Multimodal in vivo staging in amyotrophic lateral sclerosis using artificial intelligence.

backgroundThe underlying neuropathological process of amyotrophic lateral sclerosis (ALS) can be classified in a four-stage sequential pTDP-43 cerebral propagation scheme. Using diffusion tensor imaging (DTI), in vivo imaging of these stages has already been shown to be feasible for the specific corticoefferent tract systems. Because both cognitive and oculomotor dysfunctions are associated with microstructural changes at the brain level in ALS, a cognitive and an oculomotor staging classification were developed, respectively. The association of these different in vivo staging schemes has not been attempted to date.

methodsA total of 245 patients with ALS underwent DTI, video-oculography, and cognitive testing using Edinburgh Cognitive and Behavioral ALS Screen (ECAS). A set of tract-related diffusion metrics, cognitive, and oculomotor parameters was selected for further analysis. Hierarchical and k-means clustering algorithms were used to obtain an optimal cluster solution.

resultsAccording to cluster analysis, differentiation of patients with ALS into four clusters resulted: Cluster A showed the highest fractional anisotropy (FA) values and thereby the best performances in executive oculomotor tasks and cognitive tests, whereas cluster D showed the lowest FA values, the lowest ECAS scores, and the worst executive oculomotor performance across all clusters. Clusters B and C showed intermediate results regarding parameter values. DISCUSSION: In a multimodal dataset of technical assessments of brain structure and function in ALS, an artificial intelligence-based cluster analysis showed high congruence of DTI, executive oculomotor function, and neuropsychological performance for mapping in vivo correlates of neuropathological spreading.