The Philadelphia Brief Assessment of Cognition (PBAC): A Validated Screening Measure for Dementia

Abstract

The Philadelphia Brief Assessment of the Cognition (PBAC) is a brief dementia-screening instrument. The PBAC assesses five cognitive domains: working memory/executive control; lexical retrieval/language; visuospatial/visuoconstructional operations; verbal/visual episodic memory; and behavior/social comportment. A revised version of the PBAC was administered to 198 participants including patients with Alzheimer's disease (AD) (n = 46) and four groups of patients with frontotemporal dementia (FTD) syndromes: behavioral-variant FTD (bvFTD; n = 65), semantic-variant primary progressive aphasia (PPA) (svPPA; n = 22), non-fluent/agrammatic-variant PPA (nfaPPA; n = 23), and corticobasal syndrome (CBS; n = 42), and a group of normal controls (n = 15). The total PBAC score was highly correlated with the MMSE. The criterion validity of the PBAC was assessed relative to standard neuropsychological test performance. Using standard neuropsychological test performance as a criterion, the total PBAC score accurately identified the presence and severity of dementia. Intra-class correlations between PBAC subscales and standard neuropsychological tests were highly significant. PBAC subscales demonstrated good clinical utility in distinguishing AD and FTD subtypes using receiver operating characteristic analysis and standard diagnostic performance statistics to determine optimal subscale cut scores. The PBAC is a valid tool and able to assesses differential patterns neuropsychological/behavioral impairment in a broad range of neurodegenerative conditions.

Keywords:

• Alzheimer's disease
• Frontotemporal lobar dementia
• Frontotemporal dementia
• FTD
• Philadelphia Brief Assessment of the Cognition
• PBAC
• Neuropsychological assessment, Philadelphia (repeatable) Verbal Learning Test

Acknowledgments

This work was supported in part by the US Public Health Service (AG17586, AG15116, AG10124, NS44266 and AG32953). A copy of the PBAC test form is available from the first author.

Dr. Grossman receives support from the National Institutes of Health (AG32953, AG17586, AG15116, NS44266, and NS53488) and is a consultant for Pfizer Pharmaceuticals, Forest Labs, and Allon Therapeutics. Dr. Chatterjee receives support from National Institutes of Health (RO1 DC008779, RO1 HD050199) and the National Science Foundation (SBE0541957). Drs. Libon, Rascovsky, Gross, and Xie; Mr. Dreyfuss and White; and Ms. Massimo, Moore, Boller, Kitain, report no disclosures.