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The Journal of the Acoustical Society... Jun 2023Users of cochlear implants (CIs) struggle in situations that require selective hearing to focus on a target source while ignoring other sources. One major reason for...
Users of cochlear implants (CIs) struggle in situations that require selective hearing to focus on a target source while ignoring other sources. One major reason for that is the limited access to timing cues such as temporal pitch or interaural time differences (ITDs). Various approaches to improve timing-cue sensitivity while maintaining speech understanding have been proposed, among them inserting extra pulses with short inter-pulse intervals (SIPIs) into amplitude-modulated (AM) high-rate pulse trains. Indeed, SIPI rates matching the naturally occurring AM rates improve pitch discrimination. For ITD, however, low SIPI rates are required, potentially mismatching the naturally occurring AM rates and thus creating unknown pitch effects. In this study, we investigated the perceptual contribution of AM and SIPI rate to pitch discrimination in five CI listeners and with two AM depths (0.1 and 0.5). Our results show that the SIPI-rate cue generally dominated the percept for both consistent and inconsistent cues. When tested with inconsistent cues, also the AM rate contributed, however, at the large AM depth only. These findings have implications when aiming at jointly improving temporal-pitch and ITD sensitivity in a future mixed-rate stimulation approach.
Topics: Cues; Heart Rate; Pitch Discrimination; Hearing; Cochlear Implantation
PubMed: 37307025
DOI: 10.1121/10.0019452 -
Sensors (Basel, Switzerland) Jan 2023Despite the notable recent developments in the field of remote photoplethysmography (rPPG), extracting a reliable pulse rate variability (PRV) signal still remains a...
Despite the notable recent developments in the field of remote photoplethysmography (rPPG), extracting a reliable pulse rate variability (PRV) signal still remains a challenge. In this study, eight image-based photoplethysmography (iPPG) extraction methods (GRD, AGRD, PCA, ICA, LE, SPE, CHROM, and POS) were compared in terms of pulse rate (PR) and PRV features. The algorithms were made robust for motion and illumination artifacts by using ad hoc pre- and postprocessing steps. Then, they were systematically tested on the public dataset UBFC-RPPG, containing data from 42 subjects sitting in front of a webcam (30 fps) while playing a time-sensitive mathematical game. The performances of the algorithms were evaluated by statistically comparing iPPG-based and finger-PPG-based PR and PRV features in terms of Spearman's correlation coefficient, normalized root mean square error (NRMSE), and Bland-Altman analysis. The study revealed POS and CHROM techniques to be the most robust for PR estimation and the assessment of overall autonomic nervous system (ANS) dynamics by using PRV features in time and frequency domains. Furthermore, we demonstrated that a reliable characterization of the vagal tone is made possible by computing the Poincaré map of PRV series derived from the POS and CHROM methods. This study supports the use of iPPG systems as promising tools to obtain clinically useful and specific information about ANS dynamics.
Topics: Humans; Photoplethysmography; Signal Processing, Computer-Assisted; Heart Rate; Diagnostic Imaging; Algorithms; Wearable Electronic Devices
PubMed: 36772543
DOI: 10.3390/s23031505 -
Sensors (Basel, Switzerland) Jul 2016Short-range noncontact sensors are capable of remotely detecting the precise movements of the subjects or wirelessly estimating the distance from the sensor to the... (Review)
Review
Short-range noncontact sensors are capable of remotely detecting the precise movements of the subjects or wirelessly estimating the distance from the sensor to the subject. They find wide applications in our day lives such as noncontact vital sign detection of heart beat and respiration, sleep monitoring, occupancy sensing, and gesture sensing. In recent years, short-range noncontact sensors are attracting more and more efforts from both academia and industry due to their vast applications. Compared to other radar architectures such as pulse radar and frequency-modulated continuous-wave (FMCW) radar, Doppler radar is gaining more popularity in terms of system integration and low-power operation. This paper reviews the recent technical advances in Doppler radars for healthcare applications, including system hardware improvement, digital signal processing, and chip integration. This paper also discusses the hybrid FMCW-interferometry radars and the emerging applications and the future trends.
Topics: Biosensing Techniques; Heart Rate; Humans; Monitoring, Physiologic; Respiration; Signal Processing, Computer-Assisted; Wireless Technology
PubMed: 27472330
DOI: 10.3390/s16081169 -
Physiological Reports Jun 2022Trauma patients may suffer significant blood loss, and noninvasive methods to diagnose hypovolemia in these patients are needed. Physiologic effects of hypovolemia,...
