The data about different aneurysm locations given in the present work clearly demonstrate that the quality and the severity of the neuropsycho logical impairments after subarachnoid hemorrhage are in particular dependent on the anatomical location and extent of the bleeding. In addition, the sometimes inevitable temporary clipping of perforating vessels seems to play a significant role with respect to later neuropsychological disturbances. Since modern aneurysm surgery is performed in the acute phase shortly after the hemorrhage, the findings reported in the present work are, according to my...