Fig. 4. Convergent validity: associations between DMOs and disease severity measures.

PD Parkinson’s disease, MS multiple sclerosis, COPD: chronic obstructive pulmonary disease, PFF: proximal femoral fracture. Data are presented as: Number of studies with statistically significant associations between DMOs and measures of disease severity/Total studies (%). Disease severity measures include the UPDRS, UPDRS-III, and Hoehn & Yahr scale in PD, EDSS, and PDDS in MS, FEV₁ % predicted and GOLD stage in COPD, and patient- or physician-rated global measures of improvement in all four conditions. Most relevant measures in PFF fell under different categories, such as activities of daily living. DMOs known to be highly intercorrelated were grouped (i.e., step length and stride length), and all DMOs were organized according to previously established domains of gait. *Proportion of studies exceeds the expected false-positive rate as determined by Bernoulli hypothesis testing and Benjamini–Hochberg adjustment.