Khay-Wai Leong - Academia.edu (original) (raw)
Papers by Khay-Wai Leong
2017 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2017
This paper presents an implantable, wireless, 2-channel electromyography (EMG) recording system t... more This paper presents an implantable, wireless, 2-channel electromyography (EMG) recording system that was successfully tested in a chronic experiment in a rodent for up to three months. The system comprises of an implanted device and an external reader module. The implanted device is a multi-channel neural amplifier chip coupled with inductive power and data transfer electronics. The external reader module consists of a transcutaneous power supply, EMG data recovery circuitry, and a USB to computer interface for display and storage purposes. Stainless steel EMG electrodes were connected to the implanted device, and the device was then encapsulated using biocompatible FDA compliant silicone. Chronic recordings in a rodent across a three-month period validated this system's ability to acquire EMG signals (at sample rates of 20 kSPS/channel) in in-vivo conditions. This wireless device can be incorporated into a wireless proximal muscle/neural recording and distal muscle stimulation neuroprosthesis to address peripheral nerve injuries.
2017 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2017
We have developed a fully implantable 4-channel wireless muscle stimulator system with the abilit... more We have developed a fully implantable 4-channel wireless muscle stimulator system with the ability to elicit precise and graded muscle movements for a hand grasping motion. The stimulator system consists of a WiFi enabled inductive powering and data transfer circuitry connected to a laptop, and a wireless implantable stimulator unit with biocompatible stainless steel electrodes. We shall demonstrate this stimulator package and its features through a dummy robotic rat limb. We will also show videos of the stimulator being used to activate the rodent hind limb muscles to kick a ball, and activate the forearm muscles of a non-human primate to elicit individual finger movement to play a virtual piano.
IEEE Transactions on Biomedical Circuits and Systems, 2020
We have developed a 5-electrode recording system that combines an implantable electromyography (E... more We have developed a 5-electrode recording system that combines an implantable electromyography (EMG) device package with transcutaneous inductive power transmission, near-infrared (NIR) transcutaneous data telemetry and 3 Mbps Wi-Fi data acquisition for chronic EMG recording in vivo. This system comprises a hermetically-sealed single-chip, 5-electrode Implantable EMG Acquisition Device (IEAD), a custom external powering and Implant Telemetry Module (ITM), and a custom Wi-Fi-based Raspberry Pi-based Data Acquisition (RaspDAQ) and relay device. The external unit (ITM and RaspDAQ) is powered entirely by a single battery to achieve the objective of untethered EMG recording, for the convenience of clinicians and animal researchers. The IEAD acquires intramuscular EMG signals at 17.85 ksps/electrode while being powered transcutaneously by the ITM using 22 MHz near-field inductive coupling. The acquired EMG data is transmitted transcutaneously via NIR telemetry to the ITM, which in turn, transfers the data to the RaspDAQ for relaying to a laptop computer for display and storage. We have also validated the complete system by acquiring EMG signals from rodents for up to two months. Following the explantation of the devices, we have also conducted failure and histological analysis on the devices and the surrounding tissue, respectively.
![Research paper thumbnail of Erratum to “A 3-Mbps, 802.11g-Based EMG Recording System With Fully Implantable 5-Electrode EMG Acquisition Device” [Aug 20 889-902]](https://attachments.academia-assets.com/98127884/thumbnails/1.jpg)
](IEEE Transactions on Biomedical Circuits and Systems, 2020
Journal of Aircraft, 2020
We discuss the requirements of a predictive microburst flight trajectory guidance system, and ana... more We discuss the requirements of a predictive microburst flight trajectory guidance system, and analyze the trajectories of low thrust-to-weight ratio airplanes passing through a microburst downdraft...
