PMC5825893_01
The locations of the deep brain stimulation leads in coronal (A) and sagittal (B) slices. Panels (C-E) illustrate the estimated distribution of the electrical field (orange) generated by different active contacts (red) in both right and left ANT (green). Inactive contacts are represented with blue color. Images were generated using the SureTune software (Medtronic, Minneapolis, MN, USA). From bottom to top, contacts are labeled as 0, 1, 2, and 3 on the left side and as 8, 9, 10, and 11 on the right side. (C) Contacts 1 and 9 are active. The electrical field completely misses the ANT. (D) Contacts 2 and 10 are active. The electrical field still barely reaches the ANT. (E) Contacts 3 and 11 are active. The electrical field extends to the inferior section of ANT. Clinical effect was achieved only with this setting.
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F1
Contacts labeled 2 and 10 were initially active (Figure 1). As the effect of microlesion began to recede and the patient's seizures returned to baseline values, active contacts were switched to contacts 1 and 9 (Figure 1). DBS device was switched on during the second day, and stimulation parameters were set to 5 V, 90 micros, 180 Hz, and 1 min ON 5 min OFF:with contacts 3 and 11 being active (Figure 1).
(A) The onset of a deep brain stimulation (DBS) ON period (blue arrow) and the onset of an epileptic seizure (red arrow) shown in an EEG graph. (B) EEG graph illustrating how the ictal activity continues even after the end of DBS ON period (blue arrow). The sharp "drop" seen in the graph in some channels is an artifact caused by the monopolar cathodal stimulation.
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F2
Later the same day, the onset of stimulator ON phase simultaneously provoked seizure activity clearly seen in the EEG (Figure 2).
Seizure frequencies and the amount of seizure free days before and after the deep brain stimulation (DBS) surgery in a follow-up of 40 months. First five months represent the baseline seizure frequency (gray area), DBS-surgery was conducted on month 5. The vEEG-recording was conducted on month 11. Seizures that occurred during the video electroencephalography not included. Seizure classification according to ILAE 2017 guidelines. *Focal to bilateral tonic-clonic.
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F3
In addition, most of our patient's seizures during later ANT-DBS therapy were his habitual focal unaware seizures instead of tonic-clonic seizures, which indicates that DBS prevented seizure propagation and reduced seizure severity (Figure 3).