WO2014081401A1

WO2014081401A1 - A system for measuring and evaluating preterm feeding maturation based on sucking and swallowing patterns

Info

Publication number: WO2014081401A1
Application number: PCT/TR2013/000349
Authority: WO
Inventors: Aylin TARCAN; Ayse ECEVIT; Ahmet SARACOGLU; Banu Oskay ACAR; Deniz ANUK; Mehmet Ziya KADIOGLU; Sukru Alphan ES
Original assignee: Gedik, Osman Serdar
Priority date: 2012-11-22
Filing date: 2013-11-20
Publication date: 2014-05-30

Abstract

The invention relates to a device that can objectively monitor feeding maturity in premature babies using swallowing patterns.

Description

DESCRIPTION

A SYSTEM FOR MEASURING AND EVALUATING PRETERM FEEDING MATURATION BASED ON SUCKING AND SWALLOWING PATTERNS

Technical Field

The present invention relates to a device allowing objective monitoring of feeding maturation in infants that are born prematurely using swallowing patterns. Prior Art

Most babies who are born after the regular gestation period display developed sucking -swallowing capabilities. However, these capabilities are underdeveloped in babies who are bom prematurely. The lack of development of effective feeding in premature babies can lead to eating disorders, accidental deposits of food in the respiratory tract and the lungs, respiratory illnesses related thereto, infections, respiratory arrest and death. Further, this can also cause infants to quickly become fatigued and thus impact their growth. For this reason, babies are fed with probes fitted in the stomach for the majority of their intensive care observation.

Currently, in practice, doctors utilize trial-and-error techniques or observational criteria that are, for the most part, subjective, in order to gauge effective and safe feeding. Efforts aimed at more objective assessment techniques have focused on invasive, pressure measurement methods that can be particularly painful for infants. However, such methods are not practical or well-suited for regular monitoring. Numerous methods, most of which include invasive applications, are used to evaluate swallowing function in adults and children. These include evaluating pharyngo-esophageal motility through miromanometry, recording motor response potential in pharyngeal and frontal hyomandibular muscles, video fluoroscopic swallow studies and fiber-optic endoscopic evaluation of swallowing (8). Videofluoroscopic swallow studies (VFSS) are frequently evaluated using modified barium and are employed to examine the swallowing mechanism and define the pathophysiology of swallowing disorders (1) In a study carried out on preterm newborns, 12 preterm newborns were evaluated for tongue and soft palate elevation coordination during swallowing using VFSS and mother's milk or formula mixed with barium sulfate. Video footage was recorded during a maximum total radiation exposure time of three minutes. Through this method, tongue movements and the elevation of the soft palate were observed (2).

Fiberoptic endoscopic evaluation of swallowing (FEES): The pharynx and larynx are observed during swallowing using transnasal flexible fiberoptic laryngoscopy. A comparison of the videofluoroscopic swallow study and FEES shows FEES to be advantageous in that it is capable of evaluating the anatomy of the larynx and preventing the patient's exposure to radiation. Five factors are examined during a fiberoptic endoscopic swallowing evaluation: These are: the anatomy of the pharynx and the larynx, the functional movements of the larynx and the hypopharynx, approach to secretion, the pharyngeal swallowing function and the impact of therapeutic maneuvers (3). Ultrasonographic imaging: Ultrasonography is a safe and non-invasive technique and is capable of evaluating the oral phase of swallowing. During the oral phase of swallowing, the tongue moves downwards while the negative pressure being applied to the nipple is reduced (the vacuum effect is increased) and the oral gap between the nipple and the soft palate fills with milk. The negative pressure is increased (the vacuum effect is reduced) as the tongue moves toward the palate and the bolus proceeds towards the pharynx. All of these phases are captured by ultrasonography. However, due to being unable to detect the residue during swallowing and the need for experienced individuals in carrying out the procedure, it has a number drawbacks (4-5).

Cervical auscultation: Cervical auscultation involves the use of an acoustic detector to listen to sounds made during swallowing and a microphone or an accelerometer to record them. When using cervical auscultation, a stethoscope diaphragm is placed beneath the cricoid cartilage lateral to the thyroid to listen to sounds made during swallowing (6). The accelerometer enables the recording of audible sounds and changes in pressure and is thus susceptible to variations depending on the microphone. The cervical auscultation technique requires the fitting of a nasopharyngeal catheter to determine the swallowing sounds made by newborns and to record changes (7).