Trauma patients may suffer significant blood loss, and noninvasive methods to diagnose hypovolemia in these patients are needed. Physiologic effects of hypovolemia, aiming to maintain blood pressure, are largely mediated by increased sympathetic nervous activity. Trauma patients may however experience pain, which also increases sympathetic nervous activity, potentially confounding measures of hypovolemia. Elucidating the common and separate effects of the two stimuli on diagnostic methods is therefore important. Lower body negative pressure (LBNP) and cold pressor test (CPT) are experimental models of central hypovolemia and pain, respectively. In the present analysis, we explored the effects of LBNP and CPT on pre-ejection period and pulse transit time, aiming to further elucidate the potential use of these variables in diagnosing hypovolemia in trauma patients. We exposed healthy volunteers to four experimental sequences with hypovolemia (LBNP 60 mmHg) or normovolemia (LBNP 0 mmHg) and pain (CPT) or no pain (sham) in a 2 × 2 fashion. We calculated pre-ejection period and pulse transit time from ECG and ascending aortic blood velocity (suprasternal Doppler) and continuous noninvasive arterial pressure waveform (volume-clamp method). Fourteen subjects were available for the current analyses. This experimental study found that pre-ejection period increased with hypovolemia and remained unaltered with pain. Pulse transit time was reduced by pain and increased with hypovolemia. Thus, the direction of change in pulse transit time has the potential to distinguish hypovolemia and pain.
Topics: Healthy Volunteers; Heart Rate; Humans; Hypovolemia; Lower Body Negative Pressure; Pain; Pulse Wave Analysis
PubMed: 35748055
DOI: 10.14814/phy2.15355 -
Journal of Neurophysiology Dec 2021Phrenic afferents project to brainstem areas responsible for cardiorespiratory control and the mid-cervical spinal cord containing the phrenic motor nucleus. Our purpose...
Phrenic afferents project to brainstem areas responsible for cardiorespiratory control and the mid-cervical spinal cord containing the phrenic motor nucleus. Our purpose was to quantify the impact of small- and large-diameter phrenic afferent activation on phrenic motor output. Anesthetized and ventilated rats received unilateral phrenic nerve stimulation while contralateral phrenic motor output and blood pressure were recorded. Twelve currents of 40-Hz inspiratory-triggered stimulation were delivered (20 s on, 5 min off) to establish current response curves. Stimulation pulse width was varied to preferentially activate large-diameter phrenic afferents (narrow pulse width) and recruit small-diameter fibers (wide pulse width). Contralateral phrenic amplitude was elevated immediately poststimulation at currents above 35 µA for wide and 70 µA for narrow pulse stimulation when compared with animals not receiving stimulation (time controls). Wide pulse width stimulation also increased phrenic burst frequency at currents ≥35 µA, caused a transient decrease in mean arterial blood pressure at currents ≥50 µA, and resulted in a small change in heart rate at 300 µA. Unilateral dorsal rhizotomy attenuated stimulation-induced cardiorespiratory responses indicating that phrenic afferent activation is required. Additional analyses compared phrenic motor amplitude with output before stimulation and showed that episodic activation of phrenic afferents with narrow pulse stimulation can induce short-term plasticity. We conclude that the activation of phrenic afferents ) enhances contralateral phrenic motor amplitude when large-diameter afferents are activated, and ) when small-diameter fibers are recruited, the amplitude response is associated with changes in burst frequency and cardiovascular parameters. Acute, inspiratory-triggered stimulation of phrenic afferents increases contralateral phrenic motor amplitude in adult rats. When small-diameter afferents are recruited, the amplitude response is accompanied by an increase in phrenic burst frequency, a transient decrease in mean arterial blood pressure, and a slight increase in heart rate. Repeated episodes of large-diameter phrenic afferent activation may also be capable of inducing short-term plasticity.
Topics: Afferent Pathways; Animals; Arterial Pressure; Blood Gas Analysis; Electrophysiological Phenomena; Female; Heart Rate; Hemodynamics; Inhalation; Male; Neuronal Plasticity; Neurons, Afferent; Phrenic Nerve; Rats; Rats, Sprague-Dawley
PubMed: 34788165
DOI: 10.1152/jn.00433.2021 -
Arquivos Brasileiros de Cardiologia May 2017High resting heart rate is considered an important factor for increasing mortality chance in adults. However, it remains unclear whether the observed associations would...
BACKGROUND:
High resting heart rate is considered an important factor for increasing mortality chance in adults. However, it remains unclear whether the observed associations would remain after adjustment for confounders in adolescents.
OBJECTIVES:
To analyze the relationship between resting heart rate, blood pressure and pulse pressure in adolescents of both sexes.
METHODS:
A cross-sectional study with 1231 adolescents (716 girls and 515 boys) aged 14-17 years. Heart rate, blood pressure and pulse pressure were evaluated using an oscillometric blood pressure device, validated for this population. Weight and height were measured with an electronic scale and a stadiometer, respectively, and waist circumference with a non-elastic tape. Multivariate analysis using linear regression investigated the relationship between resting heart rate and blood pressure and pulse pressure in boys and girls, controlling for general and abdominal obesity.
