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Chang AB, Oppenheimer JJ, Irwin RS, Adams TM, Altman KW, Azoulay E, Blackhall F, Birring SS, Bolser DC, Boulet LP, Braman SS, Brightling C, Callahan-Lyon P, Chang AB, Cowley T, Davenport P, El Solh AA, Escalante P, Field SK, Fisher D, French CT, Grant C, Harding SM, Harnden A, Hill AT, Irwin RS, Kahrilas PJ, Kavanagh J, Keogh KA, Lai K, Lane AP, Lilly C, Lim K, Lown M, Madison JM, Malesker MA, Mazzone S, McGarvey L, Molasoitis A, Murad MH, Narasimhan M, Oppenheimer J, Russell RJ, Ryu JH, Singh S, Smith MP, Tarlo SM, Vertigan AE. Managing Chronic Cough as a Symptom in Children and Management Algorithms. Chest 2020; 158:303-329. [DOI: 10.1016/j.chest.2020.01.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/11/2019] [Accepted: 01/09/2020] [Indexed: 12/12/2022] Open
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Rhee H, Belyea MJ, Sterling M, Bocko MF. Evaluating the Validity of an Automated Device for Asthma Monitoring for Adolescents: Correlational Design. J Med Internet Res 2015; 17:e234. [PMID: 26475634 PMCID: PMC4704980 DOI: 10.2196/jmir.4975] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 08/18/2015] [Accepted: 08/19/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Symptom monitoring is a cornerstone of asthma self-management. Conventional methods of symptom monitoring have fallen short in producing objective data and eliciting patients' consistent adherence, particularly in teen patients. We have recently developed an Automated Device for Asthma Monitoring (ADAM) using a consumer mobile device as a platform to facilitate continuous and objective symptom monitoring in adolescents in vivo. OBJECTIVE The objectives of the study were to evaluate the validity of the device using spirometer data, fractional exhaled nitric oxide (FeNO), existing measures of asthma symptoms/control and health care utilization data, and to examine the sensitivity and specificity of the device in discriminating asthma cases from nonasthma cases. METHODS A total of 84 teens (42 teens with a current asthma diagnosis; 42 without asthma) aged between 13 and 17 years participated in the study. All participants used ADAM for 7 consecutive days during which participants with asthma completed an asthma diary two times a day. ADAM recorded the frequency of coughing for 24 hours throughout the 7-day trial. Pearson correlation and multiple regression were used to examine the relationships between ADAM data and asthma control, quality of life, and health care utilization at the time of the 7-day trial and 3 months later. A receiver operating characteristic (ROC) curve analysis was conducted to examine sensitivity and specificity based on the area under the curve (AUC) as an indicator of the device's capacity to discriminate between asthma versus nonasthma cases. RESULTS ADAM data (cough counts) were negatively associated with forced expiratory volume in first second of expiration (FEV1) (r=-.26, P=.05), forced vital capacity (FVC) (r=-.31, P=.02), and overall asthma control (r=-.41, P=.009) and positively associated with daily activity limitation (r=.46, P=.01), nighttime (r=.40, P=.02) and daytime symptoms (r=.38, P=.02), and health care utilization (r=.61, P<.001). Device data were also a significant predictor of asthma control (β=-.48, P=.003), quality of life (β=-.55, P=.001), and health care utilization (β=.74, P=.004) after 3 months. The ROC curve analysis for the presence of asthma diagnosis had an AUC of 0.71 (95% CI 0.58-0.84), which was significantly different from chance (χ(2) 1=9.7, P=.002), indicating the device's discriminating capacity. The optimal cutoff value of the device was 0.56 with a sensitivity of 51.3% and a specificity of 72.7%. CONCLUSIONS This study demonstrates validity of ADAM as a symptom-monitoring device in teens with asthma. ADAM data reflect the current status of asthma control and predict asthma morbidity and quality of life for the near future. A monitoring device such as ADAM can increase patients' awareness of the patterns of cough for early detection of worsening asthma and has the potential for preventing serious and costly future consequences of asthma.
