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Platform Session – Evoked potentials & NIOM: Somatosensory evoked potentials and central motor conduction times help predict outcomes from deep brain stimulation (DBS) in children with dystonia
Abstracts / Clinical Neurophysiology 129 (2018) e223–e233
maintenance AEDs does not decrease it. Mapping in proximity to poorly defined lesions carries a significantly higher risk for triggering seizures. doi:10.1016/j.clinph.2018.04.588
Platform Session – Evoked potentials & NIOM: Prognostic value of intra- and extra-operative lateral spread responses in microvascular decompression surgeries of hemifacial spasm— Jongsuk Choi *, Sung Un Kim, Yong Chul Kwon, Je-Young Shin, Suk-Won Ahn, Kyung Seok Park (Republic of Korea) ⇑
Platform Session – Evoked potentials & NIOM: Somatosensory evoked potentials and central motor conduction times help predict outcomes from deep brain stimulation (DBS) in children with dystonia—Verity M. McClelland *, Doreen Fialho, Denise Flexney-Briscoe, Graham Holder, Markus Elze, Hortensia Gimeno, Ata Siddiqui, Kerry Mills, Richard Selway, Jean-Pierre Lin (United Kingdom) ⇑
Presenting author.
Introduction: DBS of the Globus pallidus internus has dramatic benefits in primary dystonia. Responsiveness of secondary dystonia is more modest and varies markedly between individuals. Predictive markers are lacking and the underlying pathophysiology of secondary dystonia is poorly understood. We report Somatosensory Evoked Potentials (SEPs) and Central Motor Conduction Times (CMCT) in children with dystonia and test the hypothesis that these parameters relate to outcome from DBS. Methods: Data were obtained from 180 consecutive children with dystonia undergoing multidisciplinary DBS assessment (mean age 10 years; range 2.5–19). Transcranial Magnetic Stimulation was applied to motor cortex and Motor Evoked Potentials were recorded in the activated contralateral hand and foot muscles. CMCT to each limb was calculated using the F-wave method. Median nerve SEPs were recorded over ipsilateral Erb’s point, 7th and 2nd cervical vertebrae and contralateral centroparietal scalp. Posterior tibial nerve SEPs were recorded over ipsilateral popliteal fossa and midline centroparietal scalp. A mid-frontal reference was used. Electrical stimuli of 0.2millisecond duration were applied at 2.1 Hz, just above motor threshold. SEPs were classed as abnormal if delayed, absent or of abnormal waveform. Technically unsatisfactory recordings were excluded. Structural abnormalities were assessed with cranial MRI. Outcome from DBS at 1 year was assessed as percentage improvement in Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS-m). Results: Of the 146 children with satisfactory CMCT data, 28(19%) had an abnormal CMCT to at least one limb. Of the 100 children with satisfactory cortical SEP data, 47 had at least one abnormal cortical potential. Abnormal CMCTs and SEPs were both observed more frequently in secondary than primary/primary plus dystonia (CMCT: 22% vs. 9%, SEP: 53% vs. 24%). Of children proceeding to DBS, improvement in BFMDRS-m was greater in those with normal (n = 78) than abnormal CMCT (n = 11) (Mann Whitney p = 0.002) and in those with normal (n = 35) versus abnormal SEPs (n = 16) (Mann Whitney p = 0.001). On sub-group analysis, these relationships were preserved regardless of aetiology (primary versus secondary) or cranial imaging (normal vs abnormal MRI). Conclusion: CMCTs and SEPs provide objective evidence of motor and sensory pathway dysfunction in children with dystonia. Abnormal CMCTs and SEPs relate to DBS outcome, therefore contributing to patient selection and counselling of families about potential benefit from neuromodulation. doi:10.1016/j.clinph.2018.04.589
e229
Presenting author.
