High-Fidelity sEMG Signals Recorded by an on-Skin Electrode Based on AgNWs for Hand Gesture Classification Using Machine Learning.

The human forearm is one of the most densely distributed parts of the human body, with the most irregular spatial distribution of muscles. A number of specific forearm muscles control hand motions. Acquiring high-fidelity sEMG signals from human forearm muscles is vital for human-machine interface (HMI) applications based on gesture recognition. Currently, the most commonly used commercial electrodes for detecting sEMG or other electrophysiological signals have a rigid nature without stretchability and cannot maintain conformal contact with the human skin during deformation, and the adhesive hydrogel used in them to reduce skin-electrode impedance may shrink and cause skin inflammation after long-term use. Therefore, developing elastic electrodes with stretchability and biocompatibility for sEMG signal recording is essential for developing HMI. Here, we fabricated a nanocomposite hybrid on-skin electrode by infiltrating silver nanowires (AgNWs), a one-dimensional (1D) nano metal material with conductivity, into polydimethylsiloxane (PDMS), a silicone elastomer with a similar Young's modulus to that of the human skin. The AgNW on-skin electrode has a thickness of 300 µm and low sheet resistance of 0.481 ± 0.014 Ω/sq and can withstand the mechanical strain of up to 54% and maintain a sheet resistance lower than 1 Ω/sq after 1000 dynamic strain cycles. The AgNW on-skin electrode can record high signal-to-noise ratio (SNR) sEMG signals from forearm muscles and can reflect various force levels of muscles by sEMG signals. Besides, four typical hand gestures were recognized by the multichannel AgNW on-skin electrodes with a recognition accuracy of 92.3% using machine learning method. The AgNW on-skin electrode proposed in this study has great potential and promise in various HMI applications that employ sEMG signals as control signals.

Corneal Cross-Linking for Keratoconus: Current Knowledge and Practice and Future Trends.

Corneal collagen cross-linking (CXL) with riboflavin is an accepted universal standard of care for our keratoconus patients with progressive disease. It has been a game changer in how we manage keratoconus. Early diagnosis and treatment is essential in paediatric patients as younger patients progress more rapidly and have poorer transplant outcomes. There is an ongoing debate around standard, accelerated, and transepithelial protocols of CXL, the role of CXL, and the combination of laser refractive surgery. Future developments will improve CXL safety and efficacy and the scope of utilization, but we must be careful not to leap too far ahead with clinical applications before publication of basic science research and good clinical results with standardized protocols.

Donation of discarded ocular tissue in patients undergoing SMILE laser refractive surgery: developing appropriate guidelines.

Tissue Biobanks represent an invaluable resource. Despite the majority of people supporting tissue donation, the actual rate remains low overall. Tissue discarded from surgical procedures represents a further avenue for collection for use in research. We aim to understand the information and consent requirements in a cohort of healthy, post-ophthalmic surgical subjects to optimise future tissue collection in living donors. Patients attending an ophthalmic clinic following refractive surgery for myopia (SMILE) were identified. Patient consent was implied with the completion of the provided survey. The questionnaire included gender, age range and education status. The majority of 31 subjects identified a benefit for future patients as the main motive for potential donation of discarded tissue (71%). Payment for the discarded tissue would not influence their decision in 77.4%. Explanation of the potential benefits of research was the most important information to consider before making a decision to donate. Only 12.9% of patients would have refused to include further information. Almost half of patients felt that the Biobank became the owner of tissue following donation. Current surgical patients may be more inclined to participate in research than the general public because of a sense of duty or an increased understanding of the role of research in evolving treatment. Despite minor uncertainty about the eventual use of the tissue and data, most subjects were positive to donation of discarded ocular tissue and de-identified information. Consent and education processes should be revised within an ophthalmic practice to minimise future patient anxiety.

Evaluation and treatment of thoracic outlet syndrome during the global pandemic due to SARS-CoV-2 and COVID-19.

