Intraoperative trans-laryngeal ultrasound (LUSG) of the vocal cord is a novel method of confirming the recurrent laryngeal nerve (RLN) integrity during thyroid and neck surgery.

BACKGROUND: Eliciting a normal electromyography signal has been the usual method to confirm the functional integrity of the recurrent laryngeal nerve during intraoperative nerve monitoring. Given that oscillations of the vocal cord can be detected with trans-laryngeal ultrasound when the ipsilateral recurrent laryngeal nerve is stimulated with the endotracheal tube in situ, we aimed to compare the accuracy and cost of this novel method with the conventional electromyography method. METHODS: Consecutive patients who underwent elective thyroid, parathyroid or neck dissection procedures were included. The NIM-Neuro 3.0 system was used. Endotracheal tube-based surface electrodes were utilized for electromyography signal recording. Standard anesthetic technique was adopted. Recurrent laryngeal nerve integrity was verified by both detection methods (laryngeal ultrasound and electromyography) independently. Vocal cord function was validated by flexible direct laryngoscopy postoperatively. For each method, concurrence with flexible direct laryngoscopy was defined as "true-positive" or "true-negative," based on the presence or absence of vocal cord paresis. Accuracy was calculated as the sum of all true positives and negatives divided by the total of nerves-at-risk. The cost of each method was calculated. RESULTS: One hundred and four patients were eligible. Total number of nerves-at-risk was 155. Based on flexible direct laryngoscopy findings, the test sensitivity, specificity, positive predictive value, and negative predictive value of intraoperative laryngeal ultrasound were 75.0%, 99.3%, 85.7%, and 98.6%, respectively, while those of electromyography were 87.5%, 98.0%, 70.0%, and 99.3%, respectively. The prognostic accuracy in laryngeal ultrasound versus electromyography was comparable (98.1% vs 97.4%). The cost of the laryngeal ultrasound per operation was less than electromyography ($82 vs $454). CONCLUSION: Laryngeal ultrasound has a similar detection accuracy to electromyography during intraoperative nerve monitoring. Apart from being a cheaper alternative, laryngeal ultrasound may be useful when there is unexplained loss of electromyography signals during surgery and may play a role in the intraoperative nerve monitoring troubleshooting algorithm.

A Low-Cost End-to-End sEMG-Based Gait Sub-Phase Recognition System.

As surface electromyogram (sEMG) signals have the ability to detect human movement intention, they are commonly used to be control inputs. However, gait sub-phase classification typically requires monotonous manual labeling process, and commercial sEMG acquisition devices are quite bulky and expensive, thus current sEMG-based gait sub-phase recognition systems are complex and have poor portability. This study presents a low-cost but effective end-to-end sEMG-based gait sub-phase recognition system, which contains a wireless multi-channel signal acquisition device simultaneously collecting sEMG of thigh muscles and plantar pressure signals, and a novel neural network-based sEMG signal classifier combining long-short term memory (LSTM) with multilayer perceptron (MLP). We evaluated the system with subjects walking under five conditions: flat terrain at 5 km/h, flat terrain at 3 km/h, 20 kg backpack at 5 km/h, 20 kg shoulder bag at 5 km/h and 15° slope at 5 km/h. Experimental results show that the proposed method achieved average classification accuracies of 94.10%, 87.25%, 90.71%, 94.02%, and 87.87%, respectively, which were significantly higher than existing recognition methods. Additionally, the proposed system had a good real-time performance with low average inference time in the range of 3.25 ~ 3.31 ms.

Develop a home-used EMG sensor system to identify pathological gait with less data via frequency analysis.

In order to develop a low-cost wearable electromyography (EMG) sensor system that can be used at home, compacting the data size is studied first to extract potential features via frequency analysis. A low-cost wearable home-use EMG sensor is then developed. Results show the frequency band at 40-60 Hz of tibialis anterior offers significant differences to identify walking problems (p-value < 0.05), which can be used as a detection standard with a smaller data size. More significantly, data sizes are dramatically reduced by 95.06% compared to the original data size. This finding suggests a potential examining method for identifying pathological gait with the compacted data in satisfactory processing time that can be used at home.

Inferring Static Hand Poses from a Low-Cost Non-Intrusive sEMG Sensor.

