A Data-Driven Approach to Estimate Human Center of Mass State During Perturbed Locomotion Using Simulated Wearable Sensors.

Center of mass (COM) state, specifically in a local reference frame (i.e., relative to center of pressure), is an important variable for controlling and quantifying bipedal locomotion. However, this metric is not easily attainable in real time during human locomotion experiments. This information could be valuable when controlling wearable robotic exoskeletons, specifically for stability augmentation where knowledge of COM state could enable step placement planners similar to bipedal robots. Here, we explored the ability of simulated wearable sensor-driven models to rapidly estimate COM state during steady state and perturbed walking, spanning delayed estimates (i.e., estimating past state) to anticipated estimates (i.e., estimating future state). We used various simulated inertial measurement unit (IMU) sensor configurations typically found on lower limb exoskeletons and a temporal convolutional network (TCN) model throughout this analysis. We found comparable COM estimation capabilities across hip, knee, and ankle exoskeleton sensor configurations, where device type did not significantly influence error. We also found that anticipating COM state during perturbations induced a significant increase in error proportional to anticipation time. Delaying COM state estimates significantly increased accuracy for velocity estimates but not position estimates. All tested conditions resulted in models with R2 > 0.85, with a majority resulting in R2 > 0.95, emphasizing the viability of this approach. Broadly, this preliminary work using simulated IMUs supports the efficacy of wearable sensor-driven deep learning approaches to provide real-time COM state estimates for lower limb exoskeleton control or other wearable sensor-based applications, such as mobile data collection or use in real-time biofeedback.

Fermenting a place in history: The first outbreak of Escherichia coli O157 associated with kimchi in Canada.

A Canadian outbreak investigation was initiated in January 2022 after a cluster of cases of Shiga-toxin-producing Escherichia coli (STEC) O157 was identified through whole genome sequencing (WGS). Exposure information was collected through case interviews. Traceback investigations were conducted, and samples from case homes, retail, and the manufacturer were tested for STEC O157. Fourteen cases were identified in two provinces in Western Canada, with isolates related by 0-5 whole genome multi-locus sequence typing allele differences. Symptom onset dates ranged from 11 December 2021 to 7 January 2022. The median age of cases was 29.5 (range 0-61); 64% were female. No hospitalisations or deaths were reported. Of 11 cases with information available on fermented vegetable exposures, 91% (10/11) reported consuming Kimchi Brand A during their exposure period. The traceback investigation identified Manufacturer A in Western Canada as the producer. One open and one closed sample of Kimchi Brand A tested positive for STEC O157, with isolates considered genetically related by WGS to the outbreak strain. Napa cabbage within the kimchi product was hypothesised as the most likely source of contamination. This paper summarises the investigation into this STEC O157 outbreak associated with kimchi, the first reported outside of East Asia.

Impact of the COVID-19 Pandemic on the Reported Incidence of Select Bacterial Enteric Diseases in Canada, 2020.

The aim of this study was to describe the impact of the COVID-19 pandemic on reported cases and clusters of select enteric diseases in Canada, for the period of March 2020 to December 2020. Weekly counts of laboratory confirmed cases of Salmonella, Shigella, Shiga toxin-producing Escherichia coli (STEC), and Listeria monocytogenes were obtained from laboratory surveillance data. These data were supplemented with epidemiological information on the suspected source of illness, collected for cases identified within whole genome sequencing clusters. Incidence rate ratios were calculated for each pathogen. All data were compared with a prepandemic reference period. Decreases in the number of reported cases in 2020 compared with the previous 5-year period were noted for Salmonella, Shigella, Escherichia coli O157, and non-O157 STEC. Reported number of cases for L. monocytogenes in 2020 remained similar to those of the previous 5-year period. There was a considerable decline (59.9%) in the number of cases associated with international travel compared with a 10% decline in the number of domestic cases. Comparison of reported incidence rates of clustered versus sporadic cases for each pathogen showed little variation. This study represents the first formal assessment of the impact of COVID-19 on reported enteric diseases in Canada. Reported case counts across several pathogens saw notable declines in 2020 compared with prepandemic levels, with restrictions on international travel playing a key role. Additional research is needed to understand how limitations on social gatherings, lock downs, and other public health measures have impacted enteric diseases.

Linking whole-body angular momentum and step placement during perturbed human walking.

