Cognitive training reorganizes lateralization of fronto-parietal network in vascular cognitive impairment

Vascular cognitive impairment no dementia (VCIND) represents cognitive deficits due to vascular causes, without meeting the criteria for dementia. Cognitive training has emerged as a safe and effective intervention for VCIND, though its underlying mechanisms remain obscure. This study investigates how subcortical VCIND and computerized cognitive training affect brain functional lateralization of the fronto-parietal network (FPN), whose functions are notably influenced by both VCIND and cognitive training. In a randomized, active-controlled design for VCIND patients, we assessed the resting-state functional lateralization index (LI) of the FPN and conducted neuropsychological assessments in VCIND training and control groups (n = 30 per group) at baseline, after a 7-week intervention and at a 6-month follow-up. A healthy older group (n = 30) only provided baseline data. At baseline, VCIND patients showed an FPN lateralization pattern similar to that of healthy older adults. However, a stronger right-lateralized interhemispheric heterotopic LI in FPN correlated with better memory performance only in healthy adults. After the intervention, only the VCIND training group exhibited reduced lateralization in FPN, shifting to a bilateral interhemispheric LI, with stronger leftward changes correlating with improved executive and memory functions. Notably, these changes disappeared at the 6-month follow-up. These findings suggest that subcortical VCIND modifies the relationship between FPN lateralization and cognitive functions, rather than altering the lateralization pattern itself. Short-term computerized cognitive training facilitates executive and memory functions by promoting hemispherical reorganizing of FPN and functional compensation, although the benefits may diminish over time.