Accelerometer |
Steele et al.(23)
|
To develop algorithms to detect swallowing problems using a system based on Accelerometer. |
305 individuals with stroke, other brain damage or at risk for dysphagia. |
Cervical auscultation with a dual-axis accelerometer. VFSS Exam. |
Algorithms developed by the authors. |
The system created allowed the identification of alterations in the swallowing of thin liquids with high precision (sensitivity 90.4%; specificity 60.0%). Algorithms represent a first step in the development of a device based on accelerometry for screening of deglutition. |
Electronic stethoscope |
Sánchez-Cardona et al.(21)
|
To characterize and classify the cervical auscultation signals and discriminate the swallowing sounds from those associated with the noise. |
10 individuals healthy (6 men; mean age 27.3 years old). |
Cervical auscultation with an electronic stethoscope (E- scope® Cardionics). |
Selected and Machine Learning Algorithms. |
The proposed method allowed the classification of swallowing sounds using a stethoscope. It was 97.7% accurate for detecting acoustic events and 91.7% for swallowing sounds by glottic closure, in the presence of noise sources. |
García(24)
|
To support the evaluation processes of cervical auscultation from the structuring of the spectrographic profile of the pharyngeal phase. |
93 healthy individuals, over 18 years old. |
Cervical auscultation with an electronic stethoscope (Littman® 3200). |
StethAssist software. |
The spectrographic profile of the pharyngeal phase represented four swallowing events that can be analyzed from the times obtained in the digital analysis of the acoustic wave. Thus, it provided parameters for the functional interpretation of swallowing. |
Microphone |
Bi et al.(32)
|
Accurately and conveniently monitor daily food intake through the AutoDietary system developed. |
12 individuals. |
Cervical Auscultation with a throat microphone. |
Smartphone application. |
The mean accuracy of food type recognition by AutoDietary was 84.9%, and up to 97.6% for classifying liquid and 99.7% solid food intake. AutoDietary presented itself as a promising device for the recognition of food intake in daily life. |
Honda et al.(33)
|
To Characterize and identify the sound generation process during swallowing in healthy young adults. |
33 young and healthy, subdivided into three experimental groups: 1) 10 men and 10 women, with a mean age of 25.8 years old; 2) 5 men and 5 women, with a mean age of 28.0 years old; 3 men, mean age 27.6 years old. |
Cervical auscultation with a condenser microphone. Simultaneous recording of VFSS in experiment 3. |
DADiSP software. |
The sound of swallowing can be divided into three periods: Oral phase: posterior movement of the tongue and hyoid bone; Pharyngeal phase: laryngeal movement, elevation of the hyoid bone, closure of the epiglottis and passage of the bolus into the esophagus; - Hyoid bone and laryngeal repositioning phase and epiglottis reopening. |
Frakking et al.(25)
|
To establish acoustic and perceptual profiles of swallowing sounds with and without aspiration, in children with dysphagia, and determine if there is a difference between these two types of swallowing |
47 children (57% male). |
Cervical Auscultation with an omnidirectional condenser microphone. VFSS Exam. |
Adobe Audition Software. Matlab Software. |
The presence of a glottic release sound together with normal breath sounds after swallowing are possible indicators of non-aspiration swallowing. On the other hand, the presence of noisy breathing and one or more of the sounds of coughing, wheezing, rales, hawking and stridor are indicative of swallowing aspiration, when compared to VFSS. |
Kamiyanagi et al.(34)
|
To assess swallowing ability in patients Maxilectomized with and without the obturator prosthesis placed. |
27 patients with maxillectomy (15 men; mean age 66 years old); 30 healthy controls (14 men; mean age 44.9 years old). |
Cervical auscultation with an electret condenser microphone. |
Speech Lab Computerized Software. |
Significant differences were observed, mainly in the measure of duration of the intensity peak of the analyzed variables inter and intra-groups. The swallowing ability in patients with maxillectomy can be improved with the use of an obturator prosthesis. |
Li et al.(35)
|
To characterize the temporal pattern of the tongue, hyoid and supra- and infra-hyoid muscles and determine how they are related and coordinated. |
15 healthy men (mean age 27.7 years old). |