Patent applications been filed relating to solutions and devices aimed at enabling feeding maturation through the assessment of sucking-swallowing-breathing coordination. However, there is currently no clinically proven device in the health sector that is viably able to assess feeding maturation in infants through objective measuring. A summary of information relating to said patents have been provided below: The application US 2010/0056961 AI, relating to a "Method and Device For Detecting Deglutition In Babies", discloses a device that determines swallowing function in babies and assesses and provides a diagnosis on breathing-swallowing coordination. The device senses the functions of sucking, swallowing and breathing through different sensors. The swallowing function is determined based on a method of obtaining an average of the sound signals picked up by microphones placed near the neck area. The sucking function is determined through an orokinetogram that employs electrodes positioned on the chin and the cheek (Journal of Fertility and Reproduction 114, 210-224. 1998 Voloschin et al. Ά new tool for measuring the suckling stimulus during breastfeeding in humans: the orokinetogram and the fourier series.'). Data on breathing is obtained using thermistors. A diagnosis for respiratory apnea is given in the event that swallowing and breathing functions occur concurrently.

In summary, the device analyzes the succession of occurrence on the timeline of the swallowing and breathing recordings, which are initiated together with the sucking function, and provides a diagnosis based on its assessment of swallowing-breathing coordination.

Similarly, patent application US2010/0145166 Al relates to an integrated device that assesses a baby's feeding maturation based on the times of occurrence of the sucking, swallowing and breathing events. The device employs: - the first sensor to determine sucking function,

- the second sensor to determine swallowing function,

- and the third sensor to determine breathing function.

Once the data obtained through the sensors is amplified, they are sampled and digitized as raw data to be stored in a digital environment.

An incidence matrix containing the times of events is prepared once the incidence of each of the functions is determined using the raw data on sucking, swallowing and breathing. The incidence matrix is used to assess sucking-swallowing-breathing and to diagnose the baby's feeding maturity. The baby's oral feeding performance is currently assessed by specialists using trail-and-error techniques or criteria based on observations that are, for the most, part subjective. Currently there is no device available that is able to automatically provide an objective assessment. Methods referred to above to assess the swallowing function are invasive. These methods are both painful and inconvenient for the baby. Moreover, these are not mobile methods that are easy to use. The present invention is technologically superior as a method that is easy to use, mobile and noninvasive. A Brief Description of the Invention

Given the above mentioned problems, the crucial need to gain knowledge of the time of maturity of effective sucking-swallowing in newborns and the importance of monitoring their development should be obvious. The present invention is a device allowing objective monitoring of feeding maturation in newborns using swallowing patterns.

The method, which permits the monitoring of feeding maturation in preterm babies through swallowing patterns, comprises the steps of , a) fitting 2 or more auditory sensors in the baby's neck and/or chest area,

b) fitting 3 EMG sensors in the neck area,

c) recording in a digital environment swallowing sounds and external sounds made by the baby during feeding through said sensors,

d) digitizing the collected data using an analog digital converter,

e) running noise removal/source separation algorithms on the digital audio data with a microcontroller and outputting an improved sound signal,

f) acquiring attributes to be used in determining swallowing points on a microcontroller from the EMG signal and the improved sound signal,

g) transferring attributes to a microprocessor,

h) determining swallowing points on a microprocessor,

i) assessing maturity on a microprocessor,

j) and sending the results to the user through a mobile device.

The mobile device comprises in particular 2 or more sound sensors, 3 EMG sensors, an analog digital converter, a microcontroller, a microprocessor, a cable or a wireless network allowing for the transfer of data (mobile) to the computer, a battery and/or a power adapter to be used as a power supply and a connection cable to be used for conducting recording when threaded to a computer.

A Brief Description of the Drawings

Figure 1 is an assessment graph showing swallowing sounds and swallowing intervals at the 33^rd postmenstrual week in a preterm baby who is of 32 weeks gestational age (Audacity 1.3.14); Cells marked Ύ' indicate swallowing sounds.

