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Loic Desquilbet - One of the best experts on this subject based on the ideXlab platform.
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investigation of risk factors for mortality in aged Guide Dogs a retrospective cohort study
Preventive Veterinary Medicine, 2016Co-Authors: S Hoummady, J Hua, C Muller, Jeanlouis Pouchelon, M Blondot, Caroline Gilbert, Loic DesquilbetAbstract:The overall median lifespan of domestic Dogs has been estimated to 9-12 years, but little is known about risk factors for mortality in aged and a priori healthy Dogs. The objective of this retrospective cohort study was to determine which characteristics are associated with mortality in aged and a priori healthy Guide Dogs, in a retrospective cohort study of 116 Guide Dogs followed from a systematic geriatric examination at the age of 8-10 years old. A geriatric grid collected the clinical data and usual biological parameters were measured at the time of examination. Univariate (Kaplan-Meier estimates) and multivariable (Cox proportional hazard model) survival analyses were used to assess the associations with time to all-cause death. The majority of Dogs were Golden Retrievers (n=48) and Labrador Retrievers (n=27). Median age at geriatric examination was 8.9 years. A total of 76 Dogs died during follow-up, leading to a median survival time from geriatric examination of 4.4 years. After adjustment for demographic and biological variables, an increased alanine amionotransferase level (adjusted Hazard Ratio (adjusted HR), 6.2; 95% confidence interval [95%CI], 2.0-19.0; P<0.01), presenting skin nodules (adjusted HR, 1.9; 95% CI, 1.0-3.4; P=0.04), and not being a Labrador Retriever (adjusted HR, 3.3; 95%CI, 1.4-10; P<0.01) were independently associated with a shorter time to death. This study documents independent associations of alanine aminotransferase level, skin nodules and breed with mortality in aged Guide Dogs. These results may be useful for preventive medical care when conducting a geriatric examination in working Dogs.
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Investigation of risk factors for mortality in aged Guide Dogs: A retrospective cohort study.
Preventive veterinary medicine, 2016Co-Authors: S Hoummady, J Hua, C Muller, Jeanlouis Pouchelon, M Blondot, Caroline Gilbert, Loic DesquilbetAbstract:The overall median lifespan of domestic Dogs has been estimated to 9-12 years, but little is known about risk factors for mortality in aged and a priori healthy Dogs. The objective of this retrospective cohort study was to determine which characteristics are associated with mortality in aged and a priori healthy Guide Dogs, in a retrospective cohort study of 116 Guide Dogs followed from a systematic geriatric examination at the age of 8-10 years old. A geriatric grid collected the clinical data and usual biological parameters were measured at the time of examination. Univariate (Kaplan-Meier estimates) and multivariable (Cox proportional hazard model) survival analyses were used to assess the associations with time to all-cause death. The majority of Dogs were Golden Retrievers (n=48) and Labrador Retrievers (n=27). Median age at geriatric examination was 8.9 years. A total of 76 Dogs died during follow-up, leading to a median survival time from geriatric examination of 4.4 years. After adjustment for demographic and biological variables, an increased alanine amionotransferase level (adjusted Hazard Ratio (adjusted HR), 6.2; 95% confidence interval [95%CI], 2.0-19.0; P
Lucy Asher - One of the best experts on this subject based on the ideXlab platform.
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Concurrent and Predictive Criterion Validity of a Puppy Behaviour Questionnaire for Predicting Training Outcome in Juvenile Guide Dogs.
