Abstract
The authors report the results of single photon emission computed tomography (SPECT) using N-isopropyl p-[131I] iodoamphetamine (131I-IMP) in a case of amnestic syndrome following left thalamic infarction.
The patient was a 73-year-old right-handed female. She was confused and disoriented on admission and improved to alertness after several days, but remained amnestic. After more than 2 weeks, neuropsychological tests revealed prominent impairment of short-term verbal memory, of mental arithmetic and of abstract thinkings. CT scan showed a low density area in the anteromedial part of the left thalamus.
The SPECT scan performed 18 days after the onset of the infarction indicated decreased regional cerebral blood flow in the left frontal and temporal cortices as well as in the left thalamus. The follow-up SPECT scan 41 days after the onset revealed significant improvement, showing hypoperfusion only in the left frontal region.
According to the digital subtraction angiography there was no obtruction or stenosis in the carotid artery or in the proximal part of the middle cerebral or of the anterior cerebral artery. These results suggest that the mechanism of “diaschisis” explains the influence of the thalamic lesion on the related cortex and that cortical hypofunction is related to her neuropsychological deficits.
