Publications by authors named "Amish Acharya"

14 Publications

  • Page 1 of 1

The Reliability and Quality of YouTube Videos as a Source of Public Health Information Regarding COVID-19 Vaccination: Cross-sectional Study.

JMIR Public Health Surveill 2021 07 8;7(7):e29942. Epub 2021 Jul 8.

Department of Surgery & Cancer, Imperial College London, London, United Kingdom.

Background: Recent emergency authorization and rollout of COVID-19 vaccines by regulatory bodies has generated global attention. As the most popular video-sharing platform globally, YouTube is a potent medium for the dissemination of key public health information. Understanding the nature of available content regarding COVID-19 vaccination on this widely used platform is of substantial public health interest.

Objective: This study aimed to evaluate the reliability and quality of information on COVID-19 vaccination in YouTube videos.

Methods: In this cross-sectional study, the phrases "coronavirus vaccine" and "COVID-19 vaccine" were searched on the UK version of YouTube on December 10, 2020. The 200 most viewed videos of each search were extracted and screened for relevance and English language. Video content and characteristics were extracted and independently rated against Health on the Net Foundation Code of Conduct and DISCERN quality criteria for consumer health information by 2 authors.

Results: Forty-eight videos, with a combined total view count of 30,100,561, were included in the analysis. Topics addressed comprised the following: vaccine science (n=18, 58%), vaccine trials (n=28, 58%), side effects (n=23, 48%), efficacy (n=17, 35%), and manufacturing (n=8, 17%). Ten (21%) videos encouraged continued public health measures. Only 2 (4.2%) videos made nonfactual claims. The content of 47 (98%) videos was scored to have low (n=27, 56%) or moderate (n=20, 42%) adherence to Health on the Net Foundation Code of Conduct principles. Median overall DISCERN score per channel type ranged from 40.3 (IQR 34.8-47.0) to 64.3 (IQR 58.5-66.3). Educational channels produced by both medical and nonmedical professionals achieved significantly higher DISCERN scores than those of other categories. The highest median DISCERN scores were achieved by educational videos produced by medical professionals (64.3, IQR 58.5-66.3) and the lowest median scores by independent users (18, IQR 18-20).

Conclusions: The overall quality and reliability of information on COVID-19 vaccines on YouTube remains poor. Videos produced by educational channels, especially by medical professionals, were higher in quality and reliability than those produced by other sources, including health-related organizations. Collaboration between health-related organizations and established medical and educational YouTube content producers provides an opportunity for the dissemination of high-quality information on COVID-19 vaccination. Such collaboration holds potential as a rapidly implementable public health intervention aiming to engage a wide audience and increase public vaccination awareness and knowledge.
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http://dx.doi.org/10.2196/29942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8274673PMC
July 2021

A national survey assessing public readiness for digital health strategies against COVID-19 within the United Kingdom.

Sci Rep 2021 03 16;11(1):5958. Epub 2021 Mar 16.

Department of Surgery and Cancer, Imperial College London, London, W2 1NY, UK.

There is concern that digital public health initiatives used in the management of COVID-19 may marginalise certain population groups. There is an overlap between the demographics of groups at risk of digital exclusion (older, lower social grade, low educational attainment and ethnic minorities) and those who are vulnerable to poorer health outcomes from SARS-CoV-2. In this national survey study (n = 2040), we assessed how the UK population; particularly these overlapping groups, reported their preparedness for digital health strategies. We report, with respect to using digital information to make health decisions, that those over 60 are less comfortable (net comfort: 57%) than those between 18 and 39 (net comfort: 78%) and lower social grades are less comfortable (net comfort: 63%) than higher social grades (net comfort: 75%). With respect to a preference for digital over non-digital sources in seeking COVID-19 health information, those over 60 (net preference: 21%) are less inclined than those between 18 and 39 (net preference: 60%) and those of low educational attainment (net preference: 30%) are less inclined than those of high educational attainment (net preference: 52%). Lastly, with respect to distinguishing reliable digital COVID-19 information, lower social grades (net confidence: 55%) are less confident than higher social grades (net confidence: 68%) and those of low educational attainment (net confidence: 51%) are less confident than those of high educational attainment (net confidence: 71%). All reported differences are statistically significant (p < 0.01) following multivariate regression modelling. This study suggests that digital public health approaches to COVID-19 have the potential to marginalise groups who are concurrently at risk of digital exclusion and poor health outcomes from SARS-CoV-2.
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http://dx.doi.org/10.1038/s41598-021-85514-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7966397PMC
March 2021

Factors associated with infrainguinal bypass graft patency at 1-year; a retrospective analysis of a single centre experience.

