Identification of Brain Regions and Networks Critical to Poststroke Cognitive Impairment Through Lesion-symptom and Lesion Network Analyses.

Clarifying the critical lesion regions of poststroke cognitive impairment (PSCI) could improve the understanding of how anatomical locations and functional networks jointly influence the manifestation of cognitive deficits. Lesion-symptom and lesion network analyses are performed to identify the anatomical sites and functional networks related to specific cognitive functions. The multidomain cognitive statuses and the focal brain lesions of 83 patients with PSCI were recorded during the acute poststroke period (< 2 weeks). Multivariate lesion-symptom mapping was performed to identify risk regions, i.e., lesion sites associated with worse cognitive deficits; functional lesion network mapping was performed to identify risk networks, i.e., brain networks connected to risk regional peaks. Lesion-symptom mapping analysis identified several brain regions where lesions were significantly correlated with neurological deficit, general cognitive impairment, visuospatial dysfunction, and executive dysfunction. Various types of cognitive deficits presented diverse risk region distribution patterns with different peaks. Functional lesion network mapping demonstrated that networks connected to peak risk regions for neurological deficit and general cognitive impairment were mostly similar to the default network (DN), whereas the risk network for visuospatial and executive dysfunctions was the somatomotor network (SN). Functional imaging measurements directly from PSCI patients revealed that intranetwork functional connections within the limbic network, which is functionally similar to the DN, were stably reduced in all patients, and intranetwork functional connections in the SN exhibited the same pattern. Although the decreases did not present the network preference observed in lesion network mapping, these results still support the concept that lesions to specific nodes of the DN or SN are associated with the cognitive deficits that constitute PSCI.