The Latent-Variable Structure of the Addenbrooke's Cognitive Examination-Revised.

Area of Science:

• Neuropsychology
• Psychometrics
• Cognitive Science

Background:

• The Addenbrooke's Cognitive Examination-Revised (ACE-R) is widely used for cognitive assessment.
• Establishing a theoretically justified factor structure is crucial for accurate interpretation of ACE-R scores.
• Parkinson's disease presents with diverse cognitive impairments, necessitating a robust assessment framework.

Purpose of the Study:

• To determine the underlying factor structure of the ACE-R.
• To validate this structure using established psychometric theories, specifically the Cattell-Horn-Carroll (CHC) theory.
• To provide a theoretically sound basis for the clinical interpretation of ACE-R results in neurological conditions.

Main Methods:

• Confirmatory Factor Analysis (CFA) was used to test a pre-defined five-factor model of the ACE-R.
• Exploratory Structural Equation Modeling (ESEM) was employed to explore alternative factor structures.
• The Cattell-Horn-Carroll (CHC) theory guided the examination of alternative models.
• The study included 288 patients with Parkinson's disease.

Main Results:

• Both a three-factor CHC-guided CFA and a three-factor ESEM model demonstrated acceptable fit.
• The best-fitting CFA model comprised acquired knowledge (Gc), visuospatial ability (Gv), and a combined factor of long-term memory retrieval, fluency, and working memory (Glr-Gsm).
• The ESEM results largely corroborated the CFA findings, supporting a three-factor structure.

Conclusions:

• A three-factor structure, guided by CHC theory, provides the most theoretically justified and interpretable factor structure for the ACE-R.
• This validated model is recommended for guiding the clinical interpretation of cognitive variables assessed by the ACE-R.
• The findings enhance the utility of the ACE-R in characterizing cognitive profiles, particularly in patient populations like those with Parkinson's disease.