title: Noninvasive detection of alarming intracranial pressure changes by auditory monitoring in early management of brain injury: a prospective invasive versus noninvasive study.
abstract: In brain-injured patients intracranial pressure (ICP) is monitored invasively by a ventricular or intraparenchymal transducer. The procedure requires specific expertise and exposes the patient to complications such as malposition, hemorrhage or infection. As inner-ear fluid compartments are connected to the cerebrospinal fluid space, ICP changes elicit subtle changes in the physiology of the inner ear. Notably, we previously demonstrated that the phase of cochlear microphonic potential (CM) generated by sound stimuli rotates with ICP. The aim of our study was to validate the monitoring of CM as a noninvasive method to follow ICP.
  
  
  
  Non-invasive measure of CM-phase was compared to ICP recorded invasively in a prospective series of patients with acute brain injury managed in a neuro-intensive care unit. The study focused on patients with varying ICP and normal middle-ear function.
  
  
  
  In the 24 patients with less than 4 days of endotracheal ventilation and whose ICP fluctuated (50-hour data), we demonstrated close correlation between CM-phase rotation and ICP (average 1.26 degrees/mmHg). As a binary classifier, CM phase changes of 7-10 degrees signaled 7.5-mmHg ICP increases with a sensitivity of 83% and 19% fallout.
  
  
  
  Reference methods to measure ICP require the surgical placement of a pressure transducer. Noninvasive CM-based monitoring of ICP might be beneficial to early management of brain-injured patients with initially preserved consciousness and to the diagnosis of neurological conditions, whenever invasive monitoring cannot be performed.
  
  
  
  ClinicalTrials.gov NCT01685476 , registered on 30 August 2012.
authors.affiliation: University Clermont Auvergne, Laboratory of Neurosensory Biophysics, UMR INSERM 1107, Clermont-Ferrand, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Giraudet
authors.affiliation: Department of Anesthesiology and Intensive Care, University Hospital, rue Montalembert, Clermont-Ferrand, 63000, France.
authors.forename: François
authors.initials: F
authors.lastname: Longeras
authors.affiliation: Department of Biostatistics, University Hospital, PO Box 69, Clermont-Ferrand, 63003, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Mulliez
authors.affiliation: Department of Clinical Research and Innovation, University Hospital, PO Box 69, Clermont-Ferrand, 63003, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Thalamy
authors.affiliation: Department of Biostatistics, University Hospital, PO Box 69, Clermont-Ferrand, 63003, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.affiliation: University Clermont Auvergne, Laboratory of Neurosensory Biophysics, UMR INSERM 1107, Clermont-Ferrand, France. paul.avan@udamail.fr.|Centre Jean Perrin, 30 rue Montalembert, Clermont-Ferrand, 63000, France. paul.avan@udamail.fr.|School of Medicine, 28 Place Henri Dunant, Clermont-Ferrand, 63000, France. paul.avan@udamail.fr.
authors.forename: Paul
authors.identifier: 0000-0003-1054-1479
authors.initials: P
authors.lastname: Avan
authors.affiliation: University Clermont Auvergne, Laboratory of Neurosensory Biophysics, UMR INSERM 1107, Clermont-Ferrand, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Sakka
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D001930:Brain Injuries / Q000150:complications* / Q000175:diagnosis* / Q000517:prevention & control; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000458:organization & administration; D007427:Intracranial Pressure / Q000502:physiology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D063305:Organ Dysfunction Scores; D011446:Prospective Studies; D012372:ROC Curve
keywords: Cochlear electrophysiology; Intracranial pressure; Noninvasive monitoring