Journal of Aircraft, 2020
International Journal of Aviation, Aeronautics, and Aerospace, 2018
IEEE Journal of Solid-State Circuits, 2019
The adoption of chronic implantable peripheral nerve-based prosthetic devices is currently hamper... more The adoption of chronic implantable peripheral nerve-based prosthetic devices is currently hampered by the lack of a highly integrated neural signal acquisition system-on-chip (SoC). We report a ten-channel peripheral nervous system (PNS) electroneurogram (ENG) signal acquisition SoC within an implantable package. Requiring only four off-chip capacitors, this SoC can be co-encapsulated with flexible nerve electrodes and a resonant coil antenna to form a 3.4 cm³ and 3.9 g implantable device for chronic ENG acquisition. This SoC is inductively powered and controlled through a resonant coil at 22 MHz and transmits the digitized neural signal through a near-infrared LED (NIR-LED). Fabricated in 0.18-m CMOS, each amplifier channel exhibits an input referred noise of 1.9 Vrms and a noise efficiency factor (NEF) of 4.0 within the signal bandwidth of 5.5 kHz. Each amplifier channel within the SoC is digitized with 10-bit resolution at 17.5 ksps, and the total power consumption (SoC and NIR-LED) is 4.4 mW when the NIR-LED is driven at 3 Mb/s. An electrode impedance measurement circuit with <10% magnitude and <8° angle error for measuring impedances up to 1 M is also incorporated in this SoC. This wireless, low noise ENG acquisition SoC package has been validated in vivo while implanted on a rodent to acquire ENG from its sciatic nerve. Cardiology Radio astronomy Hurricanes Delta modulation Mobile ad hoc networks Cyclic redundancy check. Regression analysis Gain measurement Multicast VPN Forecast uncertainty Well logging Authorization Plastic optical fiber Nanolithography Gears Microcavities Iron alloys IEEE Communities. Digital computers MOS integrated circuits Emergent phenomena Computer generated music Matrix decomposition Darmstadtium Fluidic microsystems Admittance Boilers Storage rings Atom optics. Mammary glands Web pages Atomic beams Sawing Transmitters Hafnium Triboelectricity Blades Predictive encoding AWGN Progenitor cells Stomach. Sensory aids Musical instrument digital interfaces Crystallography Biomedical informatics Camshafts Electromagnetic modeling Brazing Public domain software Nanocrystals Ferrimagnetic films Displacement measurement Optical fiber polarization IEEE staff Active filters. Francium Quality control Kerr effect Acoustic distortion Electronic countermeasures Internet telephony Superconducting materials HTML. Thermal noise Aerospace testing X3D Atrophy Posthuman Genetics Autonomous automobiles DC machines Internet. Persuasive systems Admission control Transhuman Titanium compounds Open area test sites Delta modulation Turbines User centered design Passive networks. Spectroradiometers Public key cryptography Network synthesis Thermal stresses Pressure effects Thick film inductors Air quality Spaceborne radar Underwater cables Whales.
Journal of Wind Engineering and Industrial Aerodynamics
2017 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2017
This paper presents an implantable, wireless, 2-channel electromyography (EMG) recording system t... more This paper presents an implantable, wireless, 2-channel electromyography (EMG) recording system that was successfully tested in a chronic experiment in a rodent for up to three months. The system comprises of an implanted device and an external reader module. The implanted device is a multi-channel neural amplifier chip coupled with inductive power and data transfer electronics. The external reader module consists of a transcutaneous power supply, EMG data recovery circuitry, and a USB to computer interface for display and storage purposes. Stainless steel EMG electrodes were connected to the implanted device, and the device was then encapsulated using biocompatible FDA compliant silicone. Chronic recordings in a rodent across a three-month period validated this system's ability to acquire EMG signals (at sample rates of 20 kSPS/channel) in in-vivo conditions. This wireless device can be incorporated into a wireless proximal muscle/neural recording and distal muscle stimulation neuroprosthesis to address peripheral nerve injuries.
2017 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2017
We have developed a fully implantable 4-channel wireless muscle stimulator system with the abilit... more We have developed a fully implantable 4-channel wireless muscle stimulator system with the ability to elicit precise and graded muscle movements for a hand grasping motion. The stimulator system consists of a WiFi enabled inductive powering and data transfer circuitry connected to a laptop, and a wireless implantable stimulator unit with biocompatible stainless steel electrodes. We shall demonstrate this stimulator package and its features through a dummy robotic rat limb. We will also show videos of the stimulator being used to activate the rodent hind limb muscles to kick a ball, and activate the forearm muscles of a non-human primate to elicit individual finger movement to play a virtual piano.
