[Multi-infarct dementia clinically simulating dementia of Alzheimer type. A comparison with angular gyrus syndrome]

A 74-year-old right-handed man with multiple cerebral infarction who presented with dementia simulating dementia of Alzheimer type (DAT) is reported. He had been well until April 20, 1987 when he developed transient right hand palsy lasting overnight. Eleven days later, he became confused, disorientated, and amnestic. He was admitted to this hospital on June 8. Physical examination revealed hypertension (170/90mmHg). On neurological examination, his consciousness was clear but he was demented. He showed disorientation, amnesia, and urinary incontinence. His most prominent symptom was disturbance of speech, including fluent aphasia and alexia with agraphia. Additionally, he showed ideomotor apraxia, construction apraxia, right-left agnosia, finger agnosia, and acalculia. On July 9, he had a transient attack of right hemiplegia with confusion. The brain CT scan performed on admission was unremarkable except for cavum septi pellucidum and a small low density area in the right basal ganglia. However, single photon emission computed tomography (SPECT) by 123I-labeled N-isopropyl-p-iodoamphetamine disclosed hypoperfusion of the cerebral blood flow in the border zones of the temporoparietal and frontal lobes on the left. A follow-up brain CT scan taken one month later demonstrated low density in the new areas corresponding to hypoperfusion shown by SPECT. Although the clinical features of the present case resembled those of DAT, dementia in this case was regarded as the result of multiple cerebral infarction since it occurred acutely with mild motor deficits, and brain CT scans and SPECT showed lesions indicating focal cerebral ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)