Reliability of Suprahyoid and Infrahyoid Electromyographic Measurements during Swallowing in Healthy Subjects / 대한연하장애학회지

Objective@#To evaluate the reliability of suprahyoid and infrahyoid electromyography (EMG) measurement during swallowing. @*Methods@#In all, 10 healthy volunteers were evaluated for the following surface EMG (sEMG) parameters in the suprahyoid and infrahyoid muscles during swallowing: onset latency, offset latency, duration, peak latency, maximal amplitude during swallowing, and the area under curve (AUC) of the rectified EMG signal. The sEMG was recorded while the participants swallowed five times each of the four fluid volumes (saliva, 2 ml, 5 ml, and 20 ml of water), totaling to 20 swallows. Moreover, the intra-participant variability per parameter was evaluated using the coefficient of variation (CV). @*Results@#Suprahyoid muscles were activated 0.095 s (95% CI, 0.062-0.128) earlier than the infrahyoid muscles.Maximal amplitudes during the 20 ml swallow were 17.484 (−1.543-36.512) and 13.490 (1.254-25.727) μV higher than values obtained during the 2 ml swallow in the suprahyoid and infrahyoid muscles, respectively. Furthermore, the AUC of the rectified EMG signal increased with the volume of swallow in both muscle groups (P=0.003, suprahyoid; P＜0.002, infrahyoid). The intra-individual variabilities of offset latency, duration, and maximal amplitude were relatively low (＜30% CV) in both muscle groups with respect to other parameters. The assessment of each parameter using EMG was highly reliable, with an intraclass correlation coefficient of ＞0.8. @*Conclusion@#Among the variable sEMG parameters assessed, the offset latency, duration, and maximal amplitude were the least variable. Although reliability on the rater side showed good results, the swallow-to-swallow variability of the parameters need to be considered in swallowing studies using sEMG.

Reliability of Suprahyoid and Infrahyoid Electromyographic Measurements during Swallowing in Healthy Subjects / 대한연하장애학회지

Objective@#To evaluate the reliability of suprahyoid and infrahyoid electromyography (EMG) measurement during swallowing. @*Methods@#In all, 10 healthy volunteers were evaluated for the following surface EMG (sEMG) parameters in the suprahyoid and infrahyoid muscles during swallowing: onset latency, offset latency, duration, peak latency, maximal amplitude during swallowing, and the area under curve (AUC) of the rectified EMG signal. The sEMG was recorded while the participants swallowed five times each of the four fluid volumes (saliva, 2 ml, 5 ml, and 20 ml of water), totaling to 20 swallows. Moreover, the intra-participant variability per parameter was evaluated using the coefficient of variation (CV). @*Results@#Suprahyoid muscles were activated 0.095 s (95% CI, 0.062-0.128) earlier than the infrahyoid muscles.Maximal amplitudes during the 20 ml swallow were 17.484 (−1.543-36.512) and 13.490 (1.254-25.727) μV higher than values obtained during the 2 ml swallow in the suprahyoid and infrahyoid muscles, respectively. Furthermore, the AUC of the rectified EMG signal increased with the volume of swallow in both muscle groups (P=0.003, suprahyoid; P＜0.002, infrahyoid). The intra-individual variabilities of offset latency, duration, and maximal amplitude were relatively low (＜30% CV) in both muscle groups with respect to other parameters. The assessment of each parameter using EMG was highly reliable, with an intraclass correlation coefficient of ＞0.8. @*Conclusion@#Among the variable sEMG parameters assessed, the offset latency, duration, and maximal amplitude were the least variable. Although reliability on the rater side showed good results, the swallow-to-swallow variability of the parameters need to be considered in swallowing studies using sEMG.

