Fig 3.

The effect of coughing on cardiac cycle–related CSF flow waveforms is seen in a patient with CMI (A) and a healthy participant (B). Left-to-right resting (blue), coughing (red), and immediate postcoughing (green) periods are seen. In the patient with CMI, the CSF flow-pulsation magnitude in the immediate postcoughing period decreases to ∼50% of the resting value before gradually returning to the resting level. In contrast, for the healthy participant, the CSF flow-pulsation magnitude immediately postcoughing is not significantly different compared with that of the resting period. X-axis indicates time in seconds; y-axis, CSF flow rate in milliliters per minute.