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Tobias Martens - One of the best experts on this subject based on the ideXlab platform.
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A comparison between Threshold Criterion and amplitude Criterion in transcranial motor evoked potentials during surgery for supratentorial lesions.
Journal of neurosurgery, 2018Co-Authors: Tammam Abboud, Cindy Schwarz, Manfred Westphal, Tobias MartensAbstract:OBJECTIVEThe aim of this study was to compare sensitivity and specificity between the novel Threshold and amplitude criteria for motor evoked potentials (MEPs) monitoring after transcranial electrical stimulation (TES) during surgery for supratentorial lesions in the same patient cohort.METHODSOne hundred twenty-six patients were included. All procedures were performed under general anesthesia. Craniotomies did not expose motor cortex, so that direct mapping was less suitable. After TES, MEPs were recorded bilaterally from abductor pollicis brevis (APB), from orbicularis oris (OO), and/or from tibialis anterior (TA). The percentage increase in the Threshold level was assessed and considered significant if it exceeded by more than 20% on the affected side the percentage increase on the unaffected side. Amplitude on the affected side was measured with a stimulus intensity of 150% of the Threshold level set for each muscle.RESULTSEighteen of 126 patients showed a significant change in the Threshold level as ...
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A novel Threshold Criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway
Journal of neurosurgery, 2016Co-Authors: Tammam Abboud, Miriam Schaper, Lasse Dührsen, Cindy Schwarz, Nils Ole Schmidt, Manfred Westphal, Tobias MartensAbstract:OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring Threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in Threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of Threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in Threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in Threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in Threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in Threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel Threshold Criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in Threshold level has led to a high sensitivity and specificity.
Tammam Abboud - One of the best experts on this subject based on the ideXlab platform.
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A comparison between Threshold Criterion and amplitude Criterion in transcranial motor evoked potentials during surgery for supratentorial lesions.
Journal of neurosurgery, 2018Co-Authors: Tammam Abboud, Cindy Schwarz, Manfred Westphal, Tobias MartensAbstract:OBJECTIVEThe aim of this study was to compare sensitivity and specificity between the novel Threshold and amplitude criteria for motor evoked potentials (MEPs) monitoring after transcranial electrical stimulation (TES) during surgery for supratentorial lesions in the same patient cohort.METHODSOne hundred twenty-six patients were included. All procedures were performed under general anesthesia. Craniotomies did not expose motor cortex, so that direct mapping was less suitable. After TES, MEPs were recorded bilaterally from abductor pollicis brevis (APB), from orbicularis oris (OO), and/or from tibialis anterior (TA). The percentage increase in the Threshold level was assessed and considered significant if it exceeded by more than 20% on the affected side the percentage increase on the unaffected side. Amplitude on the affected side was measured with a stimulus intensity of 150% of the Threshold level set for each muscle.RESULTSEighteen of 126 patients showed a significant change in the Threshold level as ...
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A novel Threshold Criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway
Journal of neurosurgery, 2016Co-Authors: Tammam Abboud, Miriam Schaper, Lasse Dührsen, Cindy Schwarz, Nils Ole Schmidt, Manfred Westphal, Tobias MartensAbstract:OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring Threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in Threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of Threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in Threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in Threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in Threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in Threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel Threshold Criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in Threshold level has led to a high sensitivity and specificity.
Henk J. A. M. Heijmans - One of the best experts on this subject based on the ideXlab platform.
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ICASSP - Adaptive update lifting with gradient criteria modeling high-order differences
IEEE International Conference on Acoustics Speech and Signal Processing, 2002Co-Authors: Beatrice Pesquet-popescu, Gemma Piellat, Henk J. A. M. HeijmansAbstract:This paper treats a class of adaptive update lifting schemes which do not require bookkeeping for perfect reconstruction. The choice of the update lifting filter is triggered by a binary Threshold Criterion based on a generalised gradient which is chosen in such a way that it only smoothes homogeneous regions. More precisely, the Criterion can be chosen so that it ‘recognises’ signals that are polynomial up to a given order. The lifting filter updates the signal in these polynomial regions but leaves other parts unaffected.
