Conor Heneghan

Conor Heneghan
University College Dublin | UCD · School of Electrical, Electronic and Mechanical Engineering

PhD

About

156
Publications
44,422
Reads
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5,690
Citations
Additional affiliations
January 2007 - present
January 1999 - December 2010
University College Dublin
January 1996 - June 1997
Education
September 1990 - July 1995
Columbia University
Field of study
  • Electrical Engineering
September 1986 - June 1990
University College Dublin
Field of study
  • Electronic Engineering

Publications

Publications (156)
Poster
Full-text available
Evaluation of Sleep Apnea Detection from a Smart Watch- Pilot Study.
Patent
Full-text available
Disclosed is a cardio-pulmonary health monitoring apparatus. The apparatus comprises a contactless motion sensor configured to generate one or more movement signals representing bodily movement of a patient during a monitoring session; a processor; and a memory storing program instructions configured to cause the processor to carry out a method of...
Article
Full-text available
Objective: This paper aims to report on the accuracy of estimating sleep stages using a wrist-worn device that measures movement using a 3D accelerometer and an optical pulse photoplethysmograph (PPG). Approach: Overnight recordings were obtained from 60 adult participants wearing these devices on their left and right wrist, simultaneously with...
Article
Introduction We investigated the ability of a wrist-worn tracker to estimate sleep stages in normal adult sleepers. Such a device could be useful in simplifying sleep research and in increasing public knowledge of sleep. Methods Movement and cardiac data was collected from 60 adult subjects (36 M: 24 F, ages 34 ± 10 yrs) wearing two wrist worn dev...
Article
Full-text available
Aims: At least 50% of patients with heart failure (HF) may have sleep-disordered breathing (SDB). Overnight in-hospital polysomnography (PSG) is considered the gold standard for diagnosis, but a lack of access to such testing contributes to under-diagnosis of SDB. Therefore, there is a need for simple and reliable validated methods to aid diagnosis...
Patent
A processing system includes methods to promote sleep. The system may include a monitor such as a non-contact motion sensor from which sleep information may be determined. User sleep information, such as sleep stages, hypnograms, sleep scores, mind recharge scores and body scores, may be recorded, evaluated and/or displayed for a user. The system m...
Article
Full-text available
Nocturnal respiration rate parameters were collected from 20 COPD subjects over an 8?week period, to determine if changes in respiration rate were associated with exacerbations of COPD. These subjects were primarily GOLD Class 2 to 4, and had been recently discharged from hospital following a recent exacerbation. The respiration rates were collecte...
Poster
Full-text available
Objective: To determine the performance of a non-contact radiofrequency biomotion sensor in estimating sleep parameters, using polysomnography (PSG) as a reference. Methods: A dataset of 40 recordings with full PSG and non-contact biomotion signal was collected from normal healthy volunteers in a sleep-lab environment. Recordings were automatically...
Article
Despite the fact that we spend nearly one third of our lives asleep, surprisingly little was known about sleep until the 20th century. Now, sleep medicine is firmly established as a significant branch of medical practice, taking its roots strongly from the work of Nathaniel Kleitman and colleagues at the University of Chicago in the 1950s. They wer...
Patent
A sleep monitoring system includes an ECG device (2) and a respiration inductance plethysmogram (3) which monitor cardiac activity and physical (ribcage) respiration respectively and feed representative signals to a digital data processor. Operations (5-9) process the beat interval data, while in a second thread, operations (20-24) independently pr...
Article
Full-text available
Dear Editor:We thank Dr. Kawada for his comment on our work [1] as he raises an important point in relation to the use of actigraphy in sleep assessment, namely, that the optimal Actiwatch setting for maximizing sleep/wake accuracy will be subject-dependent. As noted in our paper, we used the “default” settings for Actiwatch sensitivity provided by...
Article
Full-text available
This paper aims to compare the absolute performance of three noncontact sleep measurement devices for measuring sleep parameters in normal subjects against polysomnography and to assess their relative performance. The devices investigated were two noncontact radio-frequency biomotion sensors (SleepMinder (SM) and SleepDesign (HSL-101)) and an actig...