Comparative study of glenoid version and inclination using two-dimensional images from computed tomographyand three-dimensional reconstructed bone models

Background@#This study was performed to compare glenoid version and inclination measured using two-dimensional (2D) images from computed tomography (CT) scans or three-dimensional (3D) reconstructed bone models. @*Methods@#Thirty patients who had undergone conventional CT scans were included. Two orthopedic surgeons measured glenoid version and inclination three times on 2D images from CT scans (2D measurement), and two other orthopedic surgeons performed the same measurements using 3D reconstructed bone models (3D measurement). The 3D-reconstructed bone models were acquired and measured with Mimics and 3-Matics (Materialise). @*Results@#Mean glenoid version and inclination in 2D measurements were –1.705º and 9.08º, respectively, while those in 3D measurements were 2.635º and 7.23º. The intra-observer reliability in 2D measurements was 0.605 and 0.698, respectively, while that in 3D measurements was 0.883 and 0.892. The inter-observer reliability in 2D measurements was 0.456 and 0.374, respectively, while those in 3D measurements was 0.853 and 0.845. @*Conclusions@#The difference between 2D and 3D measurements is not due to differences in image data but to the use of different tools. However, more consistent results were obtained in 3D measurement. Therefore, 3D measurement can be a good alternative for measuring glenoid version and inclination.

Augmented Reality to Localize Individual Organ in Surgical Procedure / 대한의료정보학회지

OBJECTIVES: Augmented reality (AR) technology has become rapidly available and is suitable for various medical applications since it can provide effective visualization of intricate anatomical structures inside the human body. This paper describes the procedure to develop an AR app with Unity3D and Vuforia software development kit and publish it to a smartphone for the localization of critical tissues or organs that cannot be seen easily by the naked eye during surgery. METHODS: In this study, Vuforia version 6.5 integrated with the Unity Editor was installed on a desktop computer and configured to develop the Android AR app for the visualization of internal organs. Three-dimensional segmented human organs were extracted from a computerized tomography file using Seg3D software, and overlaid on a target body surface through the developed app with an artificial marker. RESULTS: To aid beginners in using the AR technology for medical applications, a 3D model of the thyroid and surrounding structures was created from a thyroid cancer patient's DICOM file, and was visualized on the neck of a medical training mannequin through the developed AR app. The individual organs, including the thyroid, trachea, carotid artery, jugular vein, and esophagus were localized by the surgeon's Android smartphone. CONCLUSIONS: Vuforia software can help even researchers, students, or surgeons who do not possess computer vision expertise to easily develop an AR app in a user-friendly manner and use it to visualize and localize critical internal organs without incision. It could allow AR technology to be extensively utilized for various medical applications.

Electro-deposited Nanoporous Platinum Electrode for EEG Monitoring

BACKGROUND: One of the key issues in electroencephalogram (EEG) monitoring is accurate signal acquisition with less cumbersome electrodes. In this study, the L2 phase electro-deposited nanoporous platinum (L2-ePt) electrode is introduced, which is a new type of electrode that utilizes a stable nanoporous platinum surface to reduce the skin-electrode impedance. METHODS: L2-ePt electrodes were fabricated using electro-deposition technique. Then, the effect of the nanoporous surface on the surface roughness and the electrode impedance were observed from the L2-ePt electrodes and the flat platinum (FlatPt) electrode. The skin-electrode impedances of the L2-ePt electrodes, a gold cup electrode, and the FlatPt electrode were evaluated when placed on the hairy occipital area of the head in ten subjects. For the validation of using the L2-ePt electrode, a correlational analysis of the alpha rhythms was performed in the same subjects for simultaneous EEG recordings using the L2-ePt and clinically-used EEG electrodes. RESULTS: The results indicated that the L2-ePt electrode with a roughness factor of 200 had the lowest mean impedance performance. Moreover, the proposed L2-ePt electrode showed a significantly lower mean skin-electrode impedance than the FlatPt electrode. Finally, the EEG signal quality recorded by the L2-ePt electrode (r = 0.94) was comparable to that of the clinically-used gold cup electrode. CONCLUSION: Based on these results, the proposed L2-ePt electrode is suitable for use in various high-quality EEG applications.

Preliminary study on application of augmented reality visualization in robotic thyroid surgery

PURPOSE: Increased robotic surgery is attended by increased reports of complications, largely due to limited operative view and lack of tactile sense. These kinds of obstacles, which seldom occur in open surgery, are challenging for beginner surgeons. To enhance robotic surgery safety, we created an augmented reality (AR) model of the organs around the thyroid glands, and tested the AR model applicability in robotic thyroidectomy. METHODS: We created AR images of the thyroid gland, common carotid arteries, trachea, and esophagus using preoperative CT images of a thyroid carcinoma patient. For a preliminary test, we overlaid the AR images on a 3-dimensional printed model at five different angles and evaluated its accuracy using Dice similarity coefficient. We then overlaid the AR images on the real-time operative images during robotic thyroidectomy. RESULTS: The Dice similarity coefficients ranged from 0.984 to 0.9908, and the mean of the five different angles was 0.987. During the entire process of robotic thyroidectomy, the AR images were successfully overlaid on the real-time operative images using manual registration. CONCLUSION: We successfully demonstrated the use of AR on the operative field during robotic thyroidectomy. Although there are currently limitations, the use of AR in robotic surgery will become more practical as the technology advances and may contribute to the enhancement of surgical safety.

