Spatial Navigation as a Digital Marker for Clinically Differentiating Cognitive Impairment Severity

Navigation impairments emerge early in Alzheimer’s disease, but assessments targeting these deficits remain underutilised or impractical for cognitive screening. The Spatial Performance Assessment for Cognitive Evaluation (SPACE) is a digital tool that evaluates spatial navigation deficits associated with cognitive impairment. In a memory clinic and community cohort (n = 300), SPACE reliably distinguished Clinical Dementia Rating levels, exceeding the accuracy of demographic models and matching or surpassing most traditional neuropsychological tests. Including SPACE significantly increased the AUC for distinguishing between no dementia from mild dementia (0.76 to 0.94), no dementia from moderate dementia (0.79 to 0.95), and questionable dementia from mild dementia (0.70 to 0.91), all with consistently high sensitivity and specificity. A short version of SPACE (< 11 minutes) reduced administration time by 40% while maintaining high diagnostic accuracy. These findings highlight the potential of digital navigation assessments to advance early detection, contributing to scalable and accessible healthcare.