IEEE Transactions on Biomedical Circuits and Systems, 2020
We have developed a 5-electrode recording system that combines an implantable electromyography (E... more We have developed a 5-electrode recording system that combines an implantable electromyography (EMG) device package with transcutaneous inductive power transmission, near-infrared (NIR) transcutaneous data telemetry and 3 Mbps Wi-Fi data acquisition for chronic EMG recording in vivo. This system comprises a hermetically-sealed single-chip, 5-electrode Implantable EMG Acquisition Device (IEAD), a custom external powering and Implant Telemetry Module (ITM), and a custom Wi-Fi-based Raspberry Pi-based Data Acquisition (RaspDAQ) and relay device. The external unit (ITM and RaspDAQ) is powered entirely by a single battery to achieve the objective of untethered EMG recording, for the convenience of clinicians and animal researchers. The IEAD acquires intramuscular EMG signals at 17.85 ksps/electrode while being powered transcutaneously by the ITM using 22 MHz near-field inductive coupling. The acquired EMG data is transmitted transcutaneously via NIR telemetry to the ITM, which in turn, transfers the data to the RaspDAQ for relaying to a laptop computer for display and storage. We have also validated the complete system by acquiring EMG signals from rodents for up to two months. Following the explantation of the devices, we have also conducted failure and histological analysis on the devices and the surrounding tissue, respectively.
IEEE Transactions on Biomedical Circuits and Systems, 2020
Journal of Aircraft, 2020
We discuss the requirements of a predictive microburst flight trajectory guidance system, and ana... more We discuss the requirements of a predictive microburst flight trajectory guidance system, and analyze the trajectories of low thrust-to-weight ratio airplanes passing through a microburst downdraft...
Journal of Aircraft, 2020
International Journal of Aviation, Aeronautics, and Aerospace, 2018
IEEE Journal of Solid-State Circuits, 2019
The adoption of chronic implantable peripheral nerve-based prosthetic devices is currently hamper... more The adoption of chronic implantable peripheral nerve-based prosthetic devices is currently hampered by the lack of a highly integrated neural signal acquisition system-on-chip (SoC). We report a ten-channel peripheral nervous system (PNS) electroneurogram (ENG) signal acquisition SoC within an implantable package. Requiring only four off-chip capacitors, this SoC can be co-encapsulated with flexible nerve electrodes and a resonant coil antenna to form a 3.4 cm³ and 3.9 g implantable device for chronic ENG acquisition. This SoC is inductively powered and controlled through a resonant coil at 22 MHz and transmits the digitized neural signal through a near-infrared LED (NIR-LED). Fabricated in 0.18-m CMOS, each amplifier channel exhibits an input referred noise of 1.9 Vrms and a noise efficiency factor (NEF) of 4.0 within the signal bandwidth of 5.5 kHz. Each amplifier channel within the SoC is digitized with 10-bit resolution at 17.5 ksps, and the total power consumption (SoC and NIR-LED) is 4.4 mW when the NIR-LED is driven at 3 Mb/s. An electrode impedance measurement circuit with <10% magnitude and <8° angle error for measuring impedances up to 1 M is also incorporated in this SoC. This wireless, low noise ENG acquisition SoC package has been validated in vivo while implanted on a rodent to acquire ENG from its sciatic nerve. Cardiology Radio astronomy Hurricanes Delta modulation Mobile ad hoc networks Cyclic redundancy check. Regression analysis Gain measurement Multicast VPN Forecast uncertainty Well logging Authorization Plastic optical fiber Nanolithography Gears Microcavities Iron alloys IEEE Communities. Digital computers MOS integrated circuits Emergent phenomena Computer generated music Matrix decomposition Darmstadtium Fluidic microsystems Admittance Boilers Storage rings Atom optics. Mammary glands Web pages Atomic beams Sawing Transmitters Hafnium Triboelectricity Blades Predictive encoding AWGN Progenitor cells Stomach. Sensory aids Musical instrument digital interfaces Crystallography Biomedical informatics Camshafts Electromagnetic modeling Brazing Public domain software Nanocrystals Ferrimagnetic films Displacement measurement Optical fiber polarization IEEE staff Active filters. Francium Quality control Kerr effect Acoustic distortion Electronic countermeasures Internet telephony Superconducting materials HTML. Thermal noise Aerospace testing X3D Atrophy Posthuman Genetics Autonomous automobiles DC machines Internet. Persuasive systems Admission control Transhuman Titanium compounds Open area test sites Delta modulation Turbines User centered design Passive networks. Spectroradiometers Public key cryptography Network synthesis Thermal stresses Pressure effects Thick film inductors Air quality Spaceborne radar Underwater cables Whales.
Journal of Wind Engineering and Industrial Aerodynamics