Memory and Executive Functions Subserving Judgments of Learning: Cognitive Reorganization After Traumatic Brain Injury

ABSTRACT

We investigated relationships between psychometric measures of memory, executive functions (EFs), and task-based measures of Judgments of Learning (JOLs) in individuals with and without Traumatic Brain Injury (TBI), to study functional reorganization after TBI. We hypothesized that, in controls, accuracy of immediate JOLs would be associated with short-term memory and EFs (but not long-term memory, LTM), while accuracy of delayed JOLs would be associated primarily with LTM. We hypothesized that those with good recovery from TBI would demonstrate functional reorganization of the relationships between memory, EFs, and JOLs. Eighteen individuals with TBI and 18 matched controls completed eight neuropsychological tests of memory and EFs. They studied word-pairs, made immediate and delayed JOLs, and took a cued-recall test for the studied word-pairs. Stepwise regression and Lasso analyses generated a predictive model of JOL accuracy for each group. Accuracy of immediate JOLs in controls was predicted by short-term memory, inhibition, switching, and cognitive fluency, while accuracy of delayed JOLs was predicted by verbal recall. In individuals with TBI, inhibition predicted immediate JOL accuracy and switching predicted delayed JOL accuracy. Cognitive reorganization in those with good long-term recovery from TBI may account for the ability to make JOLs with accuracy similar to controls.

KEYWORDS:

• Memory
• executive functions
• metamemory
• judgments of learning
• traumatic brain injury

Acknowledgements

This research was funded by the University of Minnesota (Doctoral Dissertation Fellowship, several block grants, a scholarship from the College of Liberal Arts, and the Bryng Bryngelson fund of the Department of Speech-Language-Hearing Sciences), by the University of Connecticut (Faculty Large Grant), by a small grant from the Minnesota Speech-Language-Hearing Association, and by a Faculty Learning Community grant by California State University, East Bay (Office of Faculty Development). We would like to acknowledge Edward Carney (University of Minnesota) for his extensive technical assistance in all phases of this project, and both Krystal Baumgarten (University of Minnesota) and Deborah Lanza (University of Connecticut) for assistance in the standardized testing of participants. We express our gratitude to the Brain Injury Association of Minnesota and the Brain Injury Alliance of Connecticut for their assistance in the recruitment of participants.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Deidentified data from the study may be made available on request

Notes

1 In using the term “reorganization” we do not assume that changes to cognitive functioning necessarily reflect a neural mechanism. Rather, we use the term broadly to signify reorganization of the cognitive functions upon which the metamemory judgment process is based. The current study was not designed to determine whether this may be achieved through changes to the neural network, or via recruitment/compensatory engagement of different cognitive functions.

2 Statistical procedures such as multiple regression and EFA/PCA tend to “overfit” the data and result in errors in influences when the sample size is small or the ratio between sample size and number of variables (called the subject-to-item ratio) is small (Osborne & Costello, 2019). More specifically, small sample size or small subject-to-item ratio can cause problems such as mis-estimated regression coefficients in multiple regression (Cohen & Cohen, 1983) and mis-assignment of factors in EFA/PCA (Tabachnick & Fidell, 2001).

Additional information

Funding

This research was supported in part by grants from the University of Minnesota, the Minnesota Speech-Language-Hearing Association, the University of Connecticut, and California State University, East Bay.