Detecting HIV associated neurocognitive disorders (HAND) using neurocognitive assessment test in Uganda

A research report submitted to the Faculty of Health Sciences, University of Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Epidemiology. August, 2017.Background: HIV associated neurocognitive disorders (HAND), are a well-established consequence of HIV infection yet there is a lack of normative data required for diagnosis in Sub-Saharan Africa. Screening tools such as the International HIV dementia scale (IHDS) that are routinely used in the Sub-Saharan African region have questionable validity. This study investigates the use of the neuropsychological test battery in the detection of HAND in the absence of normative data. Further, the construct validity of the IHDS in the detection of HAND in the Ugandan context is examined. Methods Secondary data from a longitudinal Mental Health study carried out in Uganda were analysed. Information from a total of 1121 patients who underwent neuropsychological assessment in the main study qualified for the present study. A descriptive analysis of the neuropsychological performance of the study participants was conducted. To assess the relationship between demographic factors and the neurocognitive test scores of the neuropsychological test battery, multiple linear regression models were fitted. To determine how well the neuropsychological test battery predicted the IHDS score, a receiver-operating curve (ROC) analysis was conducted. The construct validity of the IHDS in detecting HAND in the Ugandan population was then assessed using ROC analysis and published normative data. Results The total study population was 1,121 participants, with the majority being female (66.3%) while almost 62% had only primary school education. The mean age of the study participants was 35.0±9.3 years. Using the IHDS, 73.3% of the HIV infected patients were identified to be at risk of developing HIV associated dementia (HAD). Using the Frascati criteria and published normative data, only 9.1% of the HIV infected patients had HAND. Ageing, being female, having a lower socio-economic score and having lower levels of education were identified as predictors for poor neurocognitive performance. Poor performance in the neurocognitive measures to assess gross and fine motor function was directly proportional to poor performance in the IHDS (score ≥10 points). Better performance in the neurocognitive measures to assess verbal leaning/working memory and attention/working memory was directly proportional to poor performance in the IHDS (score ≥10 points). The neurocognitive tests discriminated modestly between patients at risk of developing HAD and those that were not at risk of developing HAD (sensitivity=64.62%; specificity=66.67%). At the recommended cut-off score of 10 points, the IHDS had poor ability to identify patients with HAND (sensitivity=34.54%) and a high ability to identify patients without HAND (specificity=90.74%). At a cut-off point of 7 points, the IHDS discriminated modestly between patients with HAND and those without (sensitivity=65.66%; specificity=58.52%). Conclusion The neuropsychological test battery used in the present study discriminated modestly among HIV patients at risk of developing HIV associated dementia and those that were not at risk of developing dementia. In the Ugandan population, the construct validity of the IHDS in the diagnosis of HAND was poor. Further work is required to produce an algorithm to detect HAND in the absence of normative data. This includes an inclusion of important clinical biomarkers, exploration of further demographic confounders as well strengthening of the HAND diagnostic criteria using the neuropsychological test battery.LG201

The estimation of body mass from human skeletal remains

The ability to estimate body mass from human skeletal remains with a high degree of accuracy would be significant for the identification of identifying unknown individuals in a forensic anthropology context, documenting secular change in modern populations, and evaluating any prevalence in prehistoric populations. Modern research investigating body mass incorporates one of two models: morphometric and biomechanical. The morphometric model views the body as a cylinder, where weight estimates are gathered from extreme points such as the breadth of the pelvis. In contrast, the biomechanical model incorporates engineering principles and biology to understand the effects of mass on the human skeleton. Only the biomechanical model can accommodate extremes in body mass, such as those exhibited by modern populations. This study examined the accuracy of estimating body mass (obesity in particular) from human skeletal remains using a suite of traits shown to be significant in previous studies, including documented biomechanical analysis of obese individuals involving gait and sit-to-stand (STS) movements. It was hypothesized that using a combination of methods, body mass could be estimated with a high degree of accuracy. Using a large skeletal sample (n = 191), composed of male and females with documented age, weight, and height, the following three variables were examined: (1) the spinal manifestation of diffuse idiopathic skeletal hyperostosis (DISH), (2) osteoarthritis (OA) of the tibiae, and (3) external femoral dimensions. These were then subject to statistical tests. Spearman's rank-order correlation and Mann-Whitney U tests showed significant relationships between DISH and obesity in females (p<.05), but not for males. The presence and severity of OA of the medial condyles were also significantly related to BMI in females (p<.05). In males, the relationship between BMI and OA was only significant on the condyles of the right tibiae (p<.05). Finally, ANOVA and Pearson's product-moment correlation tests were performed to evaluate the cross-sectional dimensions of the femur. The effect of age, stature, and BMI were also examined. ANOVA results showed a significant effect between BMI and M-L cross-sectional dimensions among both sexes (p<.05). Initial Pearson's tests performed separately on males and females showed no significant correlations; however, after the sexes were pooled, small to moderate negative correlations between the M-L/A-P ratio along the diaphysis of the femur and BMI were found. Finally, multiple regression analyses were performed. The models for both sexes with all ten variables was statistically significant for BMI. The final accuracy rate was 78.48% for females and 84.37% for males. The primary goal of this study was to evaluate Moore's (2008) body mass estimation study. In this investigation, however, all dimensions of the femur were performed using an osteometric board and sliding calipers following the guidelines used by Agostini and Ross (2011). The results of this study paralleled many of the observations seen in previous studies, particularly the M-L lateral widening of the femur. Future research should continue to examine the relationship of DISH and OA with body mass, particularly regarding the varying manifestations between the sexes and confounding factors such as age

