**1.1 Introduction**

Sleep apnea syndrome (SAS) has been identified as a risk factor for traffic accidents because it can cause excessive daytime sleepiness. As shown in **Figure 1**, the probability of a traffic accident for ordinary people is about 5% while that for SAS sufferers range from about 7–25% depending on the level of the apnea– hypopnea index (AHI), which indicates the severity of sleep apnea. Given this finding, the Japanese government requires train drivers and airplane pilots to get periodic SAS check-ups.

The prevalence of SAS sufferers in Japan is estimated to be 4%: 2.0 million and 2.8 million yet to be identified. The polysomnography (PSG) test commonly used for diagnosing SAS is a bothersome and uncomfortable examination as shown in **Figure 2**.

In contrast, a previously developed sleep apnea syndrome (SAS) sensor using optical fibers, the "F-SAS sensor," is non-invasive and non-restrictive [1–4].

oximetry (PLSX). The F-SAS sensor is promising for screening latent SAS patients

On the other hands, obstructive sleep apnea syndrome (OSAS) in children is a

**Figure 3** shows plastic optical fiber sheets and physics of measurement. Fibers interspaces are narrower one and wider one within several centimeters. Commercially available SI plastic optical fibers (CK10) were used. Physical principle is to measure the deviation of output optical power from fiber sheet by micro-bending loss and/or bending loss. **Figure 4** is the experimental response for intentional apnea. One pulse wave form means one breath in and out. Flat parts indicate the apnea after breath in or out. Narrower fiber interspaces POF sheet is more sensitive than the wider one. As shown in **Figure 5**, a plastic optical fiber (POF) sensor sheet is simply placed under the bottom bed sheet. There is no need for the subject to wear any special clothing or devices. The measurement data is transmitted to a remote location for analysis and diagnosis. The measurement principle is illustrated in **Figure 3**. The deviation in the output optical power from the POF sheet due to micro-bending loss and/or bending loss caused by the lateral pressure change cre-

ated by the motion of the person's chest during respiration is measured.

disease in which respiratory arrest during sleep is frequently observed due to narrowing of the upper airways, such as due to tonsil hypertrophy, growth disorders, and a lowered quality of life (QOL) such as from having a decreased ability to learn. We reviewed the improvement made to pediatric analysis software by using the F-SAS sensor and report it [7–11]. Further, we report on a comparison of sleep events with the conventional F-SAS sensor and polysomnography (PSG) in children [9].

(Sleep Apnea Syndrome patients) during usual sleep.

*Optical Fiber-Based Sleep Apnea Syndrome Sensor DOI: http://dx.doi.org/10.5772/intechopen.91060*

**1.2 F-SAS sensor system**

**Figure 3.**

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*Measurement principle.*

**Figure 1.** *Probability of traffic accident for various AHI levels of Japanese adults.*

It is both quiet and compact and thus potentially useful for screening potential SAS sufferers during normal sleep at home.

This paper describes the F-SAS sensor and the measurement principle. It then describes its application in a hospital setting and in hotels [5, 6]. Under the assistance of the "Beautiful Fukushima Next-Generation Medical Industry Agglomeration Project," in Japan, we have succeeded in downsizing the F-SAS sensor and have recognized that it highly correlates with polysomnography (PSG) and pulse

*Optical Fiber-Based Sleep Apnea Syndrome Sensor DOI: http://dx.doi.org/10.5772/intechopen.91060*

oximetry (PLSX). The F-SAS sensor is promising for screening latent SAS patients (Sleep Apnea Syndrome patients) during usual sleep.

On the other hands, obstructive sleep apnea syndrome (OSAS) in children is a disease in which respiratory arrest during sleep is frequently observed due to narrowing of the upper airways, such as due to tonsil hypertrophy, growth disorders, and a lowered quality of life (QOL) such as from having a decreased ability to learn. We reviewed the improvement made to pediatric analysis software by using the F-SAS sensor and report it [7–11]. Further, we report on a comparison of sleep events with the conventional F-SAS sensor and polysomnography (PSG) in children [9].
