Previous research has focused on developing a brain-controlled switch named the low frequency asynchronous switch design (LF-ASD) that is suitable for intermittent control of devices such as environmental control systems, computers, and neural prostheses. On-line implementations of the LF-ASD have shown promising results in response to actual index finger flexions with able-bodied subjects. This paper reports the results of initial on-line evaluations of the LF-ASD brain-controlled switch with both able-bodied subjects and subjects with high-level spinal-cord injuries. This paper has demonstrated that users can activate the LF-ASD switch by imaging movement. In this paper, two able-bodied subjects were able to control the LF-ASD with imagined voluntary movements with hit (true positive) rates above 70% and false positive rates below 3% while two subjects with high-level spinal-cord injuries demonstrated hit rates ranging from 45-48% and false positive rates below 1%.

This research has focused on developing a Brain Computer Interface (BCI) for asynchronous control applications, which are characterized by alternating periods of active control and attentive idleness. We have developed an asynchronous switch that users can control through their EEG. The on-line implementation of the Low Frequency Asynchronous Switch Design (LF-ASD) has shown promising results with actual index finger flexions with able-bodied subjects. This work reports the results of the algorithm on imagined voluntary movements with able-bodied persons, demonstrating hit (true positive) rates above 70% and false positive rates below 3%. This work is a precursor to verifying the online switch operation for people with severe motor disabilities. the brain. Since voluntary movement control is an existing, internal control system in humans, which seemed naturally suited to drive a BCI, the LF-ASD feature set was based on voluntary movement-related potentials (VMRPs). Lisogurski [3] produced an on-line implementation of the LF-ASD capable of identifying VMRPs from a continuous sampling of EEG.Promising results have been obtained to date with ablebodied subjects performing actual index finger flexions. It is yet required to prove the use of the LF-ASD with imaginary movements so that it can be applied by persons with high-level disabilities. The data presented in this paper has been obtained by applying a new methodology to able-bodied subjects who were asked to imagine a right-hand index finger Hexion. This is an important step in this research since i t establishes that the LF-ASD feature set is applicable to imagined voluntary movements as well as actual movements.

Our research has focused on developing a brain-controlled switch that is suitable for asynchronous control applications. We have developed a switch, the Low Frequency Asynchronous Switch Design (LF-ASD) that users can activate by imagining movement. On-line implementations of the LF-ASD has shown promising results in respond to actual index finger flexions and imagined finger flexions within able-bodied subjects. This work reports the results of our first test with subjects with high-level spinal-cord injuries. In this study, two subjects with high-level spinal-cord injuries were able to control the LF-ASD with imagined voluntary movements with hit (true positive) rates from 45-48% and false positive rates below 1%.

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