[Memory impairment due to circumscribed infarct at the left dorsolateral prefrontal lobe].
A 65-year-old man experienced an embolism at the left dorsolateral prefrontal region of the brain (the inferior frontal gyrus and a part of the middle frontal gyrus). He was a known case of diabetes mellitus and atrial fibrillation. On evaluation his Mini-Mental State Examination (MMSE) score was 26, indicating the absence of dementia. His chief complaint was episodic memory impairment. On the Wechsler Memory Scale-Revised (WMS-R), he had lower scores for general memory, visual memory and verbal memory. In particular, his verbal memory was markedly impaired compared to visual memory. Tests performed to assess working memory, such as evaluation on the WMS-R for attention/concentration in WMS-R and both parts A and B of the trail making test, revealed normal findings; this indicated that the patient had normal working memory. However, he complained of forgettingess of either phone numbers or routes, and this suggested the impairment of working memory in his daily life. In summary, he suffered from either episodic verbal memory or working memory impairment. His executive function test revealed a slight disturbance of set-exchange on the Wisconsin Card Sorting Test-Keio version. Such a case of memory impairment caused by a lesion in the left dorsolateral prefrontal lobe has rarely been reported.
Yoshida
Motoaki
M
Department of Neurology, Health Science University, Minamitsuru-gun, Yamanashi 401 0380, Japan.
Kuroda
Hirohisa
H
D000368:Aged; D001921:Brain / Q000473:pathology; D002544:Cerebral Infarction / Q000150:complications*; D005625:Frontal Lobe / Q000098:blood supply*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology*; D015899:Tomography, Emission-Computed, Single-Photon; D014888:Wechsler Scales