Correlation of hippocampal volume and cognitive performances in patients with either mild cognitive impairment or Alzheimer's disease

Abstract

Objective: To evaluate hippocampal volume changes and neuropsychological performances in patients with either amnestic mild cognitive impairment (aMCI) or Alzheimer's disease (AD).

Methods: Thirty-eight AD dementia, 22 aMCI patients, and 20 healthy controls were enrolled. Bilateral hippocampal volume was measured concurrently with mini-mental state examination (MMSE), auditory verbal learning test (AVLT), Boston naming test (BNT), and activities of daily living (ADL) test. Baseline and two additional follow-up examinations were conducted.

Results: Baseline hippocampal volumes were significantly smaller in AD group than that in aMCI and control groups. MMSE, AVLT, ADL, and BNT scores for the AD group were significantly different from that of both aMCI and control groups. Baseline hippocampal volumes were positively correlated with MMSE and AVLT scores in AD and aMCI patients. At follow-up, left hippocampal volume loss was positively correlated with decreased MMSE and AVLT scores both in AD and aMCI groups, while right hippocampal volume loss was positively associated with decreased AVLT performance only in AD group. Increased ADL and decreased BNT scores were positively associated with left hippocampal volume reduction only in the AD group.

Conclusions: Current findings provide evidence of a close relationship between hippocampal volume and cognitive performances in patients with AD and aMCI, both at baseline and over follow-up.

Keywords: Alzheimer's disease; Amnestic mild cognitive impairment; Auditory verbal learning test; Boston naming test; Daily living activities; Hippocampal volume.

Figure 1

The images of hippocampus in sagittal and coronal plants, and the change of normalized hippocampal volumes in different groups over time. A–C: a female patient with amnestic MCI aged 69 years, and d: a female patient with moderate AD of the same age. (A) Coronal view of T1‐MRI, (B) sagittal view of T1‐MRI showing an obliquely oriented 3D‐MRI overlaid in light yellow, (C) an enlarged view of the region around the right hippocampal formation in the coronal slice of the same aMCI subject (2 mm resolution), (D) an enlarged view of the region around the right hippocampal formation in the coronal slice of a patient with moderate AD. The changes in mean normalized left (E) and right hippocampus volumes (F) in AD patients, aMCI patients, and healthy controls during 2 years of follow‐up. Average hippocampal volumes are shown in the bar graph with error bars denoting standard errors of the mean. *P < 0.05, **P < 0.01, compared with healthy controls.

Figure 2

Normalized total hippocampal volumes relative to MMSE scores (A), AVLT score (B) at baseline in mild and moderate AD patients (mAD) and aMCI patients. The scatter plot represents the total normalized hippocampal volumes of all 60 participants (22 aMCI and 38 AD) versus the respective MMSE, AVLT scores.

Figure 3

Relationship between the change in left and right hippocampal volume versus the decline of AVLT score in patients with Alzheimer's disease (A) and amnestic MCI patients (B).

Figure 4

Relationship between the change in left and right hippocampal volume versus increased ADL scores (A) and decreased BNT scores (B) in patients with Alzheimer's disease. Left or right hippocampus for each subject is indicated by marker type.