Proof of principle study: diagnostic accuracy of a novel algorithm for the estimation of sleep stages and disease severity in patients with sleep-disordered breathing based on actigraphy and respiratory inductance plethysmography.

PURPOSE: In this proof of principle study, we evaluated the diagnostic accuracy of the novel Nox BodySleepTM 1.0 algorithm (Nox Medical, Iceland) for the estimation of disease severity and sleep stages based on features extracted from actigraphy and respiratory inductance plethysmography (RIP) belts. Validation was performed against in-lab polysomnography (PSG) in patients with sleep-disordered breathing (SDB). METHODS: Patients received PSG according to AASM. Sleep stages were manually scored using the AASM criteria and the recording was evaluated by the novel algorithm. The results were analyzed by descriptive statistics methods (IBM SPSS Statistics 25.0). RESULTS: We found a strong Pearson correlation (r=0.91) with a bias of 0.2/h for AHI estimation as well as a good correlation (r=0.81) and an overestimation of 14 min for total sleep time (TST). Sleep efficiency (SE) was also valued with a good Pearson correlation (r=0.73) and an overestimation of 2.1%. Wake epochs were estimated with a sensitivity of 0.65 and a specificity of 0.59 while REM and non-REM (NREM) phases were evaluated a sensitivity of 0.72 and 0.74, respectively. Specificity was 0.74 for NREM and 0.68 for REM. Additionally, a Cohen's kappa of 0.62 was found for this 3-class classification problem. CONCLUSION: The algorithm shows a moderate diagnostic accuracy for the estimation of sleep. In addition, the algorithm determines the AHI with good agreement with the manual scoring and it shows good diagnostic accuracy in estimating wake-sleep transition. The presented algorithm seems to be an appropriate tool to increase the diagnostic accuracy of portable monitoring. The validated diagnostic algorithm promises a more appropriate and cost-effective method if integrated in out-of-center (OOC) testing of patients with suspicion for SDB.

Digital orbitoplethysmograph: A new device to study the regional cerebral circulation using extraorbital plethysmography.

BACKGROUND: Noninvasive diagnostic methods utilizing pulse wave measurements on the surface of the head are an important tool in diagnosing various types of cerebrovascular disease. The measurement of extraorbital pressure fluctuations reflects intraocular and intracranial pressure changes and can be used to estimate pressure changes in intracranial arteries and the collateral circulation. NEW METHOD: In this paper, we describe our patented (CZ 305757) digital device for noninvasive measuring and monitoring of orbital movements using pressure detection. We conducted preclinical tests (126 measurements on 42 volunteers) to evaluate the practical capabilities of our device. Two human experts visually assessed the quality of the pressure pulsation and discriminability among various test conditions (specifically, subject lying, sitting, and the Matas carotid occlusion test). RESULTS: The results showed that our device provided clinically relevant outcomes with a sufficient level of detail of the pulse wave and a high reliability (not less than 85%) in all clinically relevant situations. It was possible to record the effect of the Matas carotid occlusion test. COMPARISON WITH EXISTING METHOD(S): Our fully noninvasive, lightweight (185 g), portable, and wireless device provides a considerably cheaper alternative to the current diagnostic methods (e.g., transcranial ultrasound, X-ray, or MRI angiography) for specific assessment of cerebral circulation. Within a minute, it can detect the Willis circle integrity and thus eliminate the potential risks associated with the Matas test using standard EEG. CONCLUSIONS: Our device represents an improvement and a valid alternative to the current methods diagnosing regional cerebral circulation.

[The plethysmographic reference equations established for adult natives of Eastern Algeria are not applicable to natives of Northern Algeria]. / Les équations de référence pléthysmographiques établies chez les adultes natifs de l'Est Algérien sont inapplicables pour ceux natifs du Nord Algérien.

