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Vol. 37 No. 1, January/February 2000
Pages 53 - 64

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

Armando B. Barreto, PhD; Scott D. Scargle, MSEE; Malek Adjouadi, PhD

Digital Signal Processing Laboratory, Department of Electrical and Computer Engineering, Florida International University, Miami, FL., 33174; Center for Advanced Technology and Education, Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174

Abstract--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's 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.

Key words: Assistive Technology Act, assistive technology device, biofeedback, human-computer interface, spinal cord injury.

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