Clinical Outcome Measure Crosswalks in Alzheimer's Disease: A Systematic Review

A key challenge in studies that model outcomes, disease progression, and cost-effectiveness of existing and emerging dementia treatments is the lack of conversion criteria to translate, or 'crosswalk', scores on multiple measurement scales. Clinical status in dementia is commonly characterized in the cognitive, functional, and behavioral domains.

We conducted a systematic review of peer-reviewed dementia measure crosswalks in the three domains.

We systematically reviewed published literature for crosswalks between scales used to measure cognitive, functional, or behavioral outcomes in Alzheimer's and related dementias. The search was conducted in PubMed, and additional crosswalks were identified through snowballing and expert input from dementia modelers.

Of the reviewed articles, 2,334 were identified through a PubMed search, 842 articles were sourced from backward and forward citation snowballing, and 8 additional articles were recommended through expert input. 31 papers were eligible for inclusion, listing 74 unique crosswalks. Of those, 62 (83.8%) were between endpoints of the cognitive domain and 12 (16.2%) were either between endpoints of the functional domain or were hybrid in nature. Among crosswalks exclusively in the cognitive domain, a majority involved the Mini-Mental State Examination (MMSE) (37 crosswalks) or the Montreal Cognitive Assessment (MoCA) and its variants (25 crosswalks). MMSE was directly compared to MoCA or MoCA variants in 16 crosswalks.

Existing crosswalks between measures of dementia focus largely on a limited selection of outcome measures, particularly MMSE and MoCA. Few crosswalks exist in the functional domain, and no crosswalks were identified for solely behavioral measures.