NeuroDAC: an open-source arbitrary biosignal waveform generator

Abstract

Objective. Researchers are developing biomedical devices with embedded closed-loop algorithms for providing advanced adaptive therapies. As these devices become more capable and algorithms become more complex, tasked with integrating and interpreting multi-channel, multi-modal electrophysiological signals, there is a need for flexible bench-top testing and prototyping. We present a methodology for leveraging off-the-shelf audio equipment to construct a biosignal waveform generator capable of streaming pre-recorded biosignals from a host computer. By re-playing known, well-characterized, but physiologically relevant real-world biosignals into a device under test, researchers can evaluate their systems without the need for expensive in vivo experiments. Approach. An open-source design based on the proposed methodology is described and validated, the NeuroDAC. NeuroDAC allows for 8 independent channels of biosignal playback using a simple, custom designed attenuation and buffering circuit. Applications can communicate with the device over a USB interface using standard audio drivers. On-board analog amplitude adjustment is used to maximize the dynamic range for a given signal and can be independently tuned for each channel. Main results. Low noise component selection yields a no-signal noise floor of just 5.35 ± 0.063. NeuroDAC’s frequency response is characterized with a high pass −3 dB rolloff at 0.57 Hz, and is capable of accurately reproducing a wide assortment of biosignals ranging from EMG, EEG, and ECG to extracellularly recorded neural activity. We also present an application example using the device to test embedded algorithms on a closed-loop neural modulation device, the Medtronic RC+S. Significance. By making the design of NeuroDAC open-source we aim to present an accessible tool for rapidly prototyping new biomedical devices and algorithms than can be easily modified based on individual testing needs. ClinicalTrials.gov Identifiers: NCT04281134, NCT03437928, NCT03582891

Analysis-rcs-data: Open-Source Toolbox for the Ingestion, Time-Alignment, and Visualization of Sense and Stimulation Data From the Medtronic Summit RC+S System

“…Upon inspection of empirical patient and benchtop ( Stanslaski et al, 2012 ; Powell et al, 2021 ) data sets, we found that none of the time related variables associated with each packet of data could independently serve as DerivedTime. Table 4 describes why each variable cannot be used for DerivedTime.…”

Analysis-rcs-data: Open-source toolbox for the ingestion, time-alignment, and visualization of sense and stimulation data from the Medtronic Summit RC+S system

“…packets with timestamp that is more than 24 hours away from median timestamp; packets with negative PacketGenTime; packets where PacketGenTime goes backwards in time more than 500ms; packets where elapsed PacketGenTime disagrees with elapsed timestamp by more than 2 seconds). (Powell et al 2021;Stanslaski et al 2012) data sets, we found that none of the time related variables associated with each packet of data could independently serve as DerivedTime. Table 4 describes why each variable cannot be used for DerivedTime.…”

İnsan-makine arayüz uygulamaları için sentetik biyosinyal üretiminde yeni yaklaşım: FPAA tabanlı emülatör

“…ECG sinyali üretimi konusunda FPGA (Field Programmable Gate Array) tabanlı çalışmalar da mevcuttur ancak pratik olarak kullanım sunmayan yapılardır [14]. Sentetik EEG sinyali üretimi konusunda ise SD karttan veri okuyarak PWM tekniği ile üretim yapan bir çalışma ile ses kartı kullanılarak veritabanları kaydının tekrar oynatılmasını öneren bir çalışma mevcuttur ancak sinyallerin gösterimi bulunmamaktadır [15,16]. Sentetik EMG sinyali üretimi konusunda çalışmaya rastlanmamıştır.…”