Fig. 3
From: Transient intracranial pressure elevations (B waves) are associated with sleep apnea
Patient with iNPH with the transition from NREM to REM sleep. The peak in the transient ICP elevations is when respiration resumes, after an apnea, with a ventilatory overshoot marked by increased flow and respiratory movements in the thorax and abdominal RIP. In NREM, in the beginning, repeated transient ICP elevations with a low increase in ICP are seen together with desaturations. During the transition to REM sleep, the transient ICP elevation increases with more significant desaturations and more prolonged apneas. ICP is shown in blue, with red and purple indicating the duration of apneas and respiratory disturbances. Flow: nasal cannula registering flow changes (arbitrary units). RIP, respiratory inductance plethysmography; thorax and abdomen movements (arbitrary units). SaO2 (%), oxyhemoglobin saturation measured on the finger. Heart rate, beats/min. Hypnogram with awake and sleep stages