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Affiliation(s)
- Hyekyun Rhee
- School of Nursing, University of Rochester, Rochester, NY, United States.
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Rhee H, Miner S, Sterling M, Halterman JS, Fairbanks E. The development of an automated device for asthma monitoring for adolescents: methodologic approach and user acceptability. JMIR Mhealth Uhealth 2014; 2:e27. [PMID: 25100184 PMCID: PMC4114416 DOI: 10.2196/mhealth.3118] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/23/2014] [Accepted: 04/27/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Many adolescents suffer serious asthma related morbidity that can be prevented by adequate self-management of the disease. The accurate symptom monitoring by patients is the most fundamental antecedent to effective asthma management. Nonetheless, the adequacy and effectiveness of current methods of symptom self-monitoring have been challenged due to the individuals' fallible symptom perception, poor adherence, and inadequate technique. Recognition of these limitations led to the development of an innovative device that can facilitate continuous and accurate monitoring of asthma symptoms with minimal disruption of daily routines, thus increasing acceptability to adolescents. OBJECTIVE The objectives of this study were to: (1) describe the development of a novel symptom monitoring device for teenagers (teens), and (2) assess their perspectives on the usability and acceptability of the device. METHODS Adolescents (13-17 years old) with and without asthma participated in the evolution of an automated device for asthma monitoring (ADAM), which comprised three phases, including development (Phase 1, n=37), validation/user acceptability (Phase 2, n=84), and post hoc validation (Phase 3, n=10). In Phase 1, symptom algorithms were identified based on the acoustic analysis of raw symptom sounds and programmed into a popular mobile system, the iPod. Phase 2 involved a 7 day trial of ADAM in vivo, and the evaluation of user acceptance using an acceptance survey and individual interviews. ADAM was further modified and enhanced in Phase 3. RESULTS Through ADAM, incoming audio data were digitized and processed in two steps involving the extraction of a sequence of descriptive feature vectors, and the processing of these sequences by a hidden Markov model-based Viterbi decoder to differentiate symptom sounds from background noise. The number and times of detected symptoms were stored and displayed in the device. The sensitivity (true positive) of the updated cough algorithm was 70% (21/30), and, on average, 2 coughs per hour were identified as false positive. ADAM also kept track of the their activity level throughout the day using the mobile system's built in accelerometer function. Overall, the device was well received by participants who perceived it as attractive, convenient, and helpful. The participants recognized the potential benefits of the device in asthma care, and were eager to use it for their asthma management. CONCLUSIONS ADAM can potentially automate daily symptom monitoring with minimal intrusiveness and maximal objectivity. The users' acceptance of the device based on its recognized convenience, user-friendliness, and usefulness in increasing symptom awareness underscores ADAM's potential to overcome the issues of symptom monitoring including poor adherence, inadequate technique, and poor symptom perception in adolescents. Further refinement of the algorithm is warranted to improve the accuracy of the device. Future study is also needed to assess the efficacy of the device in promoting self-management and asthma outcomes.
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Affiliation(s)
- Hyekyun Rhee
- University of Rochester Medical Center, School of Nursing, University of Rochester, Rochester, NY, United States.
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Rhee H, Fairbanks E, Butz A. Symptoms, feelings, activities and medication use in adolescents with uncontrolled asthma: lessons learned from asthma diaries. J Pediatr Nurs 2014; 29:39-46. [PMID: 23685266 PMCID: PMC3805759 DOI: 10.1016/j.pedn.2013.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 04/10/2013] [Accepted: 04/18/2013] [Indexed: 11/28/2022]
Abstract
This study was to describe symptoms, feelings, activities and medication use reported by adolescents with uncontrolled asthma on their 24-hour asthma diaries. Adolescents with uncontrolled asthma (13-17 years, N=29) completed asthma diaries and audio-recorded symptom sounds for 24 hours. A variety of symptoms were reported, and the most frequently reported symptoms were coughing followed by wheezing. Most self-reported coughing and wheezing were verified by audio-recordings. Participants reported predominantly negative feelings and low levels of activities. High discordance between self-reports and medical records in medications was noted, raising a concern of poor treatment adherence in this vulnerable group.