Perfusion 2021 Feb 26:267659121995760. Epub 2021 Feb 26.

Imperial Vascular Unit, Imperial College London NHS Healthcare Trust, London, UK.

Introduction: The aim of this study was to identify factors associated with primary graft patency 1 year following open lower limb revascularisation (LLR) at a tertiary referral vascular service.

Methods: A retrospective analysis of patients undergoing infra-inguinal bypass surgery between January 2016 and May 2017 at a tertiary vascular centre (St Mary's Hospital, London) was performed. Data regarding patient demographics, comorbidities, type of operation and post-operative anti-thrombotic strategy were collected. Quality of run-off score was assessed from pre-operative imaging.

Results: Seventy-seven cases were included in the analysis. Overall, the primary patency rate at 1-year was 63.6% ( = 49/77) and the secondary patency rate was 67.5% ( = 52/77). Independent variables with statistically significant inferior patency rates at 1-year were (1) bypasses with below knee targets (p = 0.0096), (2) chronic limb threatening ischaemia indication (p = 0.038), (3) previous ipsilateral revascularisation (p < 0.001) and (4) absence of hypertension history (p = 0.041). There was also a trend towards significance for American Society of Anesthesiologists (ASA) grade (p = 0.06). Independent variables with log-rank test p values of <0.1 were included in a Cox proportional hazards model. The only variable with a statistically significant impact on primary patency rates was previous open or endovascular ipsilateral revascularisation (HR 2.44 (1.04-5.7), p = 0.04).

Conclusion: At 1-year follow-up, previous ipsilateral revascularisation was the most significant factor in affecting patency rates. Patients in this subgroup should therefore be deemed high-risk, which should be reflected in the informed consent and peri-operative management.
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http://dx.doi.org/10.1177/0267659121995760DOI Listing
February 2021

Evaluating the effect of infographics on public recall, sentiment and willingness to use face masks during the COVID-19 pandemic: a randomised internet-based questionnaire study.

BMC Public Health 2021 02 17;21(1):367. Epub 2021 Feb 17.

Institute of Global Health Innovation, Department of Surgery & Cancer, Imperial College London , 10th Floor Queen Elizabeth Queen Mother Building, St Mary's Hospital, London, W2 1NY, UK.

Background: The use of face masks remains contentious, with international variation in practice. Their prevalence in the UK, is likely to increase due to new legislation. Clear information regarding the appropriate use of masks is needed, to ensure compliance with policies to reduce transmission of COVID-19. We aimed to assess the impact of visual representations of guidance, or infographics, upon the knowledge of appropriate face mask usage in a representative UK cohort.

Methods: Adult patients were recruited to this randomised internet-based questionnaire study during the 12-14 May 2020 from across the UK. Respondents viewed one of five public health stimuli regarding the use of face masks, or no stimulus. The groups accessed aids by the European Centre for Disease Control (EUCDC), World Health Organisation (WHO), Singaporean Ministry of Health (SMOH), text from the UK government (UK Gov), or an infographic designed by the Behavioural Insights Team (BIT). The primary outcome was to evaluate the effect of each infographic upon participants' recall of face mask technique, sentiments and willingness to wear a face covering. Secondary outcomes included the effect of symptomology and socio-demographic factors.

Results: 4099 respondents were randomised (1009 control, 628 EUCDC, 526 WHO, 639 SMOH, 661 UKGOV and 606 BIT). Stimuli from the WHO, SMOH and BIT demonstrated significantly higher average recall scores compared to the controls (7.40 v. 7.38 v. 7.34 v. 6.97, P < 0.001). BIT's stimulus led to the highest confidence about mask-wearing (87%). Only 48.2% of the cohort felt stimuli reduced anxiety about COVID-19. However, willingness to use a mask was high, (range 84 to 88%).