INTRODUCTION: The validity of the published plethysmographic reference equations specific to adults living in Eastern Algeria (RE-EA) in the interpretation of spirometric results in adult natives of Northern Algeria has not been assessed. AIM: To test the application of the RE-EA (Constantine, mean altitude=694m) to a population of healthy adults living in Algiers (mean altitude=153m). METHODS: The plethysmographic parameters of 453 healthy adults living in Algiers (234 women; age: 45±15 years, height: 1.66±0.10m, weight: 73±14kg) were determined and were compared with those predicted from the RE-EA. In addition, the percentages of adults with an obstructive ventilatory defect (OVD), a restrictive ventilatory defect (RVD) and/or lung hyperinflation were noted. The RE-EA are considered inapplicable to healthy adults living in Algiers if, firstly, the differences between the determined and predicted plethysmographic parameters are statistically significant and, secondly, more than 5% of healthy adults have OVD and/or RVD and/or lung hyperinflation. RESULTS: The RE-EA significantly overestimated the following parameters: FEV1 by 0.27±0.39L, MMEF by 0.52±0.75L/s, FEF25% by 0.75±0.56L/s, FEF50% by 0.85±1.02L/s, FEF75% by 0.28±1.25L/s, VC by 0.21±0.50L, TLC by 0.31±0.62L, ERV by 0.06±0.48L, IC by 0.27±0.48L, FEV1/VC by 0.03±0.05, and FEV1/FVC by 0.03±0.05. They significantly underestimated the RV/TLC by 0.01±0.05. Moreover, 14.35 %, 8.83 % and 5.74 % of healthy adults had OVD, RVD and lung hyperinflation, respectively. CONCLUSION: The RE-EA are not applicable in adult natives of Northern Algeria.

Stimuli used in the measurement of problematic sexual interests.

Penile plethysmography (PPG) is the primary physiologic assessment method used to gauge sexual responses in adult men. Depending on the country or jurisdiction of assessment, stimuli used to elicit arousal can include videos, still images, and audio materials. It can depict a variety consenting and non-consenting sexual scenarios as well as neutral, non-sexual scenarios. Models in visual stimuli can be clothed, semi-clothed, or nude. Variation in stimuli modality and the type of sexual interest being tested can have a large impact on PPG outcomes. This paper reviews research on types of PPG stimuli, the different sexual interests being assessed, reliability and validity, and the impact of anonymizing models depicted in assessment materials. Innovations in stimuli development in three labs located in Canada, the United States, and the Czech Republic are also discussed. The work done in these three labs and the broader range of research on assessment stimuli are presented to highlight the need for a unified, multi-site, standardized approach to assess problematic sexual interests and their change in response to treatment.

Exploring the source of short-term variations in respiratory data.

This study explores short-term respiratory volume changes in German oral and nasal stops and discusses to what extent these changes may be explained by laryngeal-oral coordination. It is expected that respiratory volumes decrease more rapidly when the glottis and the vocal tract are open after the release of voiceless aspirated stops. Two experiments were performed using Inductance Plethysmography and acoustics, varying consonantal properties, loudness, and prosodic focus. Results show consistent differences in respiratory slopes between voiceless vs voiced and nasal stops, which are more extreme in a loud or focused position. Thus, respiratory changes can even occur at a local level.

Comparing DXA and Air Displacement Plethysmography to Assess Body Composition of Male Collegiate Hockey Players.

Delisle-Houde, P, Reid, RER, Insogna, JA, Prokop, NW, Buchan, TA, Fontaine, SL, and Andersen, RE. Comparing DXA and air-displacement-plethysmography to assess body composition of male collegiate hockey players. J Strength Cond Res 33(2): 474-478, 2019-Accurate assessment of body composition is an important consideration for athletes because it is a health/performance variable. However, little is known about the variability in values obtained across different assessment methods for specific athlete populations. The purpose of this study was to compare 2 common laboratory methods that assess body composition: air displacement plethysmography (BOD POD) and dual energy x-ray absorptiometry (DXA). Twenty-nine male collegiate hockey players, (Age = 24.07 ± 1.49, BMI = 26.5 ± 2.74) participated in this study. All participants underwent back-to-back BOD POD and DXA evaluations. Paired t-tests and Bland-Altman analyses were performed to compare differences in fat mass, fat percentage, and fat-free mass between methods. Average fat percentage reported by the DXA and BOD POD was 15.34 ± 3.53 and 11.66 ± 4.82 respectively, resulting in a bias score of 3.78 ± 2.33 kg (t(28) = 8.71, p ≤ 0.001). Average fat mass reported by the DXA and BOD POD was 13.42 ± 3.59 and 10.15 ± 4.54 kg respectively, resulting in a bias score of 3.27 ± 1.92 kg (t(28) = 9.18, p ≤ 0.001). Average fat-free mass reported by the DXA and BOD POD was 73.31 ± 5.30 and 76.25 ± 5.74 kg respectively, resulting in a bias score of -2.93 ± 2.06 kg (t(28) = -7.66, p ≤ 0.001). Our findings can help make more insightful comparisons between studies that use different body composition methodologies among athletic populations.