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Vilozni D, Livnat G, Dabbah H, Elias N, Hakim F, Bentur L. The potential use of spirometry during methacholine challenge test in young children with respiratory symptoms. Pediatr Pulmonol 2009; 44:720-7. [PMID: 19499592 DOI: 10.1002/ppul.20978] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND The concentration of methacholine that causes a fall of 20% from baseline forced expiratory volume in the first second (PC20-FEV1) in the methacholine challenge test (MCT) is not usually considered a diagnostic tool in preschool children since PC20-FEV1 may not be achievable <6 years of age. AIM To assess the usefulness of various spirometry indices obtained during MCT in a large group of 3- to 6-year-old children with respect to their clinical diagnosis. METHODS Standardized MCT (inhaled triple-concentration increments [0.057-13.925 mg] of methacholine solution) was performed by 84 children previously diagnosed with asthma (asthmatics) and 48 with prolonged cough (coughers). Spirometry was determined at baseline and between inhalations; PC20-FEV1 and PC25-FEV0.5 were calculated. RESULTS PC20-FEV1 values were significantly less in the asthmatics than in the coughers (mean +/- SD was 3.21 +/- 4.32 vs. 22.35 +/- 3.66 ml/mg). Similarly, PC25-FEV0.5 was 1.48 +/- 3.08 in the asthmatics and 9.45 +/- 12.59 mg/ml/Mch in the coughers, P < 0.0001. A cut-off at 4.0 mg/ml for PC20-FEV1 had 77.4% sensitivity and 75.0% specificity, a cut-off at 2.2 mg/ml for PC25-FEV0.5 had 73.8% sensitivity and 72.9% specificity, for clinical diagnosis of asthma. PC25-FEV0.5 also showed a correlation with age. CONCLUSIONS Our findings suggest that MCT can be performed in preschool children with various respiratory symptoms. PC25-FEV0.5 may be a better end-point parameter. Children with a clinical diagnosis of asthma respond to a lower MCT concentration than children with cough. Further studies are needed to determine airway responsiveness in healthy young children and to further assess the contribution of MCT to the clinical diagnosis in this age group.
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Affiliation(s)
- Daphna Vilozni
- Pediatric Pulmonary Unit, Meyer Children's Hospital, Rambam Medical Center, Technion-Israel Institute of Technology, Haifa 31096, Israel.
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Abstract
Although clinicians place considerable weight on the identification of the various forms of noisy breathing, there are serious questions regarding both the accuracy (validity) and the reliability (repeatability) of these noises. To avoid diagnostic errors, clinicians need to consider the whole constellation of symptoms and signs, and not focus on the specific "type" of noise. Given the high error rate with "parent-reported wheeze" there is a need to reexamine the extensive literature on the epidemiology of wheeze in infants and young children, because parent-reported wheeze is unconfirmed by a clinician. It is obvious we need more high-quality research evidence to derive better evidence on the clinical utility of these noises, and their natural history.
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Affiliation(s)
- Craig Mellis
- Central Clinical School, University of Sydney, Royal Prince Alfred Hospital, Sydney, NSW 2006, Australia.
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Rietveld S, van Beest I. Rollercoaster asthma: when positive emotional stress interferes with dyspnea perception. Behav Res Ther 2006; 45:977-87. [PMID: 16989773 DOI: 10.1016/j.brat.2006.07.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 07/13/2006] [Accepted: 07/18/2006] [Indexed: 11/25/2022]
Abstract
The current study assessed how negative and positive stress is related to dyspnea perception. The participants were 25 young women with a medical diagnosis of severe asthma, and 15 matched controls. Stress was induced during repeated rollercoaster rides. Results showed that negative emotional stress and blood pressure peaked just before, and positive emotional stress and heart beat peaked immediately after rollercoaster rides. Dyspnea in women with asthma was higher just before than immediately after rollercoaster rides, even in women with asthma with a rollercoaster-evoked reduction in lung function. These results suggest that stressed and highly aroused individuals with chronic asthma tend to perceive dyspnea in terms of acquired, familiar associations between dyspnea and positive versus negative feeling states, favoring either underperception or overperception of dyspnea, depending on the emotional valence of a situation.
