Temporal and spatial summation in generation of somatosensory evoked potential

1969 ◽  
Vol 27 (7) ◽  
pp. 688
Keyword(s):  
Evoked Potential ◽  
Spatial Summation ◽  
Somatosensory Evoked Potential ◽  
Temporal And Spatial

scholarly journals Effect of high rate rTMS on somatosensory evoked potential in migraine

Cephalalgia ◽  
2016 ◽  
Vol 37 (13) ◽  
pp. 1222-1230 ◽  
Author(s):  
Jayantee Kalita ◽  
Sanjeev K Bhoi ◽  
Usha K Misra
Keyword(s):  
Cortical Neurons ◽  
Evoked Potential ◽  
Therapeutic Response ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Hot Spot ◽  
High Rate ◽  
Somatosensory Evoked Potential ◽  
Sham Stimulation ◽  
The Third ◽  
Abductor Digiti Minimi

Background Sensitization and impaired habituation of cortical neurons have been reported in migraineurs. Repetitive transcranial magnetic stimulation (rTMS) may change these phenomena and be the basis of therapeutic response. We report the effect of 10 Hz rTMS on sensitization and habituation of median somatosensory evoked potential (SEP) in migraineurs, and correlate these changes with clinical response. Methods Migraineurs having four or more episodes of headache per month were included and their clinical details were noted. Three sessions of 10 Hz rTMS, 600 pulses in 412.4 seconds were delivered on the left frontal cortex corresponding to the hot spot of right abductor digiti minimi, on alternate days. Median SEP was done before and 30 minutes after the third rTMS session. Sensitization (block I N20 amplitude) and impaired habituation (if N20 amplitude of block 2 or 3 were not suppressed compared to block I) were noted. The reduction in frequency and severity of headache in the next month were noted and correlated with SEP changes. Results Ninety-four migraineurs were included; 56 received true rTMS and 38 sham stimulation. Following stimulation, reduction in N20 amplitude of block 1 correlated with a reduction in frequency and severity of headache at one month. The impaired habituation significantly improved in the true rTMS group compared to sham stimulation, and correlated with a reduction in the severity of headache but not with frequency. Conclusion In migraineurs, 10 Hz rTMS improves habituation and may be the biological basis of headache relief.

A Prospective Analysis of Neuromonitoring for Confirmation of Lead Placement in Dorsal Root Ganglion Stimulation

2017 ◽  
Vol 14 (6) ◽  
pp. 654-660 ◽  
Author(s):  
Steven M Falowski ◽  
Andreas Dianna
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Evoked Potential ◽  
Somatosensory Evoked Potential ◽  
Prospective Analysis ◽  
Awake Patient ◽  
Chronic Neuropathic Pain ◽  
Lead Placement

Abstract BACKGROUND Dorsal root ganglion stimulation is a neuromodulation therapy used for chronic neuropathic pain. Typically, patients are awakened intraoperatively to confirm adequate placement. OBJECTIVE To determine whether neuromonitoring can confirm placement in an asleep patient. METHODS This is a prospective analysis of 12 leads placed in 6 patients. Lead confirmation was confirmed by awake intraoperative testing, as well as asleep testing utilizing neuromonitoring. Patients were used as their own control. Sensory and motor thresholds for each patient with awake and asleep neuromonitoring testing were recorded. Intraoperative impedance and postoperative programming were also recorded. RESULTS In each patient, paresthesias were generated prior to motor contractions in the awake patient. For each patient, somatosensory evoked potential responses were present after lowering below the dropout threshold of electromyogram responses with neuromonitoring. There were varying degrees of separation in the thresholds that did not appear to be consistent across level or diagnosis. Smaller degrees of separation between thresholds during awake testing also held true in the asleep patient. This was further confirmed with postoperative programming. Impedances did not alter the separation in thresholds or amount of stimulation required for responses. One patient was combative during awake testing, and therefore motor thresholds were not obtained. This same patient was determined to have a ventral placement, confirmed with awake and asleep neuromonitoring testing. CONCLUSION This series demonstrates that the proposed neuromonitoring protocol can be used in an asleep patient to assure proper positioning of the dorsal root ganglion electrode in the dorsal foramen by generating somatosensory evoked potential responses in the absence of electromyogram responses.

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