Cognition and Motor Function: A Novel Outcome Measure for Studies on Pre-Dementia Syndromes

Advances in dementia research have shifted attention towards earlier stages in the natural history, such as Mild Cognitive Impairment. The current gold standard outcome measure, the Alzheimer’s Disease Assessment Scale-Cognitive Subscale, is not optimally responsive to changes in pre-dementia populations. Modifications to scoring methodology and content have improved the measurement performance of the ADAS-Cog. However, no published modifications have addressed a second key shift in the field towards understanding motor function as an important component of dementia and pre-dementia syndromes. This thesis used a Pooled Index approach to combine an ADAS-Cog-Proxy measure with assessments of gait velocity and dual-task cost. The responsiveness of the PI to baseline discrimination between older adults with normal cognition, Subjective Cognitive Impairment, and MCI was similar to the ADAS-Cog-Proxy. The PI demonstrated greater responsiveness than the ADAS-Cog-Proxy to change over 6mo. and 48mo., but not 36mo. of follow-up. Overall, motor function assessments improve ADAS-Cog responsiveness