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Affiliation(s)
- Simon Rietveld
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
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Li AM, Tsang TWT, Chan DFY, Lam HS, So HK, Sung RYT, Fok TF. Cough frequency in children with mild asthma correlates with sputum neutrophil count. Thorax 2006; 61:747-50. [PMID: 16670174 PMCID: PMC2117083 DOI: 10.1136/thx.2005.050815] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation. METHODS Thirty six children of median age 11.5 years (interquartile range (IQR) 9-14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters. RESULTS All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1-97.6) and 56.1 ppb (IQR 37.4-105), respectively. The median number of cough episodes per day was 25.5 (IQR 16-42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001). CONCLUSIONS Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.
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Affiliation(s)
- A M Li
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
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Rietveld S, Brosschot JF. Current perspectives on symptom perception in asthma: a biomedical and psychological review. Int J Behav Med 2006; 6:120-34. [PMID: 16250683 DOI: 10.1207/s15327558ijbm0602_2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Symptom perception in patients with asthma is often inadequate. Patients may fail to perceive serious airway obstruction or suffer from breathlessness without objective cause. These extremes are associated with fatal asthma and excessive use of medicines, respectively. This article covers symptom perception in a multidisciplinary perspective. A presentation of current definitions and methods for studying symptom perception in asthma is followed by a summary of theories on the origin of breathlessness. Next, biomedical and psychological factors influencing symptom perception are examined. Preliminary biomedical research emphasizes neural pathway impairment, but causal factors remain inconclusive, particularly regarding the overperception of symptoms. Psychological studies suggest that the accuracy of symptom perception is influenced by (a) competition between asthmatic and nonasthmatic sensory information, (b) negative emotions, and (c) acquired response tendencies (e.g. habituation to symptoms, repression of symptoms, selective perception, and false interpretation of symptoms). These factors may favor either blunted perception or overperception. Empirical data in support of psychological factors are still insufficient. Methodological problems and procedures to improve symptom perception are discussed.
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Affiliation(s)
- S Rietveld
- Department of Clinical Psychology, University of Amsterdam, The Netherlands.
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10
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Abstract
Chronic cough is a common problem in childhood. Viral infections are the most prevalent cause, but other rarer disorders should be excluded whenever cough appears unusually severe and/or frequent, and when there is evidence of failure to thrive and growth retardation. The younger the child, the more the need to exclude underlying disease at an early stage. Passive smoking is an important contributor to chronic cough in children. Chronic productive cough with purulent sputum is always reason for concern in children and is not common as a symptom of asthma. More or less specific diagnoses in children include cystic fibrosis, aspirated foreign body, congenital anatomic abnormalities and primary ciliary dyskinesia.
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Affiliation(s)
- J C de Jongste
- Department of Pediatric Respiratory Medicine, Sophia Children's Hospital/Erasmus MC University Medical Center, Rotterdam, The Netherlands.
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Li AM, Lex C, Zacharasiewicz A, Wong E, Erin E, Hansel T, Wilson NM, Bush A. Cough frequency in children with stable asthma: correlation with lung function, exhaled nitric oxide, and sputum eosinophil count. Thorax 2003; 58:974-8. [PMID: 14586052 PMCID: PMC1746522 DOI: 10.1136/thorax.58.11.974] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND A study was undertaken to assess the correlation between cough frequency in asthmatic children with lung function and two non-invasive markers of airway inflammation. METHODS Thirty two children of median age 12.0 years (interquartile range (IQR) 9.5-13.4) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring over 17 hours and 40 minutes. Coughing episodes were counted both as individual spikes and as clusters. RESULTS Complete cough frequency data were available in 29 children (90%) and their median forced expiratory volume in 1 second (FEV1) and eNO were 88.5% (IQR 79.5-98) and 23.9 ppb (IQR 11.4-41.5), respectively. The median number of cough episodes was 14 (IQR 7.0-24.0) which was significantly higher than that of normal children (6.7 (IQR 4.1-10.5), p<0.001). Sputum induction was successful in 61% of the subjects; the median induced sputum eosinophil count was 0.05% (IQR 0-9.0). Cough frequency was found to have a significant positive correlation with eNO (Spearman's r =0.781, p<0.001) but not with FEV1 or sputum eosinophil count (r =-0.270, p=0.157; r =0.173, p=0.508, respectively). CONCLUSIONS Children with stable asthma have increased cough frequency compared with normal controls and cough frequency was greater during the day than at night. Cough may be a more sensitive marker of airway inflammation than simple spirometry.