Figure 2 is an assessment graph showing swallowing sounds and swallowing intervals at the 39^th postmenstrual week in the preterm baby defined above (Audacity 1.3.14); Cells marked "t" indicate swallowing sounds.

Figure 3 shows the relationship between the postmenstrual age of preterm babies and milk consumption. The scatter graph showing the relationship between milk consumption and postmenstrual age indicates a positive correlation between postmenstrual age and milk consumption. (r2= 0,17; r= 0,43; p= 0,00)

Figure 4 shows the relationship between the postmenstrual age of preterm babies and the number of swallows. The scatter graph showing the relationship between the number of swallows: and postmenstrual age indicates a positive correlation between postmenstrual age and the number of swallows. (r2= 0,08; r= 0,27, p= 0,00)

Figure 5 shows the relationship between the postmenstrual age of preterm babies and the length of swallowing intervals. The scatter graph showing the relationship between the length of swallowing intervals and postmenstrual age indicates a negative correlation between postmenstrual age and the length of swallowing intervals. (r2= -0,06; r= -0,24; p= 0,00)

Figure 6 shows the relationship between the postmenstrual age of preterm babies and the number of regular swallows. The scatter graph showing the relationship between the number of regular swallows and postmenstrual age indicates a positive correlation between postmenstrual age and the number of regular swallows. (r2= 0,10; r= 0,31; p= 0,00)

Figure 7 shows the relationship between the postmenstrual age of preterm babies and the length of regular swallowing intervals. The scatter graph showing the relationship between the length of regular swallowing intervals and postmenstrual age indicates a negative correlation between postmenstrual age and the length of regular swallowing intervals. (r2= -0,04; r= -0,15; p= 0,033) Figure 8 shows the relationship between the postmenstrual age of preterm babies and the number of rests. The scatter graph showing the relationship between the number of rests and postmenstrual age indicates a positive correlation between postmenstrual age and the number of rests. (r2= 0,003; r= 0,02; p= 0,73) Figure 9 shows the relationship between the postmenstrual age of preterm babies and the length of resting intervals. The scatter graph showing the relationship between the length of resting intervals and postmenstrual age indicates a negative correlation between postmenstrual age and the length of resting intervals. (r2= -0,02; r= -0,19; p= 0,01)

Figure 10 shows the relationship between the postmenstrual age of preterm babies and the maximum number of regular swallows. The scatter graph showing the relationship between the maximum number of regular swallows and postmenstrual age indicates a positive correlation between postmenstrual age and the maximum number of regular swallows. (r2= 0,06; r= 0,32; p= 0,00)

Figure 11 is a box point graph of postmenstrual weeks in which reference values of milk consumption were achieved according to number of weeks of pregnancy in preterm babies.

Figure 12 is a box point graph of postmenstrual weeks in which reference values of maximum regular swallow numbers were achieved according to number of weeks of pregnancy in preterm babies. Figure 13 shows the postmenstrual weeks in which reference values were achieved in preterm babies according to maximum regular swallow numbers.

Figure 13 is a system flow chart.

A Detailed Description of the Invention

In the patent applications summarized above, both systems address feeding maturation based on an assessment of sucking-swallowing-breathing coordination. These solutions involve measuring sucking, swallowing and breathing data using an E G, a thermistor and sound sensors and assessing feeding maturation according to their times of incidence. However, these solutions, which require conducting a great number of measurements at a given time may not be sufficiently sensitive or accurate under real world conditions (the extremely low birth weight infants and their tendency to constantly move during feeding). The lack of a proven product that is based on the said patents supports our prediction.

In addition, simply controlling sucking-swallowing-breathing coordination is not sufficient for assessing the feeding maturation of babies. In accordance with the criteria for assessing newborn oral-motor function, sucking is defined under three headings: normal (or mature sucking), irregular (or disorganized) and dysfunctional (dysfunctional sucking) sucking. An incidence of normal suckling is defined as 10-30 suctions during each attempt with short pauses in between, wherein sucking-swallowing-breathing occurs at a rate of 1:1.1. Irregular suckling is defined as the total suckling activity being non-rhythmic, wherein sucking-swallowing-breathing coordination is absent. Dysfunctional suckling comprises chin and tongue movements that are disruptive to the feeding process (34). The studies referred to in the patent applications fail to measure the total suckling activity in terms of its rhythm. A system that neglects to take into account the rhythmic quality of the sucking/swallowing activity will be insufficient in its assessment of feeding maturation.

