Structural correlates of mild cognitive impairment.

Area of Science:

• Neuroimaging
• Geriatric Medicine
• Cognitive Neurology

Background:

• Mild cognitive impairment (MCI) represents a transitional stage between normal aging and dementia.
• Understanding the neuroanatomical changes associated with MCI is crucial for early diagnosis and intervention.

Purpose of the Study:

• To investigate the structural brain changes associated with mild cognitive impairment (MCI) in elderly individuals.
• To identify specific brain volumes that predict the transition from normal cognition to MCI and from MCI to dementia.

Main Methods:

• Magnetic resonance imaging (MRI) was used to segment hippocampal volumes (HcV), brain volume (BV), grey matter volume (GMV), and white matter volume (WMV) in 105 elderly subjects.
• Volumes were normalized to intracranial volume (ICV).
• Multiple logistic regression models were employed to analyze the predictive value of volumetric measures for cognitive states.

Main Results:

• Reduced normalized hippocampal volume was significantly associated with MCI compared to normal cognition.
• Global brain volume and normalized intracranial volume significantly predicted dementia versus MCI.
• White matter lesion severity did not differ across cognitive states.
• Normalized HcV and ICV predicted MCI, while normalized BV and ICV predicted dementia.

Conclusions:

• Hippocampal atrophy appears to be a critical factor in the transition from normal cognition to MCI.
• Widespread brain atrophy is associated with the progression from MCI to dementia.
• Brain volume reserve plays a role in both cognitive decline stages.