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Affiliation(s)
- A M Li
- Department of Paediatric Respiratory Medicine, Royal Brompton Hospital, London SW3 6NP, UK
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Harper VP, Pasterkamp H, Kiyokawa H, Wodicka GR. Modeling and measurement of flow effects on tracheal sounds. IEEE Trans Biomed Eng 2003; 50:1-10. [PMID: 12617519 DOI: 10.1109/tbme.2002.807327] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The analysis of breathing sounds measured over the extrathoracic trachea offers a noninvasive technique to monitor obstructions of the respiratory tract. Essential to development of this technique is a quantitative understanding of how such tracheal sounds are related to the underlying tract anatomy, airflow, and disease-induced obstructions. In this study, the first dynamic acoustic model of the respiratory tract was developed that takes into consideration such factors as turbulent sound sources and varying glottal aperture. Model predictions were compared to tracheal sounds measured on four healthy subjects at target flow rates of 0.5, 1.0, 1.5, and 2.0 L/s, and also during nontargeted breathing. Both the simulation and measurement spectra depicted increasing sound power with increasing flow, with smaller incremental increases at the higher flow rates. A sound power increase of approximately 30 dB between a flow rate of 0.5 and 2.0 L/s was observed in both the simulated and measured spectra. Variations of as much as 15 dB over the 300-600 Hz frequency band were noted in the sound power produced during targeted and nontargeted breathing maneuvers at the same flow rates. We propose that this variability was in part due to changes in glottal aperture area, which is known to vary during normal respiration and has been observed as a method of flow control. Model simulations incorporating a turbulent source at the glottis with respiratory cycle variations in glottal aperture from 0.64 cm2 to 1.4 cm2 explained approximately 10 dB of the measured variation. This study provides the first links between spatially distributed sound sources due to turbulent flow in the respiratory tract and noninvasive tracheal sounds measurements.
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Affiliation(s)
- V Paul Harper
- Department of Biomedical Engineering and School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907-1285 USA
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13
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Abstract
In childhood asthma, cough is a major symptom in some but not in others. There is only limited data on the frequency, severity and prevalence of cough in children with classical asthma. Studies have largely shown no relationship between cough frequency and cough receptor sensitivity with various asthma severity indices. However relating cough severity with asthma severity is limited by various methodological and sensitivity issues, and these are presented in this paper. Mild asthma exacerbations in a group of children with cough as a dominant symptom were characterised by an increase in cough severity (daytime cough scores) and eosinophilic inflammation but not neutrophilic inflammation. However neither cough receptor sensitivity or cough scores related to airway IL-8, eosinophil cationic protein, myeloperoxidase or serum eosinophil cationic protein, and, asthma scores consistently related to cough score only early in the asthma exacerbation phase.
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Affiliation(s)
- Anne B Chang
- Department of Respiratory Medicine, Royal Children's Hospital, Qld 4029, Brisbane, Australia.
