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Short pulse width widens the therapeutic window of subthalamic neurostimulation.

Reich MM, Steigerwald F, Sawalhe AD, Reese R, Gunalan K, Johannes S, Nickl R, Matthies C, McIntyre CC, Volkmann J - Ann Clin Transl Neurol (2015)

Bottom Line: We explored the impact of pulse durations <60 μsec on the therapeutic window of subthalamic neurostimulation in Parkinson's disease.The average therapeutic window was 2.16 mA at 60 μsec, which proportionally increased by 182% at 30 μsec, while decreasing by 46% at 120 μsec.Measured chronaxies and model data suggest, that pulse durations <60 μsec lead to a focusing of the neurostimulation effect on smaller diameter axons close to the electrode while avoiding stimulation of distant pyramidal tract fibers.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Julius-Maximilians-University Würzburg, Germany.

ABSTRACT
We explored the impact of pulse durations <60 μsec on the therapeutic window of subthalamic neurostimulation in Parkinson's disease. Current thresholds for full rigidity control and first muscle contractions were evaluated at pulse durations between 20 and 120 μsec during a monopolar review session in four patients. The average therapeutic window was 2.16 mA at 60 μsec, which proportionally increased by 182% at 30 μsec, while decreasing by 46% at 120 μsec. Measured chronaxies and model data suggest, that pulse durations <60 μsec lead to a focusing of the neurostimulation effect on smaller diameter axons close to the electrode while avoiding stimulation of distant pyramidal tract fibers.

No MeSH data available.


Related in: MedlinePlus

(A) linearized strength–duration curves for rigidity control and muscle contractions. (B) Bar graph depicting the relative change in therapeutic window compared to 60 μsec pulse duration (TW60 μsec). Error bars indicate the standard error of mean in both graphs.
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fig01: (A) linearized strength–duration curves for rigidity control and muscle contractions. (B) Bar graph depicting the relative change in therapeutic window compared to 60 μsec pulse duration (TW60 μsec). Error bars indicate the standard error of mean in both graphs.

Mentions: During the monopolar review session we observed a clear inverse relationship between PW and side effect thresholds in all patients. Mild contractions or fasciculations in hand or face muscles were elicited in all cases and served to determine the threshold for activation of pyramidal tract fibers. We did not notice other stimulation induced adverse effects below this threshold in any patient. Complete determination of TW was possible for seven implanted electrodes due to a lack of testable rigidity contralateral to one. The TW was 2.2 ± 1.6 mA (median 2.3; range 3.9) at 60 μsec, which proportionally increased by 182 ± 128% (median 160%; range 341%) at 30 μsec, while decreasing by 46 ± 28% (median 34%; range 84%) at 120 μsec (Fig.1). At 20 μsec PW assessment of the TW was unreliable, because we could not elicit a capsular response for 6/8 electrodes below our testing limit of 10 mA.


Short pulse width widens the therapeutic window of subthalamic neurostimulation.

Reich MM, Steigerwald F, Sawalhe AD, Reese R, Gunalan K, Johannes S, Nickl R, Matthies C, McIntyre CC, Volkmann J - Ann Clin Transl Neurol (2015)

(A) linearized strength–duration curves for rigidity control and muscle contractions. (B) Bar graph depicting the relative change in therapeutic window compared to 60 μsec pulse duration (TW60 μsec). Error bars indicate the standard error of mean in both graphs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4402087&req=5

fig01: (A) linearized strength–duration curves for rigidity control and muscle contractions. (B) Bar graph depicting the relative change in therapeutic window compared to 60 μsec pulse duration (TW60 μsec). Error bars indicate the standard error of mean in both graphs.
Mentions: During the monopolar review session we observed a clear inverse relationship between PW and side effect thresholds in all patients. Mild contractions or fasciculations in hand or face muscles were elicited in all cases and served to determine the threshold for activation of pyramidal tract fibers. We did not notice other stimulation induced adverse effects below this threshold in any patient. Complete determination of TW was possible for seven implanted electrodes due to a lack of testable rigidity contralateral to one. The TW was 2.2 ± 1.6 mA (median 2.3; range 3.9) at 60 μsec, which proportionally increased by 182 ± 128% (median 160%; range 341%) at 30 μsec, while decreasing by 46 ± 28% (median 34%; range 84%) at 120 μsec (Fig.1). At 20 μsec PW assessment of the TW was unreliable, because we could not elicit a capsular response for 6/8 electrodes below our testing limit of 10 mA.

Bottom Line: We explored the impact of pulse durations <60 μsec on the therapeutic window of subthalamic neurostimulation in Parkinson's disease.The average therapeutic window was 2.16 mA at 60 μsec, which proportionally increased by 182% at 30 μsec, while decreasing by 46% at 120 μsec.Measured chronaxies and model data suggest, that pulse durations <60 μsec lead to a focusing of the neurostimulation effect on smaller diameter axons close to the electrode while avoiding stimulation of distant pyramidal tract fibers.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Julius-Maximilians-University Würzburg, Germany.

ABSTRACT
We explored the impact of pulse durations <60 μsec on the therapeutic window of subthalamic neurostimulation in Parkinson's disease. Current thresholds for full rigidity control and first muscle contractions were evaluated at pulse durations between 20 and 120 μsec during a monopolar review session in four patients. The average therapeutic window was 2.16 mA at 60 μsec, which proportionally increased by 182% at 30 μsec, while decreasing by 46% at 120 μsec. Measured chronaxies and model data suggest, that pulse durations <60 μsec lead to a focusing of the neurostimulation effect on smaller diameter axons close to the electrode while avoiding stimulation of distant pyramidal tract fibers.

No MeSH data available.


Related in: MedlinePlus