Unobtrusive Estimation of Cardiorespiratory Fitness with Daily Activity in Healthy Young Men

Despite the importance of cardiorespiratory fitness, no practical method exists to estimate maximal oxygen consumption (VO₂max) without a specific exercise protocol. We developed an estimation model of VO₂max, using maximal activity energy expenditure (aEEmax) as a new feature to represent the level of physical activity. Electrocardiogram (ECG) and acceleration data were recorded for 4 days in 24 healthy young men, and reference VO₂max levels were measured using the maximal exercise test. aEE was calculated using the measured acceleration data and body weight, while heart rate (HR) was extracted from the ECG signal. aEEmax was obtained using linear regression, with aEE and HR as input parameters. The VO₂max was estimated from the aEEmax using multiple linear regression modeling in the training group (n = 16) and was verified in the test group (n = 8). High correlations between the estimated VO₂max and the measured VO₂max were identified in both groups, with a 15-hour recording being sufficient to produce a highly accurate VO₂max estimate. Additional recording time did not significantly improve the accuracy of the estimation. Our VO₂max estimation method provides a robust alternative to traditional approaches while only requiring minimal data acquisition time in daily life.

In-Silico Trials for Glucose Control in Hospitalized Patients with Type 2 Diabetes

Although various basal-bolus insulin therapy (BBIT) protocols have been used in the clinical environment, safer and more effective BBIT protocols are required for glucose control in hospitalized patients with type 2 diabetes (T2D). Modeling approaches could provide an evaluation environment for developing the optimal BBIT protocol prior to clinical trials at low cost and without risk of danger. In this study, an in-silico model was proposed to evaluate subcutaneous BBIT protocols in hospitalized patients with T2D. The proposed model was validated by comparing the BBIT protocol and sliding-scale insulin therapy (SSIT) protocol. The model was utilized for in-silico trials to compare the protocols of adjusting basal-insulin dose (BBIT1) versus adjusting total-daily-insulin dose (BBIT2). The model was also used to evaluate two different initial total-daily-insulin doses for various levels of renal function. The BBIT outcomes were superior to those of SSIT, which is consistent with earlier studies. BBIT2 also outperformed BBIT1, producing a decreased daily mean glucose level and longer time-in-target-range. Moreover, with a standard dose, the overall daily mean glucose levels reached the target range faster than with a reduced-dose for all degrees of renal function. The in-silico studies demonstrated several significant findings, including that the adjustment of total-daily-insulin dose is more effective than changes to basal-insulin dose alone. This research represents a first step toward the eventual development of an advanced model for evaluating various BBIT protocols.

Endoscopic Fluorescence Angiography with Indocyanine Green : A Preclinical Study in the Swine

OBJECTIVE: Microscopic indocyanine green (ICG) angiography is useful for identifying the completeness of aneurysm clipping and the preservation of parent arteries and small perforators. Neuroendoscopy is helpful for visualizing structures beyond the straight line of the microscopic view. We evaluated our prototype of endoscopic ICG fluorescence angiography in swine, which we developed in order to combine the merits of microscopic ICG angiography and endoscopy. METHODS: Our endoscopic ICG system consists of a camera, a light source, a display and software. This system can simultaneously display real-time visible and near infrared fluorescence imaging on the same monitor. A commercially available endoscope was used, which was 4 mm in diameter and had an angle of 30degrees. A male crossbred swine was used. RESULTS: Under general anesthesia, a small craniotomy was performed and the brain surface of the swine was exposed. ICG was injected via the ear vein with a bolus dose of 0.3 mg/kg. Visible and ICG fluorescence images of cortical vessels were simultaneously observed on the display monitor at high resolution. The real-time merging of the visible and fluorescent images corresponded well. CONCLUSION: Simultaneous visible color and ICG fluorescent imaging of the cortical vessels in the swine brain was satisfactory. Technical improvement and clinical implication are expected.

