They detect large artifacts, and it is not evident that cortical potentials are being picked up.
The TN group needs to compare the scalp measurements of these electrodes with other active dry EEG electrode systems (e.g., Gtec medical engineering) to ascertain the advantages and disadvantages of different approaches. Should there be significant differences in the scalp data, say in the signal-to-noise of averaged event-related potentials measured using the different dry electrodes and wet electrodes, the group might further make measurements of impedances and signals, humidity and perspiration testing (i.e., salt bridges), electromagnetic interference, and a standard 10-20 system for comparison of topography with the wet system to check for antenna effects from high-impedance electrodes.
The group needs to continue to consider alternative electrode types and analysis and signal enhancement methods that can reduce artifacts from electrode movement. Measures for evaluating signal quality need to be developed, and the TN group needs to ensure it is aware of and understands the lessons learned from prior work in this area.
Relevance to Protection from Traumatic Brain Injury
While the ARL is focused on the performance and protection of healthy individuals and it has noted that medical conditions are outside its mission, the problems that the group does focus on are relevant to performance and life-threatening situations that are commonly encountered by Army personnel and that are poorly understood. For example, a major threat to the performance of military personnel, during peacetime as well as wartime, is traumatic brain injury (TBI), particularly mild traumatic brain injury. Reports of soldiers recently returned from combat in Iraq found that 22.8 percent had sustained a TBI and that most of these were mild. The TN group has the potential to model and predict which areas of the brain are most susceptible to various mild TBIs and can in turn use these data to help guide the design of protective gear to militate against these injuries.
Obviously the work by TN could be of significant value with respect to identifying areas of TBI. For example, moving this work beyond impacts that might result from a blunt object striking a forehead could lead to techniques for identifying areas of brain damage when the injury is not detectable by routine imaging.
Overall, the quality of the research presented, the capabilities of the leadership, the knowledge and abilities of the investigators, their scientific productivity, and proposed future directions are impressive. The work is well aligned with the clear and substantive mission to move neuroscience from the laboratory to real-world military settings—that is, from the bench to the battlefield. The TN group conducts high-quality neuroscience research that is routinely validated by its publication in recognized, peer-reviewed journals and is on a par with work at a good university neuroscience department.
The group leadership is highly effective and qualified, and there is a palpable energy and enthusiasm in the strong mix of early-career and mid-career scientists. The facilities are, for the most part, state of the art, and the group demonstrated impressive leverage and collaboration with the broader scientific communities at universities, industry, and other government laboratories.