RESULTS:
Higher resting heart rate values were observed in girls (80.1 ± 11.0 beats/min) compared to boys (75.9 ± 12.7 beats/min) (p ≤ 0.001). Resting heart rate was associated with systolic blood pressure in boys (Beta = 0.15 [0.04; 0.26]) and girls (Beta = 0.24 [0.16; 0.33]), with diastolic blood pressure in boys (Beta = 0.50 [0.37; 0.64]) and girls (Beta = 0.41 [0.30; 0.53]), and with pulse pressure in boys (Beta = -0.16 [-0.27; -0.04]).
CONCLUSIONS:
This study demonstrated a relationship between elevated resting heart rate and increased systolic and diastolic blood pressure in both sexes and pulse pressure in boys even after controlling for potential confounders, such as general and abdominal obesity.
FUNDAMENTO:
A frequência cardíaca de repouso é considerada um importante fator de aumento de mortalidade em adultos. Entretanto, ainda é incerto se as associações observadas permanecem após ajuste para fatores de confusão em adolescentes.
OBJETIVOS:
Analisar a relação entre frequência cardíaca de repouso, pressão arterial e pressão de pulso em adolescentes dos dois sexos.
MÉTODOS:
Estudo transversal com 1231 adolescentes (716 meninas e 515 meninos, idade de 14-17 anos). Frequência cardíaca, pressão arterial e pressão de pulso foram avaliadas com esfigmomanômetro oscilométrico validado para essa população. Peso e altura foram medidos com balança eletrônica e estadiômetro, respectivamente, e a circunferência abdominal, com uma fita inextensível. Análise multivariada com regressão linear investigou a relação entre frequência cardíaca de repouso, pressão arterial e pressão de pulso em meninos e meninas, controlando para obesidade geral e abdominal.
RESULTADOS:
Valores maiores de frequência cardíaca de repouso foram observados em meninas (80,1 ± 11,0 bpm) em comparação a meninos (75,9 ± 12,7 bpm) (p ≤ 0,001). Frequência cardíaca de repouso associou-se com pressão arterial sistólica em meninos [Beta = 0,15 (0,04; 0,26)] e meninas [Beta = 0,24 (0,16; 0,33)], com pressão arterial diastólica em meninos [Beta = 0,50 (0,37; 0,64)] e meninas [Beta = 0,41 (0,30; 0,53)], e com pressão de pulso apenas em meninos [Beta = -0,16 (-0,27; -0,04)].
CONCLUSÕES:
Este estudo demonstrou a relação da frequência cardíaca de repouso elevada com aumento das pressões arteriais sistólica e diastólica em ambos os sexos e com pressão de pulso em meninos, mesmo após controle para potenciais fatores de confusão, como obesidade geral e abdominal.
Topics: Adolescent; Age Factors; Arterial Pressure; Blood Pressure; Body Mass Index; Brazil; Cross-Sectional Studies; Female; Heart Rate; Humans; Male; Rest; Sex Factors; Waist Circumference
PubMed: 28492739
DOI: 10.5935/abc.20170050 -
Scientific Reports Jan 2023Early recognition of cardiopulmonary arrest (CPA) expedites emergency calls and resuscitation and improves the survival rate of unresponsive individuals. However, the... (Observational Study)
Observational Study
Early recognition of cardiopulmonary arrest (CPA) expedites emergency calls and resuscitation and improves the survival rate of unresponsive individuals. However, the accuracy of breathing and radial artery pulse assessment by non-medical persons is poorly understood. The aim of this study was to determine the accuracy of breathing assessment and radial pulse palpation among 450 non-medical personnel using a high-fidelity simulator. We examined the accuracy of 10 second's assessment for breathing and radial pulse using a high-fidelity mannequin simulator, included 496 non-medical participants (school teachers) between 2016-2018. For a primary results, the sensitivity for the detection of the presence of the breathing and radial pulse was 96.2% (97.5% for sensitivity and 92.0% for specificity) and 91.7% (99.1% for sensitivity and 56.8% for specificity), respectively. Futher, breathing rate and radial pulse rate were strongly correlated with the assessments, with Spearman's correlation coefficients of 0.813 (P < 0.001) and 0.719 (P < 0.001), respectively. In contrast, radial pulse strength was weakly correlated with the assessment (coefficient of 0.288, P < 0.001). Our results suggested that non-medical persons would show high accuracy in detecting and measuring respiration and radial pulse, although they did not accurately determine radial pulse strength for the early recognition of CPA.