In a study conducted by faculty members Assistant Prof. Dr. Ayse Ecevit and Specialist Dr. Deniz Anuk ince of the Baskent University, research was carried out on the sucking and swallowing functions of 52 preterm newborns. The feeding habits of preterm newborns being observed in the newborn intensive care unit were monitored from the time they were being subjected to enteral feeding 1-2 times a day until they reached the 38-40^th postmenstrual week. Feeding was carried out on preterm newborns in a quiet environment when they were hungry and awake. Physiological changes such as oxygen saturation, breathing rate and heart rate were recorded during the feeding of preterm newborns. Furthermore, prior to each measurement, their body weight was recorded according to their postmenstrual week. The muscle tone of all babies was observed as normal. None of the babies displayed signs of apnea and/or bradycardia during feeding. This observation supports the notion that a solution aimed solely at assessing apnea is insufficient when determining maturity.

The present invention is able to automatically provide an assessment of babies' feeding maturity using objective measurement values based on variables involving the swallowing function in preterm and newborn babies. Our invention offers a solution that uses the rhythm of the swallowing activity as its criteria in assessing feeding maturation, while also being able to assess swallowing-breathing coordination to provide a determination on apnea when necessary. No additional measurements are required for sucking during the maturation assessment.

In a study conducted by faculty members Assistant Prof. Dr. Ayse Ecevit and Specialist Dr. Deniz Anuk ince of the Baskent University, research was carried out on the sucking and swallowing functions of 52 preterm newborns and 42 babies that were carried to full term. The sucking and swallowing functions of preterm newborns were assessed from the time they were first subjected to oral feeding until they reached the 38-40^th postmenstrual week, while the sucking and swallowing functions of babies carried to full term were assessed during the first postnatal week. The correlation was gauged between feeding maturation and milk consumption, the number of swallows per unit of time, the number of regular swallows, the average interval between regular swallowing, number of rests, the average interval between rests and the maximum number of regular swallows. Clinical studies showed a correlation between feeding maturation and milk consumption, the number of swallows per unit of time, the number of regular swallows, the average interval between regular swallowing, number of rests, the average interval between rests and the maximum number of regular swallows. Thus, it was demonstrated that a reliable decision to discharge could be given based on non-invasive measurements defining sucking-swallowing functions in babies by using an objective assessment method for determining the time of oral feeding of preterm babies.

In addition to the above, the suggested product allows for the observation of the patient's development over time by storing patient information and sucking-swallowing-breathing measurements and assessing said information automatically.

Currently there is no device available that allows for the measurement of feeding maturation based on milk consumption and variables involving swallowing (the number of swallows per unit of time, the number of regular swallows, the average interval between regular swallowing, number of rests, the average interval between rests and the maximum number of regular swallows). As our solution is a method/product that is practical, simple, non-invasive and readily usable by everyone, it is more effective, practical and useful in comparison to other patented solutions seeking to define feeding maturation based on sucking-swallowing-breathing. As there is no system/product currently in use, it is difficult to make reference to technical problems that are encountered in the prior art. Furthermore, methods found in the prior art suggest solutions that are insufficient for assessing maturity. Since other methods incorporate solutions that involve collecting data from multiple regions on very smalt babies, they cannot be considered useful or workable. What sets our solution apart is that it is a mobile and practical system that can be used for each patient and is furthermore resistant to the movements of babies, non-invasive, and assesses feeding maturity by recording patient information and the developmental process.

The present invention will emerge as a novel technology for objectively measuring feeding maturity in preterm babies. In addition, some of the sub-parts of the prototype system are expected to lay the groundwork for new and important scientific and technological advances in the area of signal processing and pattern recognition.