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Adaptive update lifting with a decision rule based on derivative filters
IEEE Signal Processing Letters, 2002Co-Authors: Gemma Piella, Beatrice Pesquet-popescu, Henk J. A. M. HeijmansAbstract:This letter treats a class of adaptive update-lifting schemes that do not require bookkeeping for perfect reconstruction. The choice of the update-lifting filter is triggered by a binary Threshold Criterion based on a generalized gradient that is chosen in such a way that it only smooths homogeneous regions. This Criterion can be chosen so that it ignores portions of a signal that are polynomial up to a given order. The update-lifting filter modifies the signal in these polynomial regions but leaves other portions unaffected.
Cindy Schwarz - One of the best experts on this subject based on the ideXlab platform.
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A comparison between Threshold Criterion and amplitude Criterion in transcranial motor evoked potentials during surgery for supratentorial lesions.
Journal of neurosurgery, 2018Co-Authors: Tammam Abboud, Cindy Schwarz, Manfred Westphal, Tobias MartensAbstract:OBJECTIVEThe aim of this study was to compare sensitivity and specificity between the novel Threshold and amplitude criteria for motor evoked potentials (MEPs) monitoring after transcranial electrical stimulation (TES) during surgery for supratentorial lesions in the same patient cohort.METHODSOne hundred twenty-six patients were included. All procedures were performed under general anesthesia. Craniotomies did not expose motor cortex, so that direct mapping was less suitable. After TES, MEPs were recorded bilaterally from abductor pollicis brevis (APB), from orbicularis oris (OO), and/or from tibialis anterior (TA). The percentage increase in the Threshold level was assessed and considered significant if it exceeded by more than 20% on the affected side the percentage increase on the unaffected side. Amplitude on the affected side was measured with a stimulus intensity of 150% of the Threshold level set for each muscle.RESULTSEighteen of 126 patients showed a significant change in the Threshold level as ...
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A novel Threshold Criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway
Journal of neurosurgery, 2016Co-Authors: Tammam Abboud, Miriam Schaper, Lasse Dührsen, Cindy Schwarz, Nils Ole Schmidt, Manfred Westphal, Tobias MartensAbstract:OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring Threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in Threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of Threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in Threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in Threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in Threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in Threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel Threshold Criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in Threshold level has led to a high sensitivity and specificity.
Manfred Westphal - One of the best experts on this subject based on the ideXlab platform.
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A comparison between Threshold Criterion and amplitude Criterion in transcranial motor evoked potentials during surgery for supratentorial lesions.
Journal of neurosurgery, 2018Co-Authors: Tammam Abboud, Cindy Schwarz, Manfred Westphal, Tobias MartensAbstract:OBJECTIVEThe aim of this study was to compare sensitivity and specificity between the novel Threshold and amplitude criteria for motor evoked potentials (MEPs) monitoring after transcranial electrical stimulation (TES) during surgery for supratentorial lesions in the same patient cohort.METHODSOne hundred twenty-six patients were included. All procedures were performed under general anesthesia. Craniotomies did not expose motor cortex, so that direct mapping was less suitable. After TES, MEPs were recorded bilaterally from abductor pollicis brevis (APB), from orbicularis oris (OO), and/or from tibialis anterior (TA). The percentage increase in the Threshold level was assessed and considered significant if it exceeded by more than 20% on the affected side the percentage increase on the unaffected side. Amplitude on the affected side was measured with a stimulus intensity of 150% of the Threshold level set for each muscle.RESULTSEighteen of 126 patients showed a significant change in the Threshold level as ...
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A novel Threshold Criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway
Journal of neurosurgery, 2016Co-Authors: Tammam Abboud, Miriam Schaper, Lasse Dührsen, Cindy Schwarz, Nils Ole Schmidt, Manfred Westphal, Tobias MartensAbstract:OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring Threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in Threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of Threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in Threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in Threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in Threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in Threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel Threshold Criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in Threshold level has led to a high sensitivity and specificity.
