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The Yale Journal of Biology and Medicine (1)
Lucas, John P.
Armstrong, John A. (1)
Doud, Alexander J. (1)
Dowling, John N. (1)
He, Bin (1)
Ho, Monto (1)
Pisansky, Marc T. (1)
Saslow, Arnold R. (1)
Tarr, George C. (1)
Youngblood, Leona A. (1)
Year of Publication
Continuous Three-Dimensional Control of a Virtual Helicopter Using a Motor Imagery Based Brain-Computer Interface
Doud, Alexander J.
Pisansky, Marc T.
Brain-computer interfaces (BCIs) allow a user to interact with a computer system using thought. However, only recently have devices capable of providing sophisticated multi-dimensional control been achieved non-invasively. A major goal for non-invasive BCI systems has been to provide continuous, intuitive, and accurate control, while retaining a high level of user autonomy. By employing electroencephalography (EEG) to record and decode sensorimotor rhythms (SMRs) induced from motor imaginations, a consistent, user-specific control signal may be characterized. Utilizing a novel method of interactive and continuous control, we trained three normal subjects to modulate their SMRs to achieve three-dimensional movement of a virtual helicopter that is fast, accurate, and continuous. In this system, the virtual helicopter's forward-backward translation and elevation controls were actuated through the modulation of sensorimotor rhythms that were converted to forces applied to the virtual helicopter at every simulation time step, and the helicopter's angle of left or right rotation was linearly mapped, with higher resolution, from sensorimotor rhythms associated with other motor imaginations. These different resolutions of control allow for interplay between general intent actuation and fine control as is seen in the gross and fine movements of the arm and hand. Subjects controlled the helicopter with the goal of flying through rings (targets) randomly positioned and oriented in a three-dimensional space. The subjects flew through rings continuously, acquiring as many as 11 consecutive rings within a five-minute period. In total, the study group successfully acquired over 85% of presented targets. These results affirm the effective, three-dimensional control of our motor imagery based BCI system, and suggest its potential applications in biological navigation, neuroprosthetics, and other applications.
Cytomegalovirus Infection in Children Undergoing Open-Heart Surgery 1
Armstrong, John A.
Tarr, George C.
Youngblood, Leona A.
Dowling, John N.
Saslow, Arnold R.
The Yale Journal of Biology and Medicine
A group of 124 children undergoing open-heart surgery was followed prospectively in order to estimate the risk of cytomegalovirus (CMV) infection due to transfused blood.
Ninety-three patients (75%) had complement fixation (CF) titers of < 1:4 against CMV on admission. Of this seronegative subgroup, nine patients (9.7%) subsequently became infected with CMV. All nine showed seroconversion, and six were viruric 12-14 weeks after surgery. Comparative seroepidemiological studies of the hospital population showed that in the age ranges studied (3-16 yr), the infections seen in the study group represented a significant excess over expectation. This infection rate was consistent with a model of transmission by blood transfusion with a risk of 2.7% per unit but not proven.
Thirty-one patients had CF antibody to CMV on admission. CMV was isolated from 14% of urines of seropositive children both before and after surgery, but only two patients showed CF antibody rises to CMV. Thus the frequency of CMV infection associated with open-heart surgery and transfusion could not be calculated in the seropositive subgroup.
CMV infection was not related to the primary diagnosis or to Down's syndrome.
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