Neural Engineers Gather for IEEE EMBS Conference on Neural Engineering

by Warren Grill, senior technical editor

The 2nd International IEEE Engineering in Medicine and Biology Society Conference on Neural Engineering was held March 16-19, 2005 in Arlington, VA. The meeting, chaired by Metin Akay from Dartmouth, drew over 240 attendees representing 27 countries, and about half of the attendees were students. There were 186 papers spanning the gamut of neurotechnology, including brain computer interfacing, neural stimulation, and hardware development.

One of the highlights was a presentation by Todd Kuiken, from Northwestern University and the Rehabilitation Institute of Chicago, on a nerve transfer technique to recover multiple command signals for prosthetic control by amputees. The terminal peripheral nerve stumps in the amputated arms(s) were surgically transferred to different regions of the pectoral muscle. Subsequently, volitional commands generated by thinking about activation of the amputated limb produced activity in the pectoral muscle that was detected by surface electromyographic recording.

Importantly, activity in the different nerve branches generated activity in different regions of the pectoral muscle and this was used to generate multiple independent signals for control of a multiple-degree of freedom prosthesis. In addition, in one case, the transferred nerves innervated the skin over the pectoral muscle, and touching the chest produced sensations referred to the amputated limb. These results represent one of the most significant recent advances in prosthetic control and demonstrate the feasibility of volitional control of complex devices with multiple degrees of freedom.

A second highlight was a presentation by Bin He, University of Minnesota, on processing single trial recordings of electroencephalographic signals. Electrical source localization methods were used to estimate the position on the cortex of the locus of brain activity. Subsequently these estimates were compared to direct brain surface recordings using implanted electrode grids, and the correlation was greater than 85 percent. This non-invasive technique to estimate the temporal and spatial distribution of activity in the brain offers promise as a means to control a brain computer interface.
Mohanasankar Sivaprakasam gave an update on hardware development by the epiretinal electrical stimulation effort including Wentai Liu at UC Santa Cruz, Mark Humayun at University of Southern California and Second Sight Medical Products. He described a 60-channel microstimulator presently in pre-clinical animal studies and suggested that the device will be implanted in humans before the end of the year.

In addition to regular paper presentations the program featured several invited speakers to highlight particular areas of neurotechnology. Neville Hogan from Massachusetts Institute of Technology spoke about mechanical interfacing between human operators and robotic devices.

Ted Berger from the University of Southern California spoke about advances in the science and technology underlying a prosthetic replacement for the damaged hippocampus. John Chapin from the State University of New York Health Science Center at Brooklyn spoke about controlling robots with the mind. In addition to reviewing his work using brain recording to control robots, he highlighted new work showing that microstimulation of the somatosensory thalamus could reproduce the pattern of activity in the cortex produced by natural cutaneous stimulation with a fidelity of 76 percent. This advances the prospects for a closed-loop system employing brain recording for control and brain stimulation for sensory feedback.

Michael Weinrich from the National Center for Medical Rehabilitation Research suggested that neurotechnology has an important role in addressing the daunting growth in healthcare costs, and when applied to ameliorate devastating diseases or injury can result is a net cost savings. He indicated that success will come from evidence-based interventions, and that functional imaging is a powerful tool to produce objective evidence of changes in the brain produced by rehabilitation. Andy Schwartz from the University of Pittsburgh reviewed his efforts using direct recordings from motor cortex to control robotic devices.

The 3rd International IEEE EMBS Conference on Neural Engineering will be held in May, 2007 in Hawaii.