A basic investigation into the optimization of cylindrical tubes used as acoustic stethoscopes for auscultation in COVID-19 diagnosis.

During the COVID-19 outbreak, the auscultation of heart and lung sounds has played an important role in the comprehensive diagnosis and real-time monitoring of confirmed cases. With clinicians wearing protective clothing in isolation wards, a potato chip tube stethoscope, which is a secure and flexible substitute for a conventional stethoscope, has been used by Chinese medical workers in the first-line treatment of COVID-19. In this study, an optimal design for this simple cylindrical stethoscope is proposed based on the fundamental theory of acoustic waveguides. Analyses of the cutoff frequency, sound power transmission coefficient, and sound wave propagation in the uniform lossless tube provide theoretical guidance for selecting the geometric parameters for this simple cylindrical stethoscope. A basic investigation into the auscultatory performances of the original tube and the optimal tube with proposed dimensions was conducted both in a semi-anechoic chamber and in a quiet laboratory. Both experimental results and front-line doctors' clinical feedback endorse the proposed theoretical optimization.

Artificial intelligence accuracy in detecting pathological breath sounds in children using digital stethoscopes.

BACKGROUND: Manual auscultation to detect abnormal breath sounds has poor inter-observer reliability. Digital stethoscopes with artificial intelligence (AI) could improve reliable detection of these sounds. We aimed to independently test the abilities of AI developed for this purpose. METHODS: One hundred and ninety two auscultation recordings collected from children using two different digital stethoscopes (Clinicloud™ and Littman™) were each tagged as containing wheezes, crackles or neither by a pediatric respiratory physician, based on audio playback and careful spectrogram and waveform analysis, with a subset validated by a blinded second clinician. These recordings were submitted for analysis by a blinded AI algorithm (StethoMe AI) specifically trained to detect pathologic pediatric breath sounds. RESULTS: With optimized AI detection thresholds, crackle detection positive percent agreement (PPA) was 0.95 and negative percent agreement (NPA) was 0.99 for Clinicloud recordings; for Littman-collected sounds PPA was 0.82 and NPA was 0.96. Wheeze detection PPA and NPA were 0.90 and 0.97 respectively (Clinicloud auscultation), with PPA 0.80 and NPA 0.95 for Littman recordings. CONCLUSIONS: AI can detect crackles and wheeze with a reasonably high degree of accuracy from breath sounds obtained from different digital stethoscope devices, although some device-dependent differences do exist.

Assessment of breath sounds at birth using digital stethoscope technology.

Newborn transition is a phase of complex change involving lung fluid clearance and lung aeration. We aimed to use a digital stethoscope (DS) to assess the change in breath sound characteristics over the first 2 h of life and its relationship to mode of delivery. A commercially available DS was used to record breath sounds of term newborns at 1-min and 2-h post-delivery via normal vaginal delivery (NVD) or elective caesarean section (CS). Sound analysis was conducted, and two comparisons were carried out: change in frequency profiles over 2 h, and effect of delivery mode. There was a significant drop in the frequency profile of breath sounds from 1 min to 2 h with mean (SD) frequency decreasing from 333.74 (35.42) to 302.71 (47.19) Hz, p < 0.001, and proportion of power (SD) in the lowest frequency band increasing from 0.27 (0.11) to 0.37 (0.15), p < 0.001. At 1 min, NVD infants had slightly higher frequency than CS but no difference at 2 h.Conclusion: We were able to use DS technology in the transitioning infant to depict significant changes to breath sound characteristics over the first 2 h of life, reflecting the process of lung aeration.What is Known:• Lung fluid clearance and lung aeration are critical processes that facilitate respiration and mode of delivery can impact this• Digital stethoscopes offer enhanced auscultation and have been used in the paediatric population for the assessment of pulmonary and cardiac soundsWhat is New:• This is the first study to use digital stethoscope technology to assess breath sounds at birth• We describe a change in breath sound characteristics over the first 2 h of life and suggest a predictive utility of this analysis to predict the development of respiratory distress in newborns prior to the onset of symptoms.

