**5. Statistical and behavioral analysis**

In order to show the effectiveness of the system, a study on muscular trajectory was performed in 18 patients for male and female genders on an age span of 22 and 24 years. Fifteen of the patients were healthy, and three presented peripheral facial palsy. The protocol to analyze the group of patients was as follows: the test subject sat in a chair with a straight back making sure that he/she was comfortable. Once the test subject was in place, he/she put on the mask and adjusted it so that the sensors were on the corresponding muscle. Immediately WaL started to record. The person contracted the muscles to be studied as intensely as possible for a couple of seconds and immediately relaxed them.

The results found from healthy people were used for calibration purposes. The ill individual results corroborate that our system is capable to quantify the muscle movement controlled by the seventh cranial nerve. The system is calibrated to take 12,000 samples of the muscular trajectory in 6.06 seconds, with this information, the standard deviation and the mean for each component are obtained. The correlation among components of the same muscle such as the thresholds that state the point of major and minor displacement, the asymmetry facial, and muscle correlation is expressed as a percentage. The data that the system collected when conducting the study on the 15 healthy people and three people with facial paralysis were used as a reference to establish the thresholds that indicate the state of the user's facial muscles. The purpose of the system is to provide a tool that contributes with information for an accurate diagnosis. The collected data can reduce the time to find the ideal treatment for the patients. The data measured by the system are graphed and normalized in order to standardize the signal and thus, compare the reaction speed and intensity of the movement of each hemiface.

#### **5.1 Healthy person muscular trajectory**

The central trajectory measurements that appear in **Figure 5** correspond to a healthy 24-year-old woman, weighing 70 kg and 1.74 m tall. The frontal muscle trajectory shown in **Figure 5I** has a correlation percentage for all the components of 95.54%, zygomaticus minor (**Figure 5II**) has a correlation of 94.23%, risorio (**Figure 5II**) of 96.42% and for zygomaticus major (**Figure 5IV**) it is 92.61%. Although the study was applied to a healthy person. The asymmetry of the face of this particular person is accentuated in the zygomaticus minor muscle. Therefore, it can be affirmed that the muscular response is attenuated by 7.39%.

#### **5.2 Facial paralysis muscular trajectory**

The person with facial paralysis is shown in **Figure 6**. It is observed that the similarity of the signals decreases in all the muscles. By having a correlation percentage of 77.14% for the frontal muscle, 73.30% for the zygomatic minor, 84.60% for the risorius, and 5.48% for the zygomaticus major.

#### **Figure 5.**

*Set of experimental results that shows the muscle movement intensity in a healthy person where the frontal (I), zigomaticus minor (II), risorius (III), and zigomaticus major (IV) are shown. The signals are normalized and plotted against time (a) shows the "x" components of the muscle trajectory, (b) the "y" components, and (c) shows present the components in "z."*

#### **Figure 6.**

*Set of measured results that feature the intensity of frontal (I), zigomaticus minor (II), risorius (III), and zigomaticus major (IV) muscles movement in a person with facial paralysis. The signals were normalized and are plotted against time where (a), (b), and (c) are the x, y, and z components, respectively.*

*Medical System to Evaluate the Seventh Cranial Nerve through the Main Facial Mimic Muscles DOI: http://dx.doi.org/10.5772/intechopen.107134*

The signals belong to the injured hemiface that reached the maximum point of contraction starting from the minimum state in a longer time with respect to the healthy counterpart. In most cases, the signals are function of the healthy side of the face by reaching the highest intensity in approximately 1 s while the signals from the paralyzed side take twice as long.
