Description:
JR is a 52 year old male who survived a cortical hemorrhage of the ventral pons in the late summer of 1997. The ventral pons is the area of the brain stem traversed by the descending corticospinal tract that controls movements and speech. Consciousness and the sleep/wake cycle are preserved because the dorsal pons and midbrain were not damaged. JR is able to move his eyes and eyebrows, he has to use a mechanical respirator for breathing.In March of 1998, JR volunteered for an experimental project in which two electrodes were implanted in his motor cortex in the area that controlled arm movement prior to the stroke (see Kennedy 98 for details). The electodes consist of an glass cone which acts as an insulator for the two gold electrodes inside. Neurites from the surrounding neurons are induced to grow into glass electrode by coating it with three types of nerve growth factors. This growth stage takes about two months during which the neurons grow around the gold electrodes and for the myelin sheath to develop surrounding the new tissue. Once this growth has occured, the electode assembly is securely in place and does not move relative to the cortex and reliable signals will presist for at least 18 months based on non-human primate studies.
Using auditory and visual feedback, JR has trained himself to produce two patterns of nerve firing that have been mapped to horizontal and vertical cursor movement with digital signal processing of the analog data. Given that he can move the cursor but there is currently no third signal for selection, how can we best design a computer system that JR could use to type messages. Convert these messages as well as a number of commonly used phrases to synthesized speech. JR would like to use the internet as well, would current browsers be a problem?
Extra credit: Interface a local communications network so that JR could control his television, radio, bed, lights and call the nurse.
1b- In the real world, Dr. Kennedy is having problems with one of the signals. JR has good horizontal control via a continuous signal. The vertical signal is currently not continous, we can get a pulse so could move down a line or block at a time. We are looking at using a scanning system in which JR moves the signal down to the correct line and then scans across and dwells on the item for selection.
1c - Another variation on this problem is to use eye movement only for the interface.
For more details contact Greg Montgomery who has been working on the programming with Dr. Kennedy-(770)465-0299, gt0450a@prism.gatech.edu
Greg is in the Real World Lab group - Enabled Solutions that has developed an augmentative communications program called TalkAble.