Episodic memory and speed/attention deficits are associated with Alzheimer-typical CSF abnormalities in MCI

Area of Science:

• Neuroscience
• Neurology
• Biomarkers

Background:

• Mild cognitive impairment (MCI) is a precursor to dementia, including Alzheimer's disease (AD).
• Cerebrospinal fluid (CSF) biomarkers like total tau (T-tau) and Abeta42 are crucial for AD diagnosis.
• Understanding neuropsychological differences in MCI based on biomarker status is essential for early detection.

Purpose of the Study:

• To compare the cognitive performance of MCI patients with normal CSF biomarker levels (MCI-norm) against those with abnormal levels (MCI-dev).
• To investigate if specific biomarker profiles (high T-tau, low Abeta42) correlate with distinct neuropsychological deficits in MCI.
• To assess the utility of combining CSF analysis and neuropsychological testing for diagnosing prodromal AD.

Main Methods:

• Recruited 73 MCI-norm, 73 MCI-dev, and 50 normal control subjects.
• Administered a battery of neuropsychological tests assessing speed/attention, memory, visuospatial function, language, and executive function.
• Subclassified MCI-dev into MCI-tau, MCI-Abeta, and MCI-tauAbeta groups for detailed analysis.

Main Results:

• MCI-norm subjects demonstrated superior performance compared to MCI-dev subjects, particularly in speed/attention and episodic memory.
• MCI-tauAbeta subjects showed slightly worse performance than other MCI-dev subgroups.
• MCI-tau and MCI-Abeta groups exhibited similar cognitive performance.

Conclusions:

• The distinct neuropsychological profiles suggest MCI-norm may represent milder forms of MCI or other neurodegenerative conditions.
• While most MCI-dev subjects underperformed compared to MCI-norm, some showed no significant deficits against age norms.
• Integrating CSF biomarker analysis with neuropsychological assessments offers a promising approach for more precise diagnosis of MCI as prodromal AD.