Biomedical subjects

Yasunobu Handa

Publications and source records attributed to Yasunobu Handa.

5 recordsLinked to original sources

PubMed2006

Virtual reality pencil and paper tests for neglect: a protocol.

Hemispatial neglect is a common disorder that can occur after a lesion in the right hemisphere. Its main characterization is the difficulty in processing visual stimuli emanating from the space contralateral to the lesion. Pencil and paper tests (such as target cancellation, line bisection, or drawing copy) are used to diagnose neglect. We propose using virtual reality technology and haptic force feedback to enhance pencil and paper tests. Our system can track the patients' eye-gaze and their hand movements. Also, the efficiency of several techniques used to decrease the neglect in different sensory spaces are investigated.

Computer Simulation↗

PubMed2006

Magnetic resonance imaging of morphological and functional changes of the uterus induced by sacral surface electrical stimulation.

The purpose of this study is to examine the morphological and kinematical changes of the uterus induced by electrical stimulation applied to the skin just above the second and fourth posterior sacral foramens (sacral surface electrical stimulation [ssES]) in 26 healthy subjects. Out of them, eight subjects who had severe pain subjectively during every menstruation received ssES just in menstruation. Morphological and functional changes of the uterus were examined by using T2-weighted magnetic resonance (MR) imaging and T1-weighted MR cinematography, respectively. Cyclic electrical stimulation for 15 min with 5 sec ON and 5 sec OFF was applied just before MR scanning. A decrease in thickness of the muscular layer of the uterus was observed in every subject after ssES for 15 min and was significant as compared with the thickness before ssES. Periodic uterine movement during menstruation was observed in the subjects with severe menstrual pain in MR cine and the power spectrum analysis of the movement showed a marked decrease in peak power and frequency after ssES treatment. We conclude that ssES causes a reduction of static muscle tension of the uterus in all menstrual cycle periods and suppression of uterine peristalsis during menstruation in the subjects with severe menstrual pain. Possible neural mechanisms for these static and dynamic effects of ssES on the uterus at spinal level are discussed.

Adult↗

PubMed2005

Diagnosis and rehabilitation of hemispatial neglect patients with virtual reality technology.

Victims of a stroke or an accident with damage on the parietal lobe can suffer from hemispatial neglect. This disorder is characterized by misperception of the space contralateral to the damaged area. Paper and pencil tests, such as line bisection tests, are used to diagnose hemispatial neglect. Unfortunately, they fail to quantify the degree of the neglect. Moreover, the neglect has different manifestations in each sensorial space and frame of references. In order to diagnose disorders of spatial recognition and analyze the neglected area in visual and somatic spaces, we developed a 3D-haptic virtual reality system coupled with an eye-tracking device. The haptic interface was used to interact with virtual objects. The virtual world can use the eye-gaze information to let patients overcome the neglect. We tested the system at a rehabilitation center and observed different approaches between normal subjects and hemiplegics patients. The first group was getting close to the target and then slowed down to grab it, whereas the later group proceeded by trial and error. The feature of trajectories of the hand in the 3D space could be used to determine the degree of the motion handicap. However, more specific virtual worlds are needed for efficiently extracting the feature of the patients.

Adult↗

PubMed2004

Effects and indications of sacral surface therapeutic electrical stimulation in refractory urinary incontinence.

OBJECTIVE: To describe the effects and indications of sacral surface therapeutic electrical stimulation (SS-TES) for refractory urinary incontinence. DESIGN: Evaluation before and after therapy. SETTING: On clinical site and at nursing home. SUBJECTS: Seven neurogenic bladder, five unstable bladder and six nocturia cases were investigated. Twelve were outpatients and six were residents. INTERVENTIONS: Surface electrodes were placed at the posterior sacral foramens of S2 and S4. Stimulation conditions were duration 0.3 ms, frequency 20 Hz and maximum intensity. The stimulation was continued for 15 min twice daily for over one month. MAIN OUTCOME MEASURES: Therapeutic effects were evaluated on the basis of voiding charts as subjective findings and urodynamic study as objective findings before and after therapy. RESULTS: Subjective findings showed incontinence frequency significantly decreased from 2.3 +/- 1.4 times/day before therapy to 1.3 +/- 2.0 times/day after therapy (p < 0.01); 55.5% of patients were improved or greatly improved. Objective findings showed that maximum vesical capacity (MVC) significantly increased from 208.2 +/- 94.5 ml before therapy to 282.1 +/- 66.8 ml (p < 0.001). Uninhibited contraction significantly decreased from 40.4 +/- 31.4 cmH2O before therapy to 25.7 +/- 23.9 cmH2O (p < 0.01); 44% of patients were improved or greatly improved. This therapy was effective in particular for cases whose MVC was small before applying SS-TES. CONCLUSION: SS-TES was effective in some patients with refractory urinary incontinence.

Adolescent↗

PubMed2002

EMG-angle relationship of the hamstring muscles during maximum knee flexion.

The aim of the present study was to investigate the EMG-joint angle relationship during voluntary contraction with maximum effort and the differences in activity among three hamstring muscles during knee flexion. Ten healthy subjects performed maximum voluntary isometric and isokinetic knee flexion. The isometric tests were performed for 5 s at knee angles of 60 and 90 degrees. The isokinetic test, which consisted of knee flexion from 0 to 120 degrees in the prone position, was performed at an angular velocity of 30 degrees /s (0.523 rad/s). The knee flexion torque was measured using a KIN-COM isokinetic dynamometer. The individual EMG activity of the hamstrings, i.e. the semitendinosus, semimembranosus, long head of the biceps femoris and short head of the biceps femoris muscles, was detected using a bipolar fine wire electrode. With isometric testing, the knee flexion torque at 60 degrees knee flexion was greater than that at 90 degrees. The mean peak isokinetic torque occurred from 15 to 30 degrees knee flexion angle and then the torque decreased as the knee angle increased (p<0.01). The EMG activity of the hamstring muscles varied with the change in knee flexion angle except for the short head of the biceps femoris muscle under isometric condition. With isometric contraction, the integrated EMGs of the semitendinosus and semimembranosus muscles at a knee flexion angle of 60 degrees were significantly lower than that at 90 degrees. During maximum isokinetic contraction, the integrated EMGs of the semitendinosus, semimembranosus and short head of the biceps femoris muscles increased significantly as the knee angle increased from 0 to 105 degrees of knee flexion (p<0.05). On the other hand, the integrated EMG of the long head of the biceps femoris muscle at a knee angle of 60 degrees was significantly greater than that at 90 degrees knee flexion with isometric testing (p<0.01). During maximum isokinetic contraction, the integrated EMG was the greatest at a knee angle between 15 and 30 degrees, and then significantly decreased as the knee angle increased from 30 to 120 degrees (p<0.01). These results demonstrate that the EMG activity of hamstring muscles during maximum isometric and isokinetic knee flexion varies with change in muscle length or joint angle, and that the activity of the long head of the biceps femoris muscle differs considerably from the other three heads of hamstrings.

Adult↗