Detection system consisting of a pressure sensor, a curvature sensor, surface electrodes and a microphone. |
No method described. |
Significant correlations were confirmed among muscles related to swallowing, tongue pressure and hyoid. The non-invasive detection system has the potential to be a good contributor to monitor and assess the oropharyngeal phase of swallowing. |
Frakking et al.(36)
|
To obtain normative data on the acoustic parameters of swallowing and determine if they are age-related. To obtain perceptual clinical signs of breath and swallowing sounds before, during and after swallowing. |
74 healthy children, between 4 and 36 months (35 men; mean age 17.1 months). |
Cervical auscultation with an omnidirectional condenser microphone. A digital video recorder to visualize laryngeal movement associated with swallowing. |
Adobe Audition Software. Matlab Software. |
Swallowing sounds become louder as children get older, and with chewable solids they become shorter. Most children have normal breath sounds before and after swallowing. A very small number present an occasional single cough with thin fluids, said to be normal in the process of learning and controlling the flow and volume of food. |
Almeida et al.(37)
|
To characterize the acoustic signal of silent tracheal aspiration in children with oropharyngeal dysphagia. |
18 children (56% girls, median age 6 years old). Groups: 8 that aspire and 10 do not aspire. |
Cervical auscultation with an electret condenser microphone. VFSS Exam. |
Raven software. |
The spectral power density curve of swallows with aspiration showed an ascending pattern, while the curve for normal swallows was flat. The non-invasive technique identified the aspiration by an increase in the of spectral power density curve in aspirated sounds. |
Kurihara et al.(38)
|
To develop a swallowing motion detection device and a swallowing state estimation system. |
7 healthy men (mean age 22 years old; height: 175.1 cm; weight: 61.6 kg). |
Device comprises a bidirectional electret condenser microphone and air tube. The experiment included f1 (swallowing nothing), f2 (tea), f3 (thickened tea) and f 4(rice cake). |
Matlab software. |
As viscosity increased, the larynx exhibited complex movements to swallow food. These movements were reflected in the signal. The proposed method was validated based on the estimate of f1 -f4, and accuracies of 0.99, 0.81, 0.84 and 0.91, respectively, were achieved. |
Miyagi et al.(39)
|
To investigate the use of machine learning to classify swallowing sounds as: normal, or mild, moderate and severe dysphagia. |
17 healthy men and 10 healthy women (mean age 22.4); 78 men and 65 women with dysphagia (mean age 83.3). |
Cervical Auscultation with a throat microphone. |
Audacity software and machine learning algorithm. |
In normal and dysphagic individuals, the maximum F measure was 78.9%. For normal and dysphagic subjects of mild, moderate and severe degrees, the values of measure F were 65.6%, 53.1%, 51.1% and 37.1%, respectively, insufficient to use the classifier as an independent method for diagnosis. |
Microphone and Accelerometer - High Resolution Cervical Auscultation |
Dudik et al.(40)
|
To characterize the signs of cervical auscultation in individuals with dysphagia that aspire. |
76 adults (50 men; mean age 62 Years old), 17 with a diagnosis of stroke, 59 with other medical conditions. |
Cervical auscultation with a triaxial accelerometer and a contact microphone. VFSS Exam. |
LabView software and selected algorithms. |
Few differences were presented between safe and unsafe swallows based on the chosen characteristics. Several statistical resources should be used simultaneously when aspiration is chosen as a variable in future work. |
Movahedi et al.(41)
|
To investigate whether the swallowing signals recorded by a microphone and a triaxial accelerometer differ from each other or carry unique information about function of swallowing. |
72 participants (42 men; mean age 63, years old), of these, 20 with a history of stroke. |
Cervical auscultation with a triaxial accelerometer and a contact microphone. VFSS Exam. |
LabView software and selected algorithms. |
Although the sounds and vibrations of swallowing may have the same physiological sources, the signs of swallowing recorded by the microphone and by the accelerometer differed from each other in the domains of time and frequency. The information provided by the sounds and vibrations of swallowing are not interchangeable. |