Animals : an open access journal from MDPI, 2020Co-Authors: Rebecca L Hunt, Lucy Asher, Gary C.w. England, Helen Whiteside, Naomi D. HarveyAbstract:Working dog organisations regularly assess the behaviour of puppies to monitor progression. Here, we tested the predictive validity (for predicting success in Guide dog training) of a shortened version of a previously developed juvenile dog behaviour questionnaire (the refined puppy walker questionnaire, r-PWQ) and compared it with the Canine Behavioral Assessment and Research Questionnaire (C-BARQ). The r-PWQ is used by Guide Dogs UK, whereas the C-BARQ was designed for pet Dogs and is used by some other Guide dog schools internationally. A cohort of Dogs aged eight months (n = 359) were scored concurrently on the r-PWQ and C-BARQ. Analogous traits between the questionnaires were evaluated for internal consistency and association with training outcome and compared for concurrent validity. The r-PWQ was associated with training outcome for five scales (r-Excitability, Trainability, Animal Chase, r-Attachment and attention seeking and Distractibility) and the C-BARQ for two scales (Excitability and Separation-related behaviour). There were significant correlations between analogous C-BARQ and r-PWQ trait scores (p < 0.001) except for Separation-related behaviour and questionnaire scales had similar internal consistencies. The r-PWQ may be more suitable to use with Guide dog schools. However, due to the correlation between analogous scales (except for "Distractibility") some scales could be substituted for one another when reviewing the behaviour of Dogs between Guide dog schools using different questionnaires.
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Application of Survival Analysis and Multistate Modeling to Understand Animal Behavior: Examples from Guide Dogs
Frontiers in veterinary science, 2017Co-Authors: Lucy Asher, Naomi D. Harvey, Martin J. Green, Gary C.w. EnglandAbstract:Epidemiology is the study of patterns of health-related states or events in populations. Statistical models developed for epidemiology could be usefully applied to behavioural states or events. The aim of this study is to present the application of epidemiological statistics to understand animal behaviour where discrete outcomes are of interest, using data from Guide Dogs to illustrate. Specifically, survival analysis and multi-state modelling are applied to data on Guide Dogs comparing Dogs that completed training and qualified as a Guide dog, to those that were withdrawn from the training program. Survival analysis allows the time to (or between) a binary event(s) and the probability of the event occurring at or beyond a specified time point. Survival analysis, using a cox proportional hazards model, was used to examine the time taken to withdraw a dog from training. Sex, breed and other factors affected time to withdrawal. Bitches were withdrawn faster than Dogs, Labradors were withdrawn faster, and Labrador x Golden Retrievers slower, than Golden Retriever x Labradors; and Dogs not bred by Guide Dogs were withdrawn faster than those bred by Guide Dogs. Multistate Modelling (MSM) can be used as an extension of survival analysis to incorporate more than two discrete events or states. Multistate models were used to investigate transitions between states of training to qualification as a Guide dog or behavioural withdrawal, and from qualification as a Guide dog to behavioural withdrawal. Sex, breed (with purebred Labradors and Golden retrievers differing from F1 crosses) and bred by Guide Dogs or not, effected movements between states. We postulate that survival analysis and multistate modelling could be applied to a wide range of behavioural data and key examples are provided.
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An evidence-based decision assistance model for predicting training outcome in juvenile Guide Dogs.
PloS one, 2017Co-Authors: Naomi D. Harvey, Peter J. Craigon, Simon A. Blythe, Gary C.w. England, Lucy AsherAbstract:Working dog organisations, such as Guide Dogs, need to regularly assess the behaviour of the Dogs they train. In this study we developed a questionnaire-style behaviour assessment completed by training supervisors of juvenile Guide Dogs aged 5, 8 and 12 months old (n = 1,401), and evaluated aspects of its reliability and validity. Specifically, internal reliability, temporal consistency, construct validity, predictive criterion validity (comparing against later training outcome) and concurrent criterion validity (comparing against a standardised behaviour test) were evaluated. Thirty-nine questions were sourced either from previously published literature or created to meet requirements identified via Guide Dogs staff surveys and staff feedback. Internal reliability analyses revealed seven reliable and interpretable trait scales named according to the questions within them as: Adaptability; Body Sensitivity; Distractibility; Excitability; General Anxiety; Trainability and Stair Anxiety. Intra-individual temporal consistency of the scale scores between 5±8, 8±12 and 5±12 months was high. All scales excepting Body Sensitivity showed some degree of concurrent criterion validity. Predictive criterion validity was supported for all seven scales, since associations were found with training outcome, at at-least one age. Thresholds of z-scores on the scales were identified that were able to distinguish later training outcome by identifying 8.4% of all Dogs withdrawn for behaviour and 8.5% of all qualified Dogs, with 84% and 85% specificity. The questionnaire assessment was reliable and could detect traits that are consistent within individuals over time, despite juvenile Dogs undergoing development during the study period. By applying thresholds to scores produced from the questionnaire this assessment could prove to be a highly valuable decision-making tool for Guide Dogs. This is the first questionnaire-style assessment of juvenile Dogs that has shown value in predicting the training outcome of individual working Dogs.
