The impact of etiology in lesion-symptom mapping – A direct comparison between tumor and stroke

• Published in: NeuroImage clinical 2023-01, Vol.37, p.103305-103305, Article 103305
• Main Authors: van Grinsven, E.E., Smits, A.R., van Kessel, E., Raemaekers, M.A.H., de Haan, E.H.F., Huenges Wajer, I.M.C., Ruijters, V.J., Philippens, M.E.P., Verhoeff, J.J.C., Ramsey, N.F., Robe, P.A.J.T., Snijders, T.J., van Zandvoort, M.J.E.
• Format: Article
• Language: English
• Subjects: Brain - diagnostic imaging; Brain - pathology; Brain Mapping - methods; Brain tumor; Cognition; Humans; Ischemic stroke; Lesion-symptom mapping; Magnetic Resonance Imaging - methods; Neoplasms - pathology; Neuropsychological Tests; Regular; Stroke - pathology; Support vector regression
• ISSN: 2213-1582; 2213-1582
• DOI: 10.1016/j.nicl.2022.103305

•We directly compared LSM in brain tumors and ischemic stroke patients.•Known neuro-anatomical correlates were found, but differed between etiologies.•Differences in lesion topography and volume only partly drive divergent findings.•Lesion-behavior associations are influenced by the etiology causing the lesion.•Similarities across etiologies were mostly found in white matter tracts. Lesion-symptom mapping is a key tool in understanding the relationship between brain structures and behavior. However, the behavioral consequences of lesions from different etiologies may vary because of how they affect brain tissue and how they are distributed. The inclusion of different etiologies would increase the statistical power but has been critically debated. Meanwhile, findings from lesion studies are a valuable resource for clinicians and used across different etiologies. Therefore, the main objective of the present study was to directly compare lesion-symptom maps for memory and language functions from two populations, a tumor versus a stroke population. Data from two different studies were combined. Both the brain tumor (N = 196) and stroke (N = 147) patient populations underwent neuropsychological testing and an MRI, pre-operatively for the tumor population and within three months after stroke. For this study, we selected two internationally widely used standardized cognitive tasks, the Rey Auditory Verbal Learning Test and the Verbal Fluency Test. We used a state-of-the-art machine learning-based, multivariate voxel-wise approach to produce lesion-symptom maps for these cognitive tasks for both populations separately and combined. Our lesion-symptom mapping results for the separate patient populations largely followed the expected neuroanatomical pattern based on previous literature. Substantial differences in lesion distribution hindered direct comparison. Still, in brain areas with adequate coverage in both groups, considerable LSM differences between the two populations were present for both memory and fluency tasks. Post-hoc analyses of these locations confirmed that the cognitive consequences of focal brain damage varied between etiologies. The differences in the lesion-symptom maps between the stroke and tumor population could partly be explained by differences in lesion volume and topography. Despite these methodological limitations, both the lesion-symptom mapping results and the post-hoc analyses confirmed that etiology matters when investigating the cog