The global SARS-CoV-2/COVID-19 pandemic has required a reduction in nonemergency treatment for a variety of disorders. This report summarizes conclusions of an international multidisciplinary consensus group assembled to address evaluation and treatment of patients with thoracic outlet syndrome (TOS), a group of conditions characterized by extrinsic compression of the neurovascular structures serving the upper extremity. The following recommendations were developed in relation to the three defined types of TOS (neurogenic, venous, and arterial) and three phases of pandemic response (preparatory, urgent with limited resources, and emergency with complete diversion of resources). • In-person evaluation and treatment for neurogenic TOS (interventional or surgical) are generally postponed during all pandemic phases, with telephone/telemedicine visits and at-home physical therapy exercises recommended when feasible. • Venous TOS presenting with acute upper extremity deep venous thrombosis (Paget-Schroetter syndrome) is managed primarily with anticoagulation, with percutaneous interventions for venous TOS (thrombolysis) considered in early phases (I and II) and surgical treatment delayed until pandemic conditions resolve. Catheter-based interventions may also be considered for selected patients with central subclavian vein obstruction and threatened hemodialysis access in all pandemic phases, with definitive surgical treatment postponed. • Evaluation and surgical treatment for arterial TOS should be reserved for limb-threatening situations, such as acute upper extremity ischemia or acute digital embolization, in all phases of pandemic response. In late pandemic phases, surgery should be restricted to thrombolysis or brachial artery thromboembolectomy, with more definitive treatment delayed until pandemic conditions resolve.

Quantitative Assessment of Gait Characteristics in Degenerative Cervical Myelopathy: A Prospective Clinical Study.

It is challenging to discriminate the early presentation of Degenerative Cervical Myelopathy (DCM) as well as sensitively and accurately distinguishing between mild, moderate, and severe levels of impairment. As gait dysfunction is one of the cardinal symptoms of DCM, we hypothesized that spatiotemporal gait parameters, including the enhanced gait variability index (eGVI), could be used to sensitively discriminate between different severities of DCM. A total of 153 patients recently diagnosed with DCM were recruited and stratified on the basis of DCM severity grades, as measured using the modified Japanese Orthopedic Association (mJOA) scale. Demographic information and neurological status were collected. Gait assessments were performed using an 8 m walkway. Spearman rank correlation was used to identify relationships between gait parameters and mJOA values as well as the mJOA lower extremity (LE) subscore. Kruskal-Wallis H test was performed to evaluate differences between severity groups, as defined by mJOA classification. A significant and relatively strong correlation was found between the mJOA score and eGVI, as well as between the LE subscore of the mJOA and eGVI. Significant differences in the eGVI (X2(2, N = 153) = 55.04, p < 0.0001, ε2 = 0.36) were found between all groups of DCM severity, with a significant increase in the eGVI as DCM progressed from mild to moderate. The eGVI was the most discriminative gait parameter, which facilitated objective differentiation between varying severities of DCM. Quantitative gait assessments show promise as an accurate and objective tool to diagnose and classify DCM, as well as to potentially evaluate the impact of therapeutic interventions.

Re-treatment in LASIK: To Flap Lift or Perform Surface Ablation.

PURPOSE: To review safety and efficacy outcomes following re-treatment for residual refractive errors in eyes with prior laser in situ keratomileusis (LASIK) and determine the most appropriate course of action for patients. METHODS: A review of all patients undergoing LASIK enhancement at a single refractive surgery center between 2012 and 2017 was undertaken. Refraction and biomicroscopy results before and after enhancement were collated and analyzed according to the method of enhancement (flap lift or surface ablation). RESULTS: A total of 108 eyes were included in the analysis; 58 eyes underwent flap lift and 50 underwent surface ablation retreatment with mean times to enhancement of 22.3 and 53.2 months, respectively. The mean spherical equivalent prior to enhancement was -0.43 ± 0.69 and -1.03 ± 1.01 diopters (D) for the flap lift and surface ablation groups, respectively. The absolute difference from intended refraction was statistically significant (lift 0.16 ± 0.24 versus surface ablation 0.31 ± 0.35 D; P = .01). The difference was more pronounced for eyes with prior hyperopia (P = .041). The incidence of haze following re-treatment was 3.4% in the flap lift group versus 10.0% in the surface ablation group, and 8.6% of the flap lift group had evidence of epithelial ingrowth, with 1 eye requiring washout. There was no correlation between time to enhancement, refraction, and incidence of complications following the enhancement procedure. CONCLUSIONS: There has been a trend toward treating residual LASIK refractive error through surface ablation. This review suggests that flap lift may result in a more accurate refractive outcome, albeit with an expected greater risk of epithelial ingrowth. [J Refract Surg. 2020;36(1):6-11.].

