To describe validation process of the new apathy scale for institutionalized dementia patients (APADEM-NH).

100 elderly, institutionalized patients with diagnosis of probable Alzheimer Disease (AD) (57%), possible AD (13%), AD with cerebral vascular disease (CVD) (17%), Lewy Bodies Dementia (11%) and Parkinson associated to dementia (PDD) (2%). All stages of the disease severity according to the Global Deterioration Scale (GDS) and Clinical Dementia Rating (CDR) were assessed. The Apathy Inventory (AI), Neuropsychiatric Inventory (NPI), Cornell scale for depression, and the tested scale were applied. Re-test and inter-rater reliability was carried out in 50 patients. The feasibility and acceptability, reliability, validity, and measurement precision were analyzed.

APADEM-NH final version consists of 26 items and 3 dimensions: Deficit of Thinking and Self-Generated behaviors (DT): 13 items, Emotional Blunting (EB): 7 items, and Cognitive Inertia (CI): 6 items. Mean application time was 9.56 minutes and 74% of applications were fully computable. All subscales showed floor and ceiling effect lower than 15%. Internal consistency was excellent for each dimension (Cronbach’s α DT = 0.88, α EB = 0.83, α CI= 0.88);Test-retest reliability for the items was kW=0,48-0,92; Inter-rater reliability reached kW values 0.84-1.00; The APADEM-NH total score showed a low/moderate correlation with apathy scales (Spearman ρ, AI =0.33; NPI-Apathy= 0,31), no correlation with depression scales (NPI-Dementia = -0.003; Cornell= 0,10), and high internal validity (ρ =0.69 0.80).

APADEM-NH is a brief, psychometrically acceptable, and valid scale to assess apathy in patients from mild to severe dementia and discerning between apathy and depression.