Human locomotion is remarkably robust to environmental disturbances. Previous studies have thoroughly investigated how perturbations influence body dynamics and what recovery strategies are used to regain balance. Fewer studies have attempted to establish formal links between balance and the recovery strategies that are executed to regain stability. We hypothesized that there would be a strong relationship between the magnitude of imbalance and recovery strategy during perturbed walking. To test this hypothesis, we applied transient ground surface translations that varied in magnitude, direction and onset time while 11 healthy participants walked on a treadmill. We measured stability using integrated whole-body angular momentum (iWBAM) and recovery strategy using step placement. We found the strongest relationships between iWBAM and step placement in the frontal plane for earlier perturbation onset times in the perturbed step (R2=0.52, 0.50) and later perturbation onset times in the recovery step (R2=0.18, 0.25), while correlations were very weak in the sagittal plane (all R2≤0.13). These findings suggest that iWBAM influences step placement, particularly in the frontal plane, and that this influence is sensitive to perturbation onset time. Lastly, this investigation is accompanied by an open-source dataset to facilitate research on balance and recovery strategies in response to multifactorial ground surface perturbations, including 96 perturbation conditions spanning all combinations of three magnitudes, eight directions and four gait cycle onset times.

COVID-19 in a remote First Nations community in British Columbia, Canada: an outbreak report.

BACKGROUND: In April 2020, British Columbia experienced its first outbreak of COVID-19 in a remote First Nations community. The objective of this paper was to describe the outbreak, including epidemiological and laboratory findings, and the public health response. METHODS: This report summarizes an outbreak of COVID-19 on Cormorant Island, British Columbia, in March and April 2020. Confirmed cases underwent investigation and contact tracing. Supports were provided to ensure successful isolation and quarantine for cases and contacts. Messaging to the community was circulated by trusted community members. Descriptive and social network analyses were conducted to describe the outbreak as it evolved. All case specimens underwent whole-genome sequencing. RESULTS: Thirty cases of SARS-CoV-2 infection were identified. Those infected had a median age of 34 years (range 15-77), and the majority identified as female (19, 63%) and as First Nations (27, 90%). The most common symptoms included chills, cough, diarrhea, headache and fever. Five people were hospitalized (17%) and 1 died (3%). Percent positivity in the community was 18%. Transmission occurred primarily during evening social gatherings and within households. Two weeks after control measures were initiated, no further cases were identified. All cases were genetically related by 2 single nucleotide polymorphisms or fewer, and they belonged to the most dominant SARS-CoV-2 lineage present in British Columbia in April 2020. INTERPRETATION: A community-led response was essential for the effective containment of this outbreak that included 30 cases, preventing onward transmission of the virus. Lessons learned from the management of this outbreak can inform response to other similar outbreaks in First Nations communities across Canada.

Validity of Administrative Databases in Comparison to Medical Charts for Breast Cancer Treatment Data.

OBJECTIVE: Medical chart abstraction is the gold standard for collecting breast cancer treatment data for monitoring and research. A less costly alternative is the use of administrative databases. This study will evaluate administrative data in comparison to medical charts for breast cancer treatment information. STUDY DESIGN AND SETTING: A retrospective cohort design identified 2,401 women in the Ontario Breast Screening Program diagnosed with invasive breast cancer from 2006 to 2009. Treatment data were obtained from the Activity Level Reporting and Canadian Institute of Health Information databases. Medical charts were abstracted at cancer centres. Sensitivity, specificity, positive and negative predictive value, and kappa were calculated for receipt and type of treatment, and agreement was assessed for dates. Logistic regression evaluated factors influencing agreement. RESULTS: Sensitivity and specificity for receipt of radiotherapy (92.0%, 99.3%), chemotherapy (77.7%, 99.2%), and surgery (95.8%, 100%) were high but decreased slightly for specific radiotherapy anatomic locations, chemotherapy protocols, and surgeries. Agreement increased by radiotherapy year (trend test, p < 0.0001). Stage II/III compared to stage I cancer decreased odds of agreement for chemotherapy (OR = 0.66, 95% CI: 0.48-0.91) and increased agreement for partial mastectomy (OR = 3.36, 95% CI: 2.27-4.99). Exact agreement in treatment dates varied from 83.0% to 96.5%. CONCLUSION: Administrative data can be accurately utilized for future breast cancer treatment studies.

The impact of organized breast assessment on survival by stage for screened women diagnosed with invasive breast cancer.

