Characterizing Prospective Memory Errors and Their Neuropsychological Correlations in Persons with MS

Background: Prospective memory (PM) or “remembering to remember” is an important cognitive domain for everyday tasks. PM errors (e.g., loss of content, task substitution, or loss of time) have been noted in certain neurological disorders, with detrimental effects on a person’s quality of life and independent functioning. While PM deficits have been documented in multiple sclerosis (MS), little is known about the specific errors made.

Objectives: 1) To characterize types and frequencies of PM errors and 2) investigate whether other cognitive processes (i.e., processing speed and verbal learning) or personality traits (i.e., Five Factor Model of Personality) are associated with PM errors in persons with MS (PwMS).

Methods: Participants (n = 111) were PwMS who completed the Memory for Intentions Test (MIST) as part of a cross-sectional study. As part of the assessment battery, participants also completed the Symbol Digits Modalities Test (SDMT), Rey Auditory Verbal Learning Test (RAVLT), and NEO Five Factor Inventory-3 (NEO FFI-3). Descriptive statistics were used to characterize PM errors, with chi-squares used to examine frequency differences across the types of errors. Spearman’s correlations were run between the number of PM errors and the cognitive processes and personality traits. Variables with a p-value of <.1 were entered into a linear regression with PM errors as the outcome, and age, gender, and education as covariates, with non-significant factors manually removed.

Results: About 92% of participants made at least one PM error. There was an overall difference in the type of PM error (χ²(3) = 98.71, p <.001), with loss of content errors (45%) being the most common. PwMS were also more likely to make errors on time-based tasks (χ²(1) = 43.35, p <.001). RAVLT total learning (b = -0.58, p <.001) and SDMT (b = -0.42, p = .003) were both significantly associated with PM errors. There were no significant relationships between PM errors and personality traits (ps ≥ .116).

Conclusions: PM errors are common in PwMS, particularly loss of content errors and errors on time-based tasks. Verbal learning and processing speed are also negatively associated with the number of PM errors, suggesting that deficits in these cognitive domains likely contribute to PM difficulties.