Precision and accuracy of quantitative scanning transmission electron microscopy (STEM) methods such as ptychography, and the mapping of electric, magnetic, and strain fields depend on the dose. Reasonable acquisition time requires high beam current and the ability to quantitatively detect both large and minute changes in signal. A new hybrid pixel array detector (PAD), the second-generation Electron Microscope Pixel Array Detector (EMPAD-G2), addresses this challenge by advancing the technology of a previous generation PAD, the EMPAD. The EMPAD-G2 images continuously at a frame-rates up to 10 kHz with a dynamic range that spans from low-noise detection of single electrons to electron beam currents exceeding 180 pA per pixel, even at electron energies of 300 keV. The EMPAD-G2 enables rapid collection of high-quality STEM data that simultaneously contain full diffraction information from unsaturated bright-field disks to usable Kikuchi bands and higher-order Laue zones. Test results from 80 to 300 keV are presented, as are first experimental results demonstrating ptychographic reconstructions, strain and polarization maps. We introduce a new information metric, the maximum usable imaging speed (MUIS), to identify when a detector becomes electron-starved, saturated or its pixel count is mismatched with the beam current.

Background: For the rising number of people living with dementia, cost-effective community-based interventions to support psychosocial care are needed. The FindMyApps program helps people with dementia and their caregivers learn to use tablet computers and find user-friendly apps that facilitate self-management and engagement in meaningful activities. This definitive trial builds on previous feasibility pilot trials of FindMyApps and further evaluates cost-effectiveness.

Method: This is a protocol for a non-blinded randomized controlled trial (RCT) with two arms (intervention and usual care). 150 dyads (person with dementia and their carer) will be recruited. Participants must be resident in the community, with a diagnosis of Mild Cognitive Impairment or mild dementia (Mini Mental-State Examination 17-26, or Global Deterioration Scale 3-4. Dyads will be randomly assigned in equal proportions to receive either the FindMyApps intervention (experimental arm) or usual care (control arm). Primary outcomes measured at 3 months will be: patient self-management and social participation; caregiver sense of competence. Data will be collected through questionnaires filled in by the researcher (patient outcomes) or participants themselves (carer outcomes). In addition to a main effect analysis, a cost-effectiveness analysis will take place. In line with Medical Research Council (MRC) guidance for the evaluation of complex interventions, a process analysis will be undertaken, to identify factors that may influence trial outcomes. Semi-structured interviews and remotely collected data regarding use of the FindMyApps app will support the process analysis.

Result: Results of this study are expected in 2022. The study will be adequately powered to detect at least a moderate effect size of the intervention with respect to the primary outcomes.

Conclusion: This study will investigate the effectiveness and cost-effectiveness of the FindMyApps intervention. The results of the study will provide strong evidence to support or oppose scaling up implementation of the intervention. This is also an example of how the MRC framework for the evaluation of complex interventions can be implemented in practice. In a field which is often criticized for a lack of high quality evidence, randomized controlled trials should be applied more frequently designed for the robust and transparent evaluation of digital tools and technologies.