Differential patterns of cognitive impairment in patients with aqueductal stenosis and normal pressure hydrocephalus

Methods. We report a preoperative neuropsychological evaluation for ten adult patients with aqueductal stenosis, and compare the results of this group with a normal pressure hydrocephalus group. Findings. For executive functions, aqueductal stenosis patients failed on isolated tests and results were heterogeneous; the normal pressure hydrocephalus group was more impaired, except for tasks which required memory processing. Memory deficits in aqueductal stenosis group are qualitatively dissimilar and more homogeneous and severe, despite the younger age, than in the normal pressure hydrocephalus group. Interpretation. These findings indicate that neuropsychological deficits of patients with aqueductal stenosis are linked with fornix damage and frontal dysfunction. In the normal pressure hydrocephalus group, deficits could be linked with a prefrontal lobe disconnection.