Fully Implantable Deep Brain Stimulation System with Wireless Power Transmission for Long-term Use in Rodent Models of Parkinson's Disease

OBJECTIVE: The purpose of this study to develop new deep-brain stimulation system for long-term use in animals, in order to develop a variety of neural prostheses. METHODS: Our system has two distinguished features, which are the fully implanted system having wearable wireless power transfer and ability to change the parameter of stimulus parameter. It is useful for obtaining a variety of data from a long-term experiment. RESULTS: To validate our system, we performed pre-clinical test in Parkinson's disease-rat models for 4 weeks. Through the in vivo test, we observed the possibility of not only long-term implantation and stability, but also free movement of animals. We confirmed that the electrical stimulation neither caused any side effect nor damaged the electrodes. CONCLUSION: We proved possibility of our system to conduct the long-term pre-clinical test in variety of parameter, which is available for development of neural prostheses.

Influence of Propofol and Fentanyl on Deep Brain Stimulation of the Subthalamic Nucleus

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinson's disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7+/-16.8 spikes/sec, n=78) and the right side MERs (35.5+/-17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinson's Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinson's disease improving the overall experience of the patients.

Simulation of Oral Glucose Tolerance Tests and the Corresponding Isoglycemic Intravenous Glucose Infusion Studies for Calculation of the Incretin Effect

The incretin effect, which is a unique stimulus of insulin secretion in response to oral ingestion of nutrients, is calculated by the difference in insulin secretory responses from an oral glucose tolerance test (OGTT) and a corresponding isoglycemic intravenous glucose infusion (IIGI) study. The OGTT model of this study, which is individualized by fitting the glucose profiles during an OGTT, was developed to predict the glucose profile during an IIGI study in the same subject. Also, the model predicts the insulin and incretin profiles during both studies. The incretin effect, estimated by simulation, was compared with that measured by physiologic studies from eight human subjects with normal glucose tolerance, and the result exhibited a good correlation (r > 0.8); the incretin effect from the simulation was 56.5% +/- 10.6% while the one from the measured data was 52.5% +/- 19.6%. In conclusion, the parameters of the OGTT model have been successfully estimated to predict the profiles of both OGTTs and IIGI studies. Therefore, with glucose data from the OGTT alone, this model could control and predict the physiologic responses, including insulin secretion during OGTTs and IIGI studies, which could eventually eliminate the need for complex and cumbersome IIGI studies in incretin research.

Impact of Chronic Simulated Snoring on Carotid Atherosclerosis in Rabbits

BACKGROUND AND PURPOSE: Chronic simulated snoring was induced in rabbits to determine the impact of snoring on the development of atherosclerosis. METHODS: The pressure wave of induced snoring at the carotid bifurcation of rabbits was acquired by gently pressing the airway. This wave was then simulated using custom-made mechanical devices. Twelve rabbits were used in this study, seven of which were assigned to the experimental group and the remaining five formed the control group. All of the rabbits were raised on a 1% high-cholesterol diet. Either working or sham devices were positioned at the ventral center of the neck in each rabbit. At the end of a 2-month observation period, all of the rabbits were sacrificed by perfusion fixation, the carotid arteries harvested, and the carotid atherosclerosis histology reviewed. RESULTS: All of the rabbits survived to the end of the experimental period. Blood sampling revealed the presence of hypercholesterolemia in both groups, with no significant difference between them. The presence and degree of atherosclerosis did not differ significantly between the groups. CONCLUSIONS: The findings of this study show the feasibility of making a chronic simulated snoring rabbit model. However, the causative role of snoring in carotid atherosclerosis was not detected in this animal study.