A Wearable Stethoscope for Long-Term Ambulatory Respiratory Health Monitoring.

Lung sounds acquired by stethoscopes are extensively used in diagnosing and differentiating respiratory diseases. Although an extensive know-how has been built to interpret these sounds and identify diseases associated with certain patterns, its effective use is limited to individual experience of practitioners. This user-dependency manifests itself as a factor impeding the digital transformation of this valuable diagnostic tool, which can improve patient outcomes by continuous long-term respiratory monitoring under real-life conditions. Particularly patients suffering from respiratory diseases with progressive nature, such as chronic obstructive pulmonary diseases, are expected to benefit from long-term monitoring. Recently, the COVID-19 pandemic has also shown the lack of respiratory monitoring systems which are ready to deploy in operational conditions while requiring minimal patient education. To address particularly the latter subject, in this article, we present a sound acquisition module which can be integrated into a dedicated garment; thus, minimizing the role of the patient for positioning the stethoscope and applying the appropriate pressure. We have implemented a diaphragm-less acousto-electric transducer by stacking a silicone rubber and a piezoelectric film to capture thoracic sounds with minimum attenuation. Furthermore, we benchmarked our device with an electronic stethoscope widely used in clinical practice to quantify its performance.

Practical implementation of artificial intelligence algorithms in pulmonary auscultation examination.

Lung auscultation is an important part of a physical examination. However, its biggest drawback is its subjectivity. The results depend on the experience and ability of the doctor to perceive and distinguish pathologies in sounds heard via a stethoscope. This paper investigates a new method of automatic sound analysis based on neural networks (NNs), which has been implemented in a system that uses an electronic stethoscope for capturing respiratory sounds. It allows the detection of auscultatory sounds in four classes: wheezes, rhonchi, and fine and coarse crackles. In the blind test, a group of 522 auscultatory sounds from 50 pediatric patients were presented, and the results provided by a group of doctors and an artificial intelligence (AI) algorithm developed by the authors were compared. The gathered data show that machine learning (ML)-based analysis is more efficient in detecting all four types of phenomena, which is reflected in high values of recall (also called as sensitivity) and F1-score.Conclusions: The obtained results suggest that the implementation of automatic sound analysis based on NNs can significantly improve the efficiency of this form of examination, leading to a minimization of the number of errors made in the interpretation of auscultation sounds. What is Known: • Auscultation performance of average physician is very low. AI solutions presented in scientific literature are based on small data bases with isolated pathological sounds (which are far from real recordings) and mainly on leave-one-out validation method thus they are not reliable. What is New: • AI learning process was based on thousands of signals from real patients and a reliable description of recordings was based on multiple validation by physicians and acoustician resulting in practical and statistical prove of AI high performance.

Diagnostic accuracy of a velcro sound detector (VECTOR) for interstitial lung disease in rheumatoid arthritis patients: the InSPIRAtE validation study (INterStitial pneumonia in rheumatoid ArThritis with an electronic device).

BACKGROUND: Interstitial lung disease (ILD) is a severe systemic manifestation of rheumatoid arthritis (RA). High-resolution computed tomography (HRCT) represents the gold standard for the diagnosis of ILD, but its routine use for screening programs is not advisable because of both high cost and X-ray exposure. Velcro crackles at lung auscultation occur very early in the course of interstitial pneumonia, and their detection is an indication for HRCT. Recently, we developed an algorithm (VECTOR) to detect the presence of Velcro crackles in pulmonary sounds and showed good results in a small sample of RA patients. The aim of the present investigation was to validate the diagnostic accuracy of VECTOR in a larger population of RA patients, compared with that of the reference standard of HRCT, from a multicentre study. METHODS: To avoid X-ray exposure, we enrolled 137 consecutive RA patients who had recently undergone HRCT. Lung sounds of all patients were recorded in 4 pulmonary fields bilaterally with a commercial electronic stethoscope (ES); subsequently, all HRCT images were blindly evaluated by a radiologist, and audio data were analysed by means of VECTOR. RESULTS: Fifty-nine of 137 patients showed ILD (43.1%). VECTOR correctly classified 115/137 patients, showing a diagnostic accuracy of 83.9% and a sensitivity and specificity of 93.2 and 76.9%, respectively. CONCLUSIONS: VECTOR may represent the first validated tool for the screening of RA patients who are suspected for ILD and who should be directed to HRCT for the diagnosis. Moreover, early identification of RA-ILD could contribute to the design of prospective studies aimed at elucidating unclear aspects of the disease.

