Link between vasogenic waves of intracranial pressure and cerebrospinal fluid outflow resistance in normal pressure hydrocephalus.

Recent studies on normal pressure hydrocephalus (NPH) have pointed to a possible link between the disturbance in CSF circulation and cerebrovascular factors. We investigated the quantitative relationship between the resistance to CSF outflow (Rcsf) and vasogenic waves of ICP in patients with normal pressure hydrocephalus. Forty-five patients with NPH were investigated by an infusion study. The magnitudes of vasogenic ICP components: pulse, respiratory and slow vasogenic waves were assessed, and compared with Rcsf. Both baseline respiratory and slow waves of ICP were positively correlated with Rcsf. The respiratory wave at baseline was a single independent predictor of Rcsf (r = 0.66, p < 0.0002). All vasogenic components increased significantly during the infusion test. The magnitude of the increase was positively correlated with Rcsf. The vasogenic ICP waves, notably the respiratory wave of ICP, correlate with the resistance to CSF outflow.