Intraoperative monitoring study of ipsilateral motor evoked potentials in scoliosis surgery

Ipsilateral motor evoked potentials (MEPs) in spinal cord surgery intraoperative monitoring is not well studied. We show that ipsilateral MEPs have significantly larger amplitudes and were elicited with lower stimulation intensities than contralateral MEPs. The possible underlying mechanisms are discussed based on current knowledge of corticospinal pathways. Ipsilateral MEPs may provide additional information on the integrity of descending motor tracts during spinal surgery monitoring

Clinical and physiological effects of transcranial electrical stimulation position on motor evoked potentials in scoliosis surgery

<p>Abstract</p> <p>Background</p> <p>During intraoperative monitoring for scoliosis surgery, we have previously elicited ipsilateral and contralateral motor evoked potentials (MEP) with cross scalp stimulation. Ipsilateral MEPs, which may have comprised summation of early ipsilaterally conducted components and transcallosally or deep white matter stimulated components, can show larger amplitudes than those derived purely from contralateral motor cortex stimulation. We tested this hypothesis using two stimulating positions. We compared intraoperative MEPs in 14 neurologically normal subjects undergoing scoliosis surgery using total intravenous anesthetic regimens.</p> <p>Methods</p> <p>Trancranial electrical stimulation was applied with both cross scalp (C3C4 or C4C3) or midline (C3Cz or C4Cz) positions. The latter was assumed to be more focal and result in little transcallosal/deep white matter stimulation. A train of 5 square wave stimuli 0.5 ms in duration at up to 200 mA was delivered with 4 ms (250 Hz) interstimulus intervals. Averaged supramaximal MEPs were obtained from the tibialis anterior bilaterally.</p> <p>Results</p> <p>The cross scalp stimulating position resulted in supramaximal MEPs that were of significantly higher amplitude, shorter latency and required lower stimulating intensity to elicit overall (Wilcoxon Signed Rank test, p < 0.05 for all), as compared to the midline stimulating position. However, no significant differences were found for all 3 parameters comparing ipsilaterally and contralaterally recorded MEPs (p > 0.05 for all), seen for both stimulating positions individually.</p> <p>Conclusions</p> <p>Our findings suggest that cross scalp stimulation resulted in MEPs obtained ipsilaterally and contralaterally which may be contributed to by summation of ipsilateral and simultaneous transcallosally or deep white matter conducted stimulation of the opposite motor cortex. Use of this stimulating position is advocated to elicit MEPs under operative circumstances where anesthetic agents may cause suppression of cortical and spinal excitability. Although less focal in nature, cross scalp stimulation would be most suitable for infratentorial or spinal surgery, in contrast to supratentorial neurosurgical procedures.</p

Increased cortical excitability in human deception

NeuroReport1471021-102

Case-control study of anxiety symptoms in hemifacial spasm

10.1002/mds.21150Movement Disorders21122145-214

Comparing LRRK2 Gly2385Arg Carriers with noncarriers [4]

10.1002/mds.21381Movement Disorders225749-75

Reflex vasoconstrictor responses of the healthy human fingertip skin. Normal range, repeatability, and influencing factors

10.1016/j.mvr.2004.09.001Microvascular Research691-2101-105MIVR

Validation of a short disease specific quality of life scale for hemifacial spasm: correlation with SF-36

Background: A short, practical, and validated quality of life (QoL) scale for hemifacial spasm (HFS) is not currently available. Objectives: To examine the reliability and validity of a short self-rating scale (HFS-7) by comparing HFS patients with healthy controls. We also evaluated the correlation of HFS-7 with the physical and mental domains of SF-36, a generic QoL scale. Methods: Seven self-rating items (HFS-7) were administered to HFS patients and healthy controls. In addition, HFS patients answered the SF-36 questionnaire. The validity and reliability of HFS-7 were analysed and correlation between HFS-7 and SF-36 examined. Results: A total of 178 subjects were enrolled in the study, including 85 HFS patients with mean age of 54.8 (SD 11.0) years, of whom 52 (61.2%) were women, and 93 controls with mean age of 51.4 (SD 10.0) years, of whom 59 (63.4%) were women. The test-retest intraclass correlation coefficient for the seven items was between 0.75 and 0.90 and Cronbach's coefficient of reliability for the HFS-7 scale was 0.88. Every item in HFS-7 discriminated between disease and controls (p<0.0001). The HFS-7 summary index correlated with the SF-36 summary score (Spearman's correlation r = –0.28, p = 0.009), in particular the mental health summary score (r = –0.416, p<0.0001) and the emotional domain (r = –0.466, p<0.00001). Conclusion: HFS-7 could prove useful as a simple clinical tool to assess and monitor QoL measures in HFS patients

Cortical excitability changes associated with musical tasks: A transcranial magnetic stimulation study in humans

10.1016/j.neulet.2003.08.031Neuroscience Letters352285-88NELE