Our pilot studies suggest that time-varying changes in the fundamental fraction, comprising the lower harmonics, of the somatosensory evoked potential (EO) may be a sensitive early indicator of cerebral hypoxia. Recently we have also acquired experimental evidence that near-infrared (NIR) spectroscopy appears to estimate noninvasively the cerebral oxygen delivery. We now have the unique ability to acquire and analyze, simultaneously and continuously, the time-varying changes in the NIR spectra and the neuroelectric signals (EP and EEG) that should allow us to assess oxygen deprivation and its effect on electrical function under the conditions of acute hypoxic or ischemic injury to the brain.
The aim of the current project is to answer the questions: Is time-frequency mapping (time-varying changes in the harmonics or the spectrum) of neuroelectric signals (EP and EEG) a sensitive approach to detecting acute oxygen deprivation of the brain? Is the fundamental fraction of the neuroelectric signals a specific indicator of cerebral ischemic injury? Do the spectral changes in the neuroelectric signals correlate with oxygen delivery to the brain estimated by NIR spectroscopy? What components (oxy- and deoxy-hemoglobin, cytochrome a,a3) of the NIR spectra are sensitive to hypoxic and ischemic injuries and the associated neuroelectric response? To answer these questions, we propose the following research plan: Develop signal processing methods to obtain time-frequency distributions of EP and EEG signals by adaptive Fourier series modeling and coherence estimation techniques. Conduct experiments to determine: (i) confounding effects on the neuroelectric signals, if any, of various anesthetics, and (ii) the transient response to acute cerebral ischemia generated by temporary occlusion of cerebral arteries. Analyze, and correlate with time-frequency distributions of neuroelectric signals, the time-varying changes in the NIR spectra under conditions of altered oxygen delivery to the brain. Conduct experiments: (i) to monitor cerebral hemoglobin saturation under the conditions of global cerebral hypoxia, and (ii) to selectively evaluate the NIR response in the cytochrome band. In high risk surgeries, as well as in neurological intensive care situations, the brain may experience acute injury due to hypoxia or ischemia. Our research should help establish the noninvasive, continuous, and rapid techniques of neuroelectric signal processing and NIR spectroscopy as tools for monitoring injury to the brain at times of initial dysfunction when the insult may be reversible.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024282-05
Application #
2265149
Study Section
Surgery and Bioengineering Study Section (SB)
Project Start
1986-08-01
Project End
1995-05-31
Budget Start
1994-06-01
Budget End
1995-05-31
Support Year
5
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Biomedical Engineering
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Agrawal, Gracee; Kerr, Candace; Thakor, Nitish V et al. (2010) Characterization of graded multicenter animal spinal cord injury study contusion spinal cord injury using somatosensory-evoked potentials. Spine (Phila Pa 1976) 35:1122-7
Zhang, Weihong; Li, Xin; Zhang, Jiangyang et al. (2009) Landmark-referenced voxel-based analysis of diffusion tensor images of the brainstem white matter tracts: application in patients with middle cerebral artery stroke. Neuroimage 44:906-13
Ziai, Wendy C; Torbey, Michel T; Naff, Neal J et al. (2009) Frequency of sustained intracranial pressure elevation during treatment of severe intraventricular hemorrhage. Cerebrovasc Dis 27:403-10
Wheaton, Lewis A; Villagra, Federico; Hanley, Daniel F et al. (2009) Reliability of TMS motor evoked potentials in quadriceps of subjects with chronic hemiparesis after stroke. J Neurol Sci 276:115-7
Luft, Andreas R; Macko, Richard F; Forrester, Larry W et al. (2008) Treadmill exercise activates subcortical neural networks and improves walking after stroke: a randomized controlled trial. Stroke 39:3341-50
Schreckinger, Matthew; Geocadin, Romergryko G; Savonenko, Alena et al. (2007) Long-lasting cognitive injury in rats with apparent full gross neurological recovery after short-term cardiac arrest. Resuscitation 75:105-13
Carhuapoma, J Ricardo; Wang, Paul; Beauchamp, Norman J et al. (2005) Diffusion-perfusion MR evaluation and spectroscopy before and after surgical therapy for intracerebral hemorrhage. Neurocrit Care 2:23-7
Luft, Andreas R; Forrester, Larry; Macko, Richard F et al. (2005) Brain activation of lower extremity movement in chronically impaired stroke survivors. Neuroimage 26:184-94
Al-Nashash, Hasan; Al-Assaf, Yousef; Paul, Joseph et al. (2004) EEG signal modeling using adaptive Markov process amplitude. IEEE Trans Biomed Eng 51:744-51
Buitrago, Manuel M; Luft, Andreas R; Thakor, Nitish V et al. (2004) Effects of somatosensory electrical stimulation on neuronal injury after global hypoxia-ischemia. Exp Brain Res 158:336-44

Showing the most recent 10 out of 53 publications