Topics: Humans; Cross-Sectional Studies; Respiration; Respiratory Rate; Heart Rate; Radial Artery
PubMed: 36720983
DOI: 10.1038/s41598-023-28408-3 -
IEEE Transactions on Bio-medical... May 2021In this work, a detection and classification method for sleep apnea and hypopnea, using photopletysmography (PPG) and peripheral oxygen saturation (SpO ) signals, is...
In this work, a detection and classification method for sleep apnea and hypopnea, using photopletysmography (PPG) and peripheral oxygen saturation (SpO ) signals, is proposed. The detector consists of two parts: one that detects reductions in amplitude fluctuation of PPG (DAP)and one that detects oxygen desaturations. To further differentiate among sleep disordered breathing events (SDBE), the pulse rate variability (PRV) was extracted from the PPG signal, and then used to extract features that enhance the sympatho-vagal arousals during apneas and hypopneas. A classification was performed to discriminate between central and obstructive events, apneas and hypopneas. The algorithms were tested on 96 overnight signals recorded at the UZ Leuven hospital, annotated by clinical experts, and from patients without any kind of co-morbidity. An accuracy of 75.1% for the detection of apneas and hypopneas, in one-minute segments,was reached. The classification of the detected events showed 92.6% accuracy in separating central from obstructive apnea, 83.7% for central apnea and central hypopnea and 82.7% for obstructive apnea and obstructive hypopnea. The low implementation cost showed a potential for the proposed method of being used as screening device, in ambulatory scenarios.
Topics: Arousal; Heart Rate; Humans; Polysomnography; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
PubMed: 32997622
DOI: 10.1109/TBME.2020.3028041 -
European Review For Medical and... Jan 2021Phacoemulsification is the most common cataract surgery that needs optimum circumstances in the field of surgery. This comparative pre- and postoperative study assessed... (Comparative Study)
Comparative Study Observational Study
OBJECTIVE
Phacoemulsification is the most common cataract surgery that needs optimum circumstances in the field of surgery. This comparative pre- and postoperative study assessed the efficacy and safety of using adrenaline in the irrigating solution as an adjunct to preoperative topical mydriatics in dark irides during Phaco surgery.
PATIENTS AND METHODS
This was a prospective observational study that enrolled 421 cataract patients (421 eyes) with dark irides, who were scheduled for Phaco surgery from January 2019 to August 2020. All patients received intraoperative irrigation of a balanced salt solution containing adrenaline. The pulse rate and systolic and diastolic blood pressure of all patients were recorded pre- and postoperatively. In addition, the presence of intraoperative floppy-iris syndrome (IFIS), need for pupil mechanical dilatation, and incidence of posterior capsular rupture were recorded.
RESULTS
The sample consisted of 421 patients (421 eyes) all had dark irides. Pulse rate and systolic and diastolic blood pressure did not significantly increase post-operatively (p <0.001). Mechanical dilatation of the pupil was performed in one patient (0.24%) and seven eyes (1.66%) were found to have IFIS. There was no case of posterior capsule rupture.
CONCLUSIONS
In comparison with the use of preoperative topical mydriatics alone, adding intracameral adrenaline to the irrigation fluid maintains better pupillary dilatation throughout Phacoemulsification surgery, thereby providing better clinical outcomes in dark irides, even in those with IFIS. Its use has no incremental effect on either blood pressure or pulse rate.
Topics: Administration, Topical; Adult; Aged; Blood Pressure; Epinephrine; Eye Color; Female; Heart Rate; Humans; Injections; Intraoperative Complications; Iris; Iris Diseases; Male; Middle Aged; Mydriatics; Phacoemulsification; Prospective Studies; Pupil; Therapeutic Irrigation
PubMed: 34337725
DOI: 10.26355/eurrev_202101_26389 -
Biosensors Oct 2016To achieve sensitivity, comfort, and durability in vital sign monitoring, this study explores the use of radar technologies in wearable devices. The study first detected... (Review)
Review
To achieve sensitivity, comfort, and durability in vital sign monitoring, this study explores the use of radar technologies in wearable devices. The study first detected the respiratory rates and heart rates of a subject at a one-meter distance using a self-injection-locked (SIL) radar and a conventional continuous-wave (CW) radar to compare the sensitivity versus power consumption between the two radars. Then, a pulse rate monitor was constructed based on a bistatic SIL radar architecture. This monitor uses an active antenna that is composed of a SIL oscillator (SILO) and a patch antenna. When attached to a band worn on the subject's wrist, the active antenna can monitor the pulse on the subject's wrist by modulating the SILO with the associated Doppler signal. Subsequently, the SILO's output signal is received and demodulated by a remote frequency discriminator to obtain the pulse rate information.
Topics: Heart Rate; Humans; Monitoring, Physiologic; Pulse; Radar; Vital Signs; Wrist
PubMed: 27792176
DOI: 10.3390/bios6040054