Every year, a significant number of people lose a body part in an accident, through sickness or in high-risk manual jobs. Several studies and research works have tried to reduce the constraints and risks in their lives through the use of technology. This work proposes a learning-based approach that performs gesture recognition using a surface electromyography-based device, the Myo Armband released by Thalmic Labs, which is a commercial device and has eight non-intrusive low-cost sensors. With 35 able-bodied subjects, and using the Myo Armband device, which is able to record data at about 200 MHz, we collected a dataset that includes six dissimilar hand gestures. We used a gated recurrent unit network to train a system that, as input, takes raw signals extracted from the surface electromyography sensors. The proposed approach obtained a 99.90% training accuracy and 99.75% validation accuracy. We also evaluated the proposed system on a test set (new subjects) obtaining an accuracy of 77.85%. In addition, we showed the test prediction results for each gesture separately and analyzed which gestures for the Myo armband with our suggested network can be difficult to distinguish accurately. Moreover, we studied for first time the gated recurrent unit network capability in gesture recognition approaches. Finally, we integrated our method in a system that is able to classify live hand gestures.

Low-cost electromyography - Validation against a commercial system using both manual and automated activation timing thresholds.

Widespread use of electromyography (EMG) as an assessment and biofeedback method may be limited by costly commercial systems. Low-cost devices are available; however their validity is unknown. This study determined the concurrent validity of a low-cost EMG on a microchip compared with a commercially available system during isometric and dynamic muscle contractions. Inter-tester, intra-session reliability of manual data extraction during data processing compared to a simple, automatic thresholding method using the Teager-Kaiser energy operator (TKEO) was also evaluated. 10 healthy women (age 28.1 ±â€¯6.8 yrs, height 162.1 ±â€¯6.8 cm, mass 60.3 ±â€¯10.2 kg) were assessed simultaneously with a commercially available EMG system (Telemyo DTS) and a custom low-cost EMG system (Myoware Muscle Sensor) during voluntary isometric contractions, knee extension, squatting, stepping and jumping. Two surface electrode sets (connected to the low-cost and the commercial system) were placed end to end along the same Vastus Lateralis muscle fibre line. Peak and mean contraction intensity, and contraction duration were analysed. Overall the relative agreement between systems was excellent for peak muscle activation (ICC 0.77-0.96) and modest to excellent for mean muscle activation (ICC 0.68-0.95) and contraction duration (ICC 0.65-0.99). Inter-tester, intra-session reliability was excellent for peak contraction intensity (ICC > 0.99) and modest to excellent for mean contraction intensity, with the TKEO method primarily recording stronger agreement than the manual method. Poor to excellent inter-tester reliability occurred for contraction duration. Our findings indicate that a low-cost EMG system is comparable to a commercial system for assessing muscle activation, and that using the TKEO improved the reliability of timing related variables.

Economic analysis of routine neuromonitoring of recurrent laryngeal nerve in total thyroidectomy / Análisis económico de la monitorización neurológica rutinaria del nervio laríngeo recurrente en la tiroidectomía total

Introduction: Thyroidectomy is a common surgery. Routine searching of the recurrent laryngeal nerve is the most important strategy to avoid palsy. Neuromonitoring has been recommended to decrease recurrent laryngeal nerve palsy. Objective: To assess if neuromonitoring of recurrent laryngeal nerve during thyroidectomy is cost-effective in a developing country. Materials and methods: We designed a decision analysis to assess the cost-effectiveness of recurrent laryngeal nerve neuromonitoring. For probabilities, we used data from a meta-analysis. Utility was measured using preference values. We considered direct costs. We conducted a deterministic and a probabilistic analysis. Results: We did not find differences in utility between arms. The frequency of recurrent laryngeal nerve injury was 1% in the neuromonitor group and 1.6% for the standard group. Thyroidectomy without monitoring was the less expensive alternative. The incremental cost-effectiveness ratio was COP$ 9,112,065. Conclusion: Routine neuromonitoring in total thyroidectomy with low risk of recurrent laryngeal nerve injury is neither cost-useful nor cost-effective in the Colombian health system.

Introducción. La tiroidectomía es una cirugía común. La búsqueda rutinaria del nervio laríngeo inferior es la estrategia más importante para evitar la parálisis. Objetivo. Evaluar el costo-efectividad en un país en desarrollo de la monitorización neurológica del nervio laríngeo inferior durante la tiroidectomía. Materiales y métodos. Se diseñó un análisis de decisiones para evaluar el costo-efectividad de la monitorización neurológica del nervio laríngeo inferior. Para las probabilidades se usaron datos de un meta-análisis. La utilidad se determinó con medidas de preferencia. Se incluyeron los costos directos. Se hizo un análisis determinístico y probabilístico. Resultados. No se encontraron diferencias en la utilidad entre las estrategias. La frecuencia de la lesión de este nervio fue de 1 % en el grupo bajo monitorización neurológica y de 1,6 % en el grupo de control. La tiroidectomía sin monitorización fue la alternativa menos costosa. La razón de costo-efectividad incremental fue de COP$ 9.112.065 Conclusión. La monitorización neurológica rutinaria en la tiroidectomía total con bajo riesgo de lesión del nervio laríngeo inferior, no es útil con relación a su costo ni costo-efectiva en el sistema de salud colombiano.

