TY - JOUR

T1 - B-waves are present in patients without intracranial pressure disturbances

AU - Riedel, Casper Schwartz

AU - Martinez-Tejada, Isabel

AU - Norager, Nicolas Hernandez

AU - Kempfner, Lykke

AU - Jennum, Poul

AU - Juhler, Marianne

PY - 2021

Y1 - 2021

N2 - 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.

AB - 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.

KW - hydrocephalus

KW - Lundberg B-waves

KW - normal ICP

KW - polysomnography

KW - sleep apnea

KW - sleep-disordered breathing

U2 - 10.1111/jsr.13214

DO - 10.1111/jsr.13214

M3 - Journal article

C2 - 33155362

AN - SCOPUS:85096683324

VL - 30

JO - Journal of Sleep Research

JF - Journal of Sleep Research

SN - 1365-2869

IS - 4

M1 - e13214

ER -