Thalamic volume loss as an early sign of amnestic mild cognitive impairment

Abstract

The aim of this study was to compare brain volume reduction in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) with age-related changes in age- and gender-matched healthy individuals. Sixty-six patients were divided in three groups based on medical history, neurological and neurocognitive assessment: 26 patients with AD, 20 patients with aMCI and 20 healthy controls. All participants underwent high-resolution magnetic resonance (MR) imaging on 3 T unit. MR volumetry of cerebral cortex, white matter and lateral ventricles volumes, as well as volumes of subcortical nuclei (hippocampus, amygdala, thalamus) was performed. Global cerebral and grey matter volumes were lower in AD patients compared to aMCI (p = 0.023 and p = 0.001, respectively) and controls (p < 0.001 and p < 0.001, respectively). Volume of lateral ventricles was significantly higher in AD patients compared to controls (right p = 0.007, left p = 0.007). Volumes of thalamus were lower in AD patients (right p < 0.001, left p < 0.001), and in aMCI patients (right p = 0.004, left p = 0.015), compared to controls. Hippocampal volume was lower in AD patients compared to both aMCI patients (right p = 0.047, left p = 0.003) and controls (right p < 0.001, left p < 0.001). In aMCI patients, hippocampal volume was lower than in controls (right p = 0.004, left p = 0.007). Volumes of amygdala were lower in AD patients compared to controls (righ p = 0.003, left p = 0.001). Our results show that thalamic volume loss could be an early sign associated with poorercognitiveperformance in aMCI, preceeding the atrophy of amygdala, global grey and white matter volume loss, and cerebrospinal fluid spaces dilatation.

Keywords: Alzheimer disease; Brain; MR volumetry; Mild cognitive impairment.