Investigation of Stethoscope Technology for En Route Care.

OBJECTIVE: Occupational challenges in air transport domains make auscultation with traditional stethoscopes difficult. This study aimed to investigate two commercial off-the-shelf stethoscopes for use in high noise military patient transport environments. The stethoscopes were assessed by Aeromedical Evacuation providers in a simulated C-130 trainer on live standardized mock patients. Device 1 was a dual-mode stethoscope developed for rotary wing military airframes. Device 2 was an electronic stethoscope developed for high noise civilian environments. Twenty clinicians performed cardiopulmonary auscultation using the devices on the same two standardized patients in a simulated C-130 then completed a subjective questionnaire on their ability to identify heart and lung sounds. Results indicated the dual-mode stethoscope had limited utility with clinician likeliness of use rated as low (median = 2; interquartile range = 1.75-3.25), whereas the electronic stethoscope had potential utility with likeliness of use rated as good (median = 4; interquartile range = 3.25-5). We conclude that further examination of devices capable of auscultation in high noise military environments is needed. In-flight testing of device 2 for use by end users has been completed and will be reported in a separate manuscript.

Comparison of analogue and electronic stethoscopes for pulmonary auscultation by internal medicine residents.

BACKGROUND: Electronic stethoscopes are becoming more common in clinical practice. They may improve the accuracy and efficiency of pulmonary auscultation, but the data to support their benefit are limited. OBJECTIVE: To determine how auscultation with an electronic stethoscope may affect clinical decision making. METHODS: An online module consisting of six fictional ambulatory cases was developed. Each case included a brief history and lung sounds recorded with an analogue and electronic stethoscope. Internal medicine resident participants were randomly selected to hear either the analogue or electronic lung sounds. Numbers of correct answers, time spent on each case and numbers of times the recordings were played were compared between the groups who heard each mode of auscultation, with a p value of less than 0.05 indicating statistical significance. RESULTS: 61 internal medicine residents completed at least one case, and 41 residents completed all six cases. There were no significant differences in overall scores between participants who heard analogue and electronic lung sounds (3.14±0.10 out of 6 correct for analogue, 3.20±0.10 out of 6 for electronic, p=0.74). There were no significant differences in performance for any of the six cases (p=0.78), time spent on the cases (p=0.67) or numbers of times the recordings were played (p=0.85). CONCLUSION: When lung sounds were amplified with an electronic stethoscope, we did not detect an effect on performance, time spent on the cases or numbers of times participants listened to the recordings.

Tabla: A Proof-of-Concept Auscultatory Percussion Device for Low-Cost Pneumonia Detection.

Pneumonia causes the deaths of over a million people worldwide each year, with most occurring in countries with limited access to expensive but effective diagnostic methods, e.g., chest X-rays. Physical examination, the other major established method of diagnosis, suffers from several drawbacks, most notably low accuracy and high interobserver error. We sought to address this diagnostic gap by developing a proof-of-concept non-invasive device to identify the accumulation of fluid in the lungs (consolidation) characteristic of pneumonia. This device, named Tabla after the percussive instrument of the same name, utilizes the technique of auscultatory percussion; a percussive input sound is sent through the chest and recorded with a digital stethoscope for analysis. Tabla analyzes differences in sound transmission through the chest at audible frequencies as a marker for lung consolidation. This paper presents preliminary data from five pneumonia patients and eight healthy subjects. We demonstrate 92.3% accuracy in distinguishing between healthy subjects and patients with pneumonia after data analysis with a K-nearest neighbors algorithm. This prototype device is low cost and simple to implement and may offer a rapid and inexpensive method for pneumonia diagnosis appropriate for general use and in areas with limited medical infrastructure.