Introduction: Lateral spread response is observed in patients with hemifacial spasm (HFS) by eletrically stimulating one branch of the facial nerve activates facial muscles innervated by other branches of the facial nerve by electromyography. Nowadays, LSR has been used to confirm adequacy of microvascular decompression (MVD). The aim of this study was to evaluate the prognostic value of intra- and extra-operative lateral spread response (LSR) in microvascular decompression (MVD) surgeries of hemifacial spasm (HFS). Methods: A retrospective review was made of consecutive 25 patients who underwent continuous intraoperative monitoring during MVD. LSR and continuous electromyography were monitored in the frontalis, orbicularis oculi, and mentalis muscles. Extra-operative LSRs were done pre- and postoperatively. The neurological status of each patient was evaluated before and immediately after surgery, on discharge, and at 3 months after surgery. Results: Intraoperative neurophysiologic monitorings were successful in all patients. On admission and discharge, extra-operative LSR recordings were done in 23 patients. Twenty-one patients completed a follow- up evaluation. In 17, the intraoperative LSRs disappeared during surgery. In 5, the intraoperative LSRs were absent before incision and remained the same until the end of surgery. In one, the intraoperative LSR were present before incision and persisted despite MVD. For extra-operative LSRs, they disappeared after surgery in 10. LSRs were absent before and after surgery in 7. In 6, LSRs were present before surgery and persisted after MVD. For 5, intraoperative LSRs disappeared during surgery but extra-operative LSRs were persisted despite adequate MVD. In one, intraoperative LSRs were absent before incision and remained during the surgery. But extra-operative LSRs were present before surgery and disappeared after adequate MVD. Statistically, the extra-operative disappearance of LSR was correlated with the HFS relief in 4 days after surgery and the 3-month follow up period. (P = 0.049 and 0.044). However, the intaroperative disapearance of LSR was not. Conclusion: In our study, extra-operative LSR monitoring may be more predictive of the surgical outcome compared with intraoperative LSR during the 3-month follow up. doi:10.1016/j.clinph.2018.04.590
Platform Session – Evoked potentials & NIOM: Percutaneous threshold of facial nerve stimulation predicts facial canal dehiscence—Richard Vogel *, Patricia Johnson, Taha Mur, Pamela Roehm (USA) ⇑
Presenting author.
Introduction: Iatrogenic facial nerve injury is one of the most feared complications of otologic surgery. While the incidence of facial nerve (FN) injury is low, dehiscence of the fallopian canal increases the FN’s vulnerability to accidental injury. Highresolution computed tomography (HRCT) of the temporal bone is used preoperatively to assess middle ear and mastoid anatomy;
maintenance AEDs does not decrease it. Mapping in proximity to poorly defined lesions carries a significantly higher risk for triggering seizures. doi:10.1016/j.clinph.2018.04.588
Platform Session – Evoked potentials & NIOM: Prognostic value of intra- and extra-operative lateral spread responses in microvascular decompression surgeries of hemifacial spasm— Jongsuk Choi *, Sung Un Kim, Yong Chul Kwon, Je-Young Shin, Suk-Won Ahn, Kyung Seok Park (Republic of Korea) ⇑
Platform Session – Evoked potentials & NIOM: Somatosensory evoked potentials and central motor conduction times help predict outcomes from deep brain stimulation (DBS) in children with dystonia—Verity M. McClelland *, Doreen Fialho, Denise Flexney-Briscoe, Graham Holder, Markus Elze, Hortensia Gimeno, Ata Siddiqui, Kerry Mills, Richard Selway, Jean-Pierre Lin (United Kingdom) ⇑
Presenting author.
