Biomedical subjects

Yoshiharu Yonezawa

Publications and source records attributed to Yoshiharu Yonezawa.

At least 19 recordsLinked to original sources

PubMed2006

A mobile phone-based ECG monitoring system.

We have developed a telemedicine system for monitoring a patient's electrocardiogram during daily activities. The recording system consists of three ECG chest electrodes, a variable gain instrumentation amplifier, a low power 8-bit single-chip microcomputer, a 256 KB EEPROM and a 2.4 GHz low transmitting power mobile phone (PHS). The complete system is mounted on a single, lightweight, chest electrode array. When a heart discomfort is felt, the patient pushes the data transmission switch on the recording system. The system sends the recorded ECG waveforms of the two prior minutes and ECG waveforms of the two minutes after the switch is pressed, directly in the hospital server computer via the PHS. The server computer sends the data to the physician on call. The data is displayed on the doctor's Java mobile phone LCD (Liquid Crystal Display), so he or she can monitor the ECG regardless of their location. The developed ECG monitoring system is not only applicable to at-home patients, but should also be useful for monitoring hospital patients.

Amplifiers, Electronic↗

PubMed2006

A new infusion pathway monitoring system utilizing electrostatic induced potential.

We have developed a new infusion pathway monitoring system employing linear integrated circuits and a low-power 8-bit single chip microcomputer. The system is available for hospital and home use and it constantly monitors the intactness of the pathway. The sensor is an electro-conductive polymer electrode wrapped around the infusion polyvinyl chloride infusion tube. This records an AC (alternating current) voltage induced on the patient's body by electrostatic coupling from the normal 100 volt, 60 Hz AC power line wiring field in the patient's room. If the injection needle or infusion tube becomes detached, then the system detects changes in the induced AC voltage and alerts the nursing station, via the nurse call system or PHS (personal handy phone System).

Amplifiers, Electronic↗

PubMed2006

A new communication support system employing a tablet computer.

A new communication support system has been developed for assisting elderly people communicating by telephone and e-mail. The system consists of a conventional tablet computer, a computer-telephony interface board, a microphone, a speaker, a telephone line and the Internet. The tablet liquid crystal screen (TLCS) is used as a display device and an entry device, instead of a keyboard. When an elderly person telephones or sends an email, they then choose a communication person from the registered support personnel pictures displayed on the TLCS. The computer dials or sends e-mail, which is directly handwritten on the TLCS. When their home system receives a telephone call or e-mail, the computer displays the calling communication person's picture and name on the TLCS. The elderly person can therefore easily recognize and verify the person. Since this newly-developed communication support system does not employ a keyboard, it is easily operated by elderly persons.

Communication Devices for People with Disabilities↗

PubMed2005

Use of gyroscopic sensors for objective evaluation of trimming and shoeing to alter time between heel and toe lift-off at end of the stance phase in horses walking and trotting on a treadmill.

OBJECTIVE: To determine whether a shoe with an axialcontoured lateral branch would induce greater lateral roll of the forelimb hoof during the time between heel and toe lift-off at end of the stance phase (breakover). Animals-10 adult horses. PROCEDURE: A gyroscopic transducer was placed on the hoof of the right forelimb and connected to a transmitter. Data on hoof angular velocity were collected as each horse walked and trotted on a treadmill before (treatment 1, no trim-no shoe) and after 2 treatments by a farrier (treatment 2, trim-standard shoe; and treatment 3, trim-contoured shoe). Data were converted to hoof angles by mathematical integration. Breakover duration was divided into 4 segments, and hoof angles in 3 planes (pitch, roll, and yaw) were calculated at the end of each segment. Multivariable ANOVA was performed to detect differences among treatments and gaits. RESULTS: Trimming and shoeing with a shoe with contoured lateral branches induced greater mean lateral roll to the hoof of 3.2 degrees and 2.5 degrees during the first half of breakover when trotting, compared with values for no trim-no shoe and trim-standard shoe, respectively. This effect dissipated during the second half of breakover. When horses walked, lateral roll during breakover was not significantly enhanced by use of this shoe. CONCLUSIONS AND CLINICAL RELEVANCE: A shoe with an axial-contoured lateral branch induced greater lateral roll during breakover in trotting horses, but change in orientation of the hoof was small and limited to the first half of breakover.