Economic analysis of routine neuromonitoring of recurrent laryngeal nerve in total thyroidectomy.

INTRODUCTION: Thyroidectomy is a common surgery. Routine searching of the recurrent laryngeal nerve is the most important strategy to avoid palsy. Neuromonitoring has been recommended to decrease recurrent laryngeal nerve palsy. OBJECTIVE: To assess if neuromonitoring of recurrent laryngeal nerve during thyroidectomy is cost-effective in a developing country. MATERIALS AND METHODS: We designed a decision analysis to assess the cost-effectiveness of recurrent laryngeal nerve neuromonitoring. For probabilities, we used data from a meta-analysis. Utility was measured using preference values. We considered direct costs. We conducted a deterministic and a probabilistic analysis. RESULTS: We did not find differences in utility between arms. The frequency of recurrent laryngeal nerve injury was 1% in the neuromonitor group and 1.6% for the standard group. Thyroidectomy without monitoring was the less expensive alternative. The incremental cost-effectiveness ratio was COP$ 9,112,065. CONCLUSION: Routine neuromonitoring in total thyroidectomy with low risk of recurrent laryngeal nerve injury is neither cost-useful nor cost-effective in the Colombian health system.

Design, development and testing of a low-cost sEMG system and its use in recording muscle activity in human gait.

Surface electromyography (sEMG) is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics), we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet-based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius). The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics.

Tests and expenditures in the initial evaluation of peripheral neuropathy.

BACKGROUND: Peripheral neuropathy is a common disorder in which an extensive evaluation is often unrevealing. METHODS: We sought to define diagnostic practice patterns as an early step in identifying opportunities to improve efficiency of care. The 1996-2007 Health and Retirement Study Medicare claims-linked database was used to identify individuals with an incident diagnosis of peripheral neuropathy using International Classification of Diseases, Ninth Revision, codes and required no previous neuropathy diagnosis during the preceding 30 months. Focusing on 15 relevant tests, we examined the number and patterns of tests and specific test utilization 6 months before and after the incident neuropathy diagnosis. Medicare expenditures were assessed during the baseline, diagnostic, and follow-up periods. RESULTS: Of the 12, 673 patients, 1031 (8.1%) received a new International Classification of Diseases, Ninth Revision, diagnosis of neuropathy and met the study inclusion criteria. Of the 15 tests considered, a median of 4 (interquartile range, 2-5) tests were performed, with more than 400 patterns of testing. Magnetic resonance imaging of the brain or spine was ordered in 23.2% of patients, whereas a glucose tolerance test was rarely obtained (1.0%). Mean Medicare expenditures were significantly higher in the diagnostic period than in the baseline period ($14,362 vs $8067, P < .001). CONCLUSIONS: Patients diagnosed as having peripheral neuropathy typically undergo many tests, but testing patterns are highly variable. Almost one-quarter of patients receiving neuropathy diagnoses undergo high-cost, low-yield magnetic resonance imaging, whereas few receive low-cost, high-yield glucose tolerance tests. Expenditures increase substantially in the diagnostic period. More research is needed to define effective and efficient strategies for the diagnostic evaluation of peripheral neuropathy.

A comparison of a commercially made pedicle stimulating probe with a custom-made device: does the commercial device detect pedicle wall breaches more reliably?

STUDY DESIGN: Clinical trial. OBJECTIVE: To compare the efficacy of a commercially available stimulating pedicle probe with a custom-made probe for the detection of pedicle wall breaches during screw insertion for the surgical correction of scoliosis. SUMMARY OF BACKGROUND DATA: Stimulus triggered electromyography has been used to detect small breaches in the walls of the spinal pedicles during pedicle screw insertion. We routinely use a reusable, custom-made clip that can be attached to the screw, pedicle probe, or other instruments. Commercial systems are available in which the instrument is electrically instrumented to deliver current. METHODS: In five patients (173 pairs of tests), we compared the threshold current required to trigger an electromyographic response during testing of the pedicle. Each track or screw was tested with both the custom-made and the commercial probe and the threshold current recorded. RESULTS: Both systems were able to detect pedicle wall breaches using triggered electromyography. The threshold current recorded was not significantly different between the two systems (P > 0.1, paired t test) nor was the difference (0.16 mA) clinically significant. CONCLUSION: No difference was found between the thresholds detected with either system. There is however, a significant difference in the costs of the two probe systems.