Conclusions: To ensure the appropriate use of masks, as mandated by UK law, guidance must provide sufficient information, yet remain understandable. Infographics can aid the recall of correct mask techniques by highlighting salient steps and reducing cognitive burden. They have also demonstrated greater trustworthiness than text-only guidance. The effect of infographics upon COVID-19-related anxiety was poor, and they should be further developed to address this sentiment. A willingness to wear face masks has, however, been demonstrated.
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http://dx.doi.org/10.1186/s12889-021-10356-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886844PMC
February 2021

Wearable Activity Monitors in Home Based Exercise Therapy for Patients with Intermittent Claudication: A Systematic Review.

Eur J Vasc Endovasc Surg 2021 04 12;61(4):676-687. Epub 2021 Jan 12.

Department of Surgery and Cancer, Imperial College London, London, UK; Institute of Global Health Innovation, Imperial College London, London, UK; Imperial Vascular Unit, Imperial College Healthcare NHS Trust, London, UK.

Objective: Intermittent claudication (IC) can severely limit functional capacity and quality of life. Supervised exercise therapy is the recommended first line management; however, this is often limited by accessibility, compliance and cost. As such, there has been an increased interest in the use of wearable activity monitors (WAMs) in home based telemonitoring exercise programmes for claudicants. This review aims to evaluate the efficacy of WAM as a feedback and monitoring tool in home based exercise programmes for patients with IC.

Data Sources: A search strategy was devised. The databases MEDLINE, EMBASE, and Web of Science were searched through to April 2020.

Review Methods: Randomised trials and prospective trials were included. Eligible trials had to incorporate WAMs as a feedback tool to target walking/exercise behaviour. The primary outcome was the change in walking ability. Study quality was assessed with risk of bias tool.

Results: A total of 1148 records were retrieved. Of these, eight randomised controlled trials and one prospective cohort study, all of which compared a WAM intervention against standard care and/or supervised exercise, met the inclusion criteria. Owing to heterogeneity between studies, no meta-analysis was conducted. WAM interventions improved measures of walking ability (heterogeneous outcomes such as maximum walking distance, claudication distance and six minute walk distance), increased daily walking activity (steps/day), cardiovascular metrics (maximum oxygen consumption), and quality of life.

Conclusion: There is some evidence that home based WAM interventions are beneficial for improving walking ability and quality of life in patients with IC. However, existing studies are limited by inadequate sample size, duration, and appropriate power. Achieving consensus on outcome reporting and study methods, as well as maximising device adherence, is needed.
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http://dx.doi.org/10.1016/j.ejvs.2020.11.044DOI Listing
April 2021

Prognostic significance of peritoneal lavage cytology in staging gastric cancer: systematic review and meta-analysis.

Gastric Cancer 2018 Jan 4;21(1):10-18. Epub 2017 Aug 4.

Department of Surgery and Cancer, Imperial College London, 10th Floor QEQM Building, St Mary's Hospital, South Wharf Road, London, W2 1NY, UK.

Background: Peritoneal cytology has been used as a part of the cancer staging of gastric cancer patients. The primary aim of this systematic review was to evaluate the value of peritoneal cytology as part of the staging of gastric cancer and survival prediction. The second aim was to establish if positive cytology may be modified by neoadjuvant therapy, to improve prognosis.

Methods: An electronic literature search was performed using Embase, Medline, Web of Science, and Cochrane library databases up to January 2016. The logarithm of the hazard ratio (HR) with 95% confidence intervals (CI) was used as the primary summary statistic. Comparative studies were used, and the outcome measure was survival in three groups: (1) positive versus negative cytology at staging laparoscopy immediately preceding surgery; (2) effect of neoadjuvant therapy on cytology and survival; and (3) positive cytology in the absence of macroscopic peritoneal disease was compared with obvious macroscopic peritoneal disease.

Results: Pooled analysis demonstrated that positive cytology was associated with significantly reduced overall survival (HR, 3.46; 95% CI, 2.77-4.31; P < 0.0001). Interestingly, negative cytology following neoadjuvant chemotherapy was associated with significantly improved overall survival (HR, 0.42; 95% CI, 0.31-0.57; P < 0.0001). The absence of macroscopic peritoneal disease with positive cytology was associated with significantly improved overall survival (HR, 0.64; 95% CI, 0.56-0.73; P < 0.0001).

Conclusion: This study suggests that patients with initial positive cytology may have a good prognosis following neoadjuvant treatment if the cytology results change to negative after treatment.
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http://dx.doi.org/10.1007/s10120-017-0749-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741790PMC
January 2018

Use of Tumor Markers in Gastrointestinal Cancers: Surgeon Perceptions and Cost-Benefit Trade-Off Analysis.