The graded redefined assessment of strength sensibility and prehension version 2 (GV2): Psychometric properties.

Context: GRASSP Version 1 (GV1) was developed in 2010, is an upper extremity measure specifically designed to assess recovery after traumatic tetraplegia. A second version was developed to reduce length of the test and refine instructions/standardization. The purpose of this post hoc analysis was to calculate psychometric properties of GRASSP Version 2 (GV2). Design/Setting: A post-hoc analysis of datasets for the GRASSP cross-sectional (n = 72 chronic,) and longitudinal (n = 127 acute) studies was conducted. Reliability, validity and MDD were calculated from the chronic sample and responsiveness was re-calculated from the longitudinal sample. Both studies were observational. Participants: A chronic sample (n = 72) and acute longitudinal sample (n = 127) of individuals with traumatic tetraplegia (AIS A to D, NLI C2 to C8) were studied. Outcome Measures: GV1, the Spinal Cord Independence Measure III (SCIM), International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI) were administered in both studies at all centers and the Capabilities of the Upper Extremity Questionnaire (CUE-Q) was administered in North American sites only. GRASSP-Palmar Sensation, GRASSP-Prehension Performance subtest items included in GV2 were re-analyzed for reliability; validity, MDD and responsiveness. Results: Inter-rater and test-retest reliability for all subtests ranged between 0.849-0.971 and 0.950-0.971 respectively. Concurrent validity between domains of GV2 were positively and moderately (0.530-0.830, P < 0.0001) correlated to SCIM, SCIM self-care subscore (SS) and CUE-Q. MDD values were 4 and 3 points for sensation and prehension performance (single side). Responsiveness values were .84-.88 for GR-Sens and .93-1.22 for GR-PP respectively. Conclusions: GV2 retains excellent psychometric properties as does GV1.

Defining the needs and preferences of patients with dry eye disease.

OBJECTIVE: Dry eye disease is a multifactorial chronic disease, leading to ocular discomfort and visual disturbance with a substantial impact on quality of life. Therefore, the patient's perspective should be taken into account early in the drug development process. We have developed a step-by-step methodology based on the self-explicated conjoint approach to assess the needs and preferences of patients with moderate-to-severe dry eye disease. METHODS AND ANALYSIS: Following a literature review and social media listening (step 0), qualitative phone call interviews were conducted with 12 patients (step 1). Patients' responses underwent content analysis and were coded, quantified and displayed as charts. Based on the emerging trends and attributes identified as relevant in steps 0 and 1, a quantitative online questionnaire was designed and conducted with 160 patients across four countries (step 2). RESULTS: The online questionnaire was rated as easy/very easy to understand by 60% of respondents, 62% rated the survey as easy/very easy to complete and 71% rated it as interesting/very interesting. Treatment satisfaction was the most important aspect for patients, and the three most relevant attributes were as follows (with the most important indexed to 100%): 'treatment effectiveness on symptoms of dry eyes' (100%), 'frequency of treatment use' (96%) and 'how the treatment works' (95%). CONCLUSION: Our methodology was well received by patients, and the results will help inform future clinical trial development and discussions with health technology assessment bodies and regulators on unmet needs and product attributes that are of most value to patients with dry eye disease.

Comparing the needs and preferences of patients with moderate and severe dry eye symptoms across four countries.

