Corpus callosum functioning in patients with normal pressure hydrocephalus before and after surgery.

OBJECTIVES

Our aim was to evaluate corpus callosum functioning in a group of patients with normal pressure hydrocephalus (NPH) before and after shunting.

METHODS

Left ear-extinction under a dichotic listening task was evaluated in twenty-three patients with NPH, 30 patients with Alzheimer's disease and 30 aged controls.

RESULTS

Patients with NPH had higher levels of left ear extinction than the control and Alzheimer's groups. Sixty-one percent of NPH patients exhibited left ear suppression, compared with 13% of Alzheimer's patients and 17% of controls. Following surgery, NPH patients showed a significant change in the degree of asymmetry in the dichotic listening task.

CONCLUSIONS

Hydrocephalus was associated with left-ear extinction,which diminished after surgery. Our results may indicate reversible functional damage in the corpus callosum.