Optimal Number of States in Hidden Markov Models and its Application to the Detection of Human Movement

In this paper, Hidden Markov Model is applied to model human movements as to facilitate an automatic  detection of the same. A number of activities were simulated with the help of two persons. The four  movements considered are walking, sitting down-getting up, fall while walking and fall while standing. The data is acquired using a biaxial accelerometer attached to the person’s body. Data of the four body gestures were then trained to construct several Hidden Markov models for the two people. The problem is to get a good  representation of the data in terms of the number of states of the HMM. Standard general methods used for training pose some drawbacks i.e. the computational burden and initialisation process for the model estimate.  For this reason, a sequential pruning strategy is implemented to address the problems mentioned.Keywords: Hidden Markov Models, sequential pruning strategy, Bayesian Inference Criterio

ERS International Congress 2021: highlights from the Pulmonary Vascular Diseases Assembly

This article aims to summarise the latest research presented at the virtual 2021 European Respiratory Society (ERS) International Congress in the field of pulmonary vascular disease. In light of the current guidelines and proceedings, knowledge gaps are addressed and the newest findings of the various forms of pulmonary hypertension as well as key points on pulmonary embolism are discussed.Despite the comprehensive coverage of the guidelines for pulmonary embolism at previous conferences, discussions about controversies in the diagnosis and treatment of this condition in specific cases were debated and are addressed in the first section of this article.We then report on an interesting pro–con debate about the current classification of pulmonary hypertension.We further report on presentations on Group 3 pulmonary hypertension, with research exploring pathogenesis, phenotyping, diagnosis and treatment; important contributions on the diagnosis of post-capillary pulmonary hypertension are also included.Finally, we summarise the latest evidence presented on pulmonary vascular disease and COVID-19 and a statement on the new imaging guidelines for pulmonary vascular disease from the Fleischner Society

Isolated anterior cruciate ligament deficiency, knee scores and function.

The aim of this study was to ascertain whether there was a correlation between commonly used scoring scales used for follow-up study of management of knee problems and whether age, gender, and time interval between injury and management and type of management affect the assessment of outcome in the management of ACL insufficiency. One hundred and twelve patients who had received ACL reconstruction were identified from hospital records. Each of them received a package containing three questionnaires, namely the Lysholm knee score, Mothadi-QoL, and the Modified Cincinnati Rating Scale. The overall response rate was 55%. There was a relatively strong relationship between all three scores, with a very strong correlation between Cincinnati and Mohtadi questionnaires. The Lysholm score showed significant correlation between the method of treatment and outcome. Our study shows a good relationship between the three scoring systems, and helps to understand what questions should be asked to the patient with an ACL injury to elicit a true representation of their knee function

Pulmonary arterial hypertension associated with congenital heart disease: Comparison of clinical and anatomic-pathophysiologic classification

BACKGROUND: Between 5% and 10% of patients with congenital heart disease (CHD) develop pulmonary arterial hypertension (PAH-CHD). Patients can be classified using either a clinical or anatomic–pathophysiologic system. No study has previously utilized both systems in a large cohort of patients. METHODS: Two hundred forty consecutive PAH-CHD patients diagnosed at a pulmonary hypertension referral center during 1995 to 2014 were identified from our unit database. Baseline characteristics, treatment and survival data were retrieved and survival analyses was performed. RESULTS: Both systems identified clear differences in baseline characteristics between subgroups. The anatomic–pathophysiologic system identified patients with post-tricuspid defects as having superior survival from point of referral to those with pre-tricuspid or complex defects (p o 0.05). Survival from point of referral was, however, not significantly different when patients were grouped using the clinical classification, although survival in all 4 groups was superior to that of 175 patients with idiopathic pulmonary arterial hypertension. Older age and higher creatinine, lower transfer factor of the lung for DLCO percent predicted and FEV1 percent predicted were independent adverse prognostic factors. CONCLUSION: Both PAH-CHD classification systems identified groups of patients distinct in terms of baseline characteristics. In our cohort, however, only the anatomic–pathophysiologic classification identified significantly different survival from point of referral. The presence of adverse prognostic markers may be useful in identifying patients requiring more aggressive pulmonary vascular therap

Attitudes and barriers to pulmonary arterial hypertension screening in systemic sclerosis patients: A survey of UK-based rheumatologists

Objectives: The objectives were to explore rheumatologists’ current clinical screening practices of pulmonary arterial hypertension in patients with systemic sclerosis in the United Kingdom and to identify barriers to screening and consider potential solutions. Methods: A survey of 31 questions was developed and included six sections: clinician demographics, the importance of screening, screening practices, barriers to screening, treatment and patient education. The survey was disseminated among rheumatologists working in the United Kingdom. Results: Forty-four rheumatologists working in the United Kingdom participated in the study, and the majority completed all the questions. Around one-third (37.0%) worked in specialised systemic sclerosis units (university or general hospitals (54.5% and 45.4%, respectively)). The majority recognised that systemic sclerosis-pulmonary arterial hypertension is a major cause of morbidity and mortality. Over half (60.0%) reported using the DETECT algorithm to screen for systemic sclerosis-pulmonary arterial hypertension, although other algorithms were also sometimes used. All of the respondents utilised transthoracic echocardiogram, and almost all (95.0%) performed pulmonary function tests for screening purposes. Various challenges and barriers were identified relating to systemic sclerosis-pulmonary arterial hypertension screening, with the difficulty in interpreting results from other hospitals and extended wait times for diagnostic tests being the most reported (76.0% and 74.0%, respectively). Most respondents agreed that access to key investigations (87.0%), ongoing clinician education (82.0%), multidisciplinary meetings (79.5%) and a better understanding of proposed screening algorithms (79.5%) could be potential solutions. Conclusion: Screening patients with systemic sclerosis for pulmonary arterial hypertension is crucial to improve survival, but variable practices exist among UK rheumatologists. Solutions include educating healthcare professionals on guidelines, sharing information between centres and integrating care services

ERS International Congress 2021: highlights from the Pulmonary Vascular Diseases Assembly

This article aims to summarise the latest research presented at the virtual 2021 European Respiratory Society (ERS) International Congress in the field of pulmonary vascular disease. In light of the current guidelines and proceedings, knowledge gaps are addressed and the newest findings of the various forms of pulmonary hypertension as well as key points on pulmonary embolism are discussed. Despite the comprehensive coverage of the guidelines for pulmonary embolism at previous conferences, discussions about controversies in the diagnosis and treatment of this condition in specific cases were debated and are addressed in the first section of this article. We then report on an interesting pro–con debate about the current classification of pulmonary hypertension. We further report on presentations on Group 3 pulmonary hypertension, with research exploring pathogenesis, phenotyping, diagnosis and treatment; important contributions on the diagnosis of post-capillary pulmonary hypertension are also included. Finally, we summarise the latest evidence presented on pulmonary vascular disease and COVID-19 and a statement on the new imaging guidelines for pulmonary vascular disease from the Fleischner Society