Alternate scoring of the Paced Auditory Serial Addition Test (PASAT): Evaluating strings of consecutive correct responses as predictors of cognitive functioning in patients with multiple sclerosis

Abstract

Objective: The Paced Auditory Serial Addition Test (PASAT) is a commonly used test for patients with multiple sclerosis (MS). This study aimed to evaluate the usefulness of novel scoring methods of the test, including the total number of three (triads), four (quads), and five (quints) consecutive correct responses as well as the longest string of consecutive correct responses. These were compared to the traditional total correct responses and the more recently developed dyad scores. Specifically, evaluating the usefulness of these scores for predicting overall cognitive function, detecting impairment, and predicting overall disability in patients with MS, as well as for correctly classifying those with and without MS were the objectives of the current study.;Method: The sample consisted of 201 MS patients seen for clinical evaluation for the first three aims, and 30 research participants with MS and 30 age-, education-, ethnicity-, and intelligence-matched healthy controls for the final aim. All patients and participants were administered the Minimal Assessment of Cognitive Function in MS (MACFIMS) battery, and overall cognitive functioning was represented by a composite z-score of all test performances excluding The PASAT. Cognitive impairment was defined in three ways for the analyses: composite z-score ≤-1, ≤-1.5, and at least two domains with composite z-scores ≤-1.5. Overall disability was represented by Incapacity Status Scale ratings by neurologists and nurses.;Results: All scoring variables were found to be effective at predicting overall cognitive functioning, classifying those with cognitive impairment, predicting overall levels of disability, and discriminating between MS patients and healthy controls. Total correct and dyad scores were slightly more effective at each than the longer strings of correct responses.;Discussion: The findings provide support for the efficacy of total correct scores and dyad scores on the PASAT as predictors of cognitive functions, disability, and disease presence for patients with multiple sclerosis. Longer strings of consecutive responses may be too difficult for many MS patients to achieve, which likely contributed to their limited usefulness for this clinical sample.