Psychometric Evaluation of the Neuropsychological Test Battery in Individuals with Normal Cognition, Mild Cognitive Impairment, or Mild to Moderate Alzheimer's Disease: Results from a Longitudinal Study.

Abstract

The Neuropsychological Test Battery (NTB) is a combination of widely used clinical neuropsychological tests measuring memory and executive function and was designed to overcome some of the limitations of the traditionally used Alzheimer's disease Assessment Scale - Cognitive subscale (ADAS-Cog). A previously reported account indicated high levels of NTB reliability in patients with mild-to-moderate Alzheimer's disease (AD) and mild cognitive impairment (MCI). We examined capacity of the Neuropsychological Test Battery (NTB) and its component subtests to measure cognitive change over time. Correlations with other cognitive and functional assessments were also determined. Design, Settings, Participants: This was a multicentre, prospective, non-interventional, longitudinal cohort study involving patients with mild-to-moderate AD (n=196), MCI (n=70), or cognitively normal control participants (NC, n=75). The NTB, as well as other Clinical Outcome Assessments including, ADAS-Cog, other cognitive measures, functional/behavioral questionnaires, health outcome questionnaires, and resource utilization tools were administered. Mean change from baseline for the NTB composite score and the six individual NTB subtests showed greater reductions in performance over time in the AD and MCI groups, compared with NC group. The ADAS-Cog was found to be more sensitive to change than the NTB in all three populations. The NTB showed high correlation with the ADAS-Cog and appears to be a sensitive and reliable assessment tool for measuring cognitive decline in patients with mild-to-moderate AD. However, the ADAS-Cog was found to be more sensitive to change over time in both the AD and MCI populations.