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14
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Abstract
Cough or cough epochs may be an important and persistent symptom in many respiratory diseases requiring both a continuous and objective observation. The research presented in this paper is aimed at assessing a blind data-based classification between 'spontaneous' and 'voluntary' human cough on individual sound samples. Cough sounds were registered in the free acoustic field on 3 pathological and 9 healthy non-smoking subjects, all aged between 20 and 30. Each sound is represented by the normalized power spectral density (PSD). Different transformations of the cough PSD-vector are chosen as input features to the classification algorithm. An experimental error rate comparison between different neural and fuzzy classification networks is performed. All evaluated algorithms used the Euclidean metric. This resulted in a correct class-discrimination between 'spontaneous' and 'voluntary' cough for 96% of the cough database.
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Affiliation(s)
- Annemie Van Hirtum
- Department of Agro-Engineering and Economics, K.U. Leuven, Kasteelpark Arenberg 30, 3001 Leuven, Belgium
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Leuppi JD, Downs SH, Downie SR, Marks GB, Salome CM. Exhaled nitric oxide levels in atopic children: relation to specific allergic sensitisation, AHR, and respiratory symptoms. Thorax 2002; 57:518-23. [PMID: 12037227 PMCID: PMC1746345 DOI: 10.1136/thorax.57.6.518] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Exhaled nitric oxide (eNO), which has been proposed as a measure of airway inflammation, is increased in atopic subjects. This raises the question of whether eNO provides any additional information about airway inflammation in asthmatic subjects, other than as a marker for atopy. A study was undertaken to determine whether eNO levels in a population of atopic children are associated with sensitisation or natural exposure to specific allergens, and to examine the relationship between eNO, airway responsiveness, and current respiratory symptoms. METHODS Exhaled NO and airway responsiveness to histamine were measured in winter and in summer in 235 children aged 8-14 years who had been classified as atopic by skin prick testing. Current respiratory symptoms, defined as wheeze or cough during the month preceding the test, were measured by a parent completed questionnaire. Airway hyperresponsiveness (AHR) was defined as a dose response ratio (DRR) of >8.1 (% fall in forced expiratory volume in 1 second (FEV(1))/micromol + 3). RESULTS Sensitisation to house dust mite was associated with raised eNO levels in winter while sensitisation to Cladosporium was associated with raised eNO levels in both winter and summer. Grass pollen sensitisation was not associated with raised eNO levels in either season. Exhaled NO correlated significantly with DRR histamine (r=0.43, p<0.001) independently of whether the children had current symptoms or not. In children with current wheeze, those with AHR had eNO levels 1.53 (95% CI 1.41 to 1.66) times higher than those without AHR (p=0.006). Neither DRR (p=1.0) nor eNO levels (p=0.92) differed significantly between children with or without persistent dry cough in the absence of wheeze. CONCLUSIONS In atopic children, raised eNO levels are associated with sensitisation to perennial allergens, but not to seasonal allergens such as grass pollen. In this population, an increase in eNO is associated with AHR and current wheezing, suggesting that eNO is more than just a marker for atopy.
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Affiliation(s)
- J D Leuppi
- Institute of Respiratory Medicine, University of Sydney, Australia.
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Abstract
The medical approach of chronic cough suffers from the lack of a standardised definition. The most frequently encountered criterion is a recurrent cough observed during several consecutive months, each episode lasting at least 1 week. The link between recurrent cough and asthma is still discussed. Cough-related asthma diagnosis is facilitated when wheezing is clearly confirmed, or may be reminded by a nonproductive middle night cough, or an exercise-triggered cough, or the presence of personal or familial atopy. Conversely, an early morning and productive cough associated with tobacco exposure do not suggest asthma.
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Affiliation(s)
- C Marguet
- Unité de pneumo-allergologie pédiatrique, département de pédiatrie, hôpital Charles-Nicolle, CHU Rouen, 76031 Rouen, France.