Digital stethoscopes compared to standard auscultation for detecting abnormal paediatric breath sounds.

Our study aimed to objectively describe the audiological characteristics of wheeze and crackles in children by using digital stethoscope (DS) auscultation, as well as assess concordance between standard auscultation and two different DS devices in their ability to detect pathological breath sounds. Twenty children were auscultated by a paediatric consultant doctor and digitally recorded using the Littman™ 3200 Digital Electronic Stethoscope and a Clinicloud™ DS with smart device. Using spectrographic analysis, we found those with clinically described wheeze had prominent periodic waveform segments spanning expiration for a period of 0.03-1.2 s at frequencies of 100-1050 Hz, and occasionally spanning shorter inspiratory segments; paediatric crackles were brief discontinuous sounds with a distinguishing waveform. There was moderate concordance with respect to wheeze detection between digital and standard binaural stethoscopes, and 100% concordance for crackle detection. Importantly, DS devices were more sensitive than clinician auscultation in detecting wheeze in our study. CONCLUSION: Objective definition of audio characteristics of abnormal paediatric breath sounds was achieved using DS technology. We demonstrated superiority of our DS method compared to traditional auscultation for detection of wheeze. What is Known: • The audiological characteristics of abnormal breath sounds have been well-described in adult populations but not in children. • Inter-observer agreement for detection of pathological breath sounds using standard auscultation has been shown to be poor, but the clinical value of now easily available digital stethoscopes has not been sufficiently examined. What is New: • Digital stethoscopes can objectively define the nature of pathological breath sounds such as wheeze and crackles in children. • Paediatric wheeze was better detected by digital stethoscopes than by standard auscultation performed by an expert paediatric clinician.

Intermittent auscultation (IA) of fetal heart rate in labour for fetal well-being.

