Table 3 Validation studies assessing the psychometric properties of the DS

Stern et al. 1994 [3]: Predictors I study

Mild–moderate AD

Inter-rater reliability (interclass correlation), 0.99 for total score; internal consistency (Cronbach’s α), 0.66; significant correlation with CDR (r = 0.34) and mMMS (r = − 0.27)

Lenderking et al. 2013 [10]: Predictors I + II studies

Mild-moderate AD

Internal consistency (Cronbach’s α), 0.72; construct validity, correlation with BDRS (r = 0.60), mMMS (r = − 0.30)

Lenderking et al. 2013 [10]; DADE Study

Mild-moderate AD

Internal consistency (Cronbach’s α), 0.72; construct validity, significant correlation with MMSE (r = − 0.47), CDR-SB (r = − 0.64), DAD (r = − 0.72), and NPI (r = 0.21)

Lenderking et al. 2013 [10]: ELN-AIP 901 study

Mild-moderate AD

Internal consistency (Cronbach’s α), 0.74; construct validity, significant correlation with MMSE (r = − 0.53), ADAS-cog (r = − 0.42), DAD (r = − 0.77), and NPI (r = 0.51)

Wyrwich et al. 2014 [13]

Mild-moderate AD

Internal consistency (Cronbach’s α), 0.66; construct validity, significant correlation with ADAS-cog (r = 0.36), MMSE (r = − 0.34), DAD (r = − 0.63), CDR-SB (r = 0.61), and NPI (r = 0.32); responsiveness, significant correlation with change scores on ADAS-cog, DAD, CDR-SB, and MMSE (baseline to week 78)

Brickman et al. 2002 [18]: Predictors 1 study

Mild-moderate AD

Statistically significant change in total DS score over time (0.5 points per 6 month interval) (p < 0.001).

Garre-Olmo et al. 2015 [14]: CoDep AD study*

Mild-severe AD

Internal consistency (Cronbach’s α), 0.85; significant correlation with DAD score (r = 0.900), CBI (r = 0.323), NPI (r = 0.374), and MMSE (r = 0.617)