Ann Surg Oncol 2017 May 22;24(5):1165-1173. Epub 2016 Dec 22.

Division of Surgery, Department of Surgery and Cancer, St Mary's Hospital, Imperial College London, 10th Floor QEQM Building, South Wharf Road, London, W2 1NY, UK.

Background: Gastrointestinal cancers constitute the third most common cancers worldwide. Tumor markers have long since been used in the postoperative surveillance of these malignancies; however, the true value in clinical practice remains undetermined.

Objective: This study aimed to evaluate the clinical utility of three tumor markers in colorectal and esophagogastric cancer.

Methods: A systematic review of the literature was undertaken to elicit the sensitivity, specificity, statistical heterogeneity and ability to predict recurrence and metastases for carcinoembryonic antigen (CEA), cancer antigen (CA) 19-9 and CA125. European surgeons were surveyed to assess their current practice and the characteristics of tumor markers they most valued. Data from the included studies and survey were combined in a cost-benefit trade-off analysis to assess which tumor markers are of most use in clinical practice.

Results: Diagnostic sensitivity and specificity were ranked the most desirable characteristics of a tumor marker by those surveyed. Overall, 156 studies were included to inform the cost-benefit trade-off. The cost-benefit trade-off showed that CEA outperformed both CA19-9 and CA125, with lower financial cost and a higher sensitivity, and diagnostic accuracy for metastases at presentation (area under the curve [AUC] 0.70 vs. 0.61 vs. 0.46), as well as similar diagnostic accuracy for recurrence (AUC 0.46 vs. 0.48).

Conclusions: Cost-benefit trade-off analysis identified CEA to be the best performing tumor marker. Further studies should seek to evaluate new tumor markers, with investigation tailored to factors that meet the requirements of practicing clinicians.
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http://dx.doi.org/10.1245/s10434-016-5717-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5374165PMC
May 2017

Diagnosis and management of acute appendicitis. EAES consensus development conference 2015.

Surg Endosc 2016 11 22;30(11):4668-4690. Epub 2016 Sep 22.

Department of Surgery, Noordwest Clinics Alkmaar, Alkmaar, The Netherlands.

Unequivocal international guidelines regarding the diagnosis and management of patients with acute appendicitis are lacking. The aim of the consensus meeting 2015 of the EAES was to generate a European guideline based on best available evidence and expert opinions of a panel of EAES members. After a systematic review of the literature by an international group of surgical research fellows, an expert panel with extensive clinical experience in the management of appendicitis discussed statements and recommendations. Statements and recommendations with more than 70 % agreement by the experts were selected for a web survey and the consensus meeting of the EAES in Bucharest in June 2015. EAES members and attendees at the EAES meeting in Bucharest could vote on these statements and recommendations. In the case of more than 70 % agreement, the statement or recommendation was defined as supported by the scientific community. Results from both the web survey and the consensus meeting in Bucharest are presented as percentages. In total, 46 statements and recommendations were selected for the web survey and consensus meeting. More than 232 members and attendees voted on them. In 41 of 46 statements and recommendations, more than 70 % agreement was reached. All 46 statements and recommendations are presented in this paper. They comprise topics regarding the diagnostic work-up, treatment indications, procedural aspects and post-operative care. The consensus meeting produced 46 statements and recommendations on the diagnostic work-up and management of appendicitis. The majority of the EAES members supported these statements. These consensus proceedings provide additional guidance to surgeons and surgical residents providing care to patients with appendicitis.
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http://dx.doi.org/10.1007/s00464-016-5245-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5082605PMC
November 2016

Is surgical preadmission an underused opportunity in HIV?

Lancet HIV 2016 10;3(10):e459-60

Division of Surgery, Department of Surgery and Cancer, St Mary's Hospital, Imperial College, London, UK. Electronic address:

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http://dx.doi.org/10.1016/S2352-3018(16)30159-XDOI Listing
October 2016

Biomarkers of acute appendicitis: systematic review and cost-benefit trade-off analysis.

Surg Endosc 2017 03 5;31(3):1022-1031. Epub 2016 Aug 5.

Division of Surgery, Department of Surgery and Cancer, Imperial College London, 10th Floor QEQM Building, St Mary's Hospital, South Wharf Road, London, W2 1NY, UK.

