The evaluation of GI-pill gastrointestinal electronic capsule for colonic transit test in patients with slow transit constipation.

OBJECTIVE: The evaluation of GI-pill gastrointestinal electronic capsule for colonic transit test in patients with slow transit constipation (STC) was studied. MATERIALS AND METHODS: STC patients (n = 162) were randomly divided into experimental group (n = 84, orally taken GI-pill gastrointestinal electronic capsule and X-ray granule capsule) and control group (n = 78, orally taken X-ray granule capsule). Comparison of the time in colonic transit test between the two groups was conducted. The data of GI-pill gastrointestinal electronic capsule in vivo time, time of capsule passing through the colon, the number of high amplitude propagating contractions (HAPCs), and physiological response ratio were analyzed. RESULTS: There were no significant differences in the whole colonic transit test time, right colonic transit time, left colonic transit time, and rectosigmoid colonic transit time between experimental group and control group (p > 0.05). All patients had no abdominal pain, nausea, vomiting, black stool, difficulty in electronic capsule excretion, or any other discomfort during the test. CONCLUSION: GI-pill gastrointestinal electronic capsule can continuously evaluate the dynamic characteristics of digestive tract in STC patients and is consistent with X-ray granule capsule, which is meaningful to clinical application.

A novel artificial anal sphincter system in an in vitro and in vivo experiment.

This paper presents some of the latest progress in the development of a novel artificial anal sphincter system (AASS) to treat severe fecal incontinence. We have redesigned and integrated an intelligent, remote-controlled artificial anal sphincter based on biological signal feedback mechanisms. The device consists of an external telemetry unit, an internal artificial anal sphincter (IAAS), and a transcutaneous energy transfer system (TETS). The mechanical medical micropump of the IAAS can realize bidirectional flow with a maximum flow rate of 8.5 ml/min and can build backpressure up to 170 kPa. The design of the prosthesis reduces occlusion pressure and allows for low inflation volumes (9 mL-10.5 mL); operating pressures between 4.05 kPa and 7.16 kPa indicate that the risk of ischemic injury to the bowel is minimal. Furthermore, the rechargeable battery based on TETS puts the operation time at an estimated 2 days. The performance characteristics of the AASS and its efficiency in achieving continence and sensing the stool inside the anorectum were evaluated in vitro and in vivo in a pig model. Experimental results confirm that the system can maintain continence and build the sense of defecation successfully. Moreover, this innovation can be integrated into not only severe fecal incontinence, erectile dysfunction, and therapy-resistant reflux disease, but also morbid adiposity therapeutic AASS applications.

Electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter system.

This paper reports on the electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter. The coupling coils and human tissues, including the skin, fat, muscle, liver, and blood, were considered. Specific absorption rate (SAR) and current density were analyzed by a finite-length solenoid model. First, SAR and current density as a function of frequency (10-10(7) Hz) for an emission current of 1.5 A were calculated under different tissue thickness. Then relations between SAR, current density, and five types of tissues under each frequency were deduced. As a result, both the SAR and current density were below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The results show that the analysis of these data is very important for developing the artificial anal sphincter system.

Modeling of human colonic blood flow for a novel artificial anal sphincter system.

A novel artificial anal sphincter system has been developed to simulate the normal physiology of the human anorectum. With the goal of engineering a safe and reliable device, the model of human colonic blood flow has been built and the relationship between the colonic blood flow rate and the operating occlusion pressure of the anorectum is achieved. The tissue ischemia is analyzed based on constitutive relations for human anorectum. The results suggest that at the planned operating occlusion pressure of less than 4 kPa the artificial anal sphincter should not risk the vascularity of the human colon.

[Study on a wireless energy transmission system for the noninvasive examination micro system inside alimentary tracts].

A wireless energy transmission system for the MEMS system inside alimentary tracts is reported here in the paper. It consists of an automatic frequency tracking circuit of phase lock loop and phase shift PWM control circuit. Experimental results show that the energy transmission system is capable of automatic frequency-tracking and transmission power-adjusting and has stable received energy.

Adaptive subject-based feature extraction in brain-computer interfaces using wavelet packet best basis decomposition.

In this paper we discuss a subject-based feature extraction method using wavelet packet best basis decomposition (WPBBD) in brain-computer interfaces (BCIs). The idea is to employ the wavelet packet best basis algorithm to adapt to each subject separately. Firstly, original electroencephalogram (EEG) signals are decomposed to a given level by wavelet packet transform. Secondly, for each subject, the best basis algorithm is used to find the best-adapted basis for that particular subject. Finally, subband energies contained in the best basis are used as effective features. Adaptive and specific features of a subject are so obtained. Three different motor imagery tasks of six subjects are discriminated using the above features. Experiment results show that the subject-based adaptation method yields significantly higher classification performance than the non-subject-based adaptation and non-adaptive approaches.