Article
Ambulatory monitoring is of major clinical interest in the diagnosis of obstructive sleep apnoea syndrome. We compared a novel non-contact biomotion sensor, which provides an estimate of both sleep time and sleep-disordered breathing, with wrist actigraphy in the assessment of total sleep time in adult humans suspected of obstructive sleep apnoea s...
Patent
[1] Disclosed is a cardio-pulmonary health monitoring apparatus. The apparatus comprises a contactless motion sensor configured to generate one or more movement signals representing bodily movement of a patient during a monitoring session; a processor; and a memory storing program instructions configured to cause the processor to carry out a method...
Article
Obstructive sleep apnoea is a highly prevalent but under-diagnosed disorder. The gold standard for diagnosis of obstructive sleep apnoea is inpatient polysomnography. This is resource intensive and inconvenient for the patient, and the development of ambulatory diagnostic modalities has been identified as a key research priority. SleepMinder (Bianc...
Article
Full-text available
In this paper, a non-contact method for human breathing rate estimation is discussed. The method utilises SleepMinder technology, which implements a radio-frequency Doppler radar system to capture physiological movements of the body in the form of phase modulation. To determine the breathing rate, the signals are down-converted and the baseband sig...
Article
Full-text available
We studied a novel non-contact biomotion sensor, which has been developed for identifying sleep/wake patterns in adult humans. The biomotion sensor uses ultra low-power reflected radiofrequency waves to determine the movement of a subject during sleep. An automated classification algorithm has been developed to recognize sleep/wake states on a 30-s...
Conference Paper
Nearly perfect reconstruction (N-PR) modified discrete Fourier Transform (MDFT) filter banks (FBs) have been widely applied to signal coding and their use for data transmission in multicarrier communications has also been addressed in the literature. However, comparison and assessment of the performance of alternative designs for uniform N-PR MDFT-...
Article
We investigate two signal processing methods, time and frequency-based approaches, for non-contact cardiac detection. A 5.8-GHz Doppler radar sensor was used for non-contact measurement of respiration and heart rate from stationary and semi-stationary subjects at a distance of 0.5 to 1.5 meters. We report on the accuracy of the heart rate measureme...
Article
We describe a contact-less method for measurement of respiration rate during sleep using a 5.8GHz radio-frequency bio-motion sensor. The sensor operates by sensing phase shifts in reflected radio waves from the torso caused by respiratory movements and other bodily movements such as twitches, positional changes etc. These non-respiratory motion art...
Conference Paper
Full-text available
An automated real time method for detecting human breathing rate from a non contact biosensor is considered in this paper. The method has low computational and RAM requirements making it well-suited to real-time, low power implementation on a microcontroller. Time and frequency domain methods are used to separate a 15s block of data into movement,...
Article
Full-text available
Sleep disturbance is becoming increasingly recognised as a clinically important symptom in people with chronic low back pain (CLBP, low back pain >12 weeks), associated with physical inactivity and depression. Current research and international clinical guidelines recommend people with CLBP assume a physically active role in their recovery to preve...
Article
Full-text available
There is considerable interest in non-intrusive and reliable continuous ambulatory blood pressure measurement systems. Pulse amplitude is the peak to trough amplitude of the photo-plethysmogram signal. We compared pulse amplitude with a currently popular parameter, the pulse arrival time (PAT), for estimating continuous systolic blood pressure (SBP...
Patent
Full-text available
EN)An apparatus, system, and method for monitoring a person suffering from a chronic medical condition predicts and assesses physiological changes which could affect the care of that subject. Examples of such chronic diseases include (but are not limited to) heart failure, chronic obstructive pulmonary disease, asthma, and diabetes. Monitoring incl...
Article
Full-text available
This paper studies the Hierarchical Modulation, a transmission strategy of the approaching scalable multimedia over frequency-selective fading channel for improving the perceptible quality. An optimization strategy for Hierarchical Modulation and convolutional encoding, which can achieve the target bit error rates with minimum global signal-to-nois...
Article
Full-text available
While approximately 70% of chronic low back pain (CLBP) sufferers complain of sleep disturbance, current literature is based on self report measures which can be prone to bias and no objective data of sleep quality, based exclusively on CLBP are available. In accordance with the recommendations of The American Sleep Academy, when measuring sleep, b...