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Harper P, Kraman SS, Pasterkamp H, Wodicka GR. An acoustic model of the respiratory tract. IEEE Trans Biomed Eng 2001; 48:543-50. [PMID: 11341528 DOI: 10.1109/10.918593] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
With the emerging use of tracheal sound analysis to detect and monitor respiratory tract changes such as those found in asthma and obstructive sleep apnea, there is a need to link the attributes of these easily measured sounds first to the underlying anatomy, and then to specific pathophysiology. To begin this process, we have developed a model of the acoustic properties of the entire respiratory tract (supraglottal plus subglottal airways) over the frequency range of tracheal sound measurements, 100 to 3000 Hz. The respiratory tract is represented by a transmission line acoustical analogy with varying cross sectional area, yielding walls, and dichotomous branching in the subglottal component. The model predicts the location in frequency of the natural acoustic resonances of components or the entire tract. Individually, the supra and subglottal portions of the model predict well the distinct locations of the spectral peaks (formants) from speech sounds such as /a/ as measured at the mouth and the trachea, respectively, in healthy subjects. When combining the supraglottic and subglottic portions to form a complete tract model, the predicted peak locations compare favorably with those of tracheal sounds measured during normal breathing. This modeling effort provides the first insights into the complex relationships between the spectral peaks of tracheal sounds and the underlying anatomy of the respiratory tract.
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Affiliation(s)
- P Harper
- School of Electrical and Computer Engineering, Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-1285, USA
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18
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al Hatib F, Neycheva T, Shenkada MS, Popov TA, Daskalov IK. Monitoring of fluctuating airway obstruction and episodes of coughing by thoracic electrical impedance. J Med Eng Technol 2001; 25:49-52. [PMID: 11452632 DOI: 10.1080/03091900010021662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The most prominent feature of bronchial asthma is the fluctuating airway obstruction of the affected subjects. Cough is also one of the major symptoms of asthma, but of other conditions as well. The continuous registration of airway obstruction and coughing in the working or open-air environment or at the homes of the potential sufferers may help establish a sometimes elusive diagnosis. To this purpose we developed a method using a measurement of the changes in the chest basal electrical impedance (Z0). A portable device for long-term recording of the Z0 signal was built using a microprocessor system. In order to assess both gradual Z0 changes, suggestive of altering airway patency and coughing episodes (characterized by abrupt changes), a continuous analogue-to-digital conversion (ADC) loop with a sampling frequency of 16 Hz was programmed. After completion of the recording, the memory of the portable instrument can be downloaded to a PC system for assessment and analysis. Appropriate averaging and filtering procedures have been worked out. This device may be further upgraded to give out a signal when Z0 starts to increase, so as to prevent a full-blown asthmatic crisis.
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Affiliation(s)
- F al Hatib
- Centre of Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
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Rietveld S, Van Beest I, Everaerd W. Psychological confounds in medical research: the example of excessive cough in asthma. Behav Res Ther 2000; 38:791-800. [PMID: 10937427 DOI: 10.1016/s0005-7967(99)00099-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This experiment tested the hypothesis that the setting in which research is conducted may dominate symptom magnitude. Cough was induced with inhaled citric acid and its magnitude was influenced by changing the setting in 30 adolescents with asthma. Cough thresholds for citric acid were determined. The participants were assigned to a condition emphasising asthma, or a control condition, described as estimation of lemon flavors. All participants inhaled (in different order) thresholds for citric acid, 50% of these thresholds, or placebo. Results showed that both cough frequency and subjective 'cough tendency' were significantly higher in the asthma condition. State anxiety was higher in the asthma condition, but correlated only moderately with cough. Lung function, severity of asthma, trait anxiety, age or sex did not correlate with cough. It was concluded that patients with asthma cough more often in a situation which they have learned to associate with asthma.
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Affiliation(s)
- S Rietveld
- Department of Psychology, University of Amsterdam, The Netherlands.