Background: Acute appendicitis is the most common surgical emergency and can represent a challenging diagnosis, with a negative appendectomy rate as high as 20 %. This review aimed to evaluate the clinical utility of individual biomarkers in the diagnosis of appendicitis and appraise the quality of these studies.

Methods: A systematic review of the literature between January 2000 and September 2015 using of PubMed, OvidMedline, EMBASE and Google Scholar was conducted. Studies in which the diagnostic accuracy, statistical heterogeneity and predictive ability for severity of several biomarkers could be elicited were included. Information regarding costs and process times was retrieved from the regional laboratory. European surgeons blinded to these reviews were independently asked to rank which characteristics of biomarkers were most important in acute appendicitis to inform a cost-benefit trade-off. Sensitivity testing and the QUADAS-2 tool were used to assess the robustness of the analysis and study quality, respectively.

Results: Sixty-two studies met the inclusion criteria and were assessed. Traditional biomarkers (such as white cell count) were found to have a moderate diagnostic accuracy (0.75) but lower costs in the diagnosis of acute appendicitis. Conversely, novel markers (pro-calcitonin, IL 6 and urinary 5-HIAA) were found to have high process-related costs including analytical times, but improved diagnostic accuracy. QUADAS-2 analysis revealed significant potential biases in the literature.

Conclusion: When assessing biomarkers, an appreciation of the trade-offs between the costs and benefits of individual biomarkers is needed. Further studies should seek to investigate new biomarkers and address concerns over bias, in order to improve the diagnosis of acute appendicitis.
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http://dx.doi.org/10.1007/s00464-016-5109-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315733PMC
March 2017

The Influence of Gastric Cancer Screening on the Stage at Diagnosis and Survival: A Meta-Analysis of Comparative Studies in the Far East.

J Clin Gastroenterol 2016 Mar;50(3):190-7

*Department of Surgery & Cancer, Imperial College London, St Mary's Hospital, London, UK †Division of Cancer Policy & Management, National Cancer Control Institute, Seoul, Korea ‡Division of Gastric Surgery, National Cancer Center, Seoul, Korea.

Gastric cancer is the fifth most common cancer and the second most common cause of cancer-related death worldwide. The aim of this review was to evaluate the effect of gastric cancer screening on the stage at diagnosis and survival from disease. A systematic review of the literature between January 1995 and December 2014 was performed. Studies that compared screened versus nonscreened populations for the diagnosis of gastric cancer and included the stage at diagnosis were analyzed. The QUADAS-2 and the ROBANS tools were used to assess the quality of the studies. A total of 11 studies from the Far East comprising 4039 participants in the screened and 6635 in the nonscreened groups were included. Screening was associated with a significant increase in the detection of early gastric cancer (EGC) [pooled odds ratio (POR)=3.90; 95% confidence interval (CI), 3.01-5.06; P<0.0001] and reduction in the incidence of advanced gastric cancer (POR=0.27; 95% CI, 0.20-0.35; P<0.0001). Furthermore, screening improved the 5-year survival significantly (hazard ratio=0.56; 95% CI, 0.48-0.66; P<0.0001). About 73% of the screened patients were found to have EGC compared with 43% of the nonscreened patients. About 8% of the screened patients were found to have advanced gastric cancer compared with 54% of the nonscreened patients. Screening for gastric cancer is useful in detecting asymptomatic patients with EGC in high-prevalence areas. This in turn increases the number of treatable cancers and improves the 5-year survival. There is a need for the development and the validation of alternative risk-stratification tools in low-incidence areas to allow for similar benefits.
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http://dx.doi.org/10.1097/MCG.0000000000000466DOI Listing
March 2016

Surgical training: design of a virtual care pathway approach.

Surgery 2014 Sep 28;156(3):689-97. Epub 2014 Jul 28.

Division of Surgery, Department of Surgery and Cancer, St. Mary's Campus, Imperial College Healthcare NHS Trust, London, UK; Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

Background: Both intra- and perioperative care are essential for patients' safety. Training for intraoperative technical skills on simulators and for perioperative care in virtual patients have independently demonstrated educational value, but no training combining these 2 approaches has been designed yet. The aim of this study was to design a pathway approach for training in general surgery. A common disease requiring essential skills was chosen, namely, acute appendicitis.

