B-waves are present in patients without intracranial pressure disturbances

Casper Schwartz Riedel*, Isabel Martinez Tejada, Nicolas Hernandez Norager, Lykke Kempfner, Poul Jennum, Marianne Juhler

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Intracranial pressure (ICP) B-waves are defined as short, repeating elevations of ICP of up to 50 mmHg with a frequency of 0.5-2 waves/min. The presence of B-waves in overnight recordings is regarded as a pathological phenomenon. However, the physiology of B-waves is still not fully understood and studies with transcranial Doppler, as a surrogate marker for ICP, have suggested that B-waves could be a normal physiological phenomenon. We present four patients without known structural neurological disease other than a coincidentally found unruptured intracranial aneurysm. One of the patients had experienced well-controlled epilepsy for several years, but was included because ICP under these conditions is unlikely to be abnormal. Following informed consent, all four patients had a telemetric ICP probe implanted during a prophylactic operation with closure of the aneurysm. They underwent overnight ICP monitoring with simultaneous polysomnography (PSG) sleep studies at 8 weeks after the operation. These patients exhibited nocturnal B-waves, but did not have major structural brain lesions. Their ICP values were within the normal range. Nocturnal B-waves occurred in close association with sleep-disordered breathing (SDB) in rapid eye movement (REM) and non-REM sleep stages. SDB during REM sleep was associated with ramp-type B-waves; SDB during non-REM sleep was associated with the sinusoidal type of B-wave. We propose that B-waves are a physiological phenomenon associated with SDB and that the mechanical changes during respiration could have an essential and previously unrecognised role in the generation of B-waves.
Original languageEnglish
Article numbere13214
JournalJournal of Sleep Research
Number of pages10
ISSN1365-2869
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • Hydrocephalus
  • Lundberg B-waves
  • Normal ICP
  • Polysomnography
  • Sleep apnea
  • Sleep-disordered breathing

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