations between serial position scores and other cognitive domains (attention, processing speed, executive functioning). Regression analyses were conducted to examine regional brain volumes of interest (hippocampus, entorhinal cortex, dorsolateral prefrontal cortex [DLPFC]) and their differential associations with serial position scores. Results: The serial position profile was characterized by a diminished recency effect in relation to the primacy effect. Serial position scores positively correlated with sustained attention and cognitive control. Larger hippocampal volume was associated with better primacy item recall. DLPFC volume was not associated with serial position recall after adjustment for false discovery rate. There were no associations between regional brain volumes and recency item recall. Conclusion: Our results suggest that commonly reported memory difficulties in homeless and precariously housed adults are likely secondary to a core deficit in executive control due to compromised frontal lobe functioning. These findings have implications for cognitive rehabilitation in this complex and vulnerable group.

Keywords:

• Memory
• neurocognition
• serial position effects
• homelessness
• hippocampus

Acknowledgements

We are grateful to the Hotel Study participants, research assistants, and volunteers for their involvement in the study.

Disclosure statement

FVR receives research support from the Canadian Institutes of Health Research, Brain Canada, Michael Smith Foundation for Health Research, Vancouver Coastal Health Research Institute, and Weston Brain Institute for investigator-initiated research; philanthropic support from Seedlings Foundation; and in-kind equipment support for this investigator-initiated trial from MagVenture. He has received honoraria for participation in an advisory board for Allergan. WGH has has received consulting fees or sat on paid advisory boards for: In Silico (unpaid), Translational Life Sciences (TLS), and AbbVie. KMG, KB, AET, AP, PWJ, JLS, AAJ, DJL, OL, AMB, TB, WS, ATV, AR, and GWM have no conflicts of interest to declare.

Data availability

The study data cannot be made publicly available. Data inquires can be directed to the study principal investigator (WGH; [email protected]).

Additional information

Funding

This work was supported by grants from the Canadian Institutes of Health (CBG-101827, MOP-137103, PJT-169094); BC Mental Health and Addictions Services; and the William and Ada Isabelle Steel Fund. WGH was supported by the Jack Bell Chair in Schizophrenia.