BACKGROUND/AIMS: Understanding patients' perspectives of their disease can inform drug development and treatment decisions. In this study, we compared the preferences and needs of patients with moderate and severe dry eye symptoms from four different countries. METHODS: A quantitative questionnaire was developed based on the self-explicated conjoint methodology and was administered to 160 patients with moderate or severe dry eye disease (DED) from Australia, Germany, UK and the USA. RESULTS: Patients with moderate dry eye symptoms ranked 'treatment satisfaction' as the most important aspect, whereas 'symptom bother' was more relevant for those in the severe group. Both the moderate and severe groups classified treatment effectiveness as the most important treatment attribute. This result was consistent across the four countries, although US patients gave significantly higher scores than patients from other countries (p<0.001). Furthermore, patients from Australia ranked 'treatment experience' as significantly more important than the concern of side effects, whereas respondents from Germany exhibited the opposite trend (p<0.05 for both). The health burden of DED is reflected in the average European Quality of Life-5 Dimensions 5-level (EQ-5D) scores of 0.764 and 0.658 for patients with moderate and severe disease, respectively. CONCLUSION: Our results confirm that across the countries in the study, moderate and severe DED has a major impact on patients' quality of life and daily activities. By providing insight into the patient perspective of DED, our study helps identify outcomes that are important to patients and may guide future drug development and clinical decision-making.

Corneal Collagen Crosslinking for Post-LASIK Ectasia: An Australian Study.

PURPOSE: Post laser-assisted in situ keratomileusis (LASIK) ectasia is a rare and unpredictable complication after LASIK. Corneal collagen crosslinking (CXL) has emerged as a promising technique to address this complication. Our study evaluates the long-term efficacy of CXL for post-LASIK ectasia in an Australian setting. DESIGN: Retrospective review of post-LASIK ectasia patients referred to and treated at 3 corneal refractive surgery institutions in Sydney, Australia. METHODS: Eleven patients (14 eyes; mean age, 39.7 ± 12.6 years) underwent epithelium-off CXL with follow-up ranging from 12-78 months. Best spectacle-corrected visual acuity (BSCVA), simulated keratometry, corneal topography indices, and higher-order aberrations (HOAs) [mean ± standard error of the mean (SEM)] were measured with a rotating Scheimpflug camera (Pentacam, Oculus). Comparisons between baseline measurements and postoperative outcomes were performed using paired t test analysis. RESULTS: At last follow-up, BSCVA improved significantly by 0.2 ± 0.06 logMAR (P = 0.01), and 12 of 14 eyes showed no keratometric deterioration. Of the corneal topography indices, index of height asymmetry showed a trend toward a significant improvement (P = 0.05). There was no progression of corneal HOAs. Central corneal thickness was not significantly altered (P = 0.6). No major postoperative complications were observed. CONCLUSIONS: In the Australian setting, CXL has proven effective at stabilizing the progression of post-LASIK ectasia, inducing corneal regularity, and improving visual acuity.

Small incision lenticule extraction (SMILE) in 2015.

Small incision lenticule extraction (SMILE) represents a recent addition to the refractive surgeon's range of procedures. Although there remains a number of similarities to existing techniques in terms of patient selection and treatment parameters, consideration is required to optimise patient outcomes and satisfaction. Here, we review the selection criteria, contraindications, indications and existing published safety and efficacy outcomes.

Intraocular lens power calculation following laser refractive surgery.

Refractive outcomes following cataract surgery in patients that have previously undergone laser refractive surgery have traditionally been underwhelming. This is related to several key issues including the preoperative assessment (keratometry) and intraocular lens power calculations. Peer-reviewed literature is overwhelmed by the influx of methodology to manipulate the corneal or intraocular lens (IOL) powers following refractive surgery. This would suggest that the optimal derivative formula has yet been introduced. This review discusses the problems facing surgeons approaching IOL calculations in these post-refractive laser patients, the existing formulae and programs to address these concerns. Prior published outcomes will be reviewed.

Therapeutic treatment of keratoconus: a survey of local optometric practice criteria.