Sound waves acquired from multiple points, in addition to the wave acquired by the EMG sensors for verification, are used in order to assess the swallowing function. The sensors are placed on the bab s neck at the correct locations. As the baby is unlikely to remain in the same position throughout the feeding event, data acquired from a single source will not yield reliable results. While feeding, the baby may exhibit sounds other than those made during swallowing. These sound signals add indeterminate noise to the sounds made during swallowing. In order to remove sounds made by the baby during feeding that are external to swallowing, sound data is gathered from multiple points and an improved swallowing signal is acquired through source separation methods. The points where the swallowing function takes place are determined through pattern recognition methods using sound signals. In the event that a proper sound signal cannot be acquired, the EMG signal may be used as an additional feature to determine swallowing points.

The swallowing measurements are viewed on a graphical interface by a specialist. Once the swallowing data is digitized using an analog digital converter, they are collected by means of a microprocessor and transferred via USB to a mobile computer for storage and processing, after which they are processed and transmitted to the user. These acquired measurements are then combined with the patienfs details and the findings relating to the baby's development are submitted to the specialist after being assessed by the mobile device.

For babies that are fed through the mother's nipple, the amount of sucking is calculated based on the difference between weight measurements of the baby taken before and after feeding .

The study was carried out on 52 premature babies (23 female, 29 male) bom at the Ankara Hospital for Application and Research at the Baskent University's Faculty of Medicine between June 2011 - February 2012 and having a gestation period of under 37 weeks and under observation at the Newborn Intensive Care Unit or in their mothers' care and 42 babies (22 female, 20 male) carried to regular term with a gestation period of over 37 weeks. The preterm newborns and the term babies were kept under observation at the newborn clinic after their discharge. Patients diagnosed with major congenital anomalies, craniofacial malformations, culture positive sepsis, intracranial bleeding, neuromuscular disorders, bronchopulmonary dysplasia and necrotizing enterocolitis were left out of the study.

Authorization for the study was obtained from the Baskent University's Ethics Committee (Project no: KA11/141). Informed consent was obtained from the families of patients taking part in the study. Demographic and clinical characteristics obtained for all preterm newborns during their newborn intensive care observation, including sex, method of delivery, gestation period in weeks, birth weight, clinical characteristics, apgar score, feeding method, feeding time using a nasogastric probe, parenteral feeding time, enteral feeding commencement time, time of switch to full enteral feeding, intubation and surfactant requirements, oxygen requirements during intensive care, total oxygen intake time, ventilator support and period of use, duration of hospital stay, weight at discharge and the postmenstrual week at discharge were recorded separately for each patient. In addition, milk consumption, the number of swallows, swallowing intervals, number and interval of regular swallows, number and interval of rests and maximum number of regular swallows were recorded for all babies.

Feeding was monitored from the time preterm newborns being observed in the newborn intensive care unit were subjected to enteral feeding 1-2 times a day until the postmenstrual age of 38-40 weeks. Feeding was carried out in a quiet environment when the babies were hungry and awake. Physiological changes such as oxygen saturation, breathing rate and heart rate were recorded during feeding in preterm newborns. In addition, prior to each measurement, their body weight was recorded according to their postmenstrual age in weeks. All babies displayed normal muscle tone. Apnea and/or bradycardia was not observed in any of the babies during feeding. Term babies who were brought in during the first postnatal week for checkups were assessed on their sucking and swallowing functions while awake in a quiet clinic environment.