Dudik et al.(42)
|
To develop a method for investigating swallowing disorders, and characterize and compare the swallowing of healthy and unhealthy patients. |
Control group: 55 healthy individuals (28 men; mean age 39 years old). Study group: 53 patients with suspected dysphagia: 13 (10 men; mean age 66 years old) with current diagnosis of stroke and 40 (24 men; mean age 62 years old) with other medical conditions. |
Cervical auscultation with a triaxial accelerometer and a contact microphone. Study group: VFSS exam. |
LabView software and selected algorithms. |
Almost all the resources chosen for vibrations and sounds showed significant differences between healthy and unhealthy swallows, despite the absence of aspiration. The findings should collaborate with the field of cervical auscultation and serve as a reference for future investigations into more specialized characterization methods. |
Rebrion et al.(43)
|
To compare hyoid bone displacement from VFSS images with characteristics of the auscultation signal. |
25 patients (12 men; mean age 60 years old). |
Cervical auscultation with a triaxial accelerometer and a contact microphone. VFSS Exam. |
LabView software and selected algorithms. |
The sounds and vibrations of swallowing are related to the horizontal and vertical movements of the anterior and posterior parts of the hyoid bone. |
Kurosu et al.(44)
|
To examine whether there is an association between acoustic signals of high-resolution cervical auscultation and the kinematic events of swallowing. |
35 patients with stroke and suspected dysphagia (26 men; mean age 65.8 years old). |
Cervical auscultation with a triaxial accelerometer and a contact microphone. VFSS Exam. |
LabView software and selected algorithms. |
There is a strong relationship between high-resolution cervical auscultation signals and various kinematic events of swallowing (opening of the upper esophageal sphincter; closing of the laryngeal vestibule; reopening of the laryngeal vestibule; onset, maximum displacement and rest of the hyoid). There is potential for this method of cervical auscultation to be developed for clinical diagnosis and treatment of dysphagia rehabilitation. |
Donohue et al.(45)
|
To investigate the ability of high-resolution cervical auscultation to track displacement of the hyoid bone during swallowing. |
114 patients (65 men; ages between 19 and 94 years old) with suspicion /confirmation of dysphagia; 16 healthy adults. |
Cervical auscultation with a triaxial accelerometer and a contact microphone. VFSS Exam. |
LabView Software and Machine Learning Algorithms. |
Machine learning algorithms were able to locate approximately half (51% of the patient dataset, 49.9% of the healthy dataset) of the hyoid body in each frame of the swallow segments. Accurate and automated tracking of hyoid bone displacement is possible from high-resolution cervical auscultation signals without the use of VFSS images. |
Donohue et al.(46)
|
To Know whether high-resolution cervical auscultation signals can differentiate between swallows from healthy people and people with neurodegenerative diseases. |
20 patients with neurodegenerative diseases (10 men; mean age 61.25 years old); 51 healthy adults (22 men; mean age 67.21 years old). |
Cervical auscultation with a triaxial accelerometer and a contact microphone. VFSS Exam. |
LabView Software and Machine Learning Algorithms. |
High-resolution cervical auscultation signal characteristics combined with statistical methods and machine learning techniques can effectively differentiate swallows from healthy people from people with neurodegenerative diseases, with a high degree of accuracy (99%), sensitivity (100%) and specificity (99%). |
Microphone and Acoustic Emission Sensor |
Kamiyanagi et al.(47)
|
To establish a swallow assessment method that can be used for screening reliability. |
6 healthy men (mean age 40.2 years old) and 6 men with a palatal augmentation prosthesis (mean age 72.1 years old). |
Cervical auscultation with a throat condenser microphone and an acoustic emission sensor. |
Sound it! Premium software and selected algorithms. |
The duration of the swallowing sound measured by the microphone was significantly higher in patients with palatal augmentation prosthesis. The acoustic emission sensor allowed the measurement of high frequency ranges that could not be measured with the microphone. The findings suggested the validation of the swallowing sound analysis based on the probability distributions through Q- Q graphs. |