Conference Paper
Full-text available
We describe an innovative sensor technology (SleepMinder) for contact-less and convenient measurement of sleep and breathing in the home. The system is based on a novel non-contact biomotion sensor and proprietary automated analysis software. The biomotion sensor uses an ultra low-power radio-frequency transceiver to sense the movement and respirat...
Article
Full-text available
A 5.8-GHz ISM-Band radio-frequency sensor has been developed for non-contact measurement of respiration and heart rate from stationary and semi-stationary subjects at a distance of 0.5 to 1.5 meters. We report on the accuracy of the heart rate measurements obtained using two algorithmic approaches, as compared to a reference heart rate obtained usi...
Technical Report
Full-text available
Purpose: This report describes the use of two new devices for screening of obstructive sleep apnea syndrome (OSAS). Holter apnea monitoring (continuous electrocardiogram recording) and Holter oximetry (continuous electrocardiogram recording and continuous pulse oximetry) were used on patients in the home setting to diagnose OSAS. We describe the re...
Patent
Full-text available
An apparatus, system, and method for monitoring a person suffering from a chronic medical condition predicts and assesses physiological changes which could affect the care of that subject. Examples of such chronic diseases include (but are not limited to) heart failure, chronic obstructive pulmonary disease, asthma, and diabetes. Monitoring include...
Article
The study of human cognition, and preoperative functional brain mapping, are facilitated through the use of magnetoencephalography (MEG). However, the noise present in such recordings is significant relative to the signals of interest. To circumvent this issue multiple trials are performed for the same task and an ensemble average is performed to i...
Article
Full-text available
A method for the detection of sleep apnoea, suitable for use in the home environment, is presented. The method automatically analyses night-time electrocardiogram (ECG) and oximetry recordings and identifies periods of normal and sleep-disordered breathing (SDB). The SDB is classified into one of six classes: obstructive, mixed and central apnoeas,...
Article
Full-text available
Resource limitations have raised interest in portable monitoring systems that can be used by specialist sleep physicians as part of an overall strategy to improve access to the diagnosis of sleep apnea. This study validates a combined electrocardiogram and oximetry recorder (Holter-oximeter) against simultaneous polysomnography for detection of sle...
Article
Objective To test the reliability of the Holter Oximeter for home testing of obstructive sleep apnea. Previous reports have shown a 96% correlation with simultaneous polysomnography and Holter Oximetry in the sleep laboratory. This study was designed to measure reliability of data obtained at home, as well as to obtain information from patients reg...
Article
Full-text available
There is considerable interest in unobtrusive and portable methods of monitoring sleepiness outside the laboratory setting. This study evaluates the usefulness of combined electrocardiogram (ECG) and photoplethysmogram (PPG) measurements for estimating psychomotor vigilance. The psychomotor vigilance test (PVT) was performed at various points over...
Article
Full-text available
Transient changes in heart rate associated with obstructive apneas have been suggested for screening of sleep disordered breathing (SDB). This study prospectively compares the outcomes of an automated ECG-based SDB screening tool with simultaneous polysomnography. The previously-developed automated algorithm was applied to a single channel ECG obta...
Article
Full-text available
We evaluate a contact-less continuous measuring system measuring respiration and activity patterns system for identifying sleep/wake patterns in adult humans. The system is based on the use of a novel non-contact biomotion sensor, and an automated signal analysis and classification system. The sleep/wake detection algorithm combines information fro...
Article
Full-text available
An improved technique to design prototype filters for nearly-perfect reconstruction modulated filter banks and transmultiplexers is shown. This technique is based on the frequency sampling approach, and the formulation is presented as a multi-objective optimisation problem. Results indicate that the new formulation provides arbitrary-length prototy...
Article
Full-text available
Question of study We recently investigated the possibility of obtaining simplified Sleep- Wake-REM sleep stage information from subjects being assessed for Obstructive Sleep Apnea Syndrome (OSAS), using only electrocardiogram and respiration signals. The utility of such a system may be limited somewhat by the presence of OSAS in the patient group (...
Article
Full-text available
We present a technique called corrected integral shape averaging (CISA) for quantifying shape and shape differences in a set of signals. CISA can be used to account for signal differences which are purely due to affine time warping (jitter and dilation/compression), and hence provide access to intrinsic shape fluctuations. CISA can also be used to...
