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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

Model derived strength–duration curves for action potential initiation in smaller (2 μm) diameter axons located closer (1–2 mm) the electrode as compared to larger (5.7 μm) diameter axons located farther from (4–5 mm) the electrode. At shorter pulse duration the two curves diverge explaining an increased “therapeutic window” if benefit was associated with stimulation of the nearby fibers and adverse effects with the distant thick myeliniated axons.
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fig02: Model derived strength–duration curves for action potential initiation in smaller (2 μm) diameter axons located closer (1–2 mm) the electrode as compared to larger (5.7 μm) diameter axons located farther from (4–5 mm) the electrode. At shorter pulse duration the two curves diverge explaining an increased “therapeutic window” if benefit was associated with stimulation of the nearby fibers and adverse effects with the distant thick myeliniated axons.

Mentions: For both strength–duration curves we found a significant linear regression fit (rigidity control: r = 0.97; contractions: 0.94), when plotting mean threshold amplitudes against the inverse of pulse duration (Fig.2). The slopes of the two regression lines were significantly divergent (74.8 ± 5.8 vs. 168.4 ± 19.0; P < 0.0001) indicating the stimulation of neural elements with different membrane excitability. From the mean and confidence range of the slopes we determined a chronaxie of 225 μsec (95% confidence range: 180–270 μsec) for the suppression of rigidity and 126 μsec (95% confidence range: 90–163 μsec) for muscular contractions.


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)

Model derived strength–duration curves for action potential initiation in smaller (2 μm) diameter axons located closer (1–2 mm) the electrode as compared to larger (5.7 μm) diameter axons located farther from (4–5 mm) the electrode. At shorter pulse duration the two curves diverge explaining an increased “therapeutic window” if benefit was associated with stimulation of the nearby fibers and adverse effects with the distant thick myeliniated axons.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig02: Model derived strength–duration curves for action potential initiation in smaller (2 μm) diameter axons located closer (1–2 mm) the electrode as compared to larger (5.7 μm) diameter axons located farther from (4–5 mm) the electrode. At shorter pulse duration the two curves diverge explaining an increased “therapeutic window” if benefit was associated with stimulation of the nearby fibers and adverse effects with the distant thick myeliniated axons.
Mentions: For both strength–duration curves we found a significant linear regression fit (rigidity control: r = 0.97; contractions: 0.94), when plotting mean threshold amplitudes against the inverse of pulse duration (Fig.2). The slopes of the two regression lines were significantly divergent (74.8 ± 5.8 vs. 168.4 ± 19.0; P < 0.0001) indicating the stimulation of neural elements with different membrane excitability. From the mean and confidence range of the slopes we determined a chronaxie of 225 μsec (95% confidence range: 180–270 μsec) for the suppression of rigidity and 126 μsec (95% confidence range: 90–163 μsec) for muscular contractions.

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