Introduction: DBS of the Globus pallidus internus has dramatic benefits in primary dystonia. Responsiveness of secondary dystonia is more modest and varies markedly between individuals. Predictive markers are lacking and the underlying pathophysiology of secondary dystonia is poorly understood. We report Somatosensory Evoked Potentials (SEPs) and Central Motor Conduction Times (CMCT) in children with dystonia and test the hypothesis that these parameters relate to outcome from DBS. Methods: Data were obtained from 180 consecutive children with dystonia undergoing multidisciplinary DBS assessment (mean age 10 years; range 2.5–19). Transcranial Magnetic Stimulation was applied to motor cortex and Motor Evoked Potentials were recorded in the activated contralateral hand and foot muscles. CMCT to each limb was calculated using the F-wave method. Median nerve SEPs were recorded over ipsilateral Erb’s point, 7th and 2nd cervical vertebrae and contralateral centroparietal scalp. Posterior tibial nerve SEPs were recorded over ipsilateral popliteal fossa and midline centroparietal scalp. A mid-frontal reference was used. Electrical stimuli of 0.2millisecond duration were applied at 2.1 Hz, just above motor threshold. SEPs were classed as abnormal if delayed, absent or of abnormal waveform. Technically unsatisfactory recordings were excluded. Structural abnormalities were assessed with cranial MRI. Outcome from DBS at 1 year was assessed as percentage improvement in Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS-m). Results: Of the 146 children with satisfactory CMCT data, 28(19%) had an abnormal CMCT to at least one limb. Of the 100 children with satisfactory cortical SEP data, 47 had at least one abnormal cortical potential. Abnormal CMCTs and SEPs were both observed more frequently in secondary than primary/primary plus dystonia (CMCT: 22% vs. 9%, SEP: 53% vs. 24%). Of children proceeding to DBS, improvement in BFMDRS-m was greater in those with normal (n = 78) than abnormal CMCT (n = 11) (Mann Whitney p = 0.002) and in those with normal (n = 35) versus abnormal SEPs (n = 16) (Mann Whitney p = 0.001). On sub-group analysis, these relationships were preserved regardless of aetiology (primary versus secondary) or cranial imaging (normal vs abnormal MRI). Conclusion: CMCTs and SEPs provide objective evidence of motor and sensory pathway dysfunction in children with dystonia. Abnormal CMCTs and SEPs relate to DBS outcome, therefore contributing to patient selection and counselling of families about potential benefit from neuromodulation. doi:10.1016/j.clinph.2018.04.589
e229
Presenting author.
Introduction: Lateral spread response is observed in patients with hemifacial spasm (HFS) by eletrically stimulating one branch of the facial nerve activates facial muscles innervated by other branches of the facial nerve by electromyography. Nowadays, LSR has been used to confirm adequacy of microvascular decompression (MVD). The aim of this study was to evaluate the prognostic value of intra- and extra-operative lateral spread response (LSR) in microvascular decompression (MVD) surgeries of hemifacial spasm (HFS). Methods: A retrospective review was made of consecutive 25 patients who underwent continuous intraoperative monitoring during MVD. LSR and continuous electromyography were monitored in the frontalis, orbicularis oculi, and mentalis muscles. Extra-operative LSRs were done pre- and postoperatively. The neurological status of each patient was evaluated before and immediately after surgery, on discharge, and at 3 months after surgery. Results: Intraoperative neurophysiologic monitorings were successful in all patients. On admission and discharge, extra-operative LSR recordings were done in 23 patients. Twenty-one patients completed a follow- up evaluation. In 17, the intraoperative LSRs disappeared during surgery. In 5, the intraoperative LSRs were absent before incision and remained the same until the end of surgery. In one, the intraoperative LSR were present before incision and persisted despite MVD. For extra-operative LSRs, they disappeared after surgery in 10. LSRs were absent before and after surgery in 7. In 6, LSRs were present before surgery and persisted after MVD. For 5, intraoperative LSRs disappeared during surgery but extra-operative LSRs were persisted despite adequate MVD. In one, intraoperative LSRs were absent before incision and remained during the surgery. But extra-operative LSRs were present before surgery and disappeared after adequate MVD. Statistically, the extra-operative disappearance of LSR was correlated with the HFS relief in 4 days after surgery and the 3-month follow up period. (P = 0.049 and 0.044). However, the intaroperative disapearance of LSR was not. Conclusion: In our study, extra-operative LSR monitoring may be more predictive of the surgical outcome compared with intraoperative LSR during the 3-month follow up. doi:10.1016/j.clinph.2018.04.590
Platform Session – Evoked potentials & NIOM: Percutaneous threshold of facial nerve stimulation predicts facial canal dehiscence—Richard Vogel *, Patricia Johnson, Taha Mur, Pamela Roehm (USA) ⇑
Presenting author.
Introduction: Iatrogenic facial nerve injury is one of the most feared complications of otologic surgery. While the incidence of facial nerve (FN) injury is low, dehiscence of the fallopian canal increases the FN’s vulnerability to accidental injury. Highresolution computed tomography (HRCT) of the temporal bone is used preoperatively to assess middle ear and mastoid anatomy;