Analysis of Variance↗

PubMed2005

A web-based care-requiring client and Home Helper mutual support system.

For the improved efficiency of home care of the elderly, a web-based system has been developed to enable faster communications between care-requiring clients, their Home Helper and the care manager. Changes to care items, such as cooking, bathing, washing, cleaning and shopping are usually requested by the elderly client over the telephone. However, the care central office often requires 24 hours to process and respond to such spoken requests. The system we have developed consists of Internet client computers with liquid crystal input tablets, wireless Internet Java enabled mobile phones and a central office server that yields almost instant communication. The care clients enter requests on the liquid crystal tablet at their home and then their computer sends these requests to the server at the Home Helper central office. The server automatically creates a new file of the requested items, and then immediately transfers them to the care manager and Home Helper's mobile phone. With this non-vocal and paperless system, the care-requiring clients, who can easily operate the liquid crystal tablet, can very quickly communicate their needed care change requests to their Home Helper.

Aged↗

PubMed2005

A wearable, mobile phone-based respiration monitoring system for sleep apnea syndrome detection.

A new wearable respiration monitoring system has been developed for non-invasive detection of sleep apnea syndrome. The system, which is attached to a shirt, consists of a piezoelectric sensor, a low-power 8-bit single chip microcontroller, EEPROM and a 2.4 GHz low-power transmitting mobile phone (PHS). The piezoelectric sensor, whose electrical polarization voltage is produced by body movements, is installed inside the shirt and closely contacts the patient's chest. The low frequency components of body movements recorded by the sensor are mainly generated by respiration. The microcontroller sequentially stores the movement signal to the EEPROM for 5 minutes and detects, by time-frequency analysis, whether the patient has breathed during that time. When the patient is apneic for 10 sseconds, the microcontroller sends the recorded respiration waveform during and one minute before and after the apnea directly to the hospital server computer via the mobile phone. The server computer then creates apnea "filings" automatically for every patient. The system can be used at home and be self-applied by patients. Moreover, the system does not require any extra equipment such as a personal computer, PDA, or Internet connection.

Cell Phone↗

PubMed2005

A motion control function evaluation system employing a pen tablet.

We have developed a new pen tablet based system for evaluation of hand motion control function as influenced by brain disease. The system consists of a laptop computer and a pen tablet data entry device. The pen tablet is placed in front of the subject who is instructed to tap the pen at a constant location. When the subject taps the pen, the tablet transfers the pen position to the laptop computer. The computer then saves the tap position, along with the time elapsed between each tap. The subject is instructed to tap 50 times with each hand with the eyes closed. The absolute distance moved between each two successive tap positions is detected. Tapping period, total tapping time and total distance moved are also calculated. Measurements were performed on ten normal subjects and three subjects with cerebral infarction. The results indicate that cerebral infarction subjects' average total tap point distance moved and absolute distance moved are greater than in the normal subjects. Conversely, all subjects in both groups produced only normal variations in tapping period and total tapping time. Our system can therefore quantitatively evaluate hand motion control function by the total and absolute distance moved.

Adult↗

PubMed2004

Evaluation of a sensor-based system of motion analysis for detection and quantification of forelimb and hind limb lameness in horses.

OBJECTIVE: To compare a sensor-based accelerometer-gyroscopic (A-G) system with a video-based motion analysis system (VMAS) technique for detection and quantification of lameness in horses. ANIMALS: 8 adult horses. PROCEDURE: 2 horses were evaluated once, 2 had navicular disease and were evaluated before and after nerve blocks, and 4 had 2 levels of shoe-induced lameness, alternatively, in each of 4 limbs. Horses were instrumented with an accelerometer transducer on the head and pelvis, a gyroscopic transducer on the right forelimb and hind feet, and a receiver-transmitter. Signals from the A-G system were collected simultaneously with those from the VMAS for collection of head, pelvis, and right feet positions with horses trotting on a treadmill. Lameness was detected with an algorithm that quantified lameness as asymmetry of head and pelvic movements. Comparisons between the A-G and VMAS systems were made by use of correlation and agreement (kappa value) analyses. RESULTS: Correlation between the A-G and VMAS systems for quantification of lameness was linear and high (r2 = 0.9544 and 0.8235 for forelimb and hind limb, respectively). Quantification of hind limb lameness with the A-G system was higher than measured via VMAS. Agreement between the 2 methods for detection of lameness was excellent (kappa = 0.76) for the forelimb and good (kappa = 0.56) for the hind limb. CONCLUSIONS AND CLINICAL RELEVANCE: The A-G system detected and quantified forelimb and hind limb lameness in horses trotting on the treadmill. Because the data are collected wirelessly, this system might be used to objectively evaluate lameness in the field.

