Ipsilateral hippocampal atrophy is associated with long-term memory dysfunction after ischemic stroke in young adults

Area of Science:

• Neurology
• Neuroscience
• Cognitive Science

Background:

• Memory impairment after stroke in young adults is not well understood.
• Unlike older adults, young stroke survivors typically lack neurodegenerative diseases like amyloid pathology.
• Stroke infarction may cause secondary neurodegeneration in distant brain regions.

Purpose of the Study:

• To investigate the relationship between long-term memory performance and hippocampal volume in young adults following their first ischemic stroke.
• To determine if stroke itself leads to remote hippocampal injury and subsequent memory dysfunction.

Main Methods:

• Studied 173 first-ever ischemic stroke patients (aged 18-50) and 87 stroke-free controls.
• Assessed episodic memory using the Rey Auditory Verbal Learning Test and Rey Complex Figure.
• Measured hippocampal volume using FSL-FIRST software with manual correction.

Main Results:

• Patients exhibited smaller ipsilateral hippocampal volumes post-stroke (left: 5.4%, right: 7.7%) compared to controls, averaging 10 years after stroke.
• Larger stroke volume correlated with smaller ipsilateral hippocampal volume.
• Longer follow-up duration was associated with reduced hippocampal volume, particularly after left-hemispheric strokes.

Conclusions:

• Ischemic stroke in young adults is linked to remote hippocampal injury.
• This hippocampal volume loss may lower the threshold for cognitive impairment or dementia later in life.
• Stroke-induced secondary neurodegeneration is a significant factor in long-term cognitive outcomes for young adults.