Department Publications

Dry-contact ear-electroencephalography (Ear-EEG) enables wearable neural monitoring. However, motion induced electrode-skin impedance (ESI) mismatches between electrodes can severely degrade signal quality. To the best of our knowledge, this paper presents the first proof-of-concept dry-contact EarEEG system that uses a driven-right-leg (DRL) stimulus for continuous ESI mismatch monitoring, enabling online adaptive motion artifact cancellation. A 1 kHz sinusoidal stimulus is injected through the DRL electrode. The resulting response to the injected carrier is separated from the EEG using bandpass filtering and demodulation, and then used to extract the ESI mismatch information as the reference input for a normalized least-mean-square adaptive filter followed by a Hampel filtering stage. To evaluate artifact suppression and preservation of neural activity, alpha-band EEG activity was analyzed involving four healthy participants performing head nodding, electrode tapping, and jaw clenching. The system achieved artifact power reductions of 6.5, 12.6, and 9.0 dB (77.6%, 92.8%, and 86.4%, respectively) while alpha-band modulation remained clearly observable after processing. This demonstrates the feasibility of DRL-stimulusbased ESI mismatch monitoring for motion artifact cancellation in wearable dry-contact Ear-EEG.

Neurotransmitters, such as dopamine and serotonin, are endogenous chemicals that enable neurons to communicate with one another throughout the body. Alterations in the levels of specific neurotransmitters are associated with various neuropsychiatric disorders. Dopamine (DA) - often known as the feel-good hormone – is primarily responsible for reward and motivation and is a key biomarker of Parkinson’s disease. Medications such as Levodopa alter its level in biological fluids, monitoring of which is important to ensure the proper therapeutic range for sufficient medication to cross the blood-brain barrier. Serotonin (5-HT) regulates mood, stress response, sleep, and autonomic function, and its dysregulation is implicated in depression, anxiety, and other neuropsychiatric disorders. Continuous or longitudinal monitoring of serotonin—especially in accessible biological matrices—can provide critical insights into …

Objective Young children and infants, especially newborns, are highly susceptible to seizures, which, if undetected and untreated, can lead to severe long-term neurological consequences. Early detection typically requires continuous electroencephalography (cEEG) monitoring in hospital settings, involving costly equipment and highly trained specialists. This study presents a low-cost, active dry-contact electrode–based, adjustable electroencephalography (EEG) headset, combined with an explainable deep learning model for seizure detection from reduced-montage EEG, and a multimodal artifact removal algorithm to enhance signal quality. Methods EEG signals were acquired via active electrodes and processed through a custom-designed analog front end for filtering and digitization. The adjustable headset was fabricated using three-dimensional printing and laser cutting to accommodate varying head sizes …

Objective Neonates are highly susceptible to seizures, which can have severe long-term consequences if undetected and left untreated. Early detection is crucial and typically requires continuous electroencephalography (EEG) monitoring in a hospital setting, which is costly, inconvenient, and requires specialized experts for diagnosis. In this work, we propose a new low-cost active dry-contact electrode-based adjustable EEG headset, a new explainable deep learning model to detect neonatal seizures, and an advanced signal processing algorithm to remove artifacts to address the key aspects that lead to the underdiagnosis of neonatal seizures. Methods EEG signals are acquired through active electrodes and processed using a custom-designed analog front end (AFE) that filters and digitizes the captured EEG signals. The adjustable headset is designed using three-dimensional (3D) printing and laser cutting to …

This review outlines the current status and proposes future directions for using auditory brainstem responses (ABRs) to continuous speech as a tool in hearing aid assessment. In current clinical practice, ABRs measured via electroencephalography (EEG) in response to short stimuli, averaged across repetitions, are a cornerstone of objective hearing screening and evaluation. Recent advancements have demonstrated that ABRs can be estimated from EEG recorded during continuous speech listening by using linear models which map the auditory speech features, extracted using auditory models, to continuous EEG activity. This approach enables the simultaneous investigation of multiple auditory pathway stages using complex, ecologically valid sounds; advancing potential future hearing assessments that can be seamlessly integrated into daily life. Current findings indicate that responses similar to click-ABRs …

Cardiac auscultation is an essential clinical skill, requiring excellent hearing to distinguish subtle differences in timing and pitch of heart sounds. However, diagnosing solely from these sounds is often challenging due to interference from surrounding noise, and the information may be limited. Most of the existing solutions that adaptively cancel external noise are either non-real-time or computationally intensive, making them unsuitable for implementation in a portable system. This work proposes an end-to-end system with a real-time adaptive noise cancellation pipeline integrated into a device that simultaneously acquires electrocardiogram (ECG) and phonocardiogram (PCG) signals. We employ a burst adaptive normalized least mean square algorithm that adjusts its adaptation in response to high-energy, non-stationary hospital noise. The algorithm's performance was initially assessed using datasets with artificially induced noise. Subsequently, the complete end-to-end system was validated using real-world hospital recordings captured with the dual-modality device. For PCG and ECG signals recorded from the device in noisy hospital settings, the proposed system achieved signal-to-noise ratio improvements of 37.01 dB and 30.32 dB, respectively. Furthermore, complexity analysis confirms the pipeline's suitability for embedded implementation. These results demonstrate the system's effectiveness in enabling reliable and accessible cardiac screening in noisy hospital environments typical of resource-constrained settings.

