Reduced medial temporal lobe functionality in stroke patients: a functional magnetic resonance imaging study.
Stroke is a leading cause of disability, not only because of motor limitations, but also because of the frequent occurrence of post-stroke cognitive impairment. This is illustrated by the fact that the risk of post-stroke dementia is reportedly higher than a recurrent stroke. The loss of subcortical and cortical functions in the post-stroke cognitive dysfunction spectrum is usually well explained by the size and location of the infarction. However, this does not apply for post-stroke memory dysfunction (especially episodic memory dysfunction), as there is almost never an infarction in the medial temporal lobe. Involvement of the medial temporal lobe in post-stroke memory dysfunction seems likely since this structure is essential for memory encoding and retrieval. For a proper episodic memory function, the medial temporal lobe depends on intact connections with virtually the whole brain. Disconnection from other brain areas due to the infarction could lead to a reduced medial temporal lobe function and the attendant reduced episodic memory function. We investigated medial temporal lobe functionality in 28 'first-ever' stroke patients and 22 healthy controls with the aid of functional magnetic resonance imaging. Stroke patients with a reduced episodic memory function 6-8 weeks after infarction had reduced medial temporal lobe functionality. Post-stroke reduced medial temporal lobe functionality may be responsible for the frequent observation of impaired post-stroke episodic memory function. Insight into this mechanism could be helpful in identifying which stroke patients may be at increased risk for developing post-stroke dementia and those who could benefit from early cognitive rehabilitation.
Snaphaan
Liselore
L
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Medical Centre, Radboud University Nijmegen, The Netherlands.
Rijpkema
Mark
M
van Uden
Inge
I
Fernández
Guillén
G
de Leeuw
Frank-Erik
FE
D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000503:physiopathology; D008875:Middle Aged; D009483:Neuropsychological Tests; D020521:Stroke / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D013702:Temporal Lobe / Q000503:physiopathology*