Evoked potential versus behavior to detect minor insult to the spinal cord in a rat model

Reliable outcome measurement is needed for spinal cord injury research to critically evaluate the severity of injury and recovery thereafter. However, such measurements can sometimes be affected by minor, injury to the spinal cord during surgical procedures, including laminectomy. The open-field Basso, Beattie and Bresnahan (BBB) behavior motor scores are subjective and prone to human error. We investigated somatosensory evoked potential (SEP) as an electrophysiological measure to assess the integrity of the spinal cord after injury. In our experiment, control rats with a minor unintentional spinal cord insult during laminectomy showed a decrease in SEP amplitude by 16% to 18%, which recovered in around 7 days. However, there was no change in the BBB scores for the same animals over the same period. This highlights the sensitivity of SEP to minor insult as compared to BBB. These differences may be beneficial in accurate evaluation of the severity and progression of spinal cord injury, and subsequent recovery.

[1]  D. Stolke,et al.  Observations on intraoperative somatosensory evoked potential (SEP) monitoring in the semi-sitting position , 2002, Clinical Neurophysiology.

[2]  G. Dawson,et al.  CEREBRAL RESPONSES TO ELECTRICAL STIMULATION OF PERIPHERAL NERVE IN MAN , 1947, Journal of neurology, neurosurgery, and psychiatry.

[3]  F. Sala,et al.  The Role of Intraoperative Neurophysiology in the Protection or Documentation of Surgically Induced Injury to the Spinal Cord , 2001, Annals of the New York Academy of Sciences.

[4]  Xuan Kong,et al.  Nonlinear changes in brain's response in the event of injury as detected by adaptive coherence estimation of evoked potentials , 1995, IEEE Transactions on Biomedical Engineering.

[5]  Nitish V. Thakor,et al.  Diagnostic instrumentation for neurological injury , 2002 .

[6]  C. Hulsebosch,et al.  Bridging the gap: from discovery to clinical trials in spinal cord injury. , 2000, Journal of neurotrauma.

[7]  V. Dietz,et al.  Prognosis and recovery in ischaemic and traumatic spinal cord injury: clinical and electrophysiological evaluation , 1999, Journal of neurology, neurosurgery, and psychiatry.

[8]  R. Nodar,et al.  Evoked potentials II , 2001, Clinical Neurophysiology.

[9]  B. L. Grundy.  Intraoperative monitoring of sensory-evoked potentials. , 1983, Anesthesiology.

[10]  C. Gyldensted,et al.  Sensory perception in complete spinal cord injury , 2004, Acta neurologica Scandinavica.

[11]  N. Thakor,et al.  Multiresolution wavelet analysis of evoked potentials , 1993, IEEE Transactions on Biomedical Engineering.

[12]  Allan H. Ropper,et al.  Evoked potentials in clinical medicine (second of two parts). , 1982 .

[13]  W. Young,et al.  Secondary injury mechanisms in acute spinal cord injury. , 1993, The Journal of emergency medicine.

[14]  Spinal shock and injury: experimental therapeutic approaches. , 1983 .

[15]  W. Young.  Strategies for the development of new and better pharmacological treatments for acute spinal cord injury. , 1993, Advances in neurology.

[16]  M. Viberg,et al.  Two decades of array signal processing research: the parametric approach , 1996, IEEE Signal Process. Mag..

[17]  M R Nuwer,et al.  Spinal cord monitoring with somatosensory techniques. , 1998, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[18]  Michael S. Beattie,et al.  Graded Histological and Locomotor Outcomes after Spinal Cord Contusion Using the NYU Weight-Drop Device versus Transection , 1996, Experimental Neurology.

[19]  M R Nuwer,et al.  Fundamentals of evoked potentials and common clinical applications today. , 1998, Electroencephalography and clinical neurophysiology.

[20]  D. Basso,et al.  A sensitive and reliable locomotor rating scale for open field testing in rats. , 1995, Journal of neurotrauma.

[21]  R. Minahan,et al.  Intraoperative Neuromonitoring , 2002, The neurologist.

[22]  W. Bunch,et al.  Spinal cord monitoring. , 1983, The Journal of bone and joint surgery. American volume.