Improved prosthetic hand control with concurrent use of myoelectric and inertial measurements

Abstract Background Myoelectric pattern recognition systems can decode movement intention to drive upper-limb prostheses. Despite recent advances in academic research, the commercial adoption of such systems remains low. This limitation is mainly due to the lack of classification robustness and a simultaneous requirement for a large number of electromyogram (EMG) electrodes. We propose to address these two issues by using a multi-modal approach which combines surface electromyography (sEMG) with inertial measurements (IMs) and an appropriate training data collection paradigm. We demonstrate that this can significantly improve classification performance as compared to conventional techniques exclusively based on sEMG signals. Methods We collected and analyzed a large dataset comprising recordings with 20 able-bodied and two amputee participants executing 40 movements. Additionally, we conducted a novel real-time prosthetic hand control experiment with 11 able-bodied subjects and an amputee by using a state-of-the-art commercial prosthetic hand. A systematic performance comparison was carried out to investigate the potential benefit of incorporating IMs in prosthetic hand control. Results The inclusion of IM data improved performance significantly, by increasing classification accuracy (CA) in the offline analysis and improving completion rates (CRs) in the real-time experiment. Our findings were consistent across able-bodied and amputee subjects. Integrating the sEMG electrodes and IM sensors within a single sensor package enabled us to achieve high-level performance by using on average 4-6 sensors. Conclusions The results from our experiments suggest that IMs can form an excellent complimentary source signal for upper-limb myoelectric prostheses. We trust that multi-modal control solutions have the potential of improving the usability of upper-extremity prostheses in real-life applications

Association between severity of chronic obstructive pulmonary disease and lung function tests

Introduction: The burden of chronic obstructive pulmonary disease (COPD) is quite high and its prevalence is increasing. We aimed to evaluate the correlation of COPD severity according to the ATS criteria with their spirometric measurements in patients admitted to emergency ward.Materials and Methods: In this cross-sectional descriptive study, 50 randomly selected patients with COPD attending to emergency ward in a tertiary care center were evaluated. The COPD severity according to the ATS criteria was measured and its association with spirometric findings was evaluated. The statistical analysis was performed by SPSS software and the Kendall's tau-b correlation test.Results: The mean age (±standard deviation) was 64.3 ± 11.3 years. Twelve percent were female and 88 percent were male. The COPD severity, according to the ATS criteria, was mild in 16%, moderate in 48%, severe in 32% and very severe in four percent. There was a statistically significant correlation between total lung capacity (TLC) and COPD severity (P=0.013, r=275). Besides, there was a statistically significant correlation between functional residual capacity (FRC) and COPD severity (P=0.022, r=255). Age, sex, and the other spirometric findings especially FEV1 and FVC had no association with COPD severity (P > 0.05).Conclusion: According to the obtained results, it is concluded that determining the COPD severity according to the ATS criteria may help the physicians to estimate the patients' prognosis and therapeutic planning. However the spirometric measurements may not be replaced by ATS criteria.Key words: chronic obstructive pulmonary disease (COPD), Severity, Spirometery, American Thoracic Society (ATS

Modification of Acute Physiology and Chronic Health Evaluation II score through recalibration of risk prediction model in critical care patients of a respiratory disease referral center

BACKGROUND: Several models have been developed to measure the severity of illness in intensive care unit (ICU) patients, It is suggested that the models should be customized depending on the characteristics of different population of patients. This study is aimed to assess and modify the performance of Acute Physiology and Chronic Health Evaluation II (APACHE-II) model in a respiratory diseases referral center. MATERIALS AND METHODS: A total of 730 patients, admitted to an intensive care unit during one year, were divided into two sets (71% training and 29% test). Our modified APACHE-II model was developed and calibrated on training set. Then, the integrity of the customized model was checked and compared to the original APACHE-II, on the test set. Logistic regression was used to develop ROC analysis, F-measure and kappa coefficient and were employed to calibrate the model. RESULTS: Both Original and Our modified APACHE-II scores performed acceptable discriminative power (AUC = 0.908: 95%CI 0.861-0.854; and AUC = 0.856: 95%CI 0.789-0.923, respectively); the difference was not significant (P = 0.132). Our modified APACHE-II showed improved accuracy (87.9% vs. 84.1%) and sensitivity (56.4% vs. 16.3%) compared to the original model. F-measure and Kappa also gave the impression of improvement for our modified APACHE-II system. CONCLUSION: The results demonstrated that a modified APACHE-II system in a local ICU of respiratory disease could have similar discrimination and comparable calibration to the original model