The Accuracy of the Swallowing Kinematic Analysis at Various Movement Velocities of the Hyoid and Epiglottis

OBJECTIVE: To evaluate the accuracy of the swallowing kinematic analysis. METHODS: To evaluate the accuracy at various velocities of movement, we developed an instrumental model of linear and rotational movement, representing the physiologic movement of the hyoid and epiglottis, respectively. A still image of 8 objects was also used for measuring the length of the objects as a basic screening, and 18 movie files of the instrumental model, taken from videofluoroscopy with different velocities. The images and movie files were digitized and analyzed by an experienced examiner, who was blinded to the study. RESULTS: The Pearson correlation coefficients between the measured and instrumental reference values were over 0.99 (p<0.001) for all of the analyses. Bland-Altman plots showed narrow ranges of the 95% confidence interval of agreement between the measured and reference values as follows: 0.14 to 0.94 mm for distances in a still image, -0.14 to 1.09 mm/s for linear velocities, and -1.02 to 3.81 degree/s for angular velocities. CONCLUSION: Our findings demonstrate that the distance and velocity measurements obtained by swallowing kinematic analysis are highly valid in a wide range of movement velocity.

Biomechanical Evaluation of the Capsular Stiffness and Clinical Features in Adhesive Capsulitis of Shoulders

OBJECTIVE: To evaluate the capsular stiffness of the glenohumeral joint by measuring the slope of pressure-volume curves generated during intra-articular hydraulic distension (IHD) and analyze its correlation with clinical variables and outcomes in terms of limitation of range of motion (LOM) and severity of pain. METHOD: IHD with real-time intra-articular pressure monitoring was performed for 53 patients with adhesive capsulitis and the capsular stiffness was measured from pressure-volume curves by calculating the slope of elastic deformation region. LOM, measured by LOM score and sum of ROMs (range of motion), and degree of pain, measured by visual analog scale (VAS), were evaluated before and after IHD: three days (3D) and one month (1M) after IHD. RESULTS: In patients with stiffer capsules, LOM and pain were severe before IHD (Pearson's correlation coefficient (r)= 0.291, -0.348, 0.381 and p=0.065, 0.026, 0.014 for LOM score, sum of ROMs and VAS, respectively. By this order, henceforth). On 3D follow up, the correlation between the stiffness and LOM or pain was maintained (r=0.291, -0.348, 0.381 and p=0.065, 0.026, 0.014). The improvement of LOM score on 3D follow up was less as the capsules were stiffer (r=-0.368, p=0.023). On 1M follow up, LOM remained severer in stiffer capsules whereas pain did not (r=0.372, -0.402, 0.183 and p=0.039, 0.025, 0.342). CONCLUSION: The stiffness of the glenohumeral joint capsule, measured from the slope of pressure-volume curves during IHD, showed significant correlation with the severity of LOM and pain in patients with adhesive capsulitis of shoulder.

3-Dimensional Analyses of Eye Motion in Oculopalatal Tremor

BACKGROUND: Oculopalatal tremor (OPT) is a delayed complication of damage to the dentato-rubro-olivary pathway (Guillain-Mollaret triangle) and subsequent hypertrophic olivary degeneration. Mixed torsional-vertical pendular nystagmus in OPT has been considered to signify unilateral brainstem damage while symmetrical vertical nystagmus has been regarded to indicate bilateral disease. However, 3-dimensional oculographic analysis of OPT has been sparse. METHODS: In 8 patients with OPT; binocular 3-dimensional analyses of ocular oscillations were performed by using a magnetic search coil technique. Lateralization of the lesions was determined by the imaged olivary hypertrophy in the MRI. RESULTS: One patient had conjugate vertical pendular nystagmus and four showed mixed torsional-vertical pendular nystagmus. Two patients showed mixed horizontal-torsional-vertical nystagmus. One patient had predominantly horizontal pendular nystagmus. MRI demonstrated increased signal or hypertrophy of the inferior olivary nucleus, unilateral in six and bilateral in two. Unilateral olivary changes were associated with mixed torsional-vertical nystagmus in three patients, mixed horizontal-torsional-vertical nystagmus in another two patients, and predominantly horizontal pendular nystagmus in the remaining one patient. Bilateral olivary changes were visible in one patient with conjugate vertical pendular nystagmus and in the other patient with mixed torsional-vertical nystagmus. Palatal tremor appeared to be symmetrical in all patients. CONCLUSIONS: Three-dimensional analyses of OPT indicate that conjugate vertical and mixed torsional-vertical pendular nystagmus do not correspond to the laterality of signal changes in the inferior olivary nucleus. Ocular oscillations often have all the vertical, horizontal and torsional components.

