There are not reliable methods for measuring laryngo-pharyngeal mechano-sensitivity (LPMS). We aimed to determine the reliability of a new method for measuring LPMS using a new laryngo-pharyngeal esthesiometer (LPEER) in a prospective cohort of dysphagic stroke and non-dysphagic patients. The patients underwent clinical and endoscopic evaluations of swallowing (FESSST). The LPMS assessments consisted of measurements by an expert and a novel rater of the laryngeal-adductor reflex threshold (LART), cough reflex threshold (CRT) and gag reflex threshold (GRT) using the LPEER. We assessed the Bland-Altman limits of agreement, the intraclass correlation coefficients (ICCs) and Spearman correlation coefficients (SCCs). For the inter-rater comparisons, we contrasted the expert and novel raters. A total of 1608 measurements were obtained from 34 dysphagic stroke patients and 33 non-dysphagic patients. The intra-rater ICCs for all reflex thresholds were >0.90. The inter-rater ICCs were 0.87 for the LART, 0.79 for the CRT and 0.70 for the GRT. The intra-rater SCCs for all reflex thresholds were above 0.88 (P < 0.0001). The inter-rater SCC were 0.80 for the LART, 0.79 for the CRT and 0.70 for the GRT (all P < 0.0001). The Bland-Altman plots revealed good agreement for the LART and CRT and moderate agreement for the GRT. The median normal value was 0.14 mN for the LART, 4.4 mN for the CRT and 11.9 mN for the GRT. The median thresholds values in patients with aspiration were LART: 1.31 mN; CRT: 32.9 mN and GRT: 32.9 mN (all P < 0.006 vs normal thresholds). The LPEER exhibited substantial to excellent intra- and inter-rater reliability.
BackgroundLaryngo-pharyngeal mechano-sensitivity (LPMS) is involved in dysphagia, sleep apnea, stroke, irritable larynx syndrome and cough hypersensitivity syndrome among other disorders. These conditions are associated with a wide range of airway reflex abnormalities. However, the current device for exploring LPMS is limited because it assesses only the laryngeal adductor reflex during fiber-optic endoscopic evaluations of swallowing and requires a high degree of expertise to obtain reliable results, introducing intrinsic expert variability and subjectivity.MethodsWe designed, developed and validated a new air-pulse laryngo-pharyngeal endoscopic esthesiometer with a built-in laser range-finder (LPEER) based on the evaluation and control of air-pulse variability determinants and on intrinsic observer variability and subjectivity determinants of the distance, angle and site of stimulus impact. The LPEER was designed to be capable of delivering precise and accurate stimuli with a wide range of intensities that can explore most laryngo-pharyngeal reflexes.ResultsWe initially explored the potential factors affecting the reliability of LPMS tests and included these factors in a multiple linear regression model. The following factors significantly affected the precision and accuracy of the test (P < 0.001): the tube conducting the air-pulses, the supply pressure of the system, the duration of the air-pulses, and the distance and angle between the end of the tube conducting the air-pulses and the site of impact. To control all of these factors, an LPEER consisting of an air-pulse generator and an endoscopic laser range-finder was designed and manufactured. We assessed the precision and accuracy of the LPEER’s stimulus and range-finder according to the coefficient of variation (CV) and by looking at the differences between the measured properties and the desired values, and we performed a pilot validation on ten human subjects. The air-pulses and range-finder exhibited good precision and accuracy (CV < 0.06), with differences between the desired and measured properties at <3 % and a range-finder measurement error of <1 mm. The tests in patients demonstrated obtainable and reproducible thresholds for the laryngeal adductor, cough and gag reflexes.ConclusionsThe new LPEER was capable of delivering precise and accurate stimuli for exploring laryngo-pharyngeal reflexes.
An assessment of the rainfall station distribution in the mountainous area of the Regional Autonomous Corporation of Cundinamarca (CAR, for its acronym in Spanish), Colombia, was conducted by applying concepts from information entropy and artificial neural networks (ANNs). This study was divided into two phases: first, a classification of the meteorological stations using two-dimensional self-organizing maps; second, the evaluation of the performance of the ANN by applying concepts of information entropy. Three scenarios were raised for the classification of the meteorological stations by adjusting the number of neurons in the output layer. A high number of neurons in the output layer were obtained, causing the model to over-fit while emphasizing differences amid patterns. When comparing the results of the scenarios, the permanence of certain characteristics and features was found in the system, validating the model classification. Subsequently, the results of the first scenario were used to evaluate the entropy of the historical series. Finally, the results show that the area of study presents a lack of information due to the uncertainty associated with the probabilistic arrangement, which can be corrected with the developed model. Consequently, some recommendations for the redesign of the rainfall are provided.
Obstructive sleep apnea (OSA) is a common sleep disorder characterized by repetitive upper airway obstruction, intermittent hypoxemia, and recurrent awakenings during sleep. The most used treatment for this syndrome is a device that generates a positive airway pressure—Continuous Positive Airway Pressure (CPAP), but it works continuously, whether or not there is apnea. An alternative consists on systems that detect apnea episodes and produce a stimulus that eliminates them. Article focuses on the development of a simple and autonomous processing system for the detection of obstructive sleep apneas, using polysomnography (PSG) signals: electroencephalography (EEG), electromyography (EMG), respiratory effort (RE), respiratory flow (RF), and oxygen saturation (SO2). The system is evaluated using, as a gold standard, 20 PSG tests labeled by sleep experts and it performs two analyses. A first analysis detects awake/sleep stages and is based on the accumulated amplitude in a channel-dependent frequency range, according to the criteria of the American Academy of Sleep Medicine (AASM). The second analysis detects hypopneas and apneas, based on analysis of the breathing cycle and oxygen saturation. The results show a good estimation of sleep events, where for 75% of the cases of patients analyzed it is possible to determine the awake/asleep states with an effectiveness of >92% and apneas and hypopneas with an effectiveness of >55%, through a simple processing system that could be implemented in an electronic device to be used in possible OSA treatments.
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