Article
Full-text available
Effect of anaesthetic agents in restoration rhythm procedures during atrial fibrillation (AF) has not been fully investigated. Intra-atrial recordings belong to 27 patients diagnosed with AF were analyzed ldquobeforerdquo (baseline) and ldquoduringrdquo anaesthetic infusion. Organization measurements were evaluated in time-domain and frequency-doma...
Article
We present a method for initialising the K-means clustering algorithm. Our method hinges on the use of a kd-tree to perform a density estimation of the data at various locations. We then use a modification of Katsavounidis’ algorithm, which incorporates this density information, to choose K seeds for the K-means algorithm. We test our algorithm on...
Conference Paper
Full-text available
RATIONALE Limited diagnostic systems, suitable for home monitoring, are a desirable alternative to polysomnography (PSG) in the evaluation of patients with suspected obstructive sleep apnea syndrome (OSAS). Since SaO2 and heart rate variability have been independently proposed as screening tools, we evaluated a combined electrocardiograph (EKG) and...
Article
Full-text available
In this paper, two evolutionary programming (EP) algorithms (classical EP and fast EP) are applied to design prototype lowpass Finite Impulse Response filters for use in a modulated filterbank. The chosen filter design technique is based on frequency-sampling (where the Fourier transform magnitudes of the filter are the objective variables). Design...
Article
Full-text available
The impact of obstructive sleep apnea syndrome (OSAS) on the arterial baroreflex, and its significance, is still under debate. We investigated the baroreflex sensitivity (BRS) during sleep in well-selected OSAS patient and control subject cohorts We performed a prospective study of 10 non-OSAS subjects, 14 subjects with mild-to-moderate OSAS, and 1...
Article
We provide a quantitative comparison between two new methods for deriving a respiratory signal from a single lead electrocardiogram, and the published technique of Behbehani et al. [An investigation of the mean electrical axis angle and respiration during sleep, in: Proceedings of the Second Joint EMBS/BMES Conference Houston, TX, USA, October 2002...
Article
Full-text available
Actimetry is a widely accepted technology for the diagnosis and monitoring of sleep disorders such as insomnia, circadian sleep/wake disturbance, and periodic leg movement. In this study we investigate a very sensitive non-contact biomotion sensor to measure actimetry and compare its performance to wrist-actimetry. A data corpus consisting of twent...
Article
Single-channel ECG and finger photoplethysmogram were used to estimate sleep states in obstructive sleep apnea patients. Overnight Holter-oximeter recordings from 14 subjects with suspected sleep apnea were analysed. Parameters including the RR interval, photoplethysmogram amplitude and rise time, and pulse arrival time were characterised and a Hid...
Article
An automated method for detecting episodes of probable paroxysmal atrial fibrillation based on processing blocks of inter-heartbeat intervals is considered. The method has very low computational requirements making it well-suited to near real-time, low power applications. A supervised linear discriminant classifier is used to estimate the likelihoo...
Conference Paper
The cardiopulmonary coupling measure has been proposed recently as an indicator of sleep stability. We examined changes in cardiopulmonary coupling during the sleep onset period and its usefulness in estimating sleep onset. Overnight polysomnography data from 10 male adults without sleep disordered breathing was analysed (age 40 plusmn 7 years, BMI...
Conference Paper
The mechanisms responsible for the initiation, maintenance and spontaneous termination of atrial fibrillation (AF) are not yet completely understood. Though much of the underlying physiology has been well determined, it has been demonstrated in numerous clinical investigations that the autonomic nervous system plays an important role in AF genesis...
Chapter
Full-text available
We present a simple method for detection of sleep apnoea in the home environment. The method identifies episodes of disordered breathing and provides an estimated apnoea hyponoea index (AHI) by recording and automatic analysis of nighttime ECG and oximetry recordings. At the heart of the device is a pattern recognition system that identifies episod...
Conference Paper
Full-text available
In a substantial number of patients atrial fibrillation (AF) recurs after successful electrical cardioversion, but at present there are no reliable clinical markers for confidently identifying the patients in which recurrence will occur within a short period of time. This study evaluates the predictive classification performance of some Discrete Wa...
