Background: Cognitive Training (CT) has demonstrated some benefits to cognitive and psychosocial
function in Mild Cognitive Impairment (MCI) and early dementia, but the certainty related to
those findings remains unclear. Therefore, understanding the mechanisms by which CT improves cognitive
functioning may help to understand the relationships between CT and cognitive function.
The purpose of this review was to identify the evidence for neuroimaging outcomes in studies of CT in
MCI and early Alzheimer’s Disease (AD).
Methods: Medline, Embase, Web of Science, PsycINFO, CINAHL, and The Cochrane Library were
searched with a predefined search strategy, which yielded 1778 articles. Studies were suitable for inclusion
where a CT program was used in patients with MCI or AD, with a structural or functional Magnetic
Resonance Imaging (MRI) outcome. Studies were assessed for quality using the Downs and Black criteria.
Results: A total of 19 studies met the inclusion criteria. Quality of the included studies was variable and
there was significant heterogeneity for studies included in this review. Task activation was generally
increased post-training, but functional connectivity was both increased and decreased after training. Results
varied by diagnosis, type of CT program, and brain networks examined. No effects were seen on
hippocampal volumes post-training, but cortical thickening and increased grey matter volumes were
Conclusions: CT resulted in variable functional and structural changes in dementia, and conclusions are
limited by heterogeneity and study quality. Larger, more robust studies are required to correlate these
findings with clinical benefits from CT.