Pilot study of focused ultrasound for drug‐resistant epilepsy
Cheng‐Chia Lee, Chien‐Chen Chou, Fu‐Jung Hsiao, Yi‐Hsiu Chen, Chun‐Fu Lin, Ching‐Jen Chen, Syu‐Jyun Peng, Hao‐Li Liu, Hsiang‐Yu Yu
Epilepsia 2022 · 10.1111/epi.17105
Abstract
Objective The neuromodulatory effects of focused ultrasound (FUS) have been demonstrated in animal epilepsy models; however, the safety and efficacy of FUS in humans with epilepsy have not been well established. Patients with drug-resistant epilepsy (DRE) undergoing stereo-electroencephalography (SEEG) provide an opportunity to investigate the neuromodulatory effects of FUS in humans. Methods Patients with DRE undergoing SEEG for localization of the seizure onset zone (SOZ) were prospectively enrolled. FUS was delivered to the SOZ using a neuronavigation-guided FUS system (ceiling spatial-peak temporal-average intensity level = 2.8 W/cm 2 , duty cycle = 30%, modulating duration = 10 min). Simultaneous SEEG recordings were obtained during sonication and for 3 days after treatment. Seizures, interictal epileptiform discharges, and adverse events after FUS were monitored. Results Six patients met the eligibility criteria and completed FUS treatment. A decrease in seizure frequency was observed in two patients within the 3-day follow-up; however, one patient presented an increase in the frequency of subclinical seizures. Posttreatment magnetic resonance imaging revealed neither lesion nor brain edema. Significant changes in spectral power of SEEG were noted at the targeted electrodes during FUS treatment. One patient reported subjective scalp heating during FUS, and one patient developed transient naming and memory impairment that resolved within 3 weeks after FUS. Significance FUS can be safely delivered to the SOZ of patients with DRE, resulting in significant changes in spectral power of SEEG. A larger sample cohort and pursuing optimal sonication parameters will be required to elucidate the neuromodulatory effects of FUS when used for seizure control.
Abstract via europepmc.
Exposures
Exposure 1: FUS to the seizure onset zone (SEEG-guided), patient-specific target
Target: temporal lobe, premotor cortex, frontal lobe, hippocampus, insular cortex, anterior cingulate cortex — “seizure onset zone (SOZ)”
Device: other named manufacturer · NaviFUS Corporation · neuronavigation-guided multichannel hemispheric phased array FUS system
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | not reported | ⚑ |
| Pulse duration (ms) | 3 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 100 | ✓✓✓ |
| Duty cycle (%) | 30pulse duration × PRF gives 30% | ✓✓✓ |
| Sonication duration (s) | 600 | ✓✓✓⚑ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reportedsingle value | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | 2.8 | ✓✓✓⚑ |
Burst-tone low-intensity FUS: PRF 100 Hz, burst length 3 ms, duty cycle 30%, total exposure time 10 min with SEEG recording before, during and after. Patient 2 had two sessions (first stopped at 260 s, repeat 600 s).
Flags from extraction
exposures[0].in_situ.ispta_w_cm2— 2.8 W/cm2 is a requested ceiling of transcranial Ispta, set via the device planning tool; how in situ values were obtained is not stated.exposures[0].timing.sonication_duration_s— Total exposure time 10 min is recorded as sonication duration; any on/off nesting within it is not described.exposures[0].fundamental_frequency_khz— Frequency is not stated anywhere in the paper.exposures[0].target— Targets differ per patient: fusiform gyrus, premotor gyrus, frontal operculum, hippocampus body, insula superior border, anterior cingulate gyrus; combined into one exposure because frequency is unreported.n_sessions_per_subject— One session per patient except Patient 2 (two).