Patterns of prospective memory errors differ in persons with multiple sclerosis

ABSTRACT

Introduction

Prospective memory (PM) deficits have been documented in multiple sclerosis (MS). This study aimed to explore the specific types of errors made by persons with MS (PwMS), including differences between PwMS and healthy controls (HC) and PwMS who do and do not have impairments in processing speed and/or verbal learning and memory.

Method

PwMS (n = 111) and HC (n = 75) completed the Memory for Intentions Test (MIST), an objective measure of PM that has five types of errors that can be coded (PM failure, task substitution, loss of content, loss of time, and random errors). The number and types of PM errors were calculated for the overall MIST and six subscales, which break down performance by types of delay (2-Minute and 15-Minute), cue (Time and Event), and response (Verbal and Action). Impairment was defined as performing < 1.5 SD on either the Symbol Digit Modalities Test (SDMT) or Rey Auditory Verbal Learning Test (RAVLT). Bivariate analyses were used to examine group differences, with post-hoc pairwise comparisons with Bonferroni corrections.

Results

Nearly 93% of PwMS made at least one PM error, compared to 76% of HC (V = .24, p = .001). The most commonly made PM error by PwMS was loss of content errors (45.0%). PwMS made significantly more task substitution errors (26.4% vs. 7.6%, p < .001) and fewer loss of time errors (9.5% vs. 21.2%, p < .001) than HC. Impaired PwMS made more errors than non-impaired PwMS, specifically PM failures on time-based tasks.

Conclusions

PM errors are common in PwMS, particularly when there are longer delays and time-based cues. Not only do PwMS make more errors than demographically similar HC, but they exhibit different cognitive process failures.

KEYWORDS:

• Multiple sclerosis
• prospective memory
• error analysis
• cognitive functioning

Acknowledgments

This study was presented at the Consortium of Multiple Sclerosis Center (CMSC) annual meeting in National Harbor, Maryland in June 2022.

The views and opinions expressed in this article reflect those of the authors and do not necessarily reflect those of the United States Department of Veterans Affairs.

The Patient Determined Disease Steps (PDDS) is provided for use by the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry (www.narcoms.org/pdds). NARCOMS is supported in part by the CMSC and CMSC Foundation.

Disclosure statement

Dr. Sarah Raskin is the developer of the Memory for Intentions Test (MIST). The authors have no other potential conflict of interest to report.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/13803395.2024.2348775

Additional information

Funding

The work was supported by the National Multiple Sclerosis Society [PP-1901-33103]. Dr. Gromisch is also a Harry Weaver Scholar of the National Multiple Sclerosis Society. The funding source did not contribute to the study design, collection, analysis, or interpretation of the data or writing and submission of the article.