Validity in Phallometric Testing for Sexual Interests in Children: A Meta-Analytic Review.

Valid assessment of pedohebephilic interests (i.e., sexual interest in children) is fundamental to forensic clinical practice. Phallometric testing-which measures changes in penile circumference or volume, while stimuli depicting different ages and sexual activities are presented-is widely used in clinical and research settings to detect such interests. This meta-analysis summarizes studies comparing sexual offenders against children and various types of controls on phallometric tests for pedohebephilic interests (37 samples; N = 6,785) and studies examining the relationship between phallometric test scores and sexual reoffending (16 samples; N = 2,709). The findings suggest that several phallometric testing procedures are valid indicators of pedohebephilic interest. Certain methodological features of phallometric tests were associated with greater validity, such as, slide or audio-plus-slide stimuli and z-score-based indices. In addition, phallometric tests for pedohebephilic, pedophilic, and hebephilic interests predicted sexual reoffending which provides further evidence that phallometric test scores are valid indicators of sexual interest in children. In general, the interpretation of phallometric test scores as indicators of pedohebephilic interests is supported.

[Guidelines for methacholine provocation testing]. / Recommandations pour le test de provocation bronchique à la méthacholine en pratique clinique, à partir de l'âge scolaire.

Bronchial challenge with the direct bronchoconstrictor agent methacholine is commonly used for the diagnosis of asthma. The "Lung Function" thematic group of the French Pulmonology Society (SPLF) elaborated a series of guidelines for the performance and the interpretation of methacholine challenge testing, based on French clinical guideline methodology. Specifically, guidelines are provided with regard to the choice of judgment criteria, the management of deep inspirations, and the role of methacholine bronchial challenge in the care of asthma, exercise-induced asthma, and professional asthma.

The plethysmographic variability index does not predict fluid responsiveness estimated by esophageal Doppler during kidney transplantation: A controlled study.

Research is ongoing to find a noninvasive method of monitoring, which can predict fluid responsiveness in patients undergoing kidney transplantation.To compare the responses to fluid challenges with the Pleth Variability Index, a noninvasive dynamic index derived from plethysmographic variability (Radical 7 pulse oximeter; Masimo Corporation, Irvine, CA), and the esophageal Doppler, the criterion standard.Observational study.University hospital; study from May 2011 and May 2012.Forty-eight patients with end-renal function were included and 44 analyzed. Patients with cardiac failure were not eligible.Fluid challenges were administered during maintenance of general anesthesia but before skin incision and repeated if the patient was deemed to be a "responder" (increase in stroke volume ≥10%).The primary endpoint was to assess if the Pleth Variability Index is an accurate predictor of fluid responsiveness.Among 76 fluid challenges, 38 were considered as positive (increase in stroke volume measured by Doppler ≥10%). Pleth Variability Index was similar at baseline between responders and nonresponder patients. Fluid challenges were associated with a significant decrease in Pleth Variability Index in overall cases (12 [8-14] vs 10 [6-17], P = .050), but it was not able to discriminate between responders (12 [8-15] vs 10 [5-15], P = .650) and nonresponders (11 [6-16] vs 8 [5-14], P = .047). The area under the Receiver Operating Characteristic curve for Pleth Variability Index was 0.49 (0.36-0.62).Pleth Variability Index is not an accurate predictor of fluid responsiveness during kidney transplantation.

Venous occlusion plethysmography vs. Doppler ultrasound in the assessment of leg blood flow kinetics during different intensities of calf exercise.