BACKGROUND: The goal of fetal monitoring in labour is the early detection of a hypoxic baby. There are a variety of tools and methods available for intermittent auscultation (IA) of the fetal heart rate (FHR). Low- and middle-income countries usually have only access to a Pinard/Laënnec or the use of a hand-held Doppler device. Currently, there is no robust evidence to guide clinical practice on the most effective IA tool to use, timing intervals and length of listening to the fetal heart for women during established labour. OBJECTIVES: To evaluate the effectiveness of different tools for IA of the fetal heart rate during labour including frequency and duration of auscultation. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (19 September 2016), contacted experts and searched reference lists of retrieved articles. SELECTION CRITERIA: All published and unpublished randomised controlled trials (RCTs) or cluster-RCTs comparing different tools and methods used for intermittent fetal auscultation during labour for fetal and maternal well-being. Quasi-RCTs, and cross-over designs were not eligible for inclusion. DATA COLLECTION AND ANALYSIS: All review authors independently assessed eligibility, extracted data and assessed risk of bias for each trial. Data were checked for accuracy. MAIN RESULTS: We included three studies (6241 women and 6241 babies), but only two studies are included in the meta-analyses (3242 women and 3242 babies). Both were judged as high risk for performance bias due to the inability to blind the participants and healthcare providers to the interventions. Evidence was graded as moderate to very low quality; the main reasons for downgrading were study design limitations and imprecision of effect estimates. Intermittent Electronic Fetal Monitoring (EFM) using Cardiotocography (CTG) with routine Pinard (one trial)There was no clear difference between groups in low Apgar scores at five minutes (reported as < six at five minutes after birth) (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.24 to 1.83, 633 babies, very low-quality evidence). There were no clear differences for perinatal mortality (RR 0.88, 95% CI 0.34 to 2.25; 633 infants, very low-quality evidence). Neonatal seizures were reduced in the EFM group (RR 0.05, 95% CI 0.00 to 0.89; 633 infants, very low-quality evidence). Other important infant outcomes were not reported: mortality or serious morbidity (composite outcome), cerebral palsy or neurosensory disability. For maternal outcomes, women allocated to intermittent electronic fetal monitoring (EFM) (CTG) had higher rates of caesarean section for fetal distress (RR 2.92, 95% CI 1.78 to 4.80, 633 women, moderate-quality evidence) compared with women allocated to routine Pinard. There was no clear difference between groups in instrumental vaginal births (RR 1.46, 95% CI 0.86 to 2.49, low-quality evidence). Other outcomes were not reported (maternal mortality, instrumental vaginal birth for fetal distress and or acidosis, analgesia in labour, mobility or restriction during labour, and postnatal depression). Doppler ultrasonography with routine Pinard (two trials)There was no clear difference between groups in Apgar scores < seven at five minutes after birth (reported as < six in one of the trials) (average RR 0.76, 95% CI 0.20 to 2.87; two trials, 2598 babies, I2 = 72%, very low-quality evidence); there was high heterogeneity for this outcome. There was no clear difference between groups for perinatal mortality (RR 0.69, 95% CI 0.09 to 5.40; 2597 infants, two studies, very low-quality evidence), or neonatal seizures (RR 0.05, 95% CI 0.00 to 0.91; 627 infants, one study, very low-quality evidence). Other important infant outcomes were not reported (cord blood acidosis, composite of mortality and serious morbidity, cerebral palsy, neurosensory disability). Only one study reported maternal outcomes. Women allocated to Doppler ultrasonography had higher rates of caesarean section for fetal distress compared with those allocated to routine Pinard (RR 2.71, 95% CI 1.64 to 4.48, 627 women, moderate-quality evidence). There was no clear difference in instrumental vaginal births between groups (RR 1.35, 95% CI 0.78 to 2.32, 627 women, low-quality evidence). Other maternal outcomes were not reported. Intensive Pinard versus routine Pinard (one trial)One trial compared intensive Pinard (a research midwife following the protocol in a one-to-one care situation) with routine Pinard (as per protocol but midwife may be caring for more than one woman in labour). There was no clear difference between groups in low Apgar score (reported as < six this trial) (RR 0.90, 95% CI 0.35 to 2.31, 625 babies, very low-quality evidence). There were also no clear differences identified for perinatal mortality (RR 0.56, 95% CI 0.19 to 1.67; 625 infants, very low-quality evidence), or neonatal seizures (RR 0.68, 95% CI 0.24 to 1.88, 625 infants, very low-quality evidence)). Other infant outcomes were not reported. For maternal outcomes, there were no clear differences between groups for caesarean section or instrumental delivery (RR 0.70, 95% CI 0.35 to 1.38, and RR 1.21, 95% CI 0.69 to 2.11, respectively, 625 women, both low-quality evidence)) Other outcomes were not reported. AUTHORS' CONCLUSIONS: Using a hand-held (battery and wind-up) Doppler and intermittent CTG with an abdominal transducer without paper tracing for IA in labour was associated with an increase in caesarean sections due to fetal distress. There was no clear difference in neonatal outcomes (low Apgar scores at five minutes after birth, neonatal seizures or perinatal mortality). Long-term outcomes for the baby (including neurodevelopmental disability and cerebral palsy) were not reported. The quality of the evidence was assessed as moderate to very low and several important outcomes were not reported which means that uncertainty remains regarding the use of IA of FHR in labour.As intermittent CTG and Doppler were associated with higher rates of caesarean sections compared with routine Pinard monitoring, women, health practitioners and policy makers need to consider these results in the absence of evidence of short- and long-term benefits for the mother or baby.Large high-quality randomised trials, particularly in low-income settings, are needed. Trials should assess both short- and long-term health outcomes, comparing different monitoring tools and timing for IA.

Human knee joint sound during the Lachman test: Comparison between healthy and anterior cruciate ligament-deficient knees.

