Psychometric Evaluation of the A-NKS: A Diagnostic Instrument to Assess Impairment of Activities of Daily Living in Mild and Major Neurocognitive Disorder According to DSM-5

Abstract

Background: Activities of daily living (ADL) functioning are important in the diagnosis of neurocognitive disorders (NCD), yet no standardized and validated instrument exist based on international classification systems. Objective: We aimed to psychometrically evaluate the differentiated assessment of ADL and instrumental ADL (IADL) impairments due to NCD according to DSM-5 criteria (Instrument für die Erfassung von Alltagsbeeinträchtigungen bei Neurokognitiven Störungen; A-NKS). Methods: We conducted a pilot study involving 92 participant-informant dyads of participants with mild or major NCDs, cognitively healthy individuals, and an informant, to test acceptability, internal consistency, and convergent validity with similar measures. Results: Both A-NKS versions demonstrated excellent internal consistency (α= 0.95 –0.99) and correlate with other instrumental ADL instruments (participant [informant]: Barthel Index: rs = –0.26, p≤0.05 [rs = –0.30, p≤0.01]; Amsterdam IADL: rs = 0.59, p≤0.01 [rs = 0.48, p≤0.01]; SIDAM ADL: rs = 0.46, p≤0.001 [rs = 0.47, p≤0.001]). Additionally, there are correlations with the scale autonomy of the WHOQOL-OLD (rs = -0.50, p≤0.001 [rs = –0.37, p≤0.001]) and physical, as well as cognitive activities (rs = -0.39, p≤0.001 [rs = –0.50, p≤0.001]). They were well-accepted by participants and informants. Conclusions: The A-NKS is an instrument with acceptable psychometric properties to assess ADL due to neurodegenerative decline in healthy individuals, and those with mild or major NCD. Further research is needed to confirm reliability and validity and investigate the factor structure.