PURPOSE: It has recently been shown that venous occlusion plethysmography (VOP) can successfully assess the rate of increase in leg blood flow (LBF) (LBF kinetics) responses during calf exercise, but there is lack of data supporting its validity. METHODS: Using Doppler ultrasound (DU) as a criterion standard technique, we tested the hypothesis that VOP would provide similar estimates of LBF kinetics responses as DU during calf plantar-flexion exercise at a range of different intensities. Ten healthy men performed repeated intermittent calf plantar-flexion contractions (3 s duty cycles, 1 s contraction/2 s relaxation) at 30, 50 and 70% maximum voluntary contraction (MVC) on different days. RESULTS: Resting LBF values were significantly (P < 0.05) larger for DU than VOP but the overall mean LBF responses during exercise were not different (P > 0.05) between DU and VOP (30% MVC: 330 ± 78 vs. 313 ± 92 ml/min; 50% MVC: 515 ± 145 vs. 483 ± 164 ml/min; 70% MVC: 733 ± 218 vs. 616 ± 229 ml/min). LBF kinetics analyses revealed that the end-amplitude at the highest intensity (70% MVC) was significantly higher when measured by DU compared with VOP, but all other kinetics parameters were not different between VOP and DU. CONCLUSIONS: Given that these slight differences in amplitude observed during exercise can be explained by differences in vascular regions which the two techniques assess, our results suggest that VOP can accurately assess LBF kinetics responses during calf plantar-flexion exercise at intensities between 30 and 70% MVC.

The airway hyperresponsiveness to methacholine may be predicted by impulse oscillometry and plethysmography in children with well-controlled asthma.

OBJECTIVE: Airway hyperresponsiveness (AHR) is a hallmark of asthma. Methacholine challenge test which is mostly used to confirm AHR is not routinely available. The aim of this study was to investigate the predictive values of fractional exhaled nitric oxide (FeNO), impulse oscillometry (IOS), and plethysmography for the assessment of AHR in children with well-controlled asthma. METHODS: 60 children with controlled allergic asthma aged 6-18 years participated in the study. FeNO measurement, spirometry, IOS, and plethysmography were performed. Methacholine challenge test was done to assess AHR. PC20 and dose response slope (DRS) of methacholine was calculated. RESULTS: Mild to severe AHR with PC20 < 4 mg/ml was confirmed in 31 (51.7%) patients. Baseline FeNO and total specific airway resistance (SRtot)%pred and residual volume (RV)%pred levels in plethysmography were significantly higher and FEV1%pred, FEV1/FVC%pred, MMEF%pred values were lower in the group with PC20 < 4 mg/ml. FeNO, SRtot%pred, and RV%pred levels were found to be positively correlated with DRS methacholine. The higher baseline FeNO, frequency dependence of resistance (R5-R20) in IOS and SRtot%pred in plethysmography were found to be significantly related to DRS methacholine in linear regression analysis (ß: 1.35, p = 0.046, ß: 4.58, p = 0.002, and ß: 0.78, p = 0.035, respectively). The cut-off points for FeNO and SRtot% for differentiating asthmatic children with PC20 < 4 mg/ml from those with PC20 ≥ 4 mg/ml were 28 ppb (sensitivity: 67.7%, specificity: 72.4%, p < 0.001) and 294.9% (sensitivity: 35.5%, specificity: 96.6%, p = 0.013), respectively. CONCLUSION: IOS and plethysmography may serve as reliable and practical tools for prediction of mild to severe methacholine induced AHR in otherwise "seemingly well-controlled'' asthma.

Standardised noxious stimulation-guided individual adjustment of remifentanil target-controlled infusion to prevent haemodynamic responses to laryngoscopy and surgical incision: A randomised controlled trial.