Measurement Method and Assessment For all babies being fed with either mothers' milk or formula, similar feeding bottles with an identical teat and teat hole were used during measuring. Families were informed that the feeding bottles would only be used for carrying out measurements. For two minutes during feeding, swallowing sounds were recorded in a digital environment by means of sound sensors placed in the region of the hyoid bone under the babies' chins. Recordings were made until term for preterm newborns; whereas the term babies were recorded at the end of the first week. All measurements were assessed by the same individual. The swallowing sounds were analyzed using Audacity 1.3.14, an open source software. Measurements, which were taken every two minutes, were each assessed separately and the swallowing sounds were labeled using the program's interface. Through labeling, the time index of each swallow was marked. The time intervals between successive swallows were calculated using the time indexes acquired during the labeling process. Swallowing intervals consisted of frequent swallowing activity, denoting regular swallowing, and resting intervals between swallows. As regular swallowing and swallowing intervals varied with each recording, assessments were calculated separately for each recording. Swallowing intervals were classified as swallows with short intervals, indicating regular swallowing, and swallows with long intervals, indicating rests. The classification was carried out using the k-means method; an uncontrolled clustering technique. Successive swallowing interval values obtained for each recording interval were divided into two groups using the k-means method. This is made it possible to automatically determine regular swallowing intervals and resting intervals. After collecting this data, the mean and standard deviations were calculated for regular swallowing intervals and resting intervals. Furthermore, the maximum number of regular swallows during this period were calculated in order to determine all babies' total number of swallows, number of successive regular swallows and mature sucking. Figures 1 and 2 contain assessment graphs for number of swallows and swallowing intervals. Following each measurement, the amount of milk consumed by the baby during the two minute feeding was recorded and assessed as their oral feeding performance. The maximum number of regular swallows was accepted as an indicator of swallowing maturity. All measurements and assessments were each separately determined according to the babies' postmenstrual and postnatal age. Preterm babies' measurement percentiles (25-75 percentile) were determined according to their postmenstrual age in weeks. Percentiles for term babies were provided with regard to milk consumption, number of swallows, swallowing intervals, number of regular swallows, regular swallowing intervals, number of rests, rest intervals and maximum number of regular swallows. The sucking and swallowing function of healthy term babies was considered to have reached maturity. For sucking and swallowing maturation, values greater than the 10th percentile (owing to a positive correlation with weeks of gestational age) were taken as reference according to term babies' milk consumption, number of swallows, number of regular swallows, number of rests and maximum number of regular swallows, while values greater than the 90th percentile (owing to a negative correlation with weeks of gestational age) were taken as reference according to their swallowing intervals, regular swallowing intervals and resting intervals. In measurements conducted according to postmenstrual weeks, the rate of failure in reaching the reference values and the postmenstrual weeks in which the references were achieved were determined. Statistical analysis was carried out using the SPSS program (Statistical Package for Social Sciences, version 15.0, SPSS Inc., Chicago, IL, USA). Initially, definitive statistics were provided for discrete and continuous values. During the data analysis, two independent sample t tests were applied to data complying with the prerequisites of the parametric test for continuous variables, while the Mann- hitney-U test was applied to data that did not comply with the prerequisites of the parametric test. Given that the parametric test's prerequisites for the two continuous variables were not met, a Spearman correlation analysis was carried out and a scatter graph was created. Whereas the correlation coefficient is indicative of the extent of the linear relationship between the two variables, it does not take into account the influence of other variables. However, the partial correlation coefficient is used when it is desired to examine the extent of the linear relationship between the two variables after the influence of the remaining variables has been removed. T at is why the partial correlation coefficient was used for certain parameters in our study. The Type I Error was fixed at 5% (p<0,05). Findings

Our study included 52 preterm newborns and 42 babies that were carried to term. 19 (37%) of the preterm babies were at the gestational age of 27-33 weeks, while 33 (63%) were in the late preterm (34-36) group. The demographic and clinical characteristics of the preterm and term newborns is provided in Tables 1, 2 and 3.

Table 1. The demographic and clinical characteristics of preterm and term newborns

Method of delivery 7/45 12/30

(NSVD/caesarian)

APGA minute 1 7,3±1 7,9±0,3

APGAR minute 5 8,6±0,7 9±0,2

Discharge VA (gr)* 2182.8±324

2170 (1620-2850)

Week of Discharge (PMA)* 35,4±1,3

35,5 (33-39)

* The values have been provided as mean ± standard deviation. ** Values have been provided as median (distribution). The parentheses contain minimum and maximum values. NSVD: Normal Spontaneous Vaginal Delivery, PMA: Postmenstrual age Table 1 shows the demographic characteristics of preterm and term newborns.

Table 2. Additional clinical information on preterm newborns

The table contains data on newborn preterm babies being observed at the newborn intensive care unit, including feeding characteristics, surfactant applications, the duration of mechanical ventilation and oxygen provision and the length of their hospital stay.

