Conversion Total Hip Arthroplasty: Perioperative and Postoperative Outcomes with the ABLE Approach

The ABLE™ Approach for Conversion Total Hip Arthroplasty decreases surgical duration and length of stayhttps://knowledgeconnection.mainehealth.org/lambrew-retreat-2023/1022/thumbnail.jp

From 'aisle' to 'labile': a hierarchical NART scale revealed by Mokken scaling

Decline in cognitive ability is a core diagnostic criterion for dementia. Knowing the extent of decline requires a baseline score from which change can be reckoned. In the absence of prior cognitive ability scores, vocabulary-based cognitive tests are used to estimate premorbid cognitive ability. It is important that such tests are short yet informative, to maximize information and practicability. The National Adult Reading Test (NART) is commonly used to estimate premorbid intelligence. People are asked to pronounce 50 words ranging from easy to difficult but whether its words conform to a hierarchy is unknown. Five hundred eighty-seven healthy community-dwelling older people with known age 11 IQ scores completed the NART as part of the Lothian Birth Cohort 1936 study. Mokken analysis was used to explore item responses for unidimensional, ordinal, and hierarchical scales. A strong hierarchical scale (“mini-NART”) of 23 of the 50 items was identified. These items are invariantly ordered across all ability levels. The validity of the interpretation of this briefer scale’s score as an estimate of premorbid ability was examined using the actual age 11 IQ score. The mini-NART accounted for a similar amount of the variance in age 11 IQ as the full NART (NART = 46.5%, mini-NART = 44.8%). The mini-NART is proposed as a useful short clinical tool to estimate prior cognitive ability. The mini-NART has clinical relevance, comprising highly discriminatory, invariantly ordered items allowing for sensitive measurement, and adaptive testing, reducing test administration time, and patient stress

Non-parametric item response theory applications in the assessment of dementia

This thesis sought to address the application of non-parametric item response theory (NIRT) to cognitive and functional assessment in dementia. Performance on psychometric tests is key to diagnosis and monitoring of dementia. NIRT can be used to improve the psychometric properties of tests used in dementia assessment in multiple ways: confirming an underlying unidimensional structure, establishing formal item hierarchical patterns of decline, increasing insight by examining item parameters such as difficulty and discrimination, and creating shorter tests. From a NIRT approach item difficulty refers to the ease with which an item is endorsed. Discrimination is an index of how well an item can differentiate between patients of varying levels of severity. Firstly I carried out a systematic review to identify applications of both parametric and non-parametric IRT to measures assessing global cognitive functioning in people with dementia. This review demonstrated that IRT can increase the interpretive power of cognitive assessment scales and confirmed the limited number of IRT analyses of cognitive scales in dementia populations. This thesis extended this approach by applying Mokken scaling analysis to commonly used measures of current cognitive ability (Addenbrooke’s Cognitive Examination-Revised (ACE-R)) and of premorbid cognitive ability (National Adult Reading Test (NART)). Differential item functioning (DIF) by diagnosis identified slight variations in the patterns of hierarchical decline in the ACE-R. These disease-specific sequences of decline could serve as an adjunct to diagnosis, for example where learning a name and address is a more difficult task than being orientated in time, late onset Alzheimer’s disease is a more probable diagnosis than mixed Alzheimer’s and vascular dementia. These analyses also allowed key items to be identified which can be used to create briefer scales (mini-ACE and Mini-NART) which have good psychometric properties. These scales are clinically relevant, comprising highly discriminatory, invariantly ordered items. They also allow sensitive measurement and adaptive testing and can reduce test administration time and patient stress. Impairment of functional abilities represents a crucial component of dementia diagnosis with performance on these functional tasks predictive of overall disease. A second aspect of this thesis, therefore, was the application of Mokken scaling analyses to measures of functional decline in dementia, specifically the Lawton Instrumental Activities of Daily Living (IADL) scale and Physical Self-Maintenance Scale (PSMS). While gender DIF was observed for several items, implying the likelihood of equal responses from men and women is not equal a generally consistent pattern of impairment in functional ability was observed across different types of dementia

The Mini-Addenbrooke's Cognitive Examination: a new assessment tool for dementia.

BACKGROUND/AIMS: We developed and validated the Mini-Addenbrooke's Cognitive Examination (M-ACE) in dementia patients. Comparisons were also made with the Mini Mental State Examination (MMSE). METHOD: The M-ACE was developed using Mokken scaling analysis in 117 dementia patients [behavioural variant frontotemporal dementia (bvFTD), n = 25; primary progressive aphasia (PPA), n = 49; Alzheimer's disease (AD), n = 34; corticobasal syndrome (CBS), n = 9] and validated in an independent sample of 164 dementia patients (bvFTD, n = 23; PPA, n = 82; AD, n = 38; CBS, n = 21) and 78 controls, who also completed the MMSE. RESULTS: The M-ACE consists of 5 items with a maximum score of 30. Two cut-offs were identified: (1) ≤25/30 has both high sensitivity and specificity, and (2) ≤21/30 is almost certainly a score to have come from a dementia patient regardless of the clinical setting. The M-ACE is more sensitive than the MMSE and is less likely to have ceiling effects. CONCLUSION: The M-ACE is a brief and sensitive cognitive screening tool for dementia. Two cut-offs (25 or 21) are recommended.This work was supported by funding to Forefront, a collaborative research group dedicated to the study of frontotemporal dementia and motor neurone disease, by the National Health and Medical Research council (NHMRC) of Australia program grant (1037746) and the Australian Research Council (ARC) Centre of Excellence in Cognition and Its Disorders Memory Node (CE110001021). S.H. is supported by the Graham Linford Fellowship from the Motor Neurone Disease Research Institute of Australia. S.M. is supported by Alzheimer Scotland (PhD Studentship). F.L. is supported by an Australian Postgraduate Award (PhD Scholarship). K.D. is supported by NIHR Cambridge Biomedical Research Centre. S.A. is supported by the NIHR Biomedical Research Centre, Oxford. C.R.B. is supported by a Clinician Scientist Fellowship from the Medical Research Council (MR/K010395/1). J.B.R. is supported by the Wellcome Trust (088324), Medical Research Council, McDonnell Foundation and the NIHR (Cambridge Biomedical Research Centre and Biomedical Research Unit in Dementia). E.M. is supported by the NHMRC Early Career Fellowship (1016399) and Alzheimer Association USA. J.R.H. is supported by an ARC Federation Fellowship (FF0776229).This is the final version of the article. It first appeared from Karger via http://dx.doi.org/10.1159/00036604

