Measurements of the amygdala and hippocampus in pathologically confirmed Alzheimer disease and frontotemporal lobar degeneration

Josephine Barnes, Jennifer L. Whitwell, Chris Frost, Keith A. Josephs, Martin Rossor, Nick C. Fox

Research output: Contribution to journalArticle

103 Scopus citations

Abstract

Background: Differentiating between Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD) can be difficult, particularly in the earliest stages of the diseases. Patterns of atrophy on magnetic resonance imaging may help distinguish these diseases and aid diagnosis. Objective: To assess the diagnostic utility of magnetic resonance imaging-derived amygdala and hippocampal volumes from patients with pathologically proved AD and FTLD. Design: Cross-sectional volumetric magnetic resonance imaging study of the hippocampus and amygdala. Setting: Specialist cognitive disorders clinic. Subjects: Thirty-seven subjects, including 10 patients with pathologically proved AD, 17 patients with pathologically proved FTLD, and 10 age-matched control subjects. Main Outcome Measures: Hippocampal and amygdala volumes. Results: Geometric mean amygdala and hippocampal volumes were, respectively, 15.0% (95% confidence interval [CI], 4.2%-24.5%) and 16.4% (95% CI, 5.9%-25.6%) lower in the AD than in the control group. In FTLD, the equivalent differences were 43.1% (95% CI, 31.9%-52.6%) in the amygdala and 36.1% (95% CI, 27.5%-43.7%) in the hippocampus. Volumes were significantly lower in the FTLD than in the AD group (P<.01 in both regions). Within the FTLD clinical subgroups, there was evidence of a difference in pattern of atrophy with greater asymmetry (left smaller than right) in semantic dementia compared with frontal variant FTLD (P<.001). On average, the left hippocampus was 14% smaller in semantic dementia than in frontal variant FTLD, whereas the right hippocampus was 37% larger. On average, the left amygdala was 39% smaller in semantic dementia than in frontal variant FTLD, whereas the right amygdala was only 1% smaller. Conclusions: Hippocampal atrophy is not specific to AD or FTLD. However, severe or asymmetrical amygdala atrophy should suggest FTLD. Atrophy patterns follow clinical syndromes rather than pathology.

Original languageEnglish (US)
Pages (from-to)1434-1439
Number of pages6
JournalArchives of neurology
Volume63
Issue number10
DOIs
StatePublished - Oct 17 2006

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ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Clinical Neurology

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