Table 3. Assessment of preterm newborns' body weight, breathing rate, heart rate and oxygen saturation according to their postmenstrual age in weeks at the time of the measurement

5 * The values have been provided as mean ± standard deviation. ** Values have been provided as median (distribution). T e parentheses contain minimum and maximum values.

The table contains data relating to breathing rate, heart rate and oxygen saturation during feeding in newborn preterm babies throughout their observation at the newborn intensive care unit. Feeding was carried out when the babies were awake. Apnea was not observed in any of the babies during feeding. The body weight was recorded according to the postmenstrual week in which the measurement was conducted to assess feeding.

Table 4. Assessment of preterm newborns' milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows according to their postmenstrual age in weeks at the time of the measurement

* All measurements were carried out for 120 seconds. ** 25% and 75%. Percentage values

During measuring, the milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows of preterm babies were assessed according to their postmenstrual age in weeks. The 25-75* percentile values of the measurement values according to postmenstrual age in weeks were 5 shown in Table 4. mn: mean, wks; weeks, p; percentile

Table 5. Percentiles of milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows of term babies according to measurements

(*sec.)

Maximum 10 10 12 18,5 29 33,7 35,7 regular number

of swallows

(/120sec)

* All measurements were carried out for 120 seconds. ** p; percentile, percentage values, ml; milliliter, sec; seconds

The percentiles for babies according to their milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows have been provided in Table 5.

Table 6. Correlation of the postmenstrual age of preterm newborns and milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows (using the Spearman correlation analysis)

Shown through the use of the Spearman correlation analysis are the correlation coefficient (r) and p values between postmenstrual age and milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows. Table 7. Correlation between postmenstrual age and milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows controlled for gestational age in weeks of preterm newborns (using a partial correlation analysis)

Shown in the partial correlation analysis controlling for the gestational age in weeks, are the correlation coefficient (r) and p values between postmenstrual age and milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows.

Table 8. Correlation between postnatal age and milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows controlled for gestational age in weeks of preterm newborns (using a partial correlation analysis)

(/2mins)

Regular swallow intervals (sec) 0,12 0,09

Number of rests (/2mins) 0,10 . 0,14

Rest intervals (sec) 0,15 0,031

Maximum number of regular 0,006 0,93

swallows (/2mins) mins: minutes

Shown in the partial correlation analysis controlling for the gestational age in weeks, are the correlation coefficient (r) and p values between postnatal age and milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows.

The correlation between postnatal age and milk consumption, number of swallows, swallow intervals, number of regular swallows and rest intervals was found to be significant. No statistical difference was observed with regard to a correlation to regular swallow intervals, number of rests and maximum regular number of swallows.

Table 9. Rate of failure of measurements carried out on preterm babies according to postmenstrual age in achieving the sucking swallowing characteristics of tenm babies

measurements were carried out for 120 seconds. ** percentages

Table 10. Postmenstruai weeks in which preterm babies' milk consumption and maximum regular number of swallows according to gestational age in weeks achieved reference values

* The values have been provided as mean ± standard deviation. ** Values have been provided as median (distribution). The parentheses contain minimum and maximum values.

Table 10 shows the postmenstruai weeks in which preterm babies according to birth week have achieved the reference values.

Table 11. Comparison of preterm babies who have reached their term with term babies' milk consumption, number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows of term babies

(postmenstrual week 38-40) (postnatal week 1)

Mean (±SD)** Mean (±SD)**

Median (min.-max.)*** Median (min.- max.)***

Milk consumption (ml./120 sec) 26.5± 10.1* 32.2±9.1 0.00

25 (8-60)** 30 (10-55)

Number of swallows (/120sn.) 42±10.7 45.7±11.4 0.13

41 (16-79) 43 (24-84)

Swallow intervals (120 sec) 2.7±0.9 2.3±0.6 0.05

2.6 (1.4-6.5) 2.3 (1.2-4)

Number of regular swallows (/120 35.8±9.8 39.6±11.5 0.12 sec) 35 (13-67) 37.5 (23-82)

Regular swallow intervals (/120 1.8±0.4 1.7±0.4 0.23 sec) 1.8 (1.1-3.1) 1.7 (1-3)

