| Autor: |
J. Meincke, David Liebetanz, Manuel Hewitt |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
Clinical Neurophysiology. 128:e61 |
| ISSN: |
1388-2457 |
| Popis: |
Introduction Conflicting results have been reported on the importance of optimal TMS coil rotation. Maintaining a constant coil rotation angle manually remains a challenge. However, the exact impact of rotation angle on resting motor thresholds (RMTs) has not been investigated to date. Objective Using a robot-guided and a fully automated threshold hunting procedure, we aimed at determining the relevance of optimal rotation for determining RMT. Methods FDI hotspot was located with the automated hotspot hunting procedure ( n = 7). RMTs were then determined applying the threshold-hunting algorithm at different rotation angles (360° in steps of 15°, 15 pulses per rotation angle) in a randomized order over all pulses. The coil handle in posterior position was set as 0°. The procedure was repeated with steps of 5° within a 60° range of lowest thresholds of the first session. Threshold values were normalized for individual min and max. Results With 15° steps mean threshold was lowest at angles of 30° and 45°. Using 5° steps revealed a minimum mean threshold at 40° (mean threshold: 29.0; SEM: 0.05). A second minimum was found at the opposite angle. Highest RMTs were observed at angles between 135° and 180° and 285° and 315°. The relation between the rotation angle and deviation of the measured RMTs (from the minimum RMT at the optimal rotation angle) was non-linear with a floor effect between 5° and 15°. Conclusion Optimal coil rotation angle for FDI was found at 40°. Interestingly, within a range between 25° and 55° the effect of different coil rotation angles on the RMTs was not relevant, i.e. lower than the error of the threshold hunting procedure. The results therefore suggest that manual coil positioning at a rotation angle of 40° with little positional errors is uncritical when assessing motor thresholds of the FDI. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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