BACKGROUND: The Lachman test is clinically considered to be a reliable physical examination for anterior cruciate ligament (ACL) deficiency. However, the test involves subjective judgement of differences in tibial translation and endpoint quality. An auscultation system has been developed to allow assessment of the Lachman test. The knee joint sound during the Lachman test was analyzed using fast Fourier transformation. The purpose of the present study was to quantitatively evaluate knee joint sounds in healthy and ACL-deficient human knees. METHODS: Sixty healthy volunteers and 24 patients with ACL injury were examined. The Lachman test with joint auscultation was evaluated using a microphone. Knee joint sound during the Lachman test (Lachman sound) was analyzed by fast Fourier transformation. As quantitative indices of the Lachman sound, the peak sound (Lachman peak sound) as the maximum relative amplitude (acoustic pressure) and its frequency were used. RESULTS: In healthy volunteers, the mean Lachman peak sound of intact knees was 100.6 Hz in frequency and -45 dB in acoustic pressure. Moreover, a sex difference was found in the frequency of the Lachman peak sound. In patients with ACL injury, the frequency of the Lachman peak sound of the ACL-deficient knees was widely dispersed. In the ACL-deficient knees, the mean Lachman peak sound was 306.8 Hz in frequency and -63.1 dB in acoustic pressure. If the reference range was set at the frequency of the healthy volunteer Lachman peak sound, the sensitivity, specificity, positive predictive value, and negative predictive value were 83.3%, 95.6%, 95.2%, and 85.2%, respectively. CONCLUSION: Knee joint auscultation during the Lachman test was capable of judging ACL deficiency on the basis of objective data. In particular, the frequency of the Lachman peak sound was able to assess ACL condition.

A Feasibility Study to Assess Vibration and Sound From Zygapophyseal Joints During Motion Before and After Spinal Manipulation.

OBJECTIVE: This feasibility study used novel accelerometry (vibration) and microphone (sound) methods to assess crepitus originating from the lumbar spine before and after side-posture spinal manipulative therapy (SMT). METHODS: This study included 5 healthy and 5 low back pain (LBP) participants. Nine accelerometers and 1 specialized directional microphone were applied to the lumbar region, allowing assessment of crepitus. Each participant underwent full lumbar ranges of motion (ROM), bilateral lumbar SMT, and repeated full ROM. After full ROMs the participants received side-posture lumbar SMT on both sides by a licensed doctor of chiropractic. Accelerometer and microphone recordings were made during all pre- and post-SMT ROMs. Primary outcome was a descriptive report of crepitus prevalence (average number of crepitus events/participant). Participants were also divided into 3 age groups for comparisons (18-25, 26-45, and 46-65 years). RESULTS: Overall, crepitus prevalence decreased pre-post SMT (average pre = 1.4 crepitus/participant vs post = 0.9). Prevalence progressively increased from the youngest to oldest age groups (pre-SMT = 0.0, 1.67, and 2.0, respectively; and post-SMT = 0.5, 0.83, and 1.5). Prevalence was higher in LBP participants compared with healthy (pre-SMT-LBP = 2.0, vs pre-SMT-healthy = 0.8; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.8), even though healthy participants were older than LBP participants (40.8 years vs 27.8 years); accounting for age: pre-SMT-LBP = 2.0 vs pre-SMT-healthy = 0.0; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.3. CONCLUSIONS: Our findings indicated that a larger study is feasible. Other findings included that crepitus prevalence increased with age, was higher in participants with LBP than in healthy participants, and overall decreased after SMT. This study indicated that crepitus assessment using accelerometers has the potential of being an outcome measure or biomarker for assessing spinal joint (facet/zygapophyseal joint) function during movement and the effects of LBP treatments (eg, SMT) on zygapophyseal joint function.

[Computer-aided Diagnosis and New Electronic Stethoscope].