O027 The combination of mandibular advancement devices (MAD) and supplemental oxygen dramatically improves OSA severity: preliminary results from the MADOX trial

Abstract Introduction Patients with obstructive sleep apnoea (OSA) considered ‘non-responders’ to mandibular advancement device (MAD) therapy, typically have a high loop gain contributing to their OSA physiology. While MAD does not improve loop gain, other treatments such as supplemental oxygen can have a strong effect on this pathogenic trait. Therefore, we conducted a randomised controlled trial (RCT) to determine whether the administration of supplemental oxygen in combination with a MAD, was associated with greater improvements in OSA severity compared to MAD therapy alone. Methods Patients recently diagnosed with OSA underwent an initial screening sleep study to confirm the presence of moderate-severe OSA (Apnoea-hypopnoea index [AHI]&amp;gt;20events/hr). Eligible patients were then enrolled in a randomised single-blind cross-over trial involving 4 sleep studies with the following treatments; MAD, oxygen (4L/min), MAD+oxygen and room-air/sham (control). The primary outcome was the reduction in AHI (%baseline). Results Of the 57 participants screened, 35 met the eligibility criteria (Baseline/Screening AHI = 52±22 events/hr). Compared to the sham night, all treatments significantly reduced the AHI; a 35% [CI: 18–48] was seen with oxygen (p&amp;lt;0.0002), a 53% [CI: 40–64] was seen with MAD (p&amp;lt;0.0001) and a 67% [CI: 56–76] was seen with MAD+oxygen (p&amp;lt;0.0001). Importantly, the combination of MAD+oxygen was associated with a significant reduction in AHI relative to MAD alone (15% [CI:4–24] p=0.01). Discussion In a population with moderate-severe OSA, preliminary analyses from this trial suggests that the addition of supplemental oxygen in combination with MAD therapy provided greater reductions in OSA severity than either treatment alone. </jats:sec

The Combination of an Oral Appliance and Supplemental Oxygen Markedly Improves Obstructive Sleep Apnea Severity: A Randomized Controlled Trial

Introduction: Obstructive sleep apnea (OSA) is challenging to treat due to limited tolerance of the leading therapy, continuous positive airway pressure. A leading second line therapy, oral appliances, are well tolerated but have limited efficacy. On the basis that oral appliance efficacy is lowest in patients with a high chemoreflex "loop gain", the current study tested the hypothesis that administration of supplemental oxygen (to lower loop gain) in combination with an oral appliance provides greater OSA treatment efficacy compared to oral appliance therapy alone. Methods: In a multicentre randomized crossover trial, 41 patients with moderate-to-severe OSA (apnea-hypopnea index [AHI] >20 events/hr) underwent in-laboratory polysomnography to assess the impact of a night of supplemental oxygen (4 L/min), oral appliance, both therapies in combination, compared to sham (air) on AHI. For primary analysis, hypopneas were scored regardless of desaturation/arousal criteria. Mixed model analysis compared treatment efficacy (change in AHI from baseline) between combination therapy and oral appliance alone (primary outcome). Sensitivity analysis reported AHI changes using standard 3% desaturation or arousal criteria (AHI3pa). Key secondary outcomes were arousal index and visual analog scale for sleep quality (VASSQ); higher score reflects improved sleep (0-10 units). Results: Of the 41 randomized patients (14F:27M, baseline AHI = 49 [29, 62] events/hr; median [interquartile range]), 38 completed all four interventions. Compared to sham, AHI was lowered with oxygen (−33% [CI: −46, −17]), oral appliances (−53% [−64, −41]), and the combination (−67% [−77, −57]): the combination provided a greater reduction compared to oral appliance alone (difference = −14% [−23, −4], P=0.009) confirming the study hypothesis. Sensitivity analysis using AHI3pa yielded a −73% change with the combination vs. sham (difference vs. oral appliance = −17% [−25, −7]). In secondary analysis, arousal index was lowered with oxygen (−19% [−28, −9]), oral appliances (−29% [−37, −20]), and the combination (−36% [−43, −27]; difference vs. oral appliance = −7% [−14, 2], P=0.11). VASSQ increased with oxygen (0.52 [−0.08, 1.1], borderline change), oral appliances (0.71 [0.11, 1.30]), and with the combination (0.98 [0.39, 1.58]; difference vs. oral appliance = 0.28 [−0.31, 0.86]). Conclusion: In moderate-severe OSA, the combination of supplemental oxygen and oral appliance therapy provides a greater OSA treatment efficacy compared to oral appliances alone. Combining a loop gain intervention with oral appliances is a promising approach to markedly attenuate the severity of OSA