The application of retinal fundus camera imaging in dementia:A systematic review

INTRODUCTION: The ease of imaging the retinal vasculature, and the evolving evidence suggesting this microvascular bed might reflect the cerebral microvasculature, presents an opportunity to investigate cerebrovascular disease and the contribution of microvascular disease to dementia with fundus camera imaging. METHODS: A systematic review and meta-analysis was carried out to assess the measurement of retinal properties in dementia using fundus imaging. RESULTS: Ten studies assessing retinal properties in dementia were included. Quantitative measurement revealed significant yet inconsistent pathologic changes in vessel caliber, tortuosity, and fractal dimension. Retinopathy was more prevalent in dementia. No association of age-related macular degeneration with dementia was reported. DISCUSSION: Inconsistent findings across studies provide tentative support for the application of fundus camera imaging as a means of identifying changes associated with dementia. The potential of fundus image analysis in differentiating between dementia subtypes should be investigated using larger well-characterized samples. Future work should focus on refining and standardizing methods and measurements

Ultra-Widefield Imaging of the Retinal Macrovasculature in Parkinson Disease Versus Controls With Normal Cognition Using Alpha-Shapes Analysis

Purpose: To investigate retinal vascular characteristics using ultra-widefield (UWF) scanning laser ophthalmoscopy in Parkinson disease (PD).Methods: Individuals with an expert-confirmed clinical diagnosis of PD and controls with normal cognition without PD underwent UWF imaging (California, Optos). Patients with diabetes, uncontrolled hypertension, glaucoma, dementia, other movement disorders, or known retinal or optic nerve pathology were excluded. Images were analyzed using Vasculature Assessment and Measurement Platform for Images of the Retina (VAMPIRE-UWF; Universities of Edinburgh and Dundee, UK) software which described retinal vessel width gradient and tortuosity, vascular network fractal dimension, as well as alpha-shape analysis to further characterize vascular morphology [complexity (Opαmin) and spread (OpA)].Results: In the PD cohort, 53 eyes of 38 subjects, and in the control cohort, 51 eyes of 33 subjects were assessed. Eyes with PD had more tortuous retinal arteries in the superotemporal quadrant (p = 0.043). In eyes with PD, alpha-shape analysis revealed decreased OpA, indicating less retinal vasculature spread compared to controls (p = 0.032). Opαmin was decreased in PD (p = 0.044), suggesting increased vascular network complexity. No differences were observed in fractal dimension in any ROI.Conclusions: This pilot study suggests that retinal vasculature assessment on UWF images using alpha-shape analysis reveals differences in retinal vascular network spread and complexity in PD and may be a more sensitive metric compared to fractal dimension.Translational Relevance: Retinal vasculature assessment using these novel methods may be useful in understanding ocular manifestations of PD and the development of retinal biomarkers

Ultra-Widefield Imaging of the Retinal Macrovasculature in Parkinson Disease Versus Controls With Normal Cognition Using Alpha-Shapes Analysis

PURPOSE: To investigate retinal vascular characteristics using ultra-widefield (UWF) scanning laser ophthalmoscopy in Parkinson disease (PD).METHODS: Individuals with an expert-confirmed clinical diagnosis of PD and controls with normal cognition without PD underwent Optos California UWF imaging. Patients with diabetes, uncontrolled hypertension, glaucoma, dementia, other movement disorders, or known retinal or optic nerve pathology were excluded. Images were analyzed using Vasculature Assessment and Measurement Platform for Images of the Retina (VAMPIRE-UWF) software, which describes retinal vessel width gradient and tortuosity, provides vascular network fractal dimensions, and conducts alpha-shape analysis to further characterize vascular morphology (complexity, Opαmin; spread, OpA).RESULTS: In the PD cohort, 53 eyes of 38 subjects were assessed; in the control cohort, 51 eyes of 33 subjects were assessed. Eyes with PD had more tortuous retinal arteries in the superotemporal quadrant (P = 0.043). In eyes with PD, alpha-shape analysis revealed decreased OpA, indicating less retinal vasculature spread compared to controls (P = 0.032). Opαmin was decreased in PD (P = 0.044), suggesting increased vascular network complexity. No differences were observed in fractal dimension in any region of interest.CONCLUSIONS: This pilot study suggests that retinal vasculature assessment on UWF images using alpha-shape analysis reveals differences in retinal vascular network spread and complexity in PD and may be a more sensitive metric compared to fractal dimension.TRANSLATIONAL RELEVANCE: Retinal vasculature assessment using these novel methods may be useful in understanding ocular manifestations of PD and the development of retinal biomarkers.</p