Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor.
BACKGROUND
Current assessment of sport-related concussion involves a multifaceted approach including neurocognitive testing, symptom report, and balance assessment. Lacking from this paradigm is a truly objective measure of the physiological changes associated with concussion.


METHODS
A device called the Brain Acoustic Monitor (BAM) has been developed to detect cerebral blood flow changes resulting from traumatic brain injury by amplification and comparison of sound waves created by cerebral arteries and a reference artery. The reliability of its measures is unknown, limiting its use in day-to-day assessment of concussion. Therefore, the purpose of this study was to determine the inter- and intra-rater reliability associated with BAM measures. Twenty healthy participants were assessed on two occasions, separated by at least 24h. Ten subjects were measured during the initial session by two assessors for inter-rater comparisons. Measures of positive-to-negative signal deflection (ratio) and frequency divergence from a reference arterial signal (divergence) were calculated and analyzed using Intra-class correlations (2,1).


RESULTS
Inter-rater reliability ranged from poor to excellent, showing greater reliability in right brain vs. left brain measures. Intra-rater reliability was similar with a range of poor to good.


METHODS
These findings are comparable to the reliability of current methods of concussion assessment, specifically neurocognitive testing.


CONCLUSIONS
All BAM values obtained in our healthy subjects were well below scores that would reflect potential head injury. These findings emphasize the potential usefulness of this device in future research concerning serial measurement of cerebral perfusion pressure changes associated with sport concussion.
University of Virginia, Exercise and Sport Injury Laboratory, 210 Emmet Street South, PO Box 400407, Charlottesville, VA 22901, USA. Electronic address: ss9qb@virginia.edu.
Shellie
S
Acocello
Donna K
DK
Broshek
Susan
S
Saliba
D001921:Brain / Q000098:blood supply*; D001924:Brain Concussion / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D064926:Neurophysiological Monitoring / Q000295:instrumentation* / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
Assessment; Concussion; Mild head injury; mTBI