PURPOSE: Since 1998, the Ontario Breast Screening Program (OBSP) has offered organized assessment through Breast Assessment Centres (BAC). This study compares survival between screened women diagnosed with breast cancer who have undergone assessment through a BAC and usual care (UC). METHODS: A retrospective design identified two concurrent cohorts of women aged 50 to 69 within the OBSP diagnosed with screen-detected invasive breast cancer at a BAC (n = 2010) and UC (n = 1844) between 2002 and 2010 and followed until 2016. Demographic and assessment characteristics were obtained from the OBSP. Abstraction of medical charts provided prognostic and treatment data. Death data were assessed from the Registered Person's Database and the Ontario Registrar General All-Cause Mortality File. Multivariable Cox proportional hazards models compared overall survival by assessment type (BAC/UC), stratified by stage. RESULTS: There were 505 deaths during the study (BAC = 239; UC = 266). Among women with stage I screen-detected breast cancer, those diagnosed through a BAC had 31% reduced risk of all-cause mortality (HR = 0.69, 95% CI = 0.53-0.90) compared to UC. Diagnosis within 7 weeks of an abnormal mammogram reduced the hazard of death from all causes by 34% among all women with stage I breast cancers (HR = 0.66, 95% CI = 0.47-0.91), and was more likely in BAC (79.7%) than UC (66.9%). CONCLUSION: The significant improvement in overall survival for women with stage I screen-detected invasive breast cancer assessed through BACs further supports the recommendation that women with abnormal mammograms should be managed through organized assessment.

Canadian physicians' knowledge and counseling practices related to antibiotic use and antimicrobial resistance: Two-cycle national survey.

OBJECTIVE: To establish a baseline for physicians' knowledge of and counseling practices on the use of antibiotics and antimicrobial resistance (AMR), and to determine potential changes in these measures after the implementation of a national AMR awareness campaign. DESIGN: Cross-sectional design. SETTING: Canada. PARTICIPANTS: A total of 1600 physicians. MAIN OUTCOME MEASURES: Physicians' knowledge of and counseling practices on antibiotic use and AMR at baseline and after implementation of the AMR awareness campaign. RESULTS: A total of 336 physicians responded to the first-cycle survey (before the campaign), and 351 physicians responded to the second-cycle survey (after the campaign). Overall, physicians' knowledge of appropriate antibiotic use and AMR was high and their counseling practices in relation to antibiotics were appropriate in both surveys. Counseling levels about topics related to infection prevention and control (eg, food handling, household hygiene) were slightly lower. Counseling levels were also lower for certain antibiotic-use practices (eg, proper disposal of antibiotics). In addition, physicians with less than 10 years of practice experience had significantly lower odds of counseling their patients on topics related to preventing antibiotic resistance and infection prevention than those with 15 or more years of practice experience (adjusted odds ratio = 0.27, 95% CI 0.10 to 0.74). Significantly more physicians from the second-cycle survey counseled patients on the appropriate disposal of antibiotics (P = .03), as well as on some of the infection prevention topics (eg, using antibacterial hand soap [P = .02] and cleaning supplies [P = .01]). Most respondents in both surveys reported feeling confident with respect to counseling their patients on the appropriate use of antibiotics and AMR. CONCLUSION: Physicians' knowledge of and levels of counseling on the use of antibiotics and AMR were high and fairly stable in both survey results. This shows that Canadian physicians are demonstrating behaviour patterns of AMR stewardship. Existing gaps in counseling practices might be a result of physicians believing that pharmacists or nurses are addressing these issues with patients. Future national surveys conducted among pharmacists and nurses would contribute to the evidence base for AMR stewardship activities.

Breast screening for survivors of breast cancer: A systematic review.

There is a large and growing population of women who have a personal history of breast cancer (PHBC). This systematic review was undertaken to explore the outcomes of surveillance mammography in breast cancer survivors, and to examine the evidence for screening these women within an organized population-based screening program. We searched Cochrane Central Register of Controlled Trials (CENTRAL Issue 6, 2015), OVID MEDLINE and EMBASE (January 2012 to June 22, 2015) for English-language studies of surveillance of the target population. A study author extracted study outcomes, which were audited by a research assistant. One systematic review and 5 primary studies were included. These showed that surveillance mammography may reduce breast cancer-specific mortality through early/asymptomatic detection (Hazard Ratio for those without compared to with symptoms:HR: 0.64, 95% CI 0.55 - 0.74). Three studies showed that semi-annual mammography is likely not of greater benefit than annual mammography. No evidence was found to suggest that surveillance mammography for women with a PHBC should not be conducted within an organized screening program. The small evidence-base had a high level of heterogeneity in populations, interventions and outcomes. Based on this review, organized screening programs should reassess their guidelines on surveillance mammography and consider including women with a PHBC.

