Adding Neural Network Controllers to Behavior Trees without Destroying Performance Guarantees

In this paper, we show how Behavior Trees that have performance guarantees, in terms of safety and goal convergence, can be extended with components that were designed using machine learning, without destroying those performance guarantees. Machine learning approaches such as reinforcement learning or learning from demonstration can be very appealing to AI designers that want efficient and realistic behaviors in their agents. However, those algorithms seldom provide guarantees for solving the given task in all different situations while keeping the agent safe. Instead, such guarantees are often easier to find for manually designed model based approaches. In this paper we exploit the modularity of Behavior trees to extend a given design with an efficient, but possibly unreliable, machine learning component in a way that preserves the guarantees. The approach is illustrated with an inverted pendulum example.Comment: Submitted to IEEE Transactions on Game

Older adults and withdrawal from benzodiazepine hypnotics in general practice: effects on cognitive function, sleep, mood and quality of life

Background: Older adults are the main recipients of repeat prescriptions for benzodiazepine (BZD) hypnotics. BZDs can impair cognitive function and may not aid sleep when taken continuously for years. This study therefore aimed to determine if withdrawing from BZDs leads to changes in patients' cognitive function, quality of life, mood and sleep. Method: One hundred and ninety-two long-term users of BZD hypnotics, aged [gt-or-equal, slanted]65 years, were identified in 25 general practices. One hundred and four who wished to withdraw were randomly allocated to one of two groups under double-blind, placebo controlled conditions: group A's BZD dose was tapered from week 1 of the trial; group B were given their usual dose for 12 weeks and then it was tapered. An additional group (C) of 35 patients who did not wish to withdraw from BZDs participated as ‘continuers’. All patients were assessed at 0, 12 and 24 weeks and 50% were re-assessed at 52 weeks. Results: Sixty per cent of patients had taken BZDs continuously for >10 years; 27% for >20 years. Of all patients beginning the trial, 80% had successfully withdrawn 6 months later. There was little difference between groups A and B, but these groups differed from continuers (C) in that the performance of the withdrawers on several cognitive/psychomotor tasks showed relative improvements at 24 or 52 weeks. Withdrawers and continuers did not differ in sleep or BZD withdrawal symptoms. Conclusions: These results have clear implications for clinical practice. Withdrawal from BZDs produces some subtle cognitive advantages for older people, yet little in the way of withdrawal symptoms or emergent sleep difficulties. These findings also suggest that, taken long-term, BZDs do not aid sleep

The UK experience of promoting dementia recognition and management in primary care

BACKGROUND: The early and timely recognition of dementia syndrome is a policy imperative in many countries. In the UK the achievement of earlier and timelier recognition has been pursued through educational interventions, incentivisation of general practitioners and the promotion of a network of memory clinics. OBJECTIVE: The effectiveness of education, incentivisation and memory clinic activity are unknown. This article analyses data from different sources to evaluate the impact of these interventions on the incidence and prevalence of dementia, and the diagnostic performance of memory clinics. MATERIAL AND METHODS: Three data sources were used: 1) aggregated, anonymised data from a network of general practices using the same electronic medical record software, The Health Information Network (THIN), 2) UK Health & Social Care Information Centre data reports and 3) Responses to Freedom of Information Act requests. RESULTS: Educational interventions did not appear to change the recorded incidence of dementia syndrome. There was no apparent effect of education, incentives or memory clinic activity on the reported incidence of dementia syndrome between 1997 and 2011 but there were signs of change in the documentation of consultations with people with dementia. There was no clear impact of incentivisation and memory clinic activity in prevalence data. Memory clinics are seeing more patients but fewer are being diagnosed with dementia. CONCLUSION: It is not clear why there has been no upturn in documented incidence or prevalence of dementia syndrome despite substantial efforts and this requires further investigation to guide policy changes. The performance of memory clinics also needs further study

Smoking as a predictor of frailty: a systematic review

BACKGROUND: Evidence on longitudinal associations between smoking and frailty is scarce. The objective of this study was to systematically review the literature on smoking as a predictor of frailty changes among community-dwelling middle-aged and older population. METHODS: A systematic search was performed using three electronic databases: MEDLINE, Embase and Scopus for studies published from 2000 through May 2015. Reference lists of relevant articles, articles shown as related citations in PubMed and articles citing the included studies in Google Scholar were also reviewed. Studies were included if they were prospective observational studies investigating smoking status as a predictor and subsequent changes in frailty, defined by validated criteria among community-dwelling general population aged 50 or older. A standardised data collection tool was used to extract data. Methodological quality was examined using the Newcastle-Ottawa Scale for cohort studies. RESULTS: A total of 1020 studies were identified and systematically reviewed for their titles, abstracts and full-text to assess their eligibilities. Five studies met inclusion criteria and were included in this review. These studies were critically reviewed and assessed for validity of their findings. Despite different methodologies and frailty criteria used, four of the five studies consistently showed baseline smoking was significantly associated with developing frailty or worsening frailty status at follow-up. Although not significant, the other study showed the same trend in male smokers. It is of note that most of the estimate measures were either unadjusted or only adjusted for a limited number of important covariates. CONCLUSIONS: This systematic review provides the evidence of smoking as a predictor of worsening frailty status in community-dwelling population. Smoking cessation may potentially be beneficial for preventing or reversing frailty

Socio-demographic characteristics, lifestyle factors and burden of morbidity associated with self-reported hearing and vision impairments in older British community-dwelling men: a cross-sectional study.