Acceleration↗

PubMed2004

A Java mobile phone-based "Home Helper" care report creation support system.

In Japan, Home Helpers are employed by hospitals, care companies or the welfare office and are sent to the homes of elderly persons to provide home welfare and care services. They are required to input their reports into the computer at their central office after each care visit. We developed a new Java mobile phone-based Home Helper care report creation support system for reducing the data entry time and the communication costs of their reports. The system consists of a Java mobile phone for each Home Helper and a server computer at their office. The server computer sends a Java care report creation support program to the Java mobile phone. The program runs on the mobile phone and supports the report creation in a short time. Therefore, the developed system enables easy report entry by the Home Helper and saves a significant amount of time and communication costs.

Adult↗

PubMed2003

Implantable microelectrodes with new electro-conductive materials for recording sympathetic neural discharge.

We have developed two new types of bipolar cuff microelectrodes (volume size, 2-3 mm(3)) using electro-conductive rubber or water-absorbent polymer, either of which can be applied to measure sympathetic nerve activity in small animals. A renal nerve bundle of an anesthetized rat was inserted into the center hole of the electrode (diameter, 0.15 mm) through a slit and had good contact with the electrodes. Renal sympathetic nerve activity, which was verified by sympathetic ganglionic blockade, could be recorded using either type of implantable cuff electrode.

Action Potentials↗

PubMed2003

A new microcomputer-based safety and life support system for solitary-living elderly people.

A new safety and life support system has been developed to detect emergency situations of solitary-living elderly persons. The system employs a dual axis accelerometer, two low-power active filters, a low-power 8-bit single chip microcomputer and a personal handy phone. Body movements due to walking, running and posture changes are detected by the dual axis accelerometer and sent to the microcomputer. If the patient is in an inactive state for 5 minutes after falling, or for 64 minutes without previously falling, then the system automatically alarms the emergency situation, via the personal handy phone, to the patient's family, the fire station or the hospital.

Acceleration↗

PubMed2003

A wrist-mounted arterial pulse interval and movement recording system.

A wrist movement and arterial pulse interval recording system has been developed for continuous data acquisition in studies of activity/rest time ratios, sleep quantity and quality, general activity level, resting heart rate and circadian rhythms. The system employs a wrist-mounted piezoelectric sensor, a low-power 8-bit one-chip microcomputer and a 512 KB EEPROM. The microcomputer detects whether the wrist is moving or inactive; if it is moving, wrist movement is stored into memory. If the wrist is at rest, the arterial pulse interval is continuously detected and stored. After recording, these stored data are downloaded to a desktop computer and analyzed.

Adult↗

PubMed2003

A Web-based home welfare and care services support system using a pen type image sensor.

A long-term care insurance law for elderly persons was put in force two years ago in Japan. The Home Helpers, who are employed by hospitals, care companies or the welfare office, provide home welfare and care services for the elderly, such as cooking, bathing, washing, cleaning, shopping, etc. We developed a web-based home welfare and care services support system using wireless Internet mobile phones and Internet client computers, which employs a pen type image sensor. The pen type image sensor is used by the elderly people as the entry device for their care requests. The client computer sends the requests to the server computer in the Home Helper central office, and then the server computer automatically transfers them to the Home Helper's mobile phone. This newly-developed home welfare and care services support system is easily operated by elderly persons and enables Homes Helpers to save a significant amount of time and extra travel.

Aged↗

PubMed2003

A compact ECG R-R interval, respiration and activity recording system.

