# Application of Wavelet Transform and Fractal Analysis for
###### Abstract  
In this paper, a new method for analysing gastroesophageal reflux disease (GERD) is shown. This novel method uses wavelet transform (WT) and wavelet-based fractal analysis (WBFA) on esophageal pH-metry measurements. The esophageal pH-metry is an important diagnostic tool supporting the physician's work in diagnosing some forms of reflux diseases. Interpreting the results of 24-h pH-metry monitoring is time-consuming, and the conclusions of such an analysis can sometimes be too subjective. There is no strict procedure or reference values to follow when the impedance measurements are assessed. Therefore, an attempt was made to develop a point of reference for the assessment process, helping to distinguish healthy patients from GERD patients. In this approach, wavelet transform (WT) and wavelet-based fractal analysis (WBFA) were used to aid the diagnostic process. With this approach, it was possible to develop two efficient computer methods to classify healthy and sick patients based on the pH measurement data alone. The WT method provided a sensitivity value of 93.33%, with 75% specificity. The results of the fractal analysis confirmed that the tested signals have features that enable their automatic classification and assignment to a group of sick or healthy people. The article will be interesting for those studying the application of wavelet and fractal analysis in biomedical waveforms. The authors included in the work a description of the implementation of the fractal and wavelet analysis, the descriptions of the results of the analyses, and the conclusions drawn from them. The work will also be of interest to those who study the methods of using machine learning and artificial intelligence in computer-aided, automatic medical diagnostics. gastrointestinal reflux disease (GERD); pH-metry; multichannel intraluminal impedance-pH; 1D continuous wavelet transform; wavelet-based fractal analysis Article Application of Wavelet Transform and Fractal Analysis for  
Esophageal pH-Metry to Determine a New Method to Diagnose Gastroesophageal Reflux Disease  
[PERSON] Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Tojza Toja Toja Tojaza Toja Tojaza Toja Toja Toja Tojaza Toja Tojaza Tojaza Tojaza Tojaza Toja Tojaza Tojaza Tojaza Tojazaza Toja Tojazaza Tojaza Tojazaza Tojaza Tojazaza Tojaza Tojazaza Tojazaza Tojazaza Tojazaza Tojazaza Tozazaza Tojazazaza Tozazazaza Tozazazaza Tozazazaza Tozazazaza Tozazazaza Tozazazazaza Tozazazaza Tozazazazaza Tozazazazaza Tozazazazazaza Tozazazazazaza Tozazazazazaza Tozazazazazaza Tozazazazazaza Tozazazazazazazaza Tozazazazazazaza Tozazazazazazaza Tozazazazazazazaza Tozazazazazazazaza Tozazazazazazazaza Tozazazazazazazaza Tozazazazazazazazaza Tozazazazazazazazazaza Tozazazazazazazazazazazazaza Tozaand living in a constant rush and stress [2]. Many of the affected people are not aware of the gravity of the problem; they relate their symptoms to heartburn and seek the aid of professionals only when those symptoms escalate. Therefore, it is particularly important to improve early GERD diagnostics as, if left untreated, the symptoms will further worsen the quality of life of the patients. Until recently, the most frequently used method was 24-h esophageal pH-metry, but in recent years, pH-metry with an impedance measurement was named as the new golden standard [2]. Esophageal pH measurements provide a high percentage of correct diagnoses. The main disadvantage, however, is the fact that the 24-h dataset has to be assessed by a specialist/gastroenterologist, which can be a time-consuming task. Even with the use of modern computer programs, it takes up to several hours to assess the data [5; 6; 7; 8; 9; 10]. Therefore, it is advisable to develop computer techniques that will allow the automation of the process and shorten the time needed to diagnose a patient by a specialist. Consequently, this will allow the treatment to start quicker and will also free some time for the specialist/gastroenterologist to devote to other patients.