Number of rests (/120 sec) 5.6±3.3 6.07±4 0.82

5 (1-16) 5 (1-16)

Rest intervals (120 sec) 9.2±4.9 8.9±5.1 0.48

7.8 (2.4-4.7) 7 (1.6-24.4)

Maximum regular number of 17±7 20.5±8.6 0.07 swallows (/120 sec) 16 (4-35) 18 (8-37)

* n, denotes the measurement number at week 38-40. ** The va ues have been provided as mean

± standard deviation. *** Values have been provided as median (distribution). The parentheses contain minimum and maximum values, ml.: milliliter, sec: seconds The number of swallows, swallow intervals, number of regular swallows, regular swallow intervals, number of rests, rest intervals and maximum regular number of swallows of preterm babies who have reached premenstrual week 38-40 have achieved the levels of term babies. However, a statistical difference regarding milk consumption was observed between the two groups. References:

1. Logemann JA. Manual for the videofluorographic study of swallowing. 2nd edition 1993. Austin, TX: Pro-Ed. 2. Goldfield EC, Buonomo C, Fletcher K, Perez J, Margetts S, Hansen A, Smith V, Ringer S, Richardson MJ, Wolff PH. Premature infant swallowing: Patterns of tongue-soft palate coordination based upon videofluoroscopy. Infant Behav Dev 2010;33:209-18.

3. Sitton M, Arvedson J, Visotcky A, Braun N, Kerschner J, Tarima S, Brown D. Fiberoptic endoscopic evaluation of swallowing in children: feding outcomes related to diagnostic groups and endoscopic findings. Int J Pediatr Otorhinolaryngol. 2011;75:1024-31.

4. Geddes DT, Chadwick LM, Kent JC, Garbin CP, Hartmann PE. Ultrasound imaging of infant swallowing during breast-feeding. Dysphagia 2010;25(3): 183-91.

5. Takahashi K, Groher ME, Michi K. Methodology for detecting swallowing sounds. Dysphagia. 1994;9:54-62.

6. Reynolds EW, Vice FL, Gewolb IH. Cervical accelerometry in preterm infants with and without bronchopulmonary dysplasia. Dev Med Child Neurol. 2003;45:442-6. j

7. Reynolds EW, Vice FL, Gewolb IH. Variability of swallow-associated sounds in adults and infants. Dysphagia. 2009;24:13-9.

8. (8)Barlow SM. Central pattern generation involved in oral and respiratory control for feeding in the term infant. Curr Opin Otolaryngol Head Neck Surg. 2009;17:187-93.

Claims

1. A method for monitoring feeding maturation in premature babies using swallowing patterns, characterized in that it comprises the steps of:

a) fitting 2 or more auditory sensors in the baby's neck and/or chest area, b) fitting 3 EMG sensors in the neck area,

d) digitizing the collected data using an analog digital converter,

g) transferring attributes to a microprocessor,

h) determining swallowing points on a microprocessor,

i) assessing maturity on a microprocessor,

j) and sending the results to the user through a mobile device.

2. A method according to claim 1, characterized in that the said sensors are an EMG with sound wave sensing and/or electricity potential measuring capability.

3. A method according to claim 1, characterized in that the improved sound signal is obtained by applying a noise reduction and source separation method to sound signals acquired from multiple sources.

4. A mobile device employing the method of claim 1 enabling monitoring of feeding maturation in premature babies using swallowing patterns, characterized in that it comprises

a) 2 or more sound sensors,

b) 1 EMG sensor,

c) an analog digital converter, d) a microcontroller,

e) a microprocessor,

f) a cable or a wireless network allowing data to be transferred to a (mobile) computer, g) a battery and/or a power adapter to be used as a power supply and a connection cable to be used for conducting recording when threaded to a computer.

5. A method according to claim 2, characterized in that the data acquired through sensors is synchronized in time.

6. A mobile device according to claim 4, characterized in that it is capable of measuring milk consumption, number of swallows, swallow intervals, number of regular swallows and their intervals, number of rests and their intervals, and maximum regular number of swallows.

7. A mobile device according to claim 6, characterized in that it can assess feeding maturity from measurements.