An ECG R-R interval, respiration and activity recording system has been developed for monitoring variability of heart rate and respiratory frequency during daily life. The recording system employs a variable gain instrumentation amplifier, an accelerometer, a low power 8-bit single-chip microcomputer and a 1024 KB EEPROM. It is constructed on three ECG chest electrodes. The R-R interval and respiration are detected from the ECG. Activity during walking and running is calculated from an accelerator. The detected data are stored in an EEPROM and after recording, are downloaded to a desktop computer for analysis.

Acceleration↗

PubMed2003

A microcomputer-based daily living activity recording system.

A new daily living activity recording system has been developed for monitoring health conditions and living patterns, such as respiration, posture, activity/rest ratios and general activity level. The system employs a piezoelectric sensor, a dual axis accelerometer, two low-power active filters, a low-power 8-bit single chip microcomputer and a 128 MB compact flash memory. The piezoelectric sensor, whose electrical polarization voltage is produced by mechanical strain, detects body movements. Its high-frequency output components reflect body movements produced by walking and running activities, while the low frequency components are mainly respiratory. The dual axis accelerometer detects, from body X and Y tilt angles, whether the patient is standing, sitting or lying down (prone, supine, left side or right side). The detected respiratory, behavior and posture signals are stored by the compact flash memory. After recording, these data are downloaded to a desktop computer and analyzed.

Acceleration↗

PubMed2002

Accelerometer-based system for the detection of lameness in horses.

Video-based kinematic analysis of gait in horses is accurate for quantification of lameness and reliable for identification of the affected limb. Algorithms for the measurement of the vertical head and pelvic displacement and phase correlation with vertical displacement of one forelimb and hindlimb foot have been developed for this purpose. However, because of camera field-of-view limitations, video-based analysis of gait can only be reliably accomplished with the horse constrained to move on a treadmill. This paper describes the use of 2 single-axis accelerometers and 2 gyroscopic transducers as a measurement system for the identification and quantification of forelimb and hindlimb lameness in horses. Vertical head and pelvic acceleration are converted to displacement, lameness is quantified from previously developed algorithms, and affected limb is determined by correlation of head and pelvic signals with gyroscopic signals from the right forelimb and hindlimb feet. Signals from the 4 transducers are telemeterized at 200 Hz and collected to a receiver connected to a lap top computer, freeing the horse from the constraints of a treadmill laboratory setting. In this paper we describe the reliability of this new accelerometer-based system in horses with induced lameness while trotting on a treadmill and freely outside overground.

Animals↗

PubMed2002

A microcomputer-based respiratory and activity recording system.

A respiratory and activity recording system has been developed for monitoring health conditions and living patterns, such as activity/rest time periods and general activity level. The system employs a piezoelectric sensor, a low-power operational amplifier, a low-power 8-bit microcomputer and a 512 KB EEPROM. The piezoelectric sensor, whose electrical polarization voltage is produced by mechanical strain, records body movements produced by respiration, heart pulse, walking and running. The high and low frequency components from the recorded body movements are discriminated by high and low pass filters. The high frequency components reflect the body movements produced by cardiac vibrations, walking and running activities. The low frequency components are mainly generated by respiration. The degree of activity is obtained by summing the high frequency components for 1 second. The microcomputer stores the obtained low frequency components and activity to the EEPROM at 0.2 second and 1 second intervals, respectively. After recording, these stored data are downloaded to a desktop computer. The computer then detects behavior patterns from the activity data and respiration from the low frequency components.

Diagnosis, Computer-Assisted↗

PubMed2002

A system for monitoring heart pulse, respiration and posture in bed.

A non-invasive system has been developed to monitor cardiac vibrations, respiration and posture of inbed hospitalized patients and elderly people who need constant care. These physiological variables are recorded by four 2 x 28 cm piezoelectric film acceleration sensors, eight 2 x 2 cm small pressure sensors and a 5 x 100 cm long pressure sensor. The piezoelectric sensors, attached to the chest over the heart during bed sleep or rest, detect the movements produced by the heartbeat and respiration. The eight small pressure sensors are attached at various positions on the upper and lower body. A longer pressure sensor, to detect the patient leaving the bed, is attached to the side of the bed. These sensor outputs are digitized at a sampling rate of 200 Hz using a 12-bit A/D converter and stored on a personal computer. The computer detects cardiac vibrations and respiration from upper chest movements and posture from the pressures recorded by small and long pressure sensors.

Bed Rest↗