Spatial navigation in older adults with mild cognitive impairment and dementia: A systematic review and meta-analysis

In this systematic review and meta-analysis, we compared the spatial navigation performance of older adults with mild cognitive impairment (MCI), Alzheimer's Disease (AD), and other dementias, using healthy older adults as controls. In addition, we evaluated the possible influence of the environment type (virtual and real), protocol (object- or environment-based), and the navigation mode (active and passive navigation) on spatial navigation task performance. In total, 1372 articles were identified and 24 studies were included in the meta-analysis. We found a large effect size on the spatial navigation performance of patients with cognitive decline (standardized mean difference (SMD) = 0.87, confidence interval (CI_95%) = 0.62-1.09, p < 0.001), especially amnestic MCI (SMD = 1.10, CI_95% = 0.71-1.49, p < 0.001) and patients with AD (SMD = 1.60, CI_95% = 1.25-1.95, p < 0.001). However, the tasks did not identify mixed and vascular dementia (SMD = 0.92, CI_95% = -0.33-2.18, p = 0.15 and SMD = 0.65, CI_95% = -0.67-1.97, p = 0.33, respectively). Spatial navigation ability assessed using the Floor Maze Test showed the largest effect size in differentiating healthy older adults and patients with cognitive decline (SMD = 1.98,CI_95% = 1.00-2.97, p < 0.001). In addition, tasks that require walking showed the greatest differences between the two groups. These results suggest that spatial navigation impairment is important, but disease-specific behavioral biomarker of the dementia pathology process that can be identified even in the early stages.