Non-invasive measurement of pan-colonic pressure over a whole digestive cycle: clinical applications of a capsule-style manometric system.

AIM: To study the prolonged colonic motility under normal conditions with a novel capsule-style micro-system and to assess its clinical significance. METHODS: A single use telemetry capsule (10 mm in diameter, 20 mm in length) embedded with a pressure sensor was ingested by the subjects. The sensor is capable of transmitting colonic pressure wirelessly for more than 130 h. The time of capsule entering the segmental colon was detected by ultrasound. The ultrasonic electrodes were mounted on the surface of the ileocecum and navel and at the junction of the left and rectosigmoid colon of the subjects in sequence, which were identified by abdominal X-rays with radiopaque markers. To verify the accuracy and reliability of ultrasonic detection of telemetry capsules at key points of colon, the segmental colonic transit time was simultaneously recorded by using radiopaque markers. RESULTS: The signal lamp showed that all recorders could receive the radio signal transmitted by the telemetry capsule. The X-rays showed that all telemetry capsules were detected successfully when they were passing through the key points of colon. There was a significant correlation between the transit results obtained by ultrasonic detection or by radiopaque markers. Colorectal recording was obtained from 20 healthy subjects during 613 h (411 h during waking, 202 h during sleep). Compared to waking, the number of pressure contractions and the area under pressure contractions were significantly (P < 0.05) decreased during sleep (21 +/- 5 h(-1) vs 15 +/- 4 h(-1), 463 +/- 54 mmHg x s/min vs 342 +/- 45 mmHg x s/min). The colonic motility exhibited significant regional variations both in the circadian behavior and in response to waking and meal. CONCLUSION: The capsule-style micro-system is reliable and noninvasive, and may represent a useful tool for the study of physiology and pathology of colonic motor disorders.

[Development and applications of a gastrointestinal monitoring microsystem based on the smart capsule].

A newly-developed gastrointestinal (GI) monitoring system based on a smart capsule is presented in the paper. The unprecedented 130-200 hours battery life and smaller size (10 mm x 20 mm) allows the physician to get total pan-colonic measurements of high-amplitude propagating contractions (HAPCs). To test the in vivo performance of the monitoring system, 15 healthy volunteers and 10 patients with slow transportation constipation (STC) participate in this study. The average of HAPCs occurred in patients is significantly lower than in volunteers (12.4 +/- 3.3 vs. 18.5 +/- 3.7 p = 0.013). The system provides a useful tool for STC diagnosis and treatments of patients.

Feature extraction for EEG-based brain-computer interfaces by wavelet packet best basis decomposition.

A method based on wavelet packet best basis decomposition (WPBBD) is investigated for the purpose of extracting features of electroencephalogram signals produced during motor imagery tasks in brain-computer interfaces. The method includes the following three steps. (1) Original signals are decomposed by wavelet packet transform (WPT) and a wavelet packet library can be formed. (2) The best basis for classification is selected from the library. (3) Subband energies included in the best basis are used as effective features. Three different motor imagery tasks are discriminated using the features. The WPBBD produces a 70.3% classification accuracy, which is 4.2% higher than that of the existing wavelet packet method.

[Current research and development trend of swallowable biotelemetry systems].

Swallowable biotelemetry systems are one kind of implantable biotelemetry systems. The research about swallowable biotelemetry systems is rapidly growing recently because they can be used to measure physiological and pathological parameters of human gastrointestinal tracts in vivo and they significantly improve patient comfort. This paper presents the current research of swallowable biotelemetry systems domestically and abroad. The development trend of these systems is analyzed at the end of the paper.

A non-invasive method for gastrointestinal parameter monitoring.

AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract. METHODS: The authors developed a miniature, multi-functional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder. The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison. RESULTS: Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired. CONCLUSION: A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.

[A review of brain-computer interfaces (BCIs)].

This paper introduces the general constitutions and principle of BCI systems. In addition, some characteristics and limitations of different research methods are discussed and compared. Finally, this paper points out the existing problems and future trends of BCIs. brain-computer interface (BCI), human-computer Interface (HCI), electroencephalography (EEG).

[The research on linear control of pneumatic artificial muscles used in medical robots].

This paper presents the properties of Pneumatic artificial muscles and its application in medical robots. The linear model construction and minimum predictive error control algorithm for artificial muscles are discussed here too. This paper provides the experimental results of linear adaptive control, which show the control algorithm has certain applicable value.

[A novel miniature robotic endoscope design for intestinal inspection].

This paper makes a comparison between the traditional endoscope system and the active robotic endoscope system, discusses the human intestine-working conditions of the robotic endoscope system in detail and its design requirements. An active robotic endoscope system based on earthworn-locomotion principles is proposed here and besides, its structure and locomotion mechanism are analyzed. A new method of human intestinal intervention is brought out and it can prevent the robotic endoscope guided by a cone-shaped guide pipe from being jammed or damaged.