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A New Metric for Quantifying the Relative Impact of Risk Factors on Loss of Working Life Illustrated in a Population of Working Dogs.
PloS one, 2016Co-Authors: Geoffrey Caron-lormier, Naomi D. Harvey, Gary C.w. England, Lucy AsherAbstract:In a resource-limited world, organisations attempting to reduce the impact of health or behaviour issues need to choose carefully how to allocate resources for the highest overall impact. However, such choices may not always be obvious. Which has the biggest impact? A large change to a small number of individuals, or a small change to a large number of individuals? The challenge is identifying the issues that have the greatest impact on the population so potential interventions can be prioritised. We addressed this by developing a score to quantify the impact of health conditions and behaviour problems in a population of working Guide Dogs using data from Guide Dogs, UK. The cumulative incidence of different issues was combined with information about their impact, in terms of reduction in working life, to create a work score. The work score was created at population-level to illustrate issues with the greatest impact on the population and to understand contributions of breeds or crossbreeds to the workforce. An individual work deficit score was also created and means of this score used to illustrate the impact on working life within a subgroup of the population such as a breed, or crossbreed generation. The work deficit scores showed that those removed for behavioural issues had a greater impact on the overall workforce than those removed for health reasons. Additionally trends over time illustrated the positive influence of interventions Guide Dogs have made to improve their workforce. Information highlighted by these scores is pertinent to the effort of Guide Dogs to ensure partnerships are lasting. Recognising that the scores developed here could be transferable to a wide variety of contexts and species, most notably human work force decisions; we discuss possible uses and adaptations such as reduction in lifespan, quality of life and yield in production animals.
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Using the incidence and impact of behavioural conditions in Guide Dogs to investigate patterns in undesirable behaviour in Dogs
Scientific reports, 2016Co-Authors: Geoffrey Caron-lormier, Naomi D. Harvey, Gary C.w. England, Lucy AsherAbstract:The domestic dog is one of our most popular companions and longest relationships, occupying different roles, from pet to working Guide dog for the blind. As Dogs age different behavioural issues occur and in some cases Dogs may be relinquished or removed from their working service. Here we analyse a dataset on working Guide Dogs that were removed from their service between 1994 and 2013. We use the withdrawal reasons as a proxy for the manifestation of undesirable behaviour. More than 7,500 Dogs were in the dataset used, 83% of which were retired (due to old age) and 17% were withdrawn for behavioural issues. We found that the main reasons for behaviour withdrawal were environmental anxiety, training, and fear/aggression. Breed and sex had an effect on the odds of Dogs being withdrawn under the different reasons. The age at withdrawal for the different withdrawal reasons suggested that Dogs were more likely to develop fear/aggression related issues early on, whilst issues related to training could develop at almost any age. We found no evidence for heterosis effecting behaviour. We believe that this work is relevant to the pet dog population and had implications for understanding ageing and genetic influences on behaviour.
S Hoummady - One of the best experts on this subject based on the ideXlab platform.
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investigation of risk factors for mortality in aged Guide Dogs a retrospective cohort study
Preventive Veterinary Medicine, 2016Co-Authors: S Hoummady, J Hua, C Muller, Jeanlouis Pouchelon, M Blondot, Caroline Gilbert, Loic DesquilbetAbstract:The overall median lifespan of domestic Dogs has been estimated to 9-12 years, but little is known about risk factors for mortality in aged and a priori healthy Dogs. The objective of this retrospective cohort study was to determine which characteristics are associated with mortality in aged and a priori healthy Guide Dogs, in a retrospective cohort study of 116 Guide Dogs followed from a systematic geriatric examination at the age of 8-10 years old. A geriatric grid collected the clinical data and usual biological parameters were measured at the time of examination. Univariate (Kaplan-Meier estimates) and multivariable (Cox proportional hazard model) survival analyses were used to assess the associations with time to all-cause death. The majority of Dogs were Golden Retrievers (n=48) and Labrador Retrievers (n=27). Median age at geriatric examination was 8.9 years. A total of 76 Dogs died during follow-up, leading to a median survival time from geriatric examination of 4.4 years. After adjustment for demographic and biological variables, an increased alanine amionotransferase level (adjusted Hazard Ratio (adjusted HR), 6.2; 95% confidence interval [95%CI], 2.0-19.0; P<0.01), presenting skin nodules (adjusted HR, 1.9; 95% CI, 1.0-3.4; P=0.04), and not being a Labrador Retriever (adjusted HR, 3.3; 95%CI, 1.4-10; P<0.01) were independently associated with a shorter time to death. This study documents independent associations of alanine aminotransferase level, skin nodules and breed with mortality in aged Guide Dogs. These results may be useful for preventive medical care when conducting a geriatric examination in working Dogs.
