Table 1 Clinical features distinguishing fvAD from bvFTD
From: Diagnosing the frontal variant of Alzheimer’s disease: a clinician’s yellow brick road
Clinical Features supporting fvAD | Clinical Features supporting bvFTD | |
|---|---|---|
Memory | Early memory complaints | Late memory complaints |
Language | Phonemic and semantic paraphasias | Loss of socioemotional aspects of speech |
Fluency | Semantic > phonemic fluency impairment | Phonemic > semantic fluency impairment |
Behavioral | Compulsive or perseverative behaviors are uncommon | Collection or hoarding, and ritualistic and disinhibited behaviors (particularly involving food) |
Personality Change | Agitation and irritability | Early apathy, disinhibition, loss of empathy |
Thought Content | Delusions (theft, infidelity, and paranoid) | Mental rigidity |
Body Habitus | Weight loss associated with depression | Weight gain associated with hyperphagia |
Movement Disorder | Myoclonus (often mischaracterized as tremor), late parkinsonism | Early parkinsonism |
Brain MRI pattern | Symmetric atrophy (temporal > frontal, posterior corpus callosum, and perisylvian) | Symmetric (~MAPT mutations) or asymmetric (~GRN mutations) frontotemporal atrophy |
CSF findings | CSF p-Tau/Aβ42 ratio (>0.21 ng/mL) | CSF progranulin levels (<60 ng/mL)- not validated in clinical practice |
Biomarkers | APOE ε4 allele positive | No relation to APOE allele |