BACKGROUND: Hearing and vision problems are common in older adults. We investigated the association of self-reported sensory impairment with lifestyle factors, chronic conditions, physical functioning, quality of life and social interaction. METHODS: A population-based cross-sectional study of participants of the British Regional Heart Study aged 63-85 years. RESULTS: A total of 3981 men (82% response rate) provided data. Twenty-seven per cent (n = 1074) reported hearing impairment including being able to hear with aid (n = 482), being unable to hear (no aid) (n = 424) and being unable to hear despite aid (n = 168). Three per cent (n = 124) reported vision impairment. Not being able to hear, irrespective of use of hearing aid, was associated with poor quality of life, poor social interaction and poor physical functioning. Men who could not hear despite hearing aid were more likely to report coronary heart disease (CHD) [age-adjusted odds ratios (ORs) 1.89 (95% confidence interval 1.36-2.63)]. Vision impairment was associated with symptoms of CHD including breathlessness [OR 2.06 (1.38-3.06)] and chest pain [OR 1.58 (1.07-2.35)]. Vision impairment was also associated with poor quality of life, poor social interaction and poor physical functioning. CONCLUSIONS: Sensory impairment is associated with poor physical functioning, poor health and poor social interaction in older men. Further research is warranted on pathways underlying these associations

Vitamin D Supplementation as a Potential Cause of U-shaped Associations between Vitamin D Levels and Negative Health Outcomes: A Decision Tree Analysis for Risk of Frailty

Background: A recent controversy in vitamin D research is a “U-shaped association”, with elevated disease risks at both high and low 25-hydroxyvitamin D (25 (OH) D) levels. Methods: This is a cross-sectional study of 238 male nursing home veterans in Hawaii. Classification and regression tree (CART) analysis identified groups based on 25 (OH) D and vitamin D supplementation for frailty risk. Characteristics were examined and compared across the groups using logistic regression and receiver operating characteristic (ROC) curve analyses. Results: CART analysis identified three distinct groups: vitamin D supplement users (n = 86), non-users with low vitamin D (n = 55), and non-users with high vitamin D (n = 97). Supplement users were the most frail, but had high mean 25 (OH) D of 26.6 ng/mL, which was compatible with 27.1 ng/mL in non-users with high vitamin D, while mean 25 (OH) D of non-users with low vitamin D was 11.7 ng/mL. Supplement users and non-users with low vitamin D were significantly more likely to be frail (odds ratio (OR) = 9.90, 95% CI = 2.18–44.86, p = 0.003; OR = 4.28, 95% CI = 1.44–12. 68, p = 0.009, respectively), compared with non-users with low vitamin D. ROC curve analysis showed the three groups significantly predicted frailty (area under the curve = 0.73), with sensitivity of 64.4% and specificity of 76.7%, while 25 (OH) D did not predict frailty. Conclusions: In these nursing home veterans, vitamin D supplement users were the most frail but with high 25 (OH) D. This can potentially be a cause of U-shaped associations between vitamin D levels and negative health outcomes

Managing behavioural and psychological symptoms in community dwelling older people with dementia:1. A systematic review of the effectiveness of interventions

© 2018 The Author(s) This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Two-thirds of people living with dementia live at home in the UK and many experience distressing behavioural and psychological symptoms. This systematic review evaluates the effectiveness of non-pharmacological interventions for behavioural and psychological symptoms among community-dwelling people living with dementia. Methods: This two-stage review undertook an initial mapping of the literature followed by a systematic review of relevant randomised controlled trials. We searched electronic databases for pertinent studies reporting outcomes from interventions from January 2000 to March 2015 and updated searches in October 2016. We included studies that considered behavioural and psychological symptom management for older people living with dementia who live at home and excluded studies conducted in long-term care settings. This paper presents findings from a narrative synthesis of 48 randomised controlled trials evaluating interventions for people living with dementia alone, family carers alone and patient-carer dyads. Results: We retrieved 17,871 de-duplicated records and screened them for potential inclusion. Evidence from 48 randomised controlled trials suggests that family carer training and educational programmes that target problem behaviours and potential triggers can improve outcomes. Nurses and occupational therapists appear to help people with dementia with behavioural and psychological symptoms, but professional comparisons are lacking and there is no shared language about or understanding of behavioural and psychological symptoms amongst professionals, or between professionals and family carers. Conclusions: Future research should focus on the effectiveness of components of multi-faceted programmes and their cost effectiveness and include qualitative data to better target interventions for behavioural and psychological symptoms. It is important to consider family carer readiness to use non-pharmacological strategies and to develop a shared language about the inherent needs and communications of behavioural and psychological symptoms.Peer reviewe

Four new stygobitic cirolanids (Crustacea: Isopoda) from the Caribbean: with remarks on intergeneric limits in some cirolanids

Four new stygobitic and troglomorphic cirolanids are described from various parts of the Caribbean. Cirolana (C.) troglexuma n. sp. is described from a cave on one of the Exuma Cays, Bahamas; two subgenera are recognized in g.Cirolana: sg. Cirolana including troglexuma as only presently know stygobitic species, and sg. Anopsilana equally well represented by subterranean and by epigean species. Haptolana bowmani n. sp. and H. belizana n. sp. inhabit caves of Yucatan and Belize, respectively; interestingly they are both abundantly different from the Cuban species of this stygobenthic genus, showing more similarity with the species from Somalia and W. Australia. Jamaicalana pleoscissa n.g. n. sp. was discovered in a cave from Jamaica; the new genus has affinities with Anopsilana and Bahalana, but a combination of characters -some of them highly original- renders definition of a new genus necessary. Bahalana mayana Bowman should be removed from that genus, whereas Dodecalana yagerae Carpenter is an interesting species of Bahalana