Introduction: The parahippocampal gyrus is related with cognitive function such as visuospatial processing and episodic memory. Specially, parahippocampal gyrus plays a role as episodic memory relating to associative memory, source memory, and recollection, and to visuospatial processing related to scene perception, spatial representation, and navigation. Because stroke in parahippocampal gyrus is at low incidence, we report this rare case about memory impairment and visual field defects after left parahippocampal stroke.
Case: A 44-year-old man was admitted to our hospital on March, 2015 due to stupor mental state. Brain MRI revealed a ruptured arteriovenous fistula at left parahippocampal gyrus with surrounding intracranial hemorrhage and intraventricular hemorrhage. In 30 hospital days, after the surgery of coiling and an external ventricular drainage, he was transferred to the department of rehabilitation medicine with episodic memory impairments. At that time, he had normal gait patterns and hand functions.
There was no abnormal neurologic sign in both upper and lower extremities. In cognitive evaluation, retrograde and anterograde amnesia with disorientation were remarkable. He could not remember his home address and categorize shapes with colors. His speech was fluent but confabulation was prominent. On cranial examinations, light reflex and eye movement were preserved, but right homonymous hemianopsia pattern was revealed in visual field test.
The scores of mini-mental state examination were 10, particularly low scores for orientation (0), registration (3), and recall (0). In Frontal Assessment Battery (FAB), the score he obtained was 8, and especially in similarities and fluency, the scores were 0. The result of the Western Aphasia Battery showed an anomic aphasia; especially, he had a severe difficulty in word findings and naming. The Humphrey test revealed right homonymous hemianopsia.
As a result of continuous cognitive rehabilitation and speech therapy, FAB score after one month increased from 8 to 12. Western Aphasia Battery after three months showed that his anomic aphasia state was improved at all items, and in mini-mental state examination after six months, score increased from 10 to 21 at all items except for recall.
Conclusion: Stroke in parahippocampal gyrus is a rare, and it causes distinctive episodic memory, amnesia and visual field defects without hemiplegia.
|