Biometric information analyses using computer vision techniques.

Biometric information analysis is derived from the analysis of a series of physical and biological characteristics of a person. It is widely regarded as the most fundamental task in the realms of computer vision and machine learning. With the overwhelming power of computer vision techniques, biometric information analysis have received increasing attention in the past decades. Biometric information can be analyzed from many sources including iris, retina, voice, fingerprint, facial image or even the way one walks with. Facial image and gait, because of their easy availability, are two preferable sources of biometric information analysis. In this thesis, we investigated the development of most recent computer vision techniques and proposed various state-of-the-art models to solve the four principle problems in biometric information analysis including the age estimation, age progression, face retrieval and gait recognition. For age estimation, the modeling has always been a challenge. Existing works model the age estimation problem as either a classification or a regression problem. However, these two types of models are not able to reveal the intrinsic nature of human age. To this end, we proposed a novel hierarchical framework and a ordinal metric learning based method. In the hierarchical framework, a random forest based clustering method is introduced to find an optimal age grouping protocol. In the ordinal metric learning approach, the age estimation is solved by learning an subspace where the ordinal structure of the data is preserved. Both of them have achieved state-of-the-art performance. For face retrieval, specifically under a cross-age setting, we first proposed a novel task, that is given two images, finding the target image which is supposed to have the same identity with the first input and the same age with the second input. To tackle this task, we proposed a joint manifold learning method that can disentangle the identity with the age information. Accompanied with two independent similarity measurements, the retrieval can be easily performed. For aging progression, we also proposed a novel task that has never been considered. We devoted to fuse the identity of one image with the age of another image. By proposing a novel framework based on generative adversarial networks, our model is able to generate close-to-realistic images. Lastly, although gait recognition is an ideal long-distance biometric information task that makes up the shortfall of facial image, existing works are not able to handle large scale data with various view angles. We proposed a generative model to solve this term and achieved promising results. Moreover, our model is able to generate evidences for forensic usage

VI Workshop on Computational Data Analysis and Numerical Methods: Book of Abstracts

The VI Workshop on Computational Data Analysis and Numerical Methods (WCDANM) is going to be held on June 27-29, 2019, in the Department of Mathematics of the University of Beira Interior (UBI), Covilhã, Portugal and it is a unique opportunity to disseminate scientific research related to the areas of Mathematics in general, with particular relevance to the areas of Computational Data Analysis and Numerical Methods in theoretical and/or practical field, using new techniques, giving especial emphasis to applications in Medicine, Biology, Biotechnology, Engineering, Industry, Environmental Sciences, Finance, Insurance, Management and Administration. The meeting will provide a forum for discussion and debate of ideas with interest to the scientific community in general. With this meeting new scientific collaborations among colleagues, namely new collaborations in Masters and PhD projects are expected. The event is open to the entire scientific community (with or without communication/poster)

Physical Fitness Training in Patients with Subacute Stroke (PHYS-STROKE): multicentre, randomised controlled, endpoint blinded trial