[Neuromonitoring in anaesthesia]. / Narkosetiefenmessung in der Anästhesie - Neue Möglichkeiten und Ziele der Narkoseüberwachung.

Modern computer-based methods to monitor anesthesia are widespread. They are used in order to avoid awareness, to reduce consumption of anesthetics, to optimize recovery times and to detect prolonged times of deep anesthesia and associated immunsuppression, mortality and morbidity. This review illustrates the evidence with which these goals were achieved until now. Finally, a recommendation for each indication is given. The useage of EEG-monitoring may help to avoid awareness and allows a reduced of consumption of anesthetics. The question if a cumulated time of deep anesthesia is associated with elevated mortality might be of a certain importance in the future.

Measuring low back injury risk factors in challenging work environments: an evaluation of cost and feasibility.

BACKGROUND: Measuring low back injury risk factors in field research presents challenges not encountered in laboratory environments. METHODS: We compared the practical application of five measurement methods (observations, interviews, electromyography (EMG), inclinometry, and vibration monitoring) for 223 worker days in 50 heavy-industry worksites in western Canada. Data collection successes, challenges, costs, and data detail were documented for each method. RESULTS: Measurement success rates varied from 42.2% (seatpan accelerometer) to 99.6% (post-shift interview) of worker days assessed. Missed days for direct monitoring equipment were primarily due to explosive environments, workplace conditions likely to damage the equipment, and malfunctions. Costs per successful measurement day were lowest for interviews (approximately 23 dollars), about 10-fold higher for observations and inclinometry, and more than 20-fold higher for EMG and vibration monitoring. CONCLUSIONS: Costs and successful field performance need to be weighed against the added data detail gained from monitoring equipment when making choices about exposure assessment techniques for epidemiological studies.

Functional benefits of dysphagia therapy using adjunctive sEMG biofeedback.

This article describes a retrospective analysis of functional outcome, time in therapy, and cost per unit of functional change in patients who received therapy for pharyngeal dysphagia. Twenty-five patients presenting dysphagia following stroke and 20 patients with dysphagia following treatment for head/neck cancer completed a systematic therapy program supplemented with surface electromyographic (sEMG) biofeedback. Eighty-seven percent (39/45) of all patients increased their functional oral intake of food/liquid including 92% of stroke patients and 80% of head/neck cancer patients. Patients with dysphagia following stroke demonstrated greater improvement than those in the head/neck cancer group. Patients in the stroke group completed more therapy sessions thus increasing the total cost of therapy, but they made more functional progress resulting in lower costs per unit of functional change than patients in the head/neck cancer group. Limitations of this study are described in reference to implications for future clinical research on the efficacy of this therapy approach.

Auditory evoked response test strategies to reduce cost and increase efficiency: the postauricular muscle response revisited.

We describe a number of techniques in auditory evoked response (AER) testing for hearing loss which should decrease its cost and increase its efficiency, making its use in infant hearing screening more viable. We demonstrate the use of bit-stream averaging of the electrical signals from the head as a cheap alternative to analogue averaging and show that the average waveforms obtained are similar with both techniques. We demonstrate how the postauricular muscle response (PAMR) can be potentiated by lateral rotation of the eyes and argue that uncontrolled eye movements in previous studies have led to an unfounded belief that the PAMR is not stable. When eye rotation is used to potentiate the PAMR, the response becomes very stable and so large in most subjects that it is clearly visible in the raw traces. We also demonstrate that when the PAMR is potentiated by eye rotation, stable PAMR waveforms can be reliably obtained with tone bursts with frequencies up to and above 8 kHz and with sound levels within 30 dB of the subjective detection threshold. As a result the PAMR can be used to rapidly determine an objective audiogram in most subjects within minutes. Finally, we demonstrate a correlation technique for detecting the PAMR without waveform averaging and the need for an expensive computer. We are sure that a combination of these techniques can be used to increase the efficiency of AER screening for infant deafness and lower its cost dramatically.