**5. Conclusion**

100 Practical Applications in Biomedical Engineering

**Figure 24.** Screen of EEG signals filtered by proposed filter.

masked due to noise.

did not appear.

The Figure 25 presents a EEG screen contaminated by noise of 60 Hz, eyelid blink, some oscillations and at the center of the screen epileptiform events (black arrow) obviously

**Figure 25.** EEG screen containing noise of 60 Hz and epileptiform events masked by the noise.

In Figure 26 we can observe that the noise from the power supply has been attenuated, as well as the oscillations and eyelid blinks, showing the epileptiform events that previously This work presented a study about the capability of the Wavelet Transform to be used to develop a digital filter to attenuate the background activity in the EEG signals. Four Wavelet functions were select from 65 evaluated. According to the experiments the Wavelet function Db4 proved to be the best function for the development of a digital filter in this application, according to researches performed by [9-12]. The function Db4 is indicated when there is the need to preserve the epoch of the filtered signal more like the original epoch. When there is the need to preserve the peaks of the epileptiform events the adequate function is the Rbio2.8. If the need is only to attenuate the background activity without the concern of preserves the morphology of the peaks in the epileptiform events the adequate function is the Bior3.1. Due to the fact of this function have reduced number of coefficients its application improves performance in filtering process.

## **Author details**

Geovani Rodrigo Scolaro, Fernando Mendes de Azevedo, Christine Fredel Boos and Roger Walz *Institute of Biomedical Engineering, Federal University of Santa Catarina, Brazil* 

#### **6. References**


[3] Pillai, J., Sperling, M.R. Interictal EEG and the Diagnosis of Epilepsy, Epilepsia (Vol. 47). Blackwell Pub./ ILAE; 2006.

**Chapter 5** 

© 2012 Merez et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Merez et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Impulse Oscillometric Features and Respiratory** 

**System Models Track Small Airway Function in** 

Asthma is an inflammatory condition of the airways resulting in their hyper-reactivity, generating increased mucus, mucosal swelling and airway smooth muscle contraction all of which contribute to (partial) airway obstruction. The symptoms include chest tightness, coughing and wheezing, and in severe cases shortness of breath and low blood oxygen (1). According to Dorland's medical dictionary small airway impairment (SAI) is a chronic obstructive bronchitis with narrowing of the bronchioles and small bronchi. The term small airways refer to about 7th to 19th generation of airways with an inner diameter of about 2 to 0.5 mm. These airways are considered to be an important site of inflammation in asthma and chronic obstructive pulmonary disease (COPD). The atopic manifestation just prior to asthma could be early small airway disease (SAD) and then if inflammation persists, asthma would appear. SAD includes a spectrum of inflammatory and fibrotic pulmonary diseases

According to the American Academy of Allergy Asthma & Immunology, Asthma and allergies stroke 1 out of 12 Americans and approximately 25 million Americans (8% of the U.S. population) had asthma in 2009. About 1 in 10 children (10%) had asthma and 1 in 12 adults (8%) had asthma in 2009. For the period 2008-2010, asthma prevalence was higher among children than adults. For the period 2008-2010, asthma prevalence was higher among multiplerace, black, and American Indian or Alaska Native persons than white persons. Asthma costs in the US grew from about \$53 billion in 2002 to about \$56 billion in 2007, about a 6% increase. Compared with adults, children had higher rates for asthma primary care and emergency department visits, similar hospitalization rates, and lower death rates. Asthma was linked to

Erika G. Meraz, Homer Nazeran, Carlos Ramos, Liza Rodriguez,

Lidia Rascón Madrigal and Nelly Gordillo Castillo

Additional information is available at the end of the chapter

centered on the small conducting airways.

**Children** 

http://dx.doi.org/10.5772/52579

**1. Introduction** 

