Fig. 2
A. Prototype cranial accelerometer. Each of 6 highly sensitive
accelerometers is held in place by an adjustable head holder. Signals are
converted to digital and sampled at high frequency.1
B.C. Waterfall plot with warmer colors representing higher amplitude of
FFT waveforms, showing ‘‘banding’’ around 200 Hz. 1
Cerebral accelerometry is a newly introduced technology that
measures the motion of flowing blood within the brain at
the scalp surface. Cerebral accelerometry can reveal a ‘‘cranial
bruit’’ from cerebral vasospasm. One prospective study utilized
this technology to detect cerebral vasospasm in a TCD-defined
cerebral vasospasm population to determine accuracy of this new
technique compared to TCD as the gold standard.1
Skull accelerometry was performed using an array of 6 highly
sensitive accelerometers placed in contact with the scalp. Paired
transcranial Doppler (TCD) recordings and accelerometry
epochs were obtained in consecutive patients with subarachnoid
hemorrhage undergoing TCD recordings for surveillance
of cerebral vasospasm. The energy of rectified acceleration
measurements within systolic and diastolic bands of the cardiac
cycle were measured and correlated with TCD-defined spasm.
A model predicting cerebral vasospasm was developed from
analysis of 14 unblinded subjects with varying degrees of cerebral
vasospasm as detected by TCD. They then recorded from 58
subjects obtaining 125-paired recordings of accelerometry and
TCD to test this model in a blinded analysis. Accelerometry
detection of any spasm versus non-spasm correlated with TCDdefined
vasospasm (P<0.001). The model was 81 % sensitive for
detecting any cerebral vasospasm in patients, while the negative
predictive value was 61 %. This tool holds promise in the Neuro-
ICU environment to detect as well as reject cerebral vasospasm as
the cause of neurological deficits in subarachnoid hemorrhage.
References:
1. Smith WS, Browne JL, Ko NU. Cranial Accelerometry Can
Detect Cerebral Vasospasm Caused by Subarachnoid Hemorrhage.
Neurocritical Care 2015;23(3):364-9. doi: 10.1007/s12028-015-
0118-9 published Online First: 2015/03/13
2. Rots ML, van Putten MJaM, Hoedemaekers CWE, et al.
Continuous EEG Monitoring for Early Detection of Delayed
Cerebral Ischemia in Subarachnoid Hemorrhage: A Pilot Study.
Neurocritical Care 2016;24(2):207-16. doi: 10.1007/s12028-015-
0205-y
3. Gollwitzer S, Groemer T, Rampp S, et al. Early prediction of
delayed cerebral ischemia in subarachnoid hemorrhage based
on quantitative EEG: A prospective study in adults. Clinical
Neurophysiology: Official Journal of the International Federation of
Clinical Neurophysiology 2015;126(8):1514-23. doi: 10.1016/j.
clinph.2014.10.215
4. Claassen J, Hirsch LJ, Kreiter KT, et al. Quantitative continuous
EEG for detecting delayed cerebral ischemia in patients with poorgrade
subarachnoid hemorrhage. Clinical Neurophysiology: Official
Journal of the International Federation of Clinical Neurophysiology
2004;115(12):2699-710. doi: 10.1016/j.clinph.2004.06.017
5. Garry PS, Rowland MJ, Ezra M, et al. Electroencephalographic
Response to Sodium Nitrite May Predict Delayed Cerebral
Ischemia After Severe Subarachnoid Hemorrhage. Critical
care medicine 2016;44(11):e1067-e73. doi: 10.1097/
ccm.0000000000001950 published Online First: 2016/10/19
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