A Review of Emerging Access Technologies for Individuals With Severe Motor Impairments

Abstract

Research and development in the field of access technologies for individuals with severe motor impairments has accelerated over the past 10 years. Many emergent alternatives to conventional mechanical switches, such as infrared sensing, electromyography, oculography, and computer vision, have been investigated for those retaining some limited volitional motor ability. At the same time, electroencephalography, electrocorticography, intracortical recordings, and electrodermal activity have been explored for those presenting as locked in. The relevant literature is scattered across many disciplines, obfuscating the strength of the clinical evidence in support of the different access technologies currently in development. This article systematically organizes the literature on the aforementioned access technologies, summarizing their underlying operational mechanisms while reviewing the clinical evidence reported between 1996 and 2006. Research evidence within this period is generally found to be at the case study or uncontrolled study level, with very modest sample sizes. Novel mechanical switches and electroencephalography-based access systems dominate the literature, whereas many other movement-based access modalities have emerged with promising early findings. Access methods for those without extant physical movement constitute a critical direction for future and ongoing research efforts.

Mutual Information as a Measure of Contextual Effects on Single Switch Use

“…From Fig. (5), we see that in response to various presentation modalities, 42% of the participants (participants 2, 3, 4, 6, and 11) exhibited the highest mutual information in response to written stimuli, while another 42% of the participants (participants 1,7,8,10,12) had the highest mutual information in response to pictorial stimuli. Therefore we can infer that presenting the information in the written modality can be facilitating for the former group and information presentation in the pictorial modality can be facilitating for the latter group.…”

“…An alternate channel is often required for communication and interaction with the environment. In rehabilitation terminology, that channel is termed an access pathway and constitutes the critical front end of an access solution [1]. From a system engineering perspective, an access solution is a system that receives a physical or physiological expression of the individual's intention as input.…”

“…A wide range of access pathways have been developed, from simple mechanical switches to sophisticated physiological ones. For a comprehensive review of emerging access technologies please see [1,2].…”

A Context-Aware User Interface for Wireless Personal-Area Network Assistive Environments

“…email, web, audio/video calls). This is a domain that has witnessed many research and development efforts [2]. Indeed, even when living with severe impairments such as quadriplegia, people are often still able to move body parts such as jaws, eyes, head, and tongue.…”

“…Any added feature that increases the overall price too much has reduced chances to become widespread. Typically, AT relies on three major parts [2]. The first one, the "access pathway" is composed of the physical sensors or input devices actuated by the user; their outputs are then converted into electrical signals which are further analyzed by means of digital signal processing techniques.…”