Auscultation is an important method in early-diagnosis of cardiovascular disease and respiratory system disease. This paper presents a computer-aided diagnosis of new electronic auscultation system. It has developed an electronic stethoscope based on condenser microphone and the relevant intelligent analysis software. It has implemented many functions that combined with Bluetooth, OLED, SD card storage technologies, such as real-time heart and lung sounds auscultation in three modes, recording and playback, auscultation volume control, wireless transmission. The intelligent analysis software based on PC computer utilizes C# programming language and adopts SQL Server as the background database. It has realized play and waveform display of the auscultation sound. By calculating the heart rate, extracting the characteristic parameters of T1, T2, T12, T11, it can analyze whether the heart sound is normal, and then generate diagnosis report. Finally the auscultation sound and diagnosis report can be sent to mailbox of other doctors, which can carry out remote diagnosis. The whole system has features of fully function, high portability, good user experience, and it is beneficial to promote the use of electronic stethoscope in the hospital, at the same time, the system can also be applied to auscultate teaching and other occasions.

Unbalanced lateral mandibular deviation associated with TMJ sound as a sign in TMJ disc dysfunction diagnosis.

The aim was to study the characteristics of lateral mandibular horizontal deviations during opening-closing movements and their association with TMJ sounds of the clicking type. Subjects were 28 healthy volunteers and 38 patients diagnosed with MRI imaging as having TMJ disc dysfunction, 22 with disc displacement without (DD) and 16 as having disc displacement with reduction (DDR). TMJ sounds were recorded with miniature microphones placed in the ear canals, and jaw movements were documented with a kinesiograph. A sign, unbalanced lateral deviation (ubd) was defined as a rapid, short duration, change in jaw movement direction from, and back to, a smooth deviation path in the horizontal plane. The hypotheses were that degrees of maximal deviations, proportions of unbalanced deviation (ubd) and such deviation associated with TMJ sounds (ubdS), differ between healthy subjects and patients with DD or DDR. Comparisons between groups were made using one-way anova and chi-square analysis, as appropriate. No differences were found between groups regarding degree of lateral deviation per se. The proportions of ubd and ubdS were significantly higher in patients with DDR than in healthy subjects and than in patients with DD (P < 0·001), but no such differences were found between healthy subjects and patients with DD. For prediction of DDR, the sensitivity and specificity of the sign ubdS were found to be 68·8% and 89·3%, respectively. For the sign ubd, they were 100·0% and 64·3%. This indicates that the sign ubdS has diagnostic value in screening for DDR.

[Normal and Adventitious Breath Sounds]. / Atemgeräusche und Atem-Nebengeräusche.

Auscultation of the lung is an inexpensive, noninvasive and easy-to-perform tool. It is an important part of the physical examination and is help ful to distinguish physiological respiratory sounds from pathophysiological events. Computerized lung sound analysis is a powerful tool for optimizing and quantifying electronic auscultation based on the specific lung sound spectral characteristics. The automatic analysis of respiratory sounds assumes that physiological and pathological sounds are reliably analyzed based on special algorithms. The development of automated long-term lungsound monitors enables objective assessment of different respiratory symptoms.

Developing a reference of normal lung sounds in healthy Peruvian children.

PURPOSE: Lung auscultation has long been a standard of care for the diagnosis of respiratory diseases. Recent advances in electronic auscultation and signal processing have yet to find clinical acceptance; however, computerized lung sound analysis may be ideal for pediatric populations in settings, where skilled healthcare providers are commonly unavailable. We described features of normal lung sounds in young children using a novel signal processing approach to lay a foundation for identifying pathologic respiratory sounds. METHODS: 186 healthy children with normal pulmonary exams and without respiratory complaints were enrolled at a tertiary care hospital in Lima, Peru. Lung sounds were recorded at eight thoracic sites using a digital stethoscope. 151 (81%) of the recordings were eligible for further analysis. Heavy-crying segments were automatically rejected and features extracted from spectral and temporal signal representations contributed to profiling of lung sounds. RESULTS: Mean age, height, and weight among study participants were 2.2 years (SD 1.4), 84.7 cm (SD 13.2), and 12.0 kg (SD 3.6), respectively; and, 47% were boys. We identified ten distinct spectral and spectro-temporal signal parameters and most demonstrated linear relationships with age, height, and weight, while no differences with genders were noted. Older children had a faster decaying spectrum than younger ones. Features like spectral peak width, lower-frequency Mel-frequency cepstral coefficients, and spectro-temporal modulations also showed variations with recording site. CONCLUSIONS: Lung sound extracted features varied significantly with child characteristics and lung site. A comparison with adult studies revealed differences in the extracted features for children. While sound-reduction techniques will improve analysis, we offer a novel, reproducible tool for sound analysis in real-world environments.

