Authors (including presenting author) :
Wong SY (1), Chan KL (1), Ma WL (1)
Affiliation :
(1) Community Rehabilitation Service Support Centre, Queen Elizabeth Hospital
Keyword 1: :
Assistive Technology
Keyword 2: :
Adaptive Switch
Keyword 3: :
Occupational Therapy
Keyword 4: :
Physical Impairment
Introduction :
Access to mobile devices and tablets is essential for modern social participation, environmental control, and overall quality of life. For individuals with severe physical impairments—such as Motor Neuron Disease (MND), high-level Spinal Cord Injury (SCI), or advanced neurological conditions—adaptive switches are often the only gateway to digital independence. Occupational Therapists (OTs) play a pivotal role in this process by assessing functional capabilities, selecting appropriate assistive technology, and providing specialized training to ensure patients can navigate these devices. However, a significant barrier remains: commercial interfaces (e.g., GlassOuse, AbleNet) often cost between $2,000 and $8,000. This high cost, coupled with complex setup procedures, creates a "digital divide" where socioeconomic status dictates a patient's ability to communicate and control their environment.
Objectives :
The primary objective of this project was to design and evaluate a low-cost, "plug-and-play" adaptive switch interface. The goal was to provide a functional, accessible alternative to commercial products, enabling OTs to facilitate immediate digital access for patients without the burden of high costs or technical complexity.
Methodology :
The interface was developed using a simplified USB-to-3.5mm jack circuit, leveraging Human Interface Device (HID) protocols to ensure universal "plug-and-play" compatibility with Android and iOS. This hardware allows users to connect standard mechanical switches directly to mobile devices via a basic adapter.
A pilot study was conducted with five participants diagnosed with MND, with mean age of 63 years old, all presenting with significant upper limb functional decline (Manual Muscle Test < 2/5). The OT provided individualized assessments for switch placement and conducted training sessions on switch-scanning techniques. The System Usability Scale (SUS) was employed to evaluate the interface’s usability, focusing on ease of setup and user confidence.
Result & Outcome :
The interface was successfully developed for just $50 HKD, making it approximately 40 to 160 times more affordable than commercial alternatives. Preliminary results indicated exceptional clinical utility, with a mean SUS score of 97, categorized as "Excellent" usability. Participants and caregivers reported that the simplified design significantly reduced the "tech-anxiety" often associated with complex systems, which eliminated the need for complex Bluetooth pairing or software configuration. For the OT, the $50 price point allows for immediate clinical deployment, bypassing the lengthy delays of funding applications. This cost-effective solution empowers OTs to bridge the digital divide and enhance the quality of life for patients with progressive neurological conditions.