BACKGROUND: Defining the threshold for therapeutic and surgical intervention in patients with keratoconus presents a considerable challenge given the lack of clear, evidence-based data. Little is known about the patterns of practice and referral criteria of optometrists within Australia. METHODS: All members of the NSW branch of Optometrist Association Australia were invited to complete an online survey in January 2013. This survey was designed to elicit practice information regarding the evaluation and therapeutic treatment of patients with keratoconus in the optometric setting. RESULTS: Responses were received from 71 optometrists, of whom 65.2 per cent had 15 years or greater experience as an optometrist. Many (35.4 per cent) responded that they prescribed soft contact lenses daily. This percentage dropped to 9.2 per cent for rigid gas-permeable lenses (RGP), although 47.7 per cent said they would prescribe RGP lenses at least once per month. The main barriers to prescribing were experience with fitting RGP lenses, time and low market demand. In terms of patient referral to an ophthalmologist, the results were variable, with 34.4 per cent stating that they would refer on progression of corneal signs, 23.4 per cent suggesting no set time and 7.8 per cent would refer on initial diagnosis. Many optometrists (62.9 per cent) would refer a patient for possible surgery, when visual acuity dropped to between 6/9 and 6/12. The size or location of the practice was not associated with the number of newly diagnosed cases of keratoconus. Optometrists with greater experience were more likely to prescribe RGP lenses and co-manage patients with ophthalmologists. Ownership of a corneal topographic unit suggested an increased likelihood of prescribing RGP lenses but did not appear to alter referral patterns. CONCLUSION: Optometrists have an integral role in the diagnosis and management of patients with keratoconus. Our survey provides a basic snapshot of current, local practice. Additionally, ophthalmology should continue to work with optometry to develop guidelines for referral and co-management to optimise future outcomes for our patients.

Contralateral acute lower limb ischaemia following total hip replacement in a patient with an endovascular abdominal aortic aneurysm repair.

Total hip replacement (THR) is a common procedure to treat patients with a fractured neck of femur. Ipsilateral major vessel injury with acute lower limb ischaemia is a rare but potentially devastating complication. Contralateral acute limb ischaemia is unreported. We present the case of a contralateral, acute lower limb ischaemia following THR for a fractured neck of femur in the presence of an endovascular aortic aneurysm repair (EVAR) and femoro-femoral crossover grafts. We advise early vascular surgery consultation for patients undergoing THR with an EVAR stentgraft in situ to help minimize risks of peri- and postoperative graft occlusion and consequent acute lower limb ischaemia.

Lower limb amputation in England: prevalence, regional variation and relationship with revascularisation, deprivation and risk factors. A retrospective review of hospital data.

OBJECTIVE: We describe the prevalence of major lower limb amputation across England and its relationship with revascularisation, patient demography and disease risk factors. DESIGN: Retrospective cohort study. SETTING: England 1 April 2003 to 31 March 2009. PARTICIPANTS: Patients aged 50-84 years. MAIN OUTCOME MEASURES: Age standardised prevalence rates were calculated using Hospital Episode Statistics as the numerator with census data as the denominator. The outcome measure 'amputation with revascularisation' was created if an amputation could be linked with a revascularisation. Logistic regression determined the odds of having an amputation with a revascularisation across England. Regression was performed unadjusted and repeated after controlling for demographic (age, sex, social deprivation) and disease risk factors (diabetes, hypertension, coronary heart disease, cerebrovascular disease, smoking). RESULTS: There were 25,312 amputations and 136,215 revascularisations, and 7543 cases were linked. The prevalence rate per 100,000 (95% confidence intervals) for amputation was 26.3 (26.0-26.6) with rates significantly higher in Northern England (North: 31.7; 31.0-32.3, Midlands: 26.0; 25.3-26.7, South: 23.1; 22.6-23.5). The revascularisation rate was 141.6 (140.8-142.3) with significantly higher rates again in Northern England (North: 182.1; 180.5-183.7, Midlands: 121.3; 119.8-122.9, South 124.9; 123.9-125.8). The odds of having an amputation with a revascularisation remained significantly higher in the North (OR 1.22; 1.13-1.33) even after controlling demographic and disease risk factors. CONCLUSIONS: There is a North-South divide in England for both major lower limb amputation and revascularisation. The higher odds of having an amputation with a revascularisation in the North were not fully explained by greater levels of deprivation or disease risk factors.

Toward understanding the dynamics of microbial communities in an estuarine system.