BACKGROUND: The surgical plethysmographic index (SPI) is one of the available indexes of the nociception-antinociception (NAN) balance. Individually adjusting the NAN balance to prevent somatic responses to noxious stimulation remains a challenge. OBJECTIVES: To assess whether guiding remifentanil administration according to the SPI response to a calibrated noxious stimulus (NANCAL) can blunt the haemodynamic response to tracheal intubation and surgical incision. DESIGN: Randomised multicentre study. SETTING: Two Belgian university hospitals from January 2014 to April 2015. PATIENTS: After ethic review board approval and informed consent, 48 American Society of Anesthesiologists I or II adult patients scheduled for surgery under general anaesthesia were enrolled. INTERVENTIONS: Patients were randomly assigned to a SPI group, where remifentanil effect-site concentration was adjusted according to NANCAL, or a control group, where it was fixed at 4 ng ml. Propofol concentration was always adjusted to maintain the bispectral index close to 40. NANCAL consisted of a 100 Hz, 60 mA electrical tetanic stimulation during 30 s at the wrist before tracheal intubation and before surgical incision. MAIN OUTCOME MEASURES: The primary endpoint was the efficacy of the NANCAL-guided remifentanil administration to prevent the haemodynamic response to tracheal intubation and surgical incision. The secondary aim was to compare the ability of SPI, analgesia nociception index, pupil diameter and mean arterial pressure response to NANCAL to predict the haemodynamic response to tracheal intubation and surgical incision. RESULTS: Our SPI response to NANCAL-based correcting scheme for remifentanil administration was not superior to a fixed remifentanil concentration at blunting the haemodynamic response to tracheal intubation or surgical incision. Among all tested NAN balance indices, only mean arterial pressure had significant predictive ability with regard to the haemodynamic response to surgical incision. CONCLUSION: Further research is needed to define the best NANCAL stimulus and the best remifentanil correcting scheme to help individualised tailoring of antinociception for each specific subpopulation of surgical patients. TRIAL REGISTRATION: Clinicaltrials.gov NCT: 02884310; https://clinicaltrials.gov/ct2/show/NCT02884310.

Reference data for BabyBody-plethysmographic measurements in Chinese neonates and infants.

BACKGROUND AND OBJECTIVE: Population-specific pulmonary function reference data are essential to identify the nature and severity of respiratory diseases. However, there is a lack of reference data for Chinese neonates and infants. The objective of this study was to develop reference data for tidal breathing and plethysmographic measurements for Chinese subjects during the first 2 years of life. METHODS: Data of tidal breathing and plethysmography from healthy Chinese neonates (≤28 days) and infants (1-24 months) using the Jaeger MasterScreen BabyBody were collated. All subjects were sedated for the tests. Multivariable analyses were performed to determine predictive variables for the pulmonary function parameters. Reference equations for outcomes were constructed using multilevel modelling and the LMS (lambda-mu-sigma) method was used for establishing smoothed reference percentiles. RESULTS: Four hundred and ten healthy subjects were tested. Acceptable measurements of tidal breathing analysis and plethysmography outcomes were obtained in 396 (96.6%) and 370 (90.4%) subjects, respectively. Normal reference percentiles and equations for the main parameters of tidal breathing and plethysmography were derived from test occasions of 211 neonates and 185 infants. Body weight, crown-heel length and age were significantly associated with lung function, of which length was the strongest predictor. CONCLUSION: This study provides reference data of BabyBody-plethysmographic measurements for healthy Chinese subjects in their first 2 years of life. Weight and length are the strongest predictors for neonatal and infant lung function, respectively.

Optical measurement of breathing: algorithm volume calibration and preliminary validation on healthy trained subjects.

The use of optical technologies may be beneficial when measuring breathing biomechanics. The purpose of this study was twofold: i) to enhance the optoelectronic plethysmography (OEP) algorithm performance for the volume estimation by the use of a novel volume calibration procedure and ii) to compare the OEP volumes gained by a commercial optoelectronic system against actual respiratory volumes measured by a breath-by-breath gas analyzer (BbB). The OEP volume algorithm calibration was performed by the use of a novel volume calibration procedure based on both a calibrator device that delivered known volumes changes and one ad-hoc designed software for the static and dynamic calibration analysis. OEP algorithm threshold, accuracy, repeatability and the volume algorithm calibration were investigated. Tidal volume (VT) measurements performed simultaneously by the calibrated OEP algorithm and BbB analyzer were compared. VT measured simultaneously by OEP and BbB was collected during submaximal exercise tests in five trained healthy participants in two conditions (with hunched shoulders and in normal shoulder position). The two methods were compared by linear regression and Bland-Altman analysis in both positions. The average difference between methods and the discrepancy were calculated. The OEP-BbB correlation was high in both positions, R2=0.92 and R2=0.97 for hunch and normal one, respectively. Bland-Altman analysis demonstrated that OEP algorithm systematic difference was lower than 100mL. The limits of agreement assessed in both positions are comparable. The difference between measurements suggesting that OEP may be a useful tool to analyze chest wall volume changes and breathing mechanics during intense exercise.

