The Alzheimer’s Disease Assessment Scale–Cognitive Subscale (ADAS-Cog): Modifications and Responsiveness in Pre-Dementia Populations. A Narrative Review

Abstract

The Alzheimer’s Disease Assessment Scale–Cognitive Subscale (ADAS-Cog) was developed in the 1980s to assess the level of cognitive dysfunction in Alzheimer’s disease. Advancements in the research field have shifted focus toward pre-dementia populations, and use of the ADAS-Cog has extended into these pre-dementia studies despite concerns about its ability to detect important changes at these milder stages of disease progression. If the ADAS-Cog cannot detect important changes, our understanding of pre-dementia disease progression may be compromised and trials may incorrectly conclude that a novel treatment approach is not beneficial. The purpose of this review was to assess the performance of the ADAS-Cog in pre-dementia populations, and to review all modifications that have been made to the ADAS-Cog to improve its measurement performance in dementia or pre-dementia populations. The contents of this review are based on bibliographic searches of electronic databases to locate all studies using the ADAS-Cog in pre-dementia samples or subsamples, and to locate all modified versions. Citations from relevant articles were also consulted. Overall, our results suggest the original ADAS-Cog is not an optimal outcome measure for pre-dementia studies; however, given the prominence of the ADAS-Cog, care must be taken when considering the use of alternative outcome measures. Thirty-one modified versions of the ADAS-Cog were found. Modification approaches that appear most beneficial include altering scoring methodology or adding tests of memory, executive function, and/or daily functioning. Although modifications improve the performance of the ADAS-Cog, this is at the cost of introducing heterogeneity that may limit between-study comparison.

A practical computerized decision support system for predicting the severity of Alzheimer’s disease of an individual

“…The ADAS13 is mainly applied to evaluate the severity of cognitive and non-cognitive disfunctions from mild to severe AD (Skinner et al, 2012). However, it has also been used as an outcome measure for trials of interventions in people with MCI and appeared to be able to discriminate between patients with MCI and mild AD (Kueper, Speechley, & Montero-Odasso, 2018). In contrast to MMSE, MoCA, and ADAS13, the FAQ is not used in everyday clinical routine (Ritter et al, 2015).…”

Validation study of the Alzheimer's Disease Assessment Scale‐Cognitive Subscale for people with mild cognitive impairment and Alzheimer's disease in Chinese communities

“…Although there was detectable cognitive decline in MCI patients with higher education from a longitudinal observation, the absolute value of cognitive performance may be still within the normal range due to the compensation effect of high education. Therefore, this scale is not sensitive for the MCI population . Some researchers have been to develop effective measures to optimize the efficiency of ADAS‐Cog in MCI, such as new computing methods on ADAS‐Cog total score, together with other screening tools or adding several sensible items …”

“…Therefore, this scale is not sensitive for the MCI population. [44][45][46] Some researchers have been to develop effective measures to optimize the efficiency of ADAS-Cog in MCI, such as new computing methods on ADAS-Cog total score, 47,48 together with other screening tools or adding several sensible items. 45,49 Additionally, we selected QCSS-E 35 as tool of cognition evaluation for its outstanding clinical validity.…”

Forecasting the progression of Alzheimer's disease using neural networks and a novel preprocessing algorithm

“…[23,24] ADAS11 scores range from 0 to 70, and ADAS13 scores range from 0 to 85, with higher scores indicating more advanced stages of AD. [24] Similar cognitive tests, such as the Mini-Mental State Examination (MMSE), the Rey Auditory Verbal Learning Test (RAVLT), and the Functional Activities Questionnaire (FAQ) have also been used to assess the progression of AD in individual patients. [25,26] ADAS has been found to be more precise than the MMSE [27], and the RAVLT only addresses verbal recall [28], thus providing less diagnostic information than either of the other two.…”