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Investigation of risk factors for mortality in aged Guide Dogs: A retrospective cohort study.
Preventive veterinary medicine, 2016Co-Authors: S Hoummady, J Hua, C Muller, Jeanlouis Pouchelon, M Blondot, Caroline Gilbert, Loic DesquilbetAbstract:The overall median lifespan of domestic Dogs has been estimated to 9-12 years, but little is known about risk factors for mortality in aged and a priori healthy Dogs. The objective of this retrospective cohort study was to determine which characteristics are associated with mortality in aged and a priori healthy Guide Dogs, in a retrospective cohort study of 116 Guide Dogs followed from a systematic geriatric examination at the age of 8-10 years old. A geriatric grid collected the clinical data and usual biological parameters were measured at the time of examination. Univariate (Kaplan-Meier estimates) and multivariable (Cox proportional hazard model) survival analyses were used to assess the associations with time to all-cause death. The majority of Dogs were Golden Retrievers (n=48) and Labrador Retrievers (n=27). Median age at geriatric examination was 8.9 years. A total of 76 Dogs died during follow-up, leading to a median survival time from geriatric examination of 4.4 years. After adjustment for demographic and biological variables, an increased alanine amionotransferase level (adjusted Hazard Ratio (adjusted HR), 6.2; 95% confidence interval [95%CI], 2.0-19.0; P
Caroline Gilbert - One of the best experts on this subject based on the ideXlab platform.
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investigation of risk factors for mortality in aged Guide Dogs a retrospective cohort study
Preventive Veterinary Medicine, 2016Co-Authors: S Hoummady, J Hua, C Muller, Jeanlouis Pouchelon, M Blondot, Caroline Gilbert, Loic DesquilbetAbstract:The overall median lifespan of domestic Dogs has been estimated to 9-12 years, but little is known about risk factors for mortality in aged and a priori healthy Dogs. The objective of this retrospective cohort study was to determine which characteristics are associated with mortality in aged and a priori healthy Guide Dogs, in a retrospective cohort study of 116 Guide Dogs followed from a systematic geriatric examination at the age of 8-10 years old. A geriatric grid collected the clinical data and usual biological parameters were measured at the time of examination. Univariate (Kaplan-Meier estimates) and multivariable (Cox proportional hazard model) survival analyses were used to assess the associations with time to all-cause death. The majority of Dogs were Golden Retrievers (n=48) and Labrador Retrievers (n=27). Median age at geriatric examination was 8.9 years. A total of 76 Dogs died during follow-up, leading to a median survival time from geriatric examination of 4.4 years. After adjustment for demographic and biological variables, an increased alanine amionotransferase level (adjusted Hazard Ratio (adjusted HR), 6.2; 95% confidence interval [95%CI], 2.0-19.0; P<0.01), presenting skin nodules (adjusted HR, 1.9; 95% CI, 1.0-3.4; P=0.04), and not being a Labrador Retriever (adjusted HR, 3.3; 95%CI, 1.4-10; P<0.01) were independently associated with a shorter time to death. This study documents independent associations of alanine aminotransferase level, skin nodules and breed with mortality in aged Guide Dogs. These results may be useful for preventive medical care when conducting a geriatric examination in working Dogs.
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Investigation of risk factors for mortality in aged Guide Dogs: A retrospective cohort study.