Assessment of problematic sexual interests with the penile plethysmograph: an overview of assessment laboratories.

Phallometric testing, or penile plethysmography (PPG), is an objective measure of sexual arousal for males. While extensive research on the reliability and validity of PPG has promoted its reputation as the "gold standard" of objective measurement of sexual arousal, there is a lack of standardization of stimulus sets and interpretation of results between sites. This article describes the laboratory protocol employed for PPG at the Royal Ottawa Mental Health Centre's Sexual Behaviours Clinic (SBC) in Ottawa, Ontario, as well as those used by the Sexual Behaviors Clinic and Lab (SBCL) in the Community and Public Safety Psychiatry Division (CPSPD) of the Department of Psychiatry and Behavioral Sciences at Medical University of South Carolina (MUSC) in Charleston, South Carolina. The need for standardization in both testing protocol and stimuli use across sites are highlighted.

A wearable respiratory monitoring device--the between-days variability of calibration.

The between-days variability in ascertained gain factors for calibration of a wearable respiratory inductance plethysmograph (RIP) and validity thereof for the repeated use during exercise were examined. Consecutive 5-min periods of standing still, slow running at 8 km·h(-1), fast running at 14 km·h(-1) (male) or 12 km·h(-1) (female) and recovery were repeated by 10 healthy subjects on 5 days. Breath-by-breath data were recorded simultaneously by flow meter and RIP. Gain factors were determined individually for each trial (CALIND) via least square regression. Reliability and variability in gain factors were quantified respectively by intraclass correlation coefficients (ICC) and limits of agreement. Within a predefined error range of ±20% the amount of RIP-derived tidal volumes after CALIND was compared to corresponding amounts when gain factors of the first trial were applied on the following 4 trials (CALFIRST). ICC ranged within 0.96 and 0.98. The variability in gain factors (up to ± 24.06%) was reduced compensatively by their sum. Amounts of breaths within the predefined error range did not differ between CALIND and (CALFIRST) (P>0.32). The between-days variability of gain factors for a wearable RIP-device does not show impaired reliability in further derived tidal volumes.

Influence of gravitational sympathetic stimulation on the Surgical Plethysmographic Index.

Surgical Plethysmographic Index (SPI), calculated from pulse photo-plethysmographic amplitude oscillations, has been proposed as a tool to measure nociception anti-nociception balance during general anesthesia, but it is affected by several confounding factor that alter the autonomic nervous system (ANS) modulation. We hypothesized that SPI may be mainly affected by sympathetic stimulation independently from nociception. We studied the effects of two sympathetic stimuli on SPI, delivered through passive head-up tilt at 45 and 90 degrees angles, in nine awake healthy adults. The sympathetic modulation was assessed by means of heart rate variability (HRV) analysis. Mean (SD) SPI significantly increased from baseline to 45 degrees [from 38.6 (13.7) to 60.8 (7.6), p<0.001)] and to 90 degrees angle tilt [82.3 (5.4), p<0.001]. The electrocardiographic mean R-to-R interval significantly shortened during both passive tilts, whereas systolic arterial pressure did not change during the study protocol. HRV changed significantly during the study protocol towards a predominance of sympathetic modulation during passive tilt. Gravitational sympathetic stimulation at two increasing angles, in absence of any painful stimuli, affects SPI in awake healthy volunteers. SPI seems to reflect the sympathetic outflow directed to peripheral vessels.

Test-retest reliability of the Bod Pod: the effect of multiple assessments.

The Bod Pod uses air-displacement plethysmography to estimate body fat percentage (BF%). This study was designed to assess the test-retest reliability of the Bod Pod. The study included 283 women (M age = 41.0 yr., SD = 3.0). Each participant was tested at least twice in the Bod Pod. Results showed no significant mean difference between the test and the retest. The intraclass correlation coefficient (ICC) was .991. However, the absolute value of the initial trial differences (absolute mean difference) was .96 (SD = .90). A third assessment of BF% was taken when the initial trial difference was greater than 1 percentage point, and the two closest values were compared. This strategy resulted in a significant decrease in the absolute mean difference, from .96 to .55 percentage point, and ICC increased to .998. The Bod Pod appears to measure body fat percentage reliably; however, findings suggest that multiple trials may be necessary to detect small treatment effects.