Applying cybernetic technology to diagnose human pulmonary sounds.

Chest auscultation is a crucial and efficient method for diagnosing lung disease; however, it is a subjective process that relies on physician experience and the ability to differentiate between various sound patterns. Because the physiological signals composed of heart sounds and pulmonary sounds (PSs) are greater than 120 Hz and the human ear is not sensitive to low frequencies, successfully making diagnostic classifications is difficult. To solve this problem, we constructed various PS recognition systems for classifying six PS classes: vesicular breath sounds, bronchial breath sounds, tracheal breath sounds, crackles, wheezes, and stridor sounds. First, we used a piezoelectric microphone and data acquisition card to acquire PS signals and perform signal preprocessing. A wavelet transform was used for feature extraction, and the PS signals were decomposed into frequency subbands. Using a statistical method, we extracted 17 features that were used as the input vectors of a neural network. We proposed a 2-stage classifier combined with a back-propagation (BP) neural network and learning vector quantization (LVQ) neural network, which improves classification accuracy by using a haploid neural network. The receiver operating characteristic (ROC) curve verifies the high performance level of the neural network. To expand traditional auscultation methods, we constructed various PS diagnostic systems that can correctly classify the six common PSs. The proposed device overcomes the lack of human sensitivity to low-frequency sounds and various PS waves, characteristic values, and a spectral analysis charts are provided to elucidate the design of the human-machine interface.

[LEOSound, an innovative procedure for acoustic long-term monitoring of asthma symptoms (wheezing and coughing) in children and adults]. / LEOSound - Ein innovatives Verfahren zum akustischen Langzeit-Monitoring von asthmatischen Symptomen (Wheezing und Husten) bei Kindern und Erwachsenen.

Particularly in young children the diagnosis of asthma is difficult and mostly based on clinical symptoms like wheezing, cough and dyspnea. Children with nocturnal wheezing often suffer from a low quality of sleep and impaired sense of well-being during the day. Physicians recommend that parents record the frequency of asthma attacks or symptoms to help manage their children's disease. The lack of an appropriate method for standardized and objective monitoring makes asthma management difficult. The aim of this paper is to present a new method for automated wheeze and cough detection and analysis. The mobile LEOSound recording and analysing system described here should help improve diagnosis and monitoring of asthma symptoms in children.

In-flight auscultation during medical air evacuation: comparison between traditional and amplified stethoscopes.

OBJECTIVES: The aim of this study was to evaluate the capacity of a traditional stethoscope versus an electronically amplified one (expected to reduce background and ambient noise) to assess heart and respiratory sounds during medical transport. MATERIALS AND METHODS: It was a prospective, double-blinded, randomized performed study. One traditional stethoscope (Littmann Cardiology III; 3M, St Paul, MN) and 1 electronically amplified stethoscope (Littmann 3200, 3M) were used for our tests. Heart and lung auscultation during real medical evacuations aboard a medically configured Falcon 50 aircrafts were studied. The quality of auscultation was ranged using a numeric rating scale from 0 to 10 (0 corresponding to "I hear nothing" and 10 to "I hear perfectly"). Data collected were compared using a t-test for paired values. RESULTS: A total of 40 comparative evaluations were performed. For cardiac auscultation, the value of the rating scale was 4.53 ± 1.91 and 7.18 ± 1.88 for the traditional and amplified stethoscope, respectively (paired t-test: P < .0001). For respiratory sounds, quality of auscultation was estimated at 3.1 ± 1.95 for a traditional stethoscope and 5.10 ± 2.13 for the amplified one (paired t-test: P < .0001). CONCLUSIONS: This study showed that practitioners would be better helped in hearing cardiac and respiratory sounds with an electronically amplified stethoscope than with a traditional one during air medical transport in a medically configured Falcon 50 aircraft.