Electromyogram Device Research Articles

Wearable EMG-Based Gesture Recognition Systems During Activities of Daily Living: An Exploratory Study.

Recent advancements in wearable technologies have increased the potential for practical gesture recognition systems using electromyogram (EMG) signals. However, despite the high classification accuracies reported in many studies (> 90%), there is a gap between academic results and industrial success. This is in part because state-of-the-art EMG-based gesture recognition systems are commonly evaluated in highly-controlled laboratory environments, where users are assumed to be resting and performing one of a closed set of target gestures. In real world conditions, however, a variety of non-target gestures are performed during activities of daily living (ADLs), resulting in many false positive activations. In this study, the effect of ADLs on the performance of EMG-based gesture recognition using a wearable EMG device was investigated. EMG data for 14 hand and finger gestures, as well as continuous activity during uncontrolled ADLs (>10 hours in total) were collected and analyzed. Results showed that (1) the cluster separability of 14 different gestures during ADLs was 171 times worse than during rest; (2) the probability distributions of EMG features extracted from different ADLs were significantly different (p <; 0.05). (3) of the 14 target gestures, a right angle gesture (extension of the thumb and index finger) was least often inadvertently activated during ADLs. These results suggest that ADLs and other non-trained gestures must be taken into consideration when designing EMG-based gesture recognition systems.

F34. Effects of impaired glucose regulation on large and small fibers in peripheral nerve

Introduction We use nerve conduct study (NCS) to evaluate the function of large fibers, skin sympathetic response (SSR) and contact heat evoked potential (CHEP) to evaluate the function of small fibers in patients with impaired glucose regulation (IGR), The occurrence of peripheral neuropathy and damage characteristics are analyzed. Methods According to the classification criteria of glucose metabolism proposed by WHO 2006,we selected 120 patients with IGR, and 60 normal subjects as the control group.All subjects received median, ulnar, tibial, peroneal, sural nerve conduction study (NCS), skin sympathetic response (SSR) and contact heat evoked potential (CHEP) were performed using the Keypoint.net (Medoc Ltd) electromyogram device. Results 1.The abnormal rate of NCS in IGR patients were 22.5%; the abnormal rate of SSR was 39.2%, All patients with NCS abnormalities were associated with abnormal SSR 2.Compared with the control group, the tibial, sural nerve sensory nerve action potential (SNAP) amplitude decreased in IGR group, (2.01 ± 1.5) vs (1.51 ± 1.3) uV, t = −3.01, P = 0.003; (10.5 ± 2.0) vs (6.5 ± 1.9) uV, t = −2.82, P = 0.005 respectively; SSR amplitude reduced in upper and lower limbs (2124 ± 1346) vs (1463 ± 1140) uV, t = −3.21, P = 0.002; (892 ± 387) vs (531 ± 501) uV, t = −6.18, P = 0.00 respectively; CHEP amplitude decreased in dorsum hand and peroneal area stimuli respectively (63.0 ± 10.0) vs (52.4 ± 12.6) uV, t = 3.09, P = 0.003; (44.7 ± 12.5) vs (29.3 ± 12.1) uV, t = 5.84, P = 0.00.3.Compared with the control group, CHEP amplitude decreased in peroneal area stimuli in SSRN group [(44.7 ± 12.5) vs (33.1 ± 18.9) uV, t = 2.94, P = 0.00]; In NCSN group, CHEP amplitude decreased in dorsum hand and peroneal area stimuli compared with the control group respectively (44.7 ± 12.5) vs (28.4 ± 17.4) uV, t = 1.88, P = 0.00; (63.0 ± 10.8) vs (52.4 ± 15.3) uV, t = 2.22, P = 0.00. Conclusion The incidence of peripheral neuropathy (PN) in patients with IGR was 39.2%, Neuropathy showed large and small fiber damage, mainly manifested as small fiber and lower limb sensory nerve fiber damage,CHEP can find small fiber damage earlier than SSR and NCS in patients with IGR.