OBJECTIVE: To determine the safety and efficacy of aerobic exercise on activities of daily living in the subacute phase after stroke. DESIGN: Multicentre, randomised controlled, endpoint blinded trial. SETTING: Seven inpatient rehabilitation sites in Germany (2013-17). PARTICIPANTS: 200 adults with subacute stroke (days 5-45 after stroke) with a median National Institutes of Health stroke scale (NIHSS, range 0-42 points, higher values indicating more severe strokes) score of 8 (interquartile range 5-12) were randomly assigned (1:1) to aerobic physical fitness training (n=105) or relaxation sessions (n=95, control group) in addition to standard care. INTERVENTION: Participants received either aerobic, bodyweight supported, treadmill based physical fitness training or relaxation sessions, each for 25 minutes, five times weekly for four weeks, in addition to standard rehabilitation therapy. Investigators and endpoint assessors were masked to treatment assignment. MAIN OUTCOME MEASURES: The primary outcomes were change in maximal walking speed (m/s) in the 10 m walking test and change in Barthel index scores (range 0-100 points, higher scores indicating less disability) three months after stroke compared with baseline. Safety outcomes were recurrent cardiovascular events, including stroke, hospital readmissions, and death within three months after stroke. Efficacy was tested with analysis of covariance for each primary outcome in the full analysis set. Multiple imputation was used to account for missing values. RESULTS: Compared with relaxation, aerobic physical fitness training did not result in a significantly higher mean change in maximal walking speed (adjusted treatment effect 0.1 m/s (95% confidence interval 0.0 to 0.2 m/s), P=0.23) or mean change in Barthel index score (0 (-5 to 5), P=0.99) at three months after stroke. A higher rate of serious adverse events was observed in the aerobic group compared with relaxation group (incidence rate ratio 1.81, 95% confidence interval 0.97 to 3.36). CONCLUSIONS: Among moderately to severely affected adults with subacute stroke, aerobic bodyweight supported, treadmill based physical fitness training was not superior to relaxation sessions for maximal walking speed and Barthel index score but did suggest higher rates of adverse events. These results do not appear to support the use of aerobic bodyweight supported fitness training in people with subacute stroke to improve activities of daily living or maximal walking speed and should be considered in future guidelines. TRIAL REGISTRATION: ClinicalTrials.gov NCT01953549

Gait analysis does not correlate with clinical and MR imaging parameters in patients with symptomatic lumbar spinal stenosis

<p>Abstract</p> <p>Background</p> <p>Parameters of MR imaging play a pivotal role in diagnosing lumbar spinal stenosis (LSS), and serve as an important tool in clinical decision-making. Despite the importance of MR imaging, little is known about the correlation between MRI parameters, objective gait analysis, and clinical presentation of patients with lumbar spinal stenosis.</p> <p>Methods</p> <p>Sixty-three patients from our clinic with symptomatic lumbar spinal stenosis leading to neurogenic claudication were included in this study in accordance with clearly defined inclusion and exclusion criteria. Clinical parameters, the depression status (CES-D), the subjective functional back capacity (FFbH-R), and the absolute walking distance (treadmill gait analysis) were quantitatively evaluated in correlation with morphological data from radiographs and MRI scans, in order to determine the coherence of spinal canal narrowing and clinical affliction.</p> <p>Results</p> <p>Sixty-three consecutive paents with a median age of 68 years and a mean Body Mass Index (BMI) of 28 were included in the study. The mean FFbH-R score displayed a value of 44 percent. The depression status scored an average of 13.6. Objectively measured walking distances showed a mean value of 172 m until patients stopped due to leg pain. A significant difference was found between the objectively measured and the subjectively estimated walking distance. The mean cross-sectional area of the dural tube at L1/2 was 113 mm², at L2/3 94 mm², at L3/4 73 mm², at L4/5 65 mm², and at L5/S1 93 mm². The mean overall cross sectional area of the dural tube of all segments did not correlate with the objectively measured walking distance. However, bivariate analysis found that the BMI (tau b = -0.194), functional back capacity (tau b = -0.225), and the cross sectional area of the dural tube at L1/2 (tau b = -0.188) correlated significantly with the objectively measured walking distance.</p> <p>Conclusion</p> <p>According to the results of this study MRI findings failed to show a major clinical relevance when evaluating the walking distance in patients with lumbar spinal stenosis and, therefore, should be treated with some caution as a predictor of walking distance. In determining the disease pattern of spinal stenosis functional back capacity and BMI might play a more active role than previously thought.</p