Frontal variant Alzheimer's disease: A systematic narrative synthesis

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Frontal variant Alzheimer's disease (fvAD) is a rare Alzheimer's disease (AD) subtype often misdiagnosed as behavioral variant frontotemporal dementia (bvFTD).
• Existing literature frequently conflates behavioral and executive dysfunction in fvAD, utilizing both AD and bvFTD diagnostic criteria for classification.
• This ambiguity complicates the accurate identification and study of fvAD.

Purpose of the Study:

• To synthesize neuropsychological findings in fvAD cohorts.
• To contextualize these findings within established Alzheimer's disease pathology.
• To identify potential areas for improving differential diagnosis between fvAD and bvFTD.

Main Methods:

• A narrative synthesis approach was employed.
• Literature searches were conducted across EMBASE, PsycINFO, PROQUEST, and MEDLINE databases.
• Studies included required both neuropsychological and biomarker evidence.

Main Results:

• Ten studies comprising 342 fvAD, 178 typical AD, and 250 bvFTD participants were reviewed.
• Areas for further investigation include executive dysfunction severity, symptom onset, and cognitive profile similarities between fvAD and typical AD.
• Distinctive features that may aid differential diagnosis were highlighted.

Conclusions:

• Neuropsychological evidence is currently insufficient to definitively differentiate fvAD and bvFTD cognitive phenotypes.
• Disparate diagnostic criteria used for fvAD cohorts contribute to variability in research findings.
• Distinctive features identified may guide future differential diagnostic research.