S57. The divergence phenomenon of CMAP/SNAP in early stage of amyotrophic lateral sclerosis

To evaluate the relationship of sensory fibers and functional status of motor fibers in patients with amyotrophic lateral sclerosis(ALS) through electrophysiological approach, and analyse the results. We retrospectively reviewed 64 case with early stage of upper limb-onset ALS admitted in our hospital from January 2010 to December 2015. Patients with ALS were graded as normal compound muscle action potential (CMAP) (23 cases) and abnormal CMAP group (41 cases) according to the CMAP of median nerve 39 healthy volunteers were included as control. Median and ulnar nerves electrophysiological study were performed using the Keypoint.net (Medoc Ltd) electromyogram device. The sensory nerve action potential (SNAP) amplitudes of Median and ulnar nerves were raised (28.80 ± 15.54) μV vs (21.06 ± 7.41) μV, t = 2.91, P < 0.01, (12.44 ± 4.64) μV vs (10.46 ± 2.77) μV, t = 2.41, P = 0.01 in ALS group, compared with control group. But the sensory conduction velocities (SCVs) had no difference. SNAP amplitudes of median nerve were raised (33.13 ± 13.33) μV vs (21.06 ± 7.41) μV, F = 6.39, P < 0.01 in the normal CMAP group, compared with the control group, but the SNAP amplitudes of ulnar nerve had no difference: Compared with the control group, the SNAP amplitudes of median nerve had no difference, but the SNAP amplitudes of ulnar nerve were raised (12.92 ± 5.01) μV vs (10.46 ± 2.78) μV, F = 3.71, P < 0.05 in abnormal CMAP group. ALS patients with onset of upper limb in the early stage may have increased SNAP in median and ulnar nerve,and show CMAP/SNAP separated phenomenon.

Electrophysiological evaluation of peripheral nerve in patients with impaired glucose tolerance

This study retrospectively reviewed 75 patients with impaired glucose tolerance(IGT)admitted in our hospital from March 2015 to October 2015. All patients underwent Toronto clinical scoring system(TCSS) evaluation. Patients with IGT were further divided into normal score group(TCSS-N, n=50)and abnormal score group(TCSS-A, n=25)according to their scoring results, and 30 healthy volunteers were served as control group. All patients and controls underwent motor and sensory nerve conduction studies, as well as sympathetic skin response(SSR)test using the Keypoint.Net(Medoc Ltd)electromyogram device. The results showed that the SSR amplitude of lower limbs was reduced [(0.61±0.44 vs 1.00±0.33)mv, P<0.05] and latency of lower limbs was extended [(1 880±282 vs 1 642±256)ms, P<0.05]in IGT group compared with control group. But median, ulnar, tibial, and peroneal nerve sensory and motor conduction revealed no difference between two groups. In TCSS-A group, the SSR amplitude of lower limbs was reduced [(0.47±0.39)mv, P<0.05], latency of lower limbs was extended [(2 062±291)ms, P<0.05]and the sensory nerve action potential(SNAP)amplitude of the tibial nerve was significantly lower compared with control group [(1.83±0.37 vs 2.07±0.30)μv, P<0.05]. Compared to TCSS-N group, latency of lower limbs was extended [(2 062±291 vs 1 808±246)ms, P<0.05]in TCSS-A group. The SSR amplitude of lower limbs were reduced[(0.66±0.44)mv, P<0.05]and latency were prolonged(P<0.05)in TCSS-N group compared with control group. Pearson correlation analysis showed that the SSR amplitude and latency of the lower limbs were correlated with the postprandial blood glucose, blood glucose fluctuation, body weight, as well as body mass index. These results suggest that there exists peripheral nerve damage in the patients with IGT, mainly involving the small fiber nerve of the lower limbs. Large fibers may also be mildly affected as the disease progresses. (Chin J Endocrinol Metab, 2017, 33: 574-577) Key words: Peripheral nerve; Impaired glucose tolerance; Nerve conduction; Sympathetic skin response

Wearable electromyogram device associated with disability outcomes in adults with multiple sclerosis (P1.377)

Wearable electromyogram device associated with disability outcomes in adults with multiple sclerosis (P1.377)

Design and Implementation of a Multi Sensor Based Brain Computer Interface for a Robotic Wheelchair

