A patient with Dyke-Davidoff-Masson Syndrome had a lifelong history of spatial 
disorientation and visual-spatial cognitive defects demonstrated by 
psychological tests. We suggest that the abnormalities of behavior and test 
performance may be related atrophic lesions demonstrated by 
pneumoencephalography and computerized axial tomography. We consider several 
explanations to account for the lack of compensation for these cognitive 
defects.