New scoring methodology improves the sensitivity of the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) in clinical trials

Nishant Verma, S Natasha Beretvas, Belen Pascual, Joseph C Masdeu, Mia K Markey, Alzheimer’s Disease Neuroimaging Initiative

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

INTRODUCTION: As currently used, the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) has low sensitivity for measuring Alzheimer's disease progression in clinical trials. A major reason behind the low sensitivity is its sub-optimal scoring methodology, which can be improved to obtain better sensitivity.

METHODS: Using item response theory, we developed a new scoring methodology (ADAS-CogIRT) for the ADAS-Cog, which addresses several major limitations of the current scoring methodology. The sensitivity of the ADAS-CogIRT methodology was evaluated using clinical trial simulations as well as a negative clinical trial, which had shown an evidence of a treatment effect.

RESULTS: The ADAS-Cog was found to measure impairment in three cognitive domains of memory, language, and praxis. The ADAS-CogIRT methodology required significantly fewer patients and shorter trial durations as compared to the current scoring methodology when both were evaluated in simulated clinical trials. When validated on data from a real clinical trial, the ADAS-CogIRT methodology had higher sensitivity than the current scoring methodology in detecting the treatment effect.

CONCLUSIONS: The proposed scoring methodology significantly improves the sensitivity of the ADAS-Cog in measuring progression of cognitive impairment in clinical trials focused in the mild-to-moderate Alzheimer's disease stage. This provides a boost to the efficiency of clinical trials requiring fewer patients and shorter durations for investigating disease-modifying treatments.

Original languageEnglish (US)
Article number64
Pages (from-to)64
JournalAlzheimer's Research and Therapy
Volume7
Issue number1
DOIs
StatePublished - Nov 12 2015

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cognitive Neuroscience

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