In this study, design and implementation of a multi sensor based brain computer interface for disabled and/or elderly people is proposed. Developed system consists of a wheelchair, a high-power motor controller card, a Kinect camera, electromyogram (EMG) and electroencephalogram (EEG) sensors and a computer. The Kinect sensor is installed on the system to provide safe navigation for the system. Depth frames, captured by the Kinect’s infra-red (IR) camera, are processed with a custom image processing algorithm in order to detect obstacles around the wheelchair. A Consumer grade EMG device (Thalmic Labs) was used to obtain eight channels of EMG data. Four different hand movements: Fist, release, waving hand left and right are used for EMG based control of the robotic wheelchair. EMG data is first classified using artificial neural network (ANN), support vector machines and random forest schemes. The class is then decided by a rule-based scheme constructed on the individual outputs of the three classifiers. EEG based control is adopted as an alternative controller for the developed robotic wheelchair. A wireless 14-channels EEG sensor (Emotiv Epoch) is used to acquire real time EEG data. Three different cognitive tasks: Relaxing, math problem solving, text reading are defined for the EEG based control of the system. Subjects were asked to accomplish the relative cognitive task in order to control the wheelchair. During experiments, all subjects were able to control the robotic wheelchair by hand movements and track a pre-determined route with a reasonable accuracy. The results for the EEG based control of the robotic wheelchair are promising though vary depending on user experience.

Biomechanical Analysis of Squat Jump and Countermovement Jump From Varying Starting Positions

The purpose of this study was to investigate the effect of 2 strategies, defined by foot placement during the initiation of the take-off on performance in vertical jumps. The additional area of interest in this experiment was whether technique of the take-off phase might be an exploratory factor that has different electromyogram (EMG) muscle activity during squat jump (SJ) and countermovement jump (CMJ) performed starting from the standard position, with parallel foot placement, and from the experimental one, with straddle foot placement. Six well-experienced male 100-400 m sprinters, who were members of the Polish youth and senior national team (mean values: age 21.6 years, best performance: 100 m in 10.54 seconds and 400 m in 45.54 seconds), performed vertical SJ and vertical CMJ from 2 initial positions with different foot placement. To collect all selected kinematic and kinetic data, the video recording system BTS Vixta was used in conjunction with force platforms (Kistler model 9286B). The latest system for 3D motion analysis, BTS SMART, based on the passive IR reflective markers was also applied. Electromyograms of 6 lower limb muscles were collected using a Noraxon EMG device. The CMJ was on average 7 cm higher than the SJ (CMJ, 85 cm and SJ, 78 cm), which amounts to 8.97%. This was not because of the increase of center of gravity (COG) velocity at take-off because velocities of center of gravity (COG) projection were almost equal (SJ, 2.93 m·scompared with CMJ, 2.99 m·s). No significant differences of both magnitude and rate of development of the muscle torques and powers between jumps were found, but when we analyzed the problem with division into single legs (right and left) and with division into different jumps (SJ and CMJ), the differences were evident. The profiles of EMG activity of selected muscles showed some differences between SJ and CMJ. The vertical SJ and CMJ performance measurement may be of value to coaches and conditioning specialists who wish to develop or assess the power ability of lower extremities either unilaterally (single leg) or bilaterally (sum of both legs).

Difference of Lumbar ＆ Lower Extremity Muscle Activity when Patients are Transferred by Physical Therapists

Objective: The purpose of this study is to compare the muscle activities of lumbar and lower extremity muscles between left and right sides using EMG(Electromyogram) when patients are transferred by physical therapists. Background: Asymmetrical lift was recognized as a major cause of musculoskeletal disorder. Several studies show that physical therapists’ transferring patients needs caution as it could cause a lumbar pain to patients but there is not sufficient data to support. Method: Forty healthy rehabilitation hospital physical therapists joined for this study. The subjects were transferred from wheelchair to treatment mat(from left to right) by connecting the EMG device to the patients’ body both on erector spine and rectus fermoris. At the moment when subjects were being transferred, the EMG device collected data from both erector spine and rectus femoris and it was normalized as %MVC. Then the EMG data was statistically analyzed using paired t-tests. Results: The EMG data show that the left erector spinae and rectus femoris are more activated than right erector spinae and rectus femoris in all position(p＜.05) in a significant degree. Conclusion: The result implies that physical therapists’ asymmetrical lifting when patients are transferred by them has a potential cause of musculoskeletal disorder of patients. Further studies will be conducted to find out a same tendency in other muscles of a body and to see if there are other factors to affect to patients during asymmetrical lifting. Application: These results can be used to provide baseline information for more understanding to asymmetrical lift loading.