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Abstract
OBJECTIVES To test symptom perception in asthma under natural circumstances and to establish relationships between changes in airway obstruction as indicated by wheeze, dyspnea, general sensations, and emotional state. DESIGN Continuous in vivo monitoring. METHOD Symptom perception was tested in 30 adolescents with severe, unstable asthma. They were continuously monitored in their homes for 72 h. Symptom perception was defined as the relation between self-reported dyspnea and airway obstruction as evident from audible wheeze. Tracheal sounds were continuously recorded with wireless telemetry for wheeze assessment. Dyspnea was assessed four times per day on a Likert-type 10-point scale, as well as four times randomly after pager remote command. The subjects kept records of use of medication, daily activities, general symptoms, and mood state in a diary. RESULTS There were nine subjects with one or two wheeze episodes, another three subjects with three or four episodes, and one subject with almost continuous wheeze. The presence of wheeze in general related significantly to a rise (from individual baseline) in dyspnea of > 2.5 scale points. Acute wheeze was the best predictor of a rise in dyspnea, but prolonged wheeze correlated significantly with negative mood and general symptoms. CONCLUSION Patients with prolonged airway obstruction perceived symptoms less well and were more vulnerable to negative effects of asthma than patients with acute onset airway obstruction.
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Affiliation(s)
- S Rietveld
- Department of Psychology, University of Amsterdam, The Netherlands.
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21
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Evaluation of stridor. Curr Opin Otolaryngol Head Neck Surg 1999. [DOI: 10.1097/00020840-199912000-00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rietveld S, Oud M, Rijssenbeek-Nouwens LH, Vaghi D, Dooijes EH. Characteristics and diagnostic significance of spontaneous wheezing in children with asthma: results of continuous in vivo sound recording. J Asthma 1999; 36:351-8. [PMID: 10386499 DOI: 10.3109/02770909909068228] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The characteristics and diagnostics of wheezing during induced airway obstruction are well documented. The present study addressed (a) the characteristics of spontaneous wheezing with respect to a possible distinction between wheezes during in vivo versus induced airway obstruction, and (b) the relationship between in vivo wheezing and fluctuations in peak expiratory flow (PEF). Tracheal sounds were continuously recorded from 50 children and adolescents with asthma and 10 without asthma in the home environment. Wheezes underwent a qualitative analysis, including their concomitant sound frequencies. Presence of wheezing was scored by two examiners independently and was related to PEF. Spontaneous wheeze varied from solitary rhonchi to prolonged rhythms of loud stridor, and resembled the "induced" wheezes recorded previously. Power spectra showed that the spectral contents (frequency distribution) were comparable, although the in vivo patterns were more prolonged in duration. The diagnostic sensitivity and specificity of wheezing for a reduction in PEF of >20% were 88% and 92%, respectively. It was concluded that in vivo wheeze resembled induced wheeze and was a diagnostically reliable symptom with respect to asthma exacerbations.
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Affiliation(s)
- S Rietveld
- Department of Clinical Psychology, University of Amsterdam, The Netherlands
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Rietveld S, Rijssenbeek-Nouwens LH, Prins PJ. Cough as the ambiguous indicator of airway obstruction in asthma. J Asthma 1999; 36:177-86. [PMID: 10227269 DOI: 10.3109/02770909909056315] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study tested the hypothesis that cough frequency during induced airway obstruction in children and adolescents with asthma relates significantly to other symptoms. The second hypothesis was that cough during remission may often be a conditioned or voluntary response. In experiment 1, tracheal sounds were recorded from 30 participants with asthma during a histamine challenge test. In experiment 2, tracheal sounds were recorded from 30 participants with and 30 without asthma during a standardized physical exercise task. Cough and respiratory wheeze were assessed from the sound records by two examiners independently. The results showed that cough during airway obstruction did not relate to other variables. Only the second hypothesis was supported. In both experiments the frequency of cough was independent of lung function (forced expiratory volume in 1 sec [FEV1]), wheezing, dyspnea, and severity of asthma. The percentage of participants with asthma who coughed in experiment 1 increased from 21% (baseline) to 71% after histamine inhalation. During experiment 2, the cough percentage increased from 52% to 69% in asthmatics, and from zero to 57% in controls. It was concluded that cough in asthma is not diagnostically useful for assessment of airway obstruction. Excessive baseline cough among asthmatics could be the result of acquired responses to anticipated exercise-induced symptoms.
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Affiliation(s)
- S Rietveld
- Faculty of Psychology, University of Amsterdam, Heideheuvel Asthma Center, Hilversum, The Netherlands
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