Accurate and accessible cognitive load monitoring is essential for improving personalized learning and facilitating better mental health monitoring. Existing methods for measuring cognitive load can be intrusive, costly, and less effective for individuals with high melanin concentrations, emphasizing the need for an improved approach. This study presents a novel approach to monitoring the cognitive load using functional near-infrared spectroscopy (fNIRS) technology. A lightweight, cost-effective fNIRS device with a single optode was developed to record prefrontal cortex data, specially designed to suit the skin with high melanin concentration. Data from participants performing n-back tasks revealed significant differences between hemoglobin concentrations among 1-back, 2-back, and 3-back tasks via ANOVA analysis. To further explore cognitive load assessment, various machine learning models were …

To improve spatial resolution in the PET-laparoscope system for intraoperative metastatic lymph nodes detection, design of a flat panel detector was optimized using Monte Carlo simulation tools. The performance of the new fixed detector was evaluated in point radio-source and phantom experiments. The experiment result shows that the system with the new fixed detector design has a spatial resolution better than 10 mm in three dimensions, and the system can distinguish two radio-sources clearly in a 2-minute scan.

Purpose Conventional positron emission tomography can be used only preoperatively to identify lymph node metastases, and hence, these growths are difficult to locate intraoperatively. Previously, an intraoperative laparoscopic coincidence imaging system, with an external fixed detector array and a detector probe that can be moved and inserted into the stomach, was proposed to identify lymph node metastases during stomach cancer surgery. This paper proposes a prototype detector for this system. Methods GAGG:Ce (Gd 3 Al 2 Ga 3 O 12 :Ce) scintillator crystals, one to one coupled with silicon photomultipliers (SiPMs), were used to identify 511 keV photons. An optical tracking system followed the position and orientation of the movable detector. SiPM outputs were read out by time-over-threshold (TOT)-based application-specific integrated circuits, which converted the electrical charges into digital pulses. To identify …

Intraoperative PET Navigation System for Cancer Surgery Toggle navigation J-STAGE home 資料・記事を探す 資料を探す:資料タイトルから 資料を探す:分野から 資料を探す:発行機関 から 記事を探す データを探す(J-STAGE Data) J-STAGEについて J-STAGEの概要 各種サービス・機能 公開データ 利用規約・ポリシー 新規登載の申し込み ニュース&PR お知らせ一覧 リリースノート メンテナンス情報 イベント情報 J-STAGEニュース 特集コンテンツ 各種広報媒体 サポート J-STAGE登載 機関用コンテンツ 登載ガイドライン・マニュアル 閲覧者向けヘルプ 動作確認済みブラウザ FAQ お 問い合わせ サイトマップ サインイン カート JA English 日本語 資料・記事を探す 資料を探す:資料 タイトルから 資料を探す:分野から 資料を探す:発行機関から 記事を探す データを探す(J-STAGE Data) J-STAGEについて J-STAGEの概要 各種サービス・機能 公開データ 利用規約・ポリシー 新規登載の申し込み ニュース&PR お知らせ一覧 リリースノート メンテナンス情報 イベント情報 J-STAGE…

Intraoperative PET-laparoscope system has been proposed to locate lymph node metastasis during gastric cancer surgery. The proposed system consists of an external detector array connected to a patient’s surgical bed and a movable detector probe which is inserted into the patient’s stomach along with a laparoscope. In this study a prototype detector for the PET-laparoscope system is presented with a pixelated movable detector probe tracked by an optical tracking system. Detector prototype reconstructed images of a 22 Na source with 3 mm spatial resolution in X (coronal) and Z (longitudinal) directions in a 2 min scan. The use of the pixelated multi-layer movable detector probe improved the spatial resolution of the system.

