Abstract
Background The bilateral temporo-occipital lobes are the usual site of pathology in patients
with prosopagnosia. However, the mechanisms leading to this disorder are not fully
understood. We investigated the neural mechanism of compensation for prosopagnosia
in a patient with focal right posterior temporal lobe encephalitis without prosopagnosia.
Methods A single-photon emission computed tomography (SPECT) scan was performed using a brain-dedicated
32-phototube SPECT scanner and technetium-99m hexamethyl-propylene amine oxime to
measure regional cerebral blood flow (rCBF). A SPECT activation study was performed
in each of two conditions: the familial faces retrieval task and a control task.
Results The SPECT activation study revealed a significant increase in rCBF in the contralateral
temporal lobe (from 72 during control conditions to 99 mL/100 g/min during the activation
paradigm).
Conclusions This finding suggests that the region contralateral to the brain lesion compensates
for the function of face perception. Our result may explain the reason why prosopagnosia
rarely occurs with single, well-circumscribed lesions. The activation pattern seen
in this study may be helpful for understanding the neural mechanism of compensation
for prosopagnosia.
Keywords
prosopagnosia - face perception - compensation - single-photon emission computed tomography
- regional cerebral blood flow
