Background: Event-related potentials (ERPs) are valuable tools for the early detection and monitoring of cognitive impairment in people with Multiple Sclerosis (pwMS) and towards the evaluation of the effectiveness of treatment. The Symbol Digit Modalities Test (SDMT), a screening tool for cognitive dysfunction, is often impaired in pwMS. Objective: To explore the ERPs and reaction time (RT) correlates of SDMT as indicators of cognitive impairment in pwMS. Methods: We developed an EEG-compatible (EEG-SDMT) paradigm. Ninety-two pwMS and twenty-eight healthy controls (HC) underwent ERPs and RT measurement during EEG-SDMT. Results: SDMT-ERPs presented a centro-parietal (Pz electrode) positive peak (P5) with a significantly longer latency in pwMS (611.72 ± 122.30 ms) versus HC (517.29 ± 75.53 ms) (p < 0.01). RTs and raw scores in the standard SDMT were inversely correlated (r = −.722, p < .001). Conclusion: Our EEG-SDMT paradigm identified neurophysiological correlates of SDMT performance, which was significantly affected in pwMS. Although the P5 showed longer latencies in pwMS, this component did not differentiate between cognitively impaired and preserved individuals, likely because it is still too early to capture higher-order cognitive deficits. In contrast, RTs emerged as a more reliable and sensitive indicator of cognitive performance.
Tacchini, M, Gamberini, G, Dini, M, Rossi, C, Boschetti, A, Turchi, L, Rodegher, M, Chiveri, L, Van Schependom, J, Nagels, G, Comi, G & Leocani, L 2026, 'Event-related potentials and behavioural correlates of cognitive functions in MS: An EEG study during symbol digit modalities test', Multiple Sclerosis Journal. https://doi.org/10.1177/13524585261423416
Tacchini, M., Gamberini, G., Dini, M., Rossi, C., Boschetti, A., Turchi, L., Rodegher, M., Chiveri, L., Van Schependom, J., Nagels, G., Comi, G., & Leocani, L. (2026). Event-related potentials and behavioural correlates of cognitive functions in MS: An EEG study during symbol digit modalities test. Multiple Sclerosis Journal. https://doi.org/10.1177/13524585261423416
@article{cca5992b23bd4c858c663635b891b84c,
title = "Event-related potentials and behavioural correlates of cognitive functions in MS: An EEG study during symbol digit modalities test",
abstract = "Background: Event-related potentials (ERPs) are valuable tools for the early detection and monitoring of cognitive impairment in people with Multiple Sclerosis (pwMS) and towards the evaluation of the effectiveness of treatment. The Symbol Digit Modalities Test (SDMT), a screening tool for cognitive dysfunction, is often impaired in pwMS. Objective: To explore the ERPs and reaction time (RT) correlates of SDMT as indicators of cognitive impairment in pwMS. Methods: We developed an EEG-compatible (EEG-SDMT) paradigm. Ninety-two pwMS and twenty-eight healthy controls (HC) underwent ERPs and RT measurement during EEG-SDMT. Results: SDMT-ERPs presented a centro-parietal (Pz electrode) positive peak (P5) with a significantly longer latency in pwMS (611.72 ± 122.30 ms) versus HC (517.29 ± 75.53 ms) (p < 0.01). RTs and raw scores in the standard SDMT were inversely correlated (r = −.722, p < .001). Conclusion: Our EEG-SDMT paradigm identified neurophysiological correlates of SDMT performance, which was significantly affected in pwMS. Although the P5 showed longer latencies in pwMS, this component did not differentiate between cognitively impaired and preserved individuals, likely because it is still too early to capture higher-order cognitive deficits. In contrast, RTs emerged as a more reliable and sensitive indicator of cognitive performance.",
keywords = "Cognition, Electroencephalography, Multiple sclerosis, Reaction time, Symbol digit modalities test",
author = "Marta Tacchini and Giulia Gamberini and Michelangelo Dini and Chiara Rossi and Angela Boschetti and Letizia Turchi and Mariaemma Rodegher and Luca Chiveri and \{Van Schependom\}, Jeroen and Guy Nagels and Giancarlo Comi and Letizia Leocani",
note = "Publisher Copyright: {\textcopyright} The Author(s), 2026",
year = "2026",
month = mar,
day = "13",
doi = "10.1177/13524585261423416",
language = "English",
journal = "Multiple Sclerosis Journal",
issn = "1352-4585",
publisher = "SAGE Publications Ltd",
}