We would also emphasize that instrument based assessment of capacity is only one part of a comprehensive evaluation of competency which includes consideration of diagnosis, psychiatric and/or cognitive symptomatology, risk involved in the situation, and individual and cultural differences. The development of empirically based tools for use in capacity evaluation should ultimately enhance the reliability and validity of assessment, yet clearly more research is needed to define and measure the constructs of decisional capacity. There appears to be strong evidence for good hetero-method validity for the measurement of understanding, mixed evidence for validity in the measurement of reasoning, and strong evidence for poor hetero-method validity for the concepts of appreciation and expressing a choice, although the latter is likely due to extreme range restrictions. Results find variable support for validity.
Instrument based assessment of these abilities is compared through investigation of a multi-trait multi-method matrix in 88 older adults with mild to moderate dementia. Gurrera, Ronald J.ĭoes instrument based evaluation of consent capacity increase the precision and validity of competency assessment or does ostensible precision provide a false sense of confidence without in fact improving validity? In this paper we critically examine the evidence for construct validity of three instruments for measuring four functional abilities important in consent capacity: understanding, appreciation, reasoning, and expressing a choice. Hopes and Cautions for Instrument- Based Evaluation of Consent Capacity: Results of a Construct Validity Study of Three Instruments For all outcome measures except average and peak pressures, at least two specimen models met the validation criteria with respect to experimental measurements for both articulations Contact area from the MRI- based model was very similar to the contact area measured directly from the images. Quantitative data from the model generally compared well with the experimental data for all specimens. Qualitatively, there was good correspondence between the MRI- based model data and experimental data, with consistent relative size, shape and location of radioscaphoid and radiolunate contact regions. Contact area was also measured directly from images acquired under load and compared to the experimental and model data. Validation was based on experimental versus model contact area, contact force, average contact pressure and peak contact pressure for the radioscaphoid and radiolunate articulations. Cartilage thickness was assumed uniform at 1.0 mm with an effective compressive modulus of 4 MPa.
Roland kullo series#
The carpal bone motions from the unloaded state to the loaded state were determined using a series of 3D image registrations. Geometric surface models of the radius, scaphoid and lunate (including cartilage) were constructed from the images acquired without the load. Images were also acquired during the loaded configuration used with the direct experimental measurements. Computer models were constructed based on MRI visualization of the cadaver specimens without load. For each experiment, a Pressurex film and a Tekscan sensor were sequentially placed into the radiocarpal joints during simulated grasp. We used a single validation criterion for multiple outcome measures to characterize the utility and overall validity of the modeling approach. The objective of this study was to validate the MRI- based joint contact modeling methodology in the radiocarpal joints by comparison of model results with invasive specimen-specific radiocarpal contact measurements from four cadaver experiments. MRI- based modeling for radiocarpal joint mechanics: validation criteria and results for four specimen-specific models.įischer, Kenneth J Johnson, Joshua E Waller, Alexander J McIff, Terence E Toby, E Bruce Bilgen, Mehmet
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