Chikai et al(26). |
To propose a swallowing sound measurement system that employs a sensor capable of acquiring acoustic information in a wide range frequency range. |
1 healthy male individual (age: 29 years old). |
Cervical auscultation with a throat condenser microphone and an acoustic emission sensor. |
Adobe Audition software and selected algorithms. |
The acoustic emission sensor exhibited acoustic signals above 3 KHz, which was not possible with the microphone. The data measured with the acoustic emission sensor reflected more sensitively and, combined with the Q-Q plots, showed the potential to distinguish the difference in sample viscosity. |
Microphone, Doppler Sensor and Stethoscope |
Taveira et al.(48)
|
To analyze the diagnostic validity of different methods for assessing swallowing sounds, when compared to the VFSS exam. |
3 articles: - United Kingdom (2004): stethoscope; - Brazil (2013): Doppler sonar; - Japan (2015): microphone The sample ranged from 10 to 30 individuals healthy and 14 to 70 dysphagic. |
Articles in which the main objective was to assess the accuracy of swallowing sounds were searched in five electronic databases without language or publication time limitations. |
United Kingdom (2004): not applicable. Brazil (2013): VoxMetria software. Japan (2015): Audio Director Software; Audacity and selected algorithms. |
Accuracy values were 0.94 for microphone, 0.80 for Doppler and 0.60 for stethoscope. Doppler showed excellent diagnostic accuracy in discriminating swallowing sounds. The microphone reported good sensitivity for discrimination of swallowing sounds in dysphagic patients. The stethoscope presented the best screening test in the discrimination of swallowing sounds. |
Doppler sensor and microphone |
Choi et al.(49)
|
To develop a non-invasive and quantitative swallowing monitoring and evaluation system. |
24 healthy individuals (14 men; Mean age 30.5 years old). |
System: an array of ultrasonic Doppler sensors, an omnidirectional electret condenser microphone, an inertial measurement unit and a Bluetooth module. |
Signal processing program developed by the authors. |
Peak amplitudes and energy significantly decreased with viscosity and peak-to-peak time interval and duration increased with volume. The system developed can be used effectively for tracking, monitoring and quantifying the swallowing function, through further research. |
Doppler sensor |
Soria et al.(13)
|
To compare the acoustic parameters of oropharyngeal swallowing among different age groups. |
Group I: 75 healthy elderly (Mean age 71 years old). Group II: 72 healthy adults (mean age 42 years old). |
Audible signal captured by Doppler sonar. |
VoxMetria Software. |
There was a change in the acoustic pattern of swallowing, both in terms of consistency and volume of the food bolus, when comparing elderly and adults. The main characteristic found in the elderly was a curve with smaller amplitude and longer time than in adults. |
Lee(28)
|
To detect food intake using ultrasonic Doppler sonar. |
10 individuals healthy (7 men; ages between 17 and 50 years old). |
Detection of chewing and swallowing events with acoustic Doppler sonar. |
33250A function generator, selected algorithms and machine learning. |
The method of detection of food intake based on acoustic Doppler sonar produced promising results with maximum recognition rates of 91.4% for chewing and 78.4% for swallowing. In addition to the high recognition performance, it proved to be convenient and safe and did not cause any skin problems related to the contact sensor. |
Piezoelectric sensor |
Yagi et al.(27)
|
To evaluate the efficiency and effectiveness of a swallowing monitoring system that uses respiratory flow, swallowing sound and laryngeal movement. |
11 healthy individuals (9 men; mean age 40.1 years old); 10 patients with dysphagia (4 men; mean age, 75.6 years old). |
The system comprises a nasal cannula-type flow sensor and a piezoelectric sensor. VFSS Exam. |
Matlab software and selected algorithms. |
Elevation delay time and laryngeal elevation time were significantly prolonged in patients with dysphagia, especially in food with higher viscosity. The occurrence rate of the inspiration-swallowing pattern increased significantly in the group of patients. The device can facilitate the assessment of some aspects of swallowing dysfunction, especially the coordination between swallowing and breathing. |