Finally, our data demonstrate that the presence and the severity of abnormal pressure pulsations are related to clinical manifestations of ICH in patients with chronic headache. Our data highlight the effectiveness of lumbar CSF pressure monitoring via a spinal puncture needle over a 1-h period for detecting high CSF pressure in patients with chronic headache with no papilledema or sixth nerve palsy. They also suggest that CSF pressure is a continuous, not discrete, variable.