Changes in electrocorticographic beta frequency components precede spreading depolarization in patients with acute brain injury.
OBJECTIVE
Spreading depolarization (SD) occurs after traumatic brain injury, subarachnoid hemorrhage, malignant hemispheric stroke and intracranial hemorrhage. SD has been associated with secondary brain injury, which can be reduced by ketamine. In this present study frequency bands of electrocorticographic (ECoG) recordings were investigated with regards to SDs.


METHODS
A total of 43 patients after acute brain injury were included in this retrospective and explorative study. Relative delta 0.5-4Hz, theta 4-8Hz, alpha 8-13Hz and beta 13-40Hz bands were analyzed with regards to SD occurrence and analgesic and sedative administration. Higher frequencies, including gamma 40-70Hz, fast gamma 70-100Hz and high frequency oscillations 100-200Hz were analyzed in a subset of patients with a sampling rate of up to 400Hz.


RESULTS
A close association of relative beta frequency and SD was found. Relative beta frequency was suppressed up to two hours prior to SD when compared to hours with no SD. This finding was partially explained by administration of ketamine. Even after removal of all patient data during administration of ketamine, SDs occurred predominantly during times with low relative beta frequency in a patient-independent analysis.


CONCLUSIONS
Suppression of beta frequency by ketamine or without ketamine is associated with low SD counts.


CONCLUSIONS
Alteration of beta frequency might help to predict occurrence of SDs in acutely brain injured patients.
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany. Electronic address: daniel.hertle@med.uni-heidelberg.de.
Daniel N
DN
Hertle
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany.
Marina
M
Heer
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany.
Edgar
E
Santos
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany.
Michael
M
Schöll
Department of Neurology, University of Cologne, Cologne, Germany.
Christina M
CM
Kowoll
Department of Neurology, University of Cologne, Cologne, Germany; Max Planck Institute for Metabolism Research, Cologne, Germany.
Christian
C
Dohmen
Department of Neurology, University of Heidelberg, Heidelberg, Germany.
Jennifer
J
Diedler
Department of Neurology, University of Heidelberg, Heidelberg, Germany.
Roland
R
Veltkamp
Max Planck Institute for Metabolism Research, Cologne, Germany.
Rudolf
R
Graf
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany.
Andreas W
AW
Unterberg
Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany.
Oliver W
OW
Sakowitz
D000700:Analgesics / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D001611:Beta Rhythm; D001930:Brain Injuries / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged
D000700:Analgesics; D006993:Hypnotics and Sedatives; D007649:Ketamine
Beta frequency; EEG; Ketamine; Spreading depolarization