The PET-laparoscope system has been proposed to diagnose lymph node metastases intraoperatively in gastric cancer surgeries. The system uses two detector units, a fixed detector array and a movable detector probe to acquire PET images. The detector probe can be inserted into a patient’s stomach through laparoscopic ports. A surgeon can move the detector inside the patient’s body but the movement is limited. In this study the system was evaluated with an abdomen phantom so that the probe movement was realistic. Moreover, performance of an MLEM algorithm was investigated for the PET-laparoscope system. Experiments with the abdomen phantom confirmed that the system performs well when the probe movement is similar to that achievable during a laparoscopic surgery. MLEM algorithm provided better images. Image artifacts were reduced and the spatial resolution in lateral directions were better …

Positron emission tomography is used to diagnose gastric cancer and identify lymph node metastasis preoperatively. However, locating these lymph node metastases during surgery is difficult and usually leads to unnecessary node removal and results in a deterioration of a patient’s quality of life. To improve the quality of life, intraoperative identification of lymph node metastasis is necessary. A positron emission tomography system consisting of an external detector array connected to the patient’s surgical bed and a movable detector probe which is inserted into the patient’s stomach along with a laparoscopic instrument has been proposed to identify lymph node metastasis intraoperatively. This study presents the image reconstruction of a system involving data acquisition using a movable detector. A simulation-based investigation on the refinement of the detector design is also presented. The image is …

Monitoring the ECG (Electrocardiogram) of patients with cardiac disorder is of paramount importance since they may undergo cardiac arrhythmias even without noticing it. Majority of existing devices for this purpose are only capable of recording ECG of patients which are analyzed later on by cardiologists. This paper presents a new system developed to continuously monitor the ECG of patients and analyze them in real time to identify any abnormalities. The new system consists of two parts: a portable device worn by the patient and a server side component. The arrhythmia detection algorithm used in the portable device shows 99.78% sensitivity, 99.65% positive predictivity for QRS complex detection and 93.48% sensitivity, 96.45% positive predictivity for ventricular beat classification when evaluated on MIT-BIH arrhythmia database. When an arrhythmia is detected the device automatically uploads the ECG data in …

An electroencephalogram (EEG) instrument has been successfully developed and tested for capturing, visualizing and recording brain activity using both active and passive electrodes. The key idea is to capture a noise free composite brain wave and separate out its constituent components, namely delta, theta, alpha, beta and gamma. The system consists of three functional parts including EEG signal capturing, Digitizing and wireless transmission and PC end software for visualizing and post processing. EEG signal capturing part consists of electrodes, amplification circuit for each channel and Right Leg Driver circuit to eliminate 50 Hz power line noise. The digital band pass filters and the 50 Hz notch filter which confiscates any residual noise components are built in the PC software. Battery power and wireless communication gives the sovereignty to the user to move around with the system while being monitored …

This paper presents our approach in building an image guided navigational tool for neurosurgeons. The paper emphasizes critical methods which we have implemented within the main modules of the system, namely physical space model, calibrated frame and model transformation, MRI space model and the GUI. The surgeon is provided with special tools which contain markers which are detected by cameras to compute the real time positions of the tool tip. Special plastic markers are attached to the patient's head for the registration between two sets of coordinate systems. We were able to obtain satisfactory accuracy when equipped with low quality web cameras. Our GUI provides a modeled three-dimensional viewing of the patients head with the capability of rotating around fixed axes.

The performance of nonlinear adaptive filters in modeling devices with mild and moderately strong nonlinearities such as hearing aids was investigated. The existence on nonlinearities in hearing aids and that nonlinear adaptive filters were better suited for hearing aid modeling compared to their linear counterparts with equal number of filter coefficients. The signal to noise ratio improvement in modeling showed improvements in the range of 5% to 50%. The results suggested that as the nonlinearity of the device becomes stronger, a larger number of nonlinear coefficients should be used.

審査委員会委員:(主査) 東京大学教授 佐久間 一郎, 東京大学教授 上坂 充, 東京大学教授 瀬戸 泰之, 東京大学教授 高橋 浩之, 東京大学准教授 関野 正樹, 東京大学准教授 原田 香奈子

Prototype PET-laparoscope system for surgical navigation in cancer surgery | CiNii Research CiNii 国立情報学研究所 学術情報ナビゲータ[サイニィ] 詳細へ移動 検索フォームへ移動 論文・データを さがす 大学図書館の本をさがす English 検索 タイトル 人物/団体名 著者ID/研究者番号 所属機関 ISSN DOI 期間 ~ 本文リンク 本文リンクあり データソース JaLC IRDB Crossref DataCite NDLサーチ NDLデジコレ(旧NII-ELS) RUDA JDCat NINJAL CiNii Articles CiNii Books NACSIS-CAT/ILL DBpedia KAKEN Integbio PubMed LSDB Archive 極地研ADS 極地研学術DB OpenAIRE 公共データ カタログ すべて 研究データ 論文 本 博士論文 プロジェクト 人物 > 人物検索機能について Prototype PET-laparoscope system for surgical navigation in cancer surgery NDLデジタルコレクション Madhushanka Rukshani Liyanaarachchi 書誌事項 タイトル Prototype PET-laparoscope system for surgical navigation in cancer surgery タイトル別名 がん手術ナビゲーションのため…