Journal of neuroscience methods
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J. Neurosci. Methods · Oct 2011
Clinical TrialModified flow- and oxygen-related autoregulation indices for continuous monitoring of cerebral autoregulation.
Continuous monitoring of brain tissue partial pressure of oxygen (ptiO(2)), thermal-diffusion regional cerebral blood flow (TD-rCBF) and cerebral perfusion pressure (CPP) allows the calculation of flow- and oxygen-related autoregulation indices ORx and FRx. The influence of temporal phase shifts on ORx and FRx due to a delay in the response time of ptiO(2) and TD-rCBF has received little attention. We investigated the impact of phase shifts between changes in CPP and the corresponding ptiO(2) and TD-rCBF responses on the degree of correlation of ORx and FRx. ⋯ ORx and FRx, respectively). These findings suggest that ORx and FRx are subject to temporal latency shifts of ptiO(2) and TD-rCBF in regard to spontaneous CPP fluctuations. Temporal synchronization for the calculation of both ORx and FRx may permit continuous monitoring of these indices with higher sensitivity.
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J. Neurosci. Methods · Oct 2011
Time jitter of somatosensory evoked potentials in recovery from hypoxic-ischemic brain injury.
Impaired neural conductivity shown by delayed latency and reduced amplitude of characteristic peaks in somatosensory evoked potentials (SSEPs), has been used to monitor hypoxic-ischemic brain injury after cardiac arrest (CA). However, rather than characteristic peak deferral and suppression, the time jitter of the peak in SSEP related with time-variant neurological abnormalities is diminished by the commonly used ensemble average method. This paper utilizes the second order blind identification (SOBI) technique to extract characteristic peak information from one trial of SSEPs. ⋯ Our study is the first application using SOBI detecting variance in neural signals like SSEP. N10 latency variance, related with neurophysiological dysfunction, increased after hypoxic-ischemic injury. The SOBI technique is an efficient method in the identification of peak detection and offers a favorable alternative to reveal the neural transmission variation.