Preventive veterinary medicine, 2016Co-Authors: S Hoummady, J Hua, C Muller, Jeanlouis Pouchelon, M Blondot, Caroline Gilbert, Loic DesquilbetAbstract:The overall median lifespan of domestic Dogs has been estimated to 9-12 years, but little is known about risk factors for mortality in aged and a priori healthy Dogs. The objective of this retrospective cohort study was to determine which characteristics are associated with mortality in aged and a priori healthy Guide Dogs, in a retrospective cohort study of 116 Guide Dogs followed from a systematic geriatric examination at the age of 8-10 years old. A geriatric grid collected the clinical data and usual biological parameters were measured at the time of examination. Univariate (Kaplan-Meier estimates) and multivariable (Cox proportional hazard model) survival analyses were used to assess the associations with time to all-cause death. The majority of Dogs were Golden Retrievers (n=48) and Labrador Retrievers (n=27). Median age at geriatric examination was 8.9 years. A total of 76 Dogs died during follow-up, leading to a median survival time from geriatric examination of 4.4 years. After adjustment for demographic and biological variables, an increased alanine amionotransferase level (adjusted Hazard Ratio (adjusted HR), 6.2; 95% confidence interval [95%CI], 2.0-19.0; P
Aaron D. Ames - One of the best experts on this subject based on the ideXlab platform.
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Hierarchical and Safe Motion Control for Cooperative Locomotion of Robotic Guide Dogs and Humans: A Hybrid Systems Approach
IEEE Robotics and Automation Letters, 2020Co-Authors: Kaveh Akbari Hamed, Vinay R. Kamidi, Alexander Leonessa, Aaron D. AmesAbstract:This letter presents a hierarchical control strategy based on hybrid systems theory, nonlinear control, and safety-critical systems to enable cooperative locomotion of robotic Guide Dogs and visually impaired people. We address high-dimensional and complex hybrid dynamical models that represent collaborative locomotion. At the high level of the control scheme, local and nonlinear controllers, based on the virtual constraints approach, are designed to induce exponentially stable dynamic gaits. The local controller for the leash is assumed to be a nonlinear controller that keeps the human in a safe distance from the dog while following it. At the lower level, a real-time quadratic programming (QP) is solved for modifying the local controllers of the robot as well as the leash to avoid obstacles. In particular, the QP framework is set up based on control barrier functions (CBFs) to compute optimal control inputs that guarantee safety while being close to the local controllers. The stability of the complex periodic gaits is investigated through the Poincare return map. To demonstrate the power of the analytical foundation, the control algorithms are transferred into an extensive numerical simulation of a complex model that represents cooperative locomotion of a quadrupedal robot, referred to as Vision 60, and a human model. The complex model has 16 continuous-time domains with 60 state variables and 20 control inputs.
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Hierarchical and Safe Motion Control for Cooperative Locomotion of Robotic Guide Dogs and Humans: A Hybrid Systems Approach
arXiv: Optimization and Control, 2019Co-Authors: Kaveh Akbari Hamed, Vinay R. Kamidi, Alexander Leonessa, Aaron D. AmesAbstract:This paper presents a hierarchical control strategy based on hybrid systems theory, nonlinear control, and safety-critical systems to enable cooperative locomotion of robotic Guide Dogs and visually impaired people. We address high-dimensional and complex hybrid dynamical models that represent collaborative locomotion. At the high level of the control scheme, local and nonlinear baseline controllers, based on the virtual constraints approach, are designed to induce exponentially stable dynamic gaits. The baseline controller for the leash is assumed to be a nonlinear controller that keeps the human in a safe distance from the dog while following it. At the lower level, a real-time quadratic programming (QP) is solved for modifying the baseline controllers of the robot as well as the leash to avoid obstacles. In particular, the QP framework is set up based on control barrier functions (CBFs) to compute optimal control inputs that guarantee safety while being close to the baseline controllers. The stability of the complex periodic gaits is investigated through the Poincare return map. To demonstrate the power of the analytical foundation, the control algorithms are transferred into an extensive numerical simulation of a complex model that represents cooperative locomotion of a quadrupedal robot, referred to as Vision 60, and a human model. The complex model has 16 continuous-time domains with 60 state variables and 20 control inputs.