Development of wirelessly-powered, extracranial brain activator (ECBA) in a large animal model for the future non-invasive human neuromodulation

IEEE Trans. Biomed. Circuits Syst.

Mun

Jung

et al. 2020

Self Cite

In recent years, electroceuticals have been spotlighted as an emerging treatment for various severe chronic brain diseases, owing to their intrinsic advantage of electrical interaction with the brain, which is the most electrically active organ. However, the majority of research has verified only the short-term efficacy through acute studies in laboratory tests owing to the lack of a reliable miniaturized platform for long-term animal studies. The construction of a sufficient integrated system for such a platform is extremely difficult because it requires multi-disciplinary work using state-of-the-art technologies in a wide range of fields. In this study, we propose a complete system of an implantable platform for long-term preclinical brain studies. Our proposed system, the Extra-Cranial Brain Activator (ECBA), consists of a titanium-packaged implantable module and a helmet-type base station that powers the module wirelessly. The ECBA can also be controlled by a remote handheld device. Using the ECBA, we performed a long-term non-anesthetic study with multiple canine subjects, and the resulting PET-CT scans demonstrated remarkable enhancement in brain activity relating to memory and sensory skills. Furthermore, the histological analysis and high-temperature aging test confirmed the reliability of the system for up to 31 months. Hence, the proposed ECBA system is expected to lead a new paradigm of human neuromodulation studies in the near future.

Section: A Long-term Non-anesthetic Stimulation Protocolsmentioning

confidence: 74%

Section: Long-term Non Anesthetic Preclinical Study Available Extra-cranial Brain Activator (Ecba)mentioning

confidence: 78%

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Long-Term Non Anesthetic Preclinical Study Available Extra-Cranial Brain Activator (ECBA) System for the Future Minimally Invasive Human Neuro Modulation

IEEE Trans. Biomed. Circuits Syst.

Mun

Jung

et al. 2020

Self Cite

“…The recorded waveforms of brain activity represented using dashed lines, as shown in Fig. 4A, are subdivided into four frequency bands for analysis: delta (0.5-4 Hz), theta (4-8 Hz), alpha (8)(9)(10)(11)(12)(13), and beta (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). In SES, significant changes were found in alpha and beta waves in comparison to TES ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Recently we proposed a subcutaneous electrical stimulation (SES) device to overcome the limitations of conventional TES 19 . In SES, a miniaturized stimulation device is placed under the scalp, and it applies electrical currents to the skull in contrast to TES, where the current is applied to the scalp.…”

Section: Analyzing the Advantages Of Subcutaneous Over Transcutaneousmentioning

confidence: 99%

Analyzing the advantages of subcutaneous over transcutaneous electrical stimulation for activating brainwaves

Kang

Kim

et al. 2020

Sci Rep

Self Cite

Transcranial electrical stimulation (TES) is a widely accepted neuromodulation modality for treating brain disorders. However, its clinical efficacy is fundamentally limited due to the current shunting effect of the scalp and safety issues. A newer electrical stimulation technique called subcutaneous electrical stimulation (SES) promises to overcome the limitations of TES by applying currents directly at the site of the disorder through the skull. While SES seems promising, the electrophysiological effect of SES compared to TES is still unknown, thus limiting its broader application. Here we comprehensively analyze the SES and TES to demonstrate the effectiveness and advantages of SES. Beagles were bilaterally implanted with subdural strips for intracranial electroencephalography and electric field recording. For the intracerebral electric field prediction, we designed a 3D electromagnetic simulation framework and simulated TES and SES. In the beagle model, SES induces three to four-fold larger cerebral electric fields compared to TES, and significant changes in power ratio of brainwaves were observed only in SES. Our prediction framework suggests that the field penetration of SES would be several-fold larger than TES in human brains. These results demonstrate that the SES would significantly enhance the neuromodulatory effects compared to conventional TES and overcome the TES limitations.

Metasurface Patch for Wireless Power Transfer in Implantable Devices

2023

Adv Funct Materials

Wireless power transfer (WPT) systems enable the long‐term operation and miniaturization of implantable devices by eliminating the need for battery replacement and wired power supplies. Although wireless power transfer systems for implantable devices are extensively studied, their practical application is still challenging owing to the constraints and requirements of the human body, such as reflection loss owing to differences in the tissue dielectric properties, mm‐sized devices, and electromagnetic (EM) wave attenuation of the tissue. Here, a phase‐gradient metasurface patch is presented to achieve 5.8 GHz EM power focusing at a focal point of depth 10 mm in the tissue via EM wavefront modulation at the skin–air interface. The proposed metasurface patch is fabricated by arranging subwavelength‐thickness (<λ/10) unit cell structures composed of four metallic layers separated by dielectric substrates that exhibit high‐Q resonance properties and a sufficient phase modulation range with enhanced transmission. By applying the fabricated metasurface patch to a wireless power transfer system for implantable devices, it is experimentally confirmed that the transmission coefficient (S21) is improved by 6.37 dB compared with that of a wireless power transfer system without the metasurface patch. Furthermore, it is confirmed that the transmission coefficient can be maintained for an incident angle variation up to 30° from the transmitter to the metasurface patch, resulting in a stable power delivery of the proposed wireless power transfer system.