Cognitive improvement despite minimal arachnoid cyst decompression

Then are relatively few reports that evaluate the cognitive functions of pa tients with arachnoid cysts. Presumably, these 'silent cysts' are regarded as incidental findings with no functional significance. Although postoperat ive clinical improvement is well documented in patients with significant re duction in cystic volume, the current report describes a patient who underw ent cystoperitoneal shunting due to mass effect, with minimal postoperative decompression. Neuropsychological testing indicated significant cognitive improvement in verbal learning, memory, visual-perceptual abilities, constr uctional skills, conceptual shifting, and psychomotor speed after shunt pla cement, despite marginal evidence of decompression. These findings suggest that (1) significant cognitive changes can occur in these patients, despite minimal postoperative regression of the lesion, (2) cognitive measures may provide an alternative, functional index of outcome efficacy and (3) relia nce on traditional outcome measures (i.e. anatomical decompression or resol ution of clinical symptoms) may underestimate the efficacy of surgical inte rvention for these patients. (C) 1998 Elsevier Science B.V. All rights rese rved.