Wearable Cane and App System for Improving Mobility in Toddlers/Pre-schoolers With Visual Impairment

Children with congenital severe visual impairment and blindness (SVI&B) are at greater risk of developing delays in motor and other developmental domains. This report describes a series of experiments conducted to evaluate a novel wearable cane and mobile application system prototype. The wearable cane and application system was tested on ability to (a) provide hands-free autonomous arc able to detect obstacles, level, and surface changes; (b) integrate into indoor/outdoor activities of a specialized pre-school for learners with SVI&B; and (c) be adopted by families, professionals and learners with SVI&B as a safe mobility solution. Sixteen stakeholders and 34 children under five with SVI&B evaluated the prototype system.Results: The project successfully created a hands-free wearable white cane that provided students with SVI&B under age five with next step warning when walking across a variety of terrain. Pre-school participants with SVI&B easily adopted the wearable cane into their activities with minimal to no prompting or instruction. The P20 prototype scored well across usability features, including maintaining consistent, hands-free, autonomous arc. The invention of a hands-free mobility tool was a significant outcome of this project. These data support that autonomous arc has the ability to provide developmentally appropriate safe mobility solution for toddlers with SVI&B

Quasi-static pipeline in electroconvulsive therapy computational modeling

Background: Computational models of current flow during Electroconvulsive Therapy (ECT) rely on the quasi-static assumption, yet tissue impedance during ECT may be frequency specific and change adaptively to local electric field intensity. Objectives: We systematically consider the application of the quasi-static pipeline to ECT under conditions where 1) static impedance is measured before ECT and 2) during ECT when dynamic impedance is measured. We propose an update to ECT modeling accounting for frequency-dependent impedance. Methods: The frequency content on an ECT device output is analyzed. The ECT electrode-body impedance under low-current conditions is measured with an impedance analyzer. A framework for ECT modeling under quasi-static conditions based on a single device-specific frequency (e.g., 1 kHz) is proposed. Results: Impedance using ECT electrodes under low-current is frequency dependent and subject specific, and can be approximated at >100 Hz with a subject-specific lumped parameter circuit model but at <100 Hz increased non-linearly. The ECT device uses a 2 μA 800 Hz test signal and reports a static impedance that approximate 1 kHz impedance. Combined with prior evidence suggesting that conductivity does not vary significantly across ECT output frequencies at high-currents (800–900 mA), we update the adaptive pipeline for ECT modeling centered at 1 kHz frequency. Based on individual MRI and adaptive skin properties, models match static impedance (at 2 μA) and dynamic impedance (at 900 mA) of four ECT subjects. Conclusions: By considering ECT modeling at a single representative frequency, ECT adaptive and non-adaptive modeling can be rationalized under a quasi-static pipeline