A1 Refereed original research article in a scientific journal
TSPO-PET-measurable neuroinflammation associates with information processing speed decline in multiple sclerosis
Authors: Saraste Maija; Nikkilä Taru; Matilainen Markus; Hämäläinen Päivi; Wahlroos Saara; Rajander Johan; Snellman Anniina; Rinne Juha; Airas Laura
Publisher: SAGE Publications
Publication year: 2026
Journal: Multiple Sclerosis
Article number: 13524585261446839
ISSN: 1352-4585
eISSN: 1477-0970
DOI: https://doi.org/10.1177/13524585261446839
Publication's open availability at the time of reporting: No Open Access
Publication channel's open availability : Partially Open Access publication channel
Web address : https://doi.org/10.1177/13524585261446839
Additional information: Data are available upon reasonable request. Anonymized data not published within the article will be shared on a request from a qualified investigator.
Background:
Impaired information processing speed (IPS) is a common and disabling cognitive deficit in multiple sclerosis (MS).
Objectives:
To assess whether glial activation measured using translocator protein–positron emission tomography (TSPO-PET) predicts performance and long-term change on the Symbol Digit Modalities Test (SDMT).
Methods:
Forty-eight people with MS underwent [¹¹C]PK11195 TSPO-PET, magnetic resonance imaging (MRI), diffusion tensor imaging and SDMT at baseline; 34 repeated SDMT a median (first to third quartile) 4.9 (3.7–5.2) years later. Glial activation was quantified using the distribution volume ratio (DVR). Multivariable regression models were used to identify predictors of baseline SDMT and subsequent change.
Results:
Normal-appearing white matter (NAWM) radial diffusivity (estimate [95% confidence interval (CI)] −129 [−214, −44]), thalamic DVR (−52.5 [−94.8, −10.2]) and age (−0.57 [−1.07, −0.06]) explained 41% of baseline SDMT variance. NAWM DVR was the strongest predictor of SDMT change, explaining 53% of variance when adjusted for baseline SDMT (−6.23 [−8.55, −3.91]). A model including lesion rim DVR (odds ratio 1.36 [1.06, 1.73]) and baseline SDMT (1.18 [1.01, 1.37]) predicted SDMT decline with 73% sensitivity and 83% specificity (area under the curve [AUC] = 0.85).
Conclusion:
Diffuse neuroinflammation in the NAWM is associated with future SDMT change, suggesting a potential role for chronic glial activation in IPS deterioration in MS.
Keywords:
MS-tauti, multiple sclerosis, neuroinflammatory diseases, tulehdukselliset hermoston sairaudet
Funding information in the publication:
The authors disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This work was supported by the Research Council of Finland grant for clinical researcher (grant no. 330902); the Research Council of Finland’s Flagship InFLAMES (grant nos. 337530, 357910 and 358823); The Jane and Aatos Erkko foundation (grant no. 220026); a grant from the National MS Society and the National Stem Cell Foundation (grant no. RFA-2203-39281); Sigrid Juselius Foundation (grant no. n.a.); the State Research Funding (SRF) for university-level health research, Turku University Hospital, Wellbeing Services County of Southwest Finland (grant no. n.a); Päivikki and Sakari Sohlberg Foundation (grant no. n.a).
