Regional hippocampal atrophy in multiple sclerosis

Area of Science:

• Neuroimaging
• Neurology
• Neurodegeneration

Background:

• Gray matter atrophy occurs early in multiple sclerosis (MS), independent of white matter lesions.
• The hippocampus, crucial for memory, is vulnerable to inflammation and insults in MS.

Purpose of the Study:

• To investigate hippocampal volume changes in relapsing remitting MS (RRMS) and secondary progressive MS (SPMS) patients using high-resolution MRI.
• To correlate hippocampal atrophy with cognitive function and lesion load.

Main Methods:

• High-resolution 3.0 T MRI was used to measure hippocampal volumes in RRMS, SPMS, and control groups.
• Subregional hippocampal analysis (cornu ammonis regions) was performed.
• Cognitive tests, including word-list learning and Paced Auditory Serial Addition Task (PASAT), were administered.

Main Results:

• Both RRMS and SPMS patients exhibited significant hippocampal atrophy, exceeding global brain atrophy.
• Selective volume loss was observed in the cornu ammonis (CA) 1 region in RRMS, progressing to other CA regions in SPMS.
• Hippocampal atrophy correlated with impaired memory encoding (word-list learning) but not information processing speed (PASAT).
• Hippocampal atrophy was not correlated with T2-lesion volumes.

Conclusions:

• Progressive and selective hippocampal atrophy, initially in the CA1 subregion, is a feature of MS.
• This atrophy is associated with memory encoding and retrieval deficits.
• Understanding the mechanisms of hippocampal vulnerability may reveal targets for neuroprotective therapies in MS.