Chapter
Introduction Physiological Backround Experimental Methods and Measures Models Discussion Future Trends References
Article
The study of human cognition, and preoperative functional brain mapping, are facilitated through the use of magnetoencephalography (MEG). However, the noise present in such recordings is significant relative to the signals of interest. To circumvent this issue multiple trials are performed for the same task and an ensemble average is performed to i...
Conference Paper
Pulse arrival time and the amplitude of the finger photoplethysmogram were used to track continuous systolic blood pressure over 10-minute intervals. The measures were recorded with a holter-oximeter from a sample of 8 young, healthy human subjects in the supine and standing positions. Results show that, with individual calibration, systolic blood...
Article
Full-text available
A cardiorespiratory-based automatic sleep staging system for subjects with sleep-disordered breathing is described. A simplified three-state system is used: Wakefulness (W), rapid eye movement (REM) sleep (R), and non-REM sleep (S). The system scores the sleep stages in standard 30-s epochs. A number of features associated with the epoch RR-interva...
Article
Full-text available
Pulse arrival time and the amplitude of the finger photoplethysmogram were used to track blood pressure continuously over 10-minute intervals. The measures were recorded with a holter-oximeter from a sample of 8 young, healthy human subjects in the supine and standing positions. Results indicate that, with individual calibration, systolic and diast...
Article
Baroreflex sensitivity (BRS) is assessed in subjects with and without obstructive sleep apnea (OSA) using the time domain direct sequence technique, the spectral transfer function (TF) technique and the alpha index technique. All three measures showed a significantly depressed BRS value in subjects with severe apnea. The high frequency (HF) compone...
Article
Full-text available
In this paper we propose a new criterion for solving the problem of channel shortening in multi-carrier systems. In a discrete multitone receiver, a time-domain equalizer (TEQ) reduces intersymbol interference (ISI) by shortening the effective duration of the channel impulse response. Minimum mean square error (MMSE) method for TEQ does not give sa...
Conference Paper
It is well known that the use of antenna arrays at both sides of communication link can result in high channel capacities provided that the propagation medium is rich scattering. In most previous works presented on MIMO wireless structures, Rayleigh fading conditions were considered. In this work, the capacity of MIMO systems under uncorrelated Ric...
Article
Full-text available
It is well known that the use of antenna arrays at both sides of communication link can result in high channel capacities provided that the propagation medium is rich scattering. In most previous works presented on MIMO wireless structures, Rayleigh fading conditions were considered. In this work, the capacity of MIMO systems under fully correlated...
Conference Paper
Full-text available
We present a technique for dimension reduction. The technique uses a gradient descent approach to attempt to sequentially find orthogonal vectors such that when the data is projected onto each vector the classification error is minimised. We make no assumptions about the structure of the data and the technique is independent of the classifier model...
Article
In this paper we present a low power system identification algorithm suitable for echo and crosstalk cancellation in data communications. Crosstalk and echo channels tend to be sparse systems i.e. many taps are negligible with just a few taps significant or active. The proposed adaptive algorithm, called the sparse cross-correlation (SCC) algorithm...
Patent
This invention relates to a system and method for detecting episodes of probable paroxysmal atrial fibrillation. Atrial fibrillation (AF) is the most common heart arrhythmia in clinical practice, and has serious morbidity and mortality. AF is a significant risk factor for stroke; about 15% of strokes occur in people with AF. The prevalence of AF in...
Conference Paper
Full-text available
Automated detection of sleep apnoea from the surface ECG is a challenge with potentially significant clinical benefit. The objective of this study is to explore a possible relation between P-wave shape changes and the presence of Obstructive Sleep Apnoea (OSA) episodes in ECG records. Our working hypothesis is that apnoea-related phenomena (e.g., h...
Article
We considered the capability of pulse transit time (PTT) to provide respiratory information in obstructive sleep apnea (OSA) patients. PTT-derived respiratory frequency was quite well correlated with that derived from inductance plethysmography, with amplitude slightly less so. The PTT-derived respiratory estimates were also used to distinguish sle...
Article
Full-text available
Multi-input Multi-output (MIMO) system are today regarded as one of the most promising research areas in wireless communications. This is due to the fact that MIMO channel can offer a significant capacity gain over traditional Single-input single-output (SISO) channel. This paper presents the capacity of an uncorrelated and correlated MIMO channel....