Evaluating wait times from screening to breast cancer diagnosis among women undergoing organised assessment vs usual care.

BACKGROUND: Timely coordinated diagnostic assessment following an abnormal screening mammogram reduces patient anxiety and may optimise breast cancer prognosis. Since 1998, the Ontario Breast Screening Program (OBSP) has offered organised assessment through Breast Assessment Centres (BACs). For OBSP women seen at a BAC, an abnormal mammogram is followed by coordinated referrals through the use of navigators for further imaging, biopsy, and surgical consultation as indicated. For OBSP women seen through usual care (UC), further diagnostic imaging is arranged directly from the screening centre and/or through their physician; results must be communicated to the physician who is then responsible for arranging any necessary biopsy and/or surgical consultation. This study aims to evaluate factors associated with diagnostic wait times for women undergoing assessment through BAC and UC. METHODS: Of the 2 147 257 women aged 50-69 years screened in the OBSP between 1 January 2002 and 31 December 2009, 155 866 (7.3%) had an abnormal mammogram. A retrospective design identified two concurrent cohorts of women diagnosed with screen-detected breast cancer at a BAC (n=4217; 47%) and UC (n=4827; 53%). Multivariable logistic regression analyses examined associations between wait times and assessment and prognostic characteristics by pathway. A two-sided 5% significance level was used. RESULTS: Screened women with breast cancer were two times more likely to be diagnosed within 7 weeks when assessed through a BAC vs UC (OR=1.91, 95% CI=1.73-2.10). In addition, compared with UC, women assessed through a BAC were significantly more likely to have their first assessment procedure within 3 weeks of their abnormal mammogram (OR=1.25, 95% CI=1.12-1.39), ⩽3 assessment procedures (OR=1.54, 95% CI=1.41-1.69), ⩽2 assessment visits (OR=1.86, 95% CI=1.70-2.05), and ⩾2 procedures per visit (OR=1.41, 95% CI=1.28-1.55). Women diagnosed through a BAC were also more likely than those in UC to have imaging (OR=1.99, 95% CI=1.44-2.75) or a biopsy (OR=3.69, 95% CI=2.64-5.15) vs consultation only at their first assessment visit, and two times more likely to have a core or FNA biopsy than a surgical biopsy (OR=2.08, 95% CI=1.81-2.40). Having ⩽2 assessment visits was more likely to reduce time to diagnosis for women assessed through a BAC compared with UC (BAC OR=10.58, 95% CI=8.96-12.50; UC OR=4.47, 95% CI=3.94-5.07), as was having ⩽3 assessment procedures (BAC OR=4.97, 95% CI=4.26-5.79; UC OR=2.95, 95% CI=2.61-3.33). Income quintile affected wait times only in women diagnosed in UC, with those in the two highest quintiles more likely to receive a diagnosis in 7 weeks. CONCLUSIONS: Women with screen-detected breast cancer in OBSP were more likely to have shorter wait times if they were diagnosed through organised assessment. This might be as a result of women diagnosed through a BAC having more procedures per visit, procedures scheduled in shorter intervals, and imaging or biopsy on their first visit. Given the significant improvement in timeliness to diagnosis, women with abnormal mammograms should be managed through organised assessment.

Broadly tuned face representation in older adults assessed by categorical perception.

Studies of face recognition in older adults (60 years of age and older) report increases in false alarms over younger adults (usually 18-30 years of age), but no age differences in hits. To examine this phenomenon, we compared older and younger adults in categorical perception of faces. We hypothesized that face representations in older adults would be broadly tuned, resulting in overlapping representations, manifested by a shallower slope in identity categorization than in younger adults, and age-related reductions in the advantage for between-categories, as compared with within-category, face discrimination. We morphed faces to change linearly from one identity to another. We used familiar or unfamiliar faces in separate conditions to examine the role of familiarity. Categorical perception was assessed in an identity-classification task and a discrimination task. Older adults showed a shallower slope and poorer discrimination compared with younger adults, and both groups exhibited better performance with familiar than unfamiliar faces. Enhanced discriminability for between-categories as compared with within-category faces was seen for both familiar and unfamiliar faces in younger adults, but only for familiar faces in older adults. The more broadly tuned representations of unfamiliar faces in older adults may lead to misidentification and greater false alarms for unfamiliar faces, but not for familiar faces.