Investigation of Unintentional Movement in People with Cerebral Palsy to Improve Computer Target Aquisition

People with Cerebral Palsy (CP) have difficulty using computer pointing devices due to unintentional movement in their upper extremities. Fifty percent of people with CP have impaired arm-hand function which limits their ability to interface with pointing devices and effectively control cursor movement on the computer screen. This thesis involves two studies which utilize an Isometric Joystick in order to access the computer and complete target acquisition tasks. The first study titled "Quantification of Cursor Movement of People with Athetoid and Spastic Cerebral Palsy to Improve Target Acquisition," aims to guide real-time digital filter development for people with athetoid and spastic CP for target acquisition tasks. By investigating the cursor movement measures throughout the target acquisition trajectory we gained a better insight as to when and how to compensate for unintentional movement in people with CP. Results showed that both people with athetoid CP and spastic CP have more difficulty hovering over the target than they did moving to the target, indicating that filter development should focus on the hovering portion of the target acquisition task in order to improve target acquisition time. The second study titled "Customized Control for People with Athetosis and Dystonia to Improve Computer Access," aims to develop a method to prescribe appropriate switch/scanning control for people with athetosis and dystonia as well as to determine if customized switch/scanning control is more effective in completing icon selection tasks than the proportional isometric control. Results of this study suggest that switch/scanning control could be useful in moving on the most direct path to the target as shown by a significantly smaller percent distance error for customized control as compared to proportional isometric control (F(1,6) = 361.2, p < 0.01)

Pointing Devices for Wearable Computers

We present a survey of pointing devices for wearable computers, which are body-mounted devices that users can access at any time. Since traditional pointing devices (i.e., mouse, touchpad, and trackpoint) were designed to be used on a steady and flat surface, they are inappropriate for wearable computers. Just as the advent of laptops resulted in the development of the touchpad and trackpoint, the emergence of wearable computers is leading to the development of pointing devices designed for them. However, unlike laptops, since wearable computers are operated from different body positions under different environmental conditions for different uses, researchers have developed a variety of innovative pointing devices for wearable computers characterized by their sensing mechanism, control mechanism, and form factor. We survey a representative set of pointing devices for wearable computers using an “adaptation of traditional devices” versus “new devices” dichotomy and study devices according to their control and sensing mechanisms and form factor. The objective of this paper is to showcase a variety of pointing devices developed for wearable computers and bring structure to the design space for wearable pointing devices. We conclude that a de facto pointing device for wearable computers, unlike laptops, is not likely to emerge

A practical EMG-based human-computer interface for users with motor disabilities

In line with the mission of the Assistive Technology Act of 1998 (ATA), this study proposes an integrated assistive real-time system which affirms that technology is a valuable tool that can be used to improve the lives of people with disabilities . An assistive technology device is defined by the ATA as any item, piece of equipment, or product system, whether acquired commercially, modified, or customized, that is used to increase, maintain, or improve the functional capabilities of individuals with disabilities . The purpose of this study is to design and develop an alternate input device that can be used even by individuals with severe motor disabilities . This real-time system design utilizes electromyographic (EMG) biosignals from cranial muscles and electroencephalographic (EEG) biosignals from the cerebrum\u27s occipital lobe, which are transformed into controls for two-dimensional (2-D) cursor movement, the left-click (Enter) command, and an ON/OFF switch for the cursor-control functions . This HCI system classifies biosignals into mouse functions by applying amplitude thresholds and performing power spectral density (PSD) estimations on discrete windows of data. Spectral power summations are aggregated over several frequency bands between 8 and 500 Hz and then compared to produce the correct classification . The result is an affordable DSP-based system that, when combined with an on-screen keyboard, enables the user to fully operate a computer without using any extremities

Speech planning in 4-year-old children versus adults: Acoustic and articulatory analyses

International audienceThis study investigates speech motor control in 4-year-old Canadian French children in comparison with adults. It focuses on measures of token-to-token variability in the production of isolated vowels and on anticipatory extra-syllabic coarticulation within V 1-C-V 2 sequences. Acoustic and ultrasound articulatory data were recorded. Acoustic data from 20 children and 10 adults have been analyzed. Thus far, ultrasound data have been analyzed from a subset of these participants: 6 children and 2 adults. In agreement with former studies, token-to-token variability was greater in children than in adults. Strong anticipation of V 2 in V 1 was found in all adults, but not in children. Most of the children showed no anticipation at all and some of them showed a small amount of anticipation along the antero-posterior dimension only, manifested in the acoustic F2 dimension. These results are interpreted as evidence for the immaturity of children's speech motor control from two perspectives: insufficiently stable motor control patterns for vowel production, and a lack of effectiveness in anticipating forthcoming gestures. In line with theories of optimal motor control, anticipatory coarticulation is assumed to be based on the use of internal models of the speech apparatus and the increasing maturation of these representations as speech develops