Cough syncope: the possible relation to hydrocephalus ex vacuo.

Pneumoencephalographic data in five male patients with cough syncope were compared to those from age-matched patients with syncope from other causes. The 3rd ventricle width was significantly larger in patients with cough syncope than in the control group (p less than 0.01). Theoretically, the most plausible role of hydrocephalus ex vacuo in cough syncope may be: either it causes increased sensitivity to changes normally encountered during coughing, or--which seems less likely--it may abolish mechanisms normally restraining cough.