Methods: Preoperative care training was created using virtual patients presenting with acute right iliac fossa (RIF) pain. A competency-based curriculum for laparoscopic appendectomy (LAPP) was designed on a virtual reality simulator: Novices (<10 LAPP) and experienced surgeons (>100 LAPP) were enrolled to perform 2 virtual LAPP for assessment of validity evidence; novices performed 8 further LAPP for analysis of a learning curve. Finally, postoperative virtual patients were reviewed after LAPP.

Results: Four preoperative patient scenarios were designed with different presentations of RIF; not all required operative management. Comments were provided through case progression to allow autonomous practice. Ten novices and 10 experienced surgeons were enrolled for intraoperative training. Time taken (median values) of novices versus experienced surgeons (285 vs 259 seconds; P = .026) and performance score (67% vs 99%; P < .0001) demonstrated evidence for validity, whereas path length did not (916 vs 673 cm; P = .113). Proficiency benchmark criteria were defined for measures with validity evidence. Two postoperative virtual patients were created with an uneventful or complicated outcome.

Conclusion: A virtual care pathway approach has been designed for acute appendicitis, enabling trainees to follow simulated patients from admission to discharge.
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http://dx.doi.org/10.1016/j.surg.2014.04.045DOI Listing
September 2014

Determination of biometric measures to evaluate patient suitability for transoral robotic surgery.

Head Neck 2015 Sep 29;37(9):1254-60. Epub 2014 Oct 29.

Department of Otorhinolaryngology and Head and Neck Surgery, St. Mary's Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.

Background: Transoral robotic surgery (TORS) represents a novel treatment for oropharyngeal cancer and obstructive sleep apnea. Appropriate patient selection is crucial. The purpose of this study was to investigate whether anatomic biometric measures are useful to determine the feasibility of performing TORS.

Methods: Three surgeons independently evaluated feasibility in 51 soft-fix cadavers. Transoral visualization was performed with 2 retractors commonly used in TORS. Seven anthropometric parameters and the degree of mouth opening were recorded.

Results: Mandibular body height, hyoid-mental length, and neck circumference demonstrated significant differences between "suboptimal" and "adequate" visualization of base of tongue and epiglottis (p < .05). Limited mouth opening was associated with suboptimal visualization. Neck circumference had the strongest influence on predicting TORS feasibility.

Conclusion: Mandibular body height, hyoid-mental length, and neck circumference in conjunction with the degree of mouth opening may determine patient suitability for TORS. Clinical evaluation is essential to validate their collective usefulness.
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http://dx.doi.org/10.1002/hed.23739DOI Listing
September 2015

Cognitive cues and visually induced motion sickness.

Aviat Space Environ Med 2012 May;83(5):477-82

Department of Psychology, University of Westminster, 309 Regent Street, London W1B 2UW, UK.

Background: The importance of cognitive processing of orientation cues in visually induced motion sickness and vection is often overlooked. Upright versus inverted visual scenes containing cues of different levels of salience were compared.

Methods: Panoramic scenes of 360 degrees were projected in the visual equivalent to the nauseogenic situation of rotating about an axis tilted from the vertical with a field of view of 84 degrees rotating at 0.2 Hz (72 degrees x s(-1)). Exposures were for 10 min or until moderate nausea developed. The design was counterbalanced repeated measures. Pilot Study: Subjects (N = 12) viewed visual conditions: a distant bland coastline scene as from an aircraft, tilted 30 degrees (Up); the same scene but inverted (Invert); and the scene morphed with no obvious orientation cues (Abstract). Main Experiment: Subjects (N = 22) viewed a city street scene containing numerous unambiguous and strong verticality cues under two conditions: upright (Up) and inverted (Invert), with 18 degrees tilt of rotational axis.

Results: Pilot Study: there were no significant differences between conditions in time (mean +/- SD min) to nausea endpoint (Up: 7.4 +/- 3.1; Invert: 7.1 +/- 3.1;Abstract: 7.8 +/- 2.4), nor for total symptom scores, nor for vection. Main Experiment: the upright scene was significantly more nauseogenic than the inverted, with shorter times to nausea endpoint (Up: 8.7 +/- 2.3; Invert: 9.2 +/- 2.2) and greater total symptom scores. Vection was marginally greater for Up than Invert.

Conclusions: Salient and unambiguous higher order cognitive cues may modulate the development of motion sickness induced by optokinetic stimuli. There was no one-to-one correspondence between vection and motion sickness.
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http://dx.doi.org/10.3357/asem.3095.2012DOI Listing
May 2012
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