A Phantom Study for Revealing Factors Related to Image Distortion of Three-Dimensional Reconstruction Rotational Angiogram

PURPOSE: To determine, by means of a phantom study, the distortion-related factors and appropriate iodine concentration for three-dimensional reconstruction rotational angiography. MATERIALS AND METHODS: Four phantoms were created: crossed metal rods, one metal rod, one contrast rod, and a contrast rod under water. Iodine concentrations were 300, 250, 200, and 150 Img/ml, respectively. For each phantom, rotational angiography was performed in the rotational, right-angled (90 degree to rotational), intermedial (45 degree), close to rotational (20 degree), and close to right-angled (70 degree) planes. Two-dimensional projection images were transferred to a workstation at which 3D images were produced using the volume rendering technique. Image quality in each plane was evaluated in terms of opacity, homogeneity, and margin sharpness, which were graded as low, intermediate or high by two neuroradiologists who used images obtained in the right-angled plane as the standard reference. The same assessors evaluated in terms of the same parameters, cross-sectional images obtained at the central, intermedial, and peripheral portions of one metal rod positioned in the right-angled, close to right-angled, and intermedial planes, and in order to compare the values at different sites, one neuroradiologist measured the horizontal and vertical diameters of each cut image. RESULTS: Three-dimensional images of all four phantoms were high quality in the close to right-angled and intermedial plane, but in the rotational and close to rotational plane were degraded. In particular, metal rod images obtained in the rotational plane were poor for all three items. In these two planes, image quality was better for the contrast rod than the metal rod, and at 200 and 250 Img/ml concentrations than at 300 and 150 Img/ml concentrations. There was no significant difference in image quality, nor in measured values of the diameter between cut images. CONCLUSION: A three-dimensional image was more distorted when a linear object was placed at a lesser angle to the rotational plane and when inherent X-ray attenuation was greater, a finding which must be closely related to the beam-hardening artifact. Distortion was least at 200-250 Img/ml of iodine concentration, the concentration thought to be most appropriate for in-vitro 3D angiography.

Ideal Carrier Waveform for Functional Electrical Stimulation in Upper Extremity

OBJECTIVE: This study was purposed to find the ideal carrier waveform in burst wave in Functional Electrical Stimulation (FES) for upper limbs after selection of proper site of electrode. METHOD: The 10 healthy men's non-dominant hands were studied. In 5 muscles (adductor pollicis, flexor digitorum sublimis, flexor pollicis longus, extensor digitorum communis and extensor pollicis brevis), the site where electric stimulus induced the best of purposed response was selected. A burst wave contains three carrier waveforms : sine, triphasic & rectangular. The amount of mean current was measured during key grip and open motion. Discomfort of subject was scored by three degree and compared among three waveforms. RESULTS: The amount of mean current in key grip and open motion is lowest at triphasic wave (31.3 mA, 50.5 mA) and highest at rectangular wave (79.4 mA, 82.1 mA). For the discomfort, rectangular waveform provoke the greatest discomfort in key grip and open motion. There is no statistical difference between sine and triphasic waveform. CONCLUSION: In FES of upper limbs, triangular wave can be an useful carrier waveform which require less amount of current for performing the same motion and less discomfort than rectangular or sine waveform.

Development of the Hardware and Software for the Selective Dorsal Rhizotomy Using Hoffmann Reflex: A Study on the EMG Patterns Generated by Stimulation of the Spinal Nerve Roots

This experimental study was designed to develop an electromyography(EMG) machine and a program to be used during the selective dorsal rhizotomy, and to investigate the patterns of EMG waves generated by stimulation of the normal spinal nerve roots in cat. The developed machine, consisting of nerve stimulator, EMG amplifier, analogue-digital converter and computer program, functioned well during experiment without any mechanical or electrical problems. We were able to record pure H-wave(Hoffmann wave) in EMG by stimulating posterior root in most cases, although components of motor and directly conducted waves were observed only in few cases. The peak latency of H-wave, which was about half of that of the motor wave by the mean value, was consistent as a whole. H2/H1 ratio (the ratio of the second and the first H-wave), peak amplitude and the pattern of changes of the peak amplitudes with continuous sitmulation, however, varied greatly from case to case. In conclusion, the results of this experiment suggest that EMG wave patterns, generated by the stimulation of the posterior nerve roots, may not be appropriate for the determination of the nerve roots to be cut during the selective dorsal rhizotomy.

Gerontechnology

No abstract available.