Community assembly theories such as species sorting theory provide a framework for understanding the structures and dynamics of local communities. The effect of theoretical mechanisms can vary with the scales of observation and effects of specific environmental factors. Based on 16S rRNA gene tag pyrosequencing, different structures and temporal succession patterns were discovered between the surface sediments and bottom water microbial communities in the Pearl River Estuary (PRE). The microbial communities in the surface sediment samples were more diverse than those in the bottom water samples, and several genera were specific for the water or sediment communities. Moreover, water temperature was identified as the main variable driving community dynamics and the microbial communities in the sediment showed a greater temporal change. We speculate that nutrient-based species sorting and bacterial plasticity to the temperature contribute to the variations observed between sediment and water communities in the PRE. This study provides a more comprehensive understanding of the microbial community structures in a highly dynamic estuarine system and sheds light on the applicability of ecological theoretical mechanisms.

Ethnic differences in lower limb revascularisation and amputation rates. Implications for the aetiopathology of atherosclerosis?

OBJECTIVE: Peripheral arterial disease, as a result of atherosclerosis, is the commonest reason for lower limb revascularisation and amputation in England. We describe the prevalence rate of these procedures among the White, South Asian and Black populations living in England and describe the association of ethnicity to amputation, both with and without, revascularisation. METHOD: We extracted data from 90 million English hospital admissions between 2003 and 2009 and calculated prevalence rates among 50-84 year olds using census data. Logistic regression demonstrated whether ethnicity was related to amputation, both with and without revascularisation, independent of demographic (age, sex, social class) and disease risk factors (diabetes, hypertension, hypercholesterolaemia, coronary and cerebral vascular disease, smoking). RESULTS: There were 25,308 amputations and 136,215 revascularisations. The age adjusted prevalence rate for amputation was 26/100,000 and revascularisation 142/100,000. The prevalence ratio (95% confidence intervals) (White British=100) of amputation in the Asian and Black populations was; 60 (54-66) and 169 (155-183) respectively with revascularisation ratios; 89 (86-92) and 94 (89-98) respectively. South Asians had approximately half the risk of amputation both with and without a revascularisation than Whites despite much higher rates of known atherosclerotic risk factors. The odds of having an amputation without any revascularisation was 63% higher in Blacks but fully attenuated by demographic and disease risk factors. CONCLUSION: South Asians experience the lowest rate of both major lower limb amputation and revascularisation in England. The association cannot be explained by demographic or cardiovascular risk factors. This may have implications in the aetiopathology of atherosclerosis.

Time course variations in the mechanisms by which cerebral oxygen delivery is maintained on exposure to hypoxia/altitude.

Normal cerebral function is dependent upon an adequate and continuous supply of oxygen. This study calculated cerebral blood flow based on assessment of the right middle cerebral artery (MCA) velocity (MCAVel) and MCA diameter (MCADiam) by trans-cranial Doppler and trans-cranial Duplex in normoxia, during acute exposure to 12% normobaric hypoxia for up to 6 hours, and after 3 days exposure to the equivalent altitude, 4392 m, in nine subjects. Mean (SD) MCAVel increased both after 6 hours hypoxia from 76.8 (11.4) to 97.2 (17.4) cms/sec (p<0.001), and after 3 days at altitude from 68.1 (7.5) [sea level] to 76.2 (10.2) [4392 m] (p=0.015). MCADiam increased from 5.07 (0.6) to 6.1 (0.6) mm (p<0.001) after 6 hours of 12% hypoxia. Calculated mean MCA blood flow increased after 6 hours of 12% hypoxia from 5.0 (0.6) mL/sec to 8.9 (1.2) mL/sec, but there was no difference between sea level and 4392 m. Calculated mean cerebral oxygen delivery increased from 72.4 (14.4) to 107 (20.1) mL/sec (p<0.001) after 6 hours of 12% hypoxia and was maintained unchanged at 4392 m. An increase in MCA caliber, rather than blood velocity, was a major contributor to increased oxygen delivery accompanying within the first few hours of exposure to acute hypoxia. During more long-term exposure, increases in MCA velocity and a rise in hemoglobin appeared to be the more important mechanisms in maintaining cerebral oxygen delivery. The implication of this observed change in MCA diameter questions the widely held assumption that MCA velocity is a surrogate for flow during acute hypoxic exposure.