POTENTIALS ASSOCIATED WITH THE GO NO-GO PARADIGM IN TRAUMATIC BRAIN INJURY/

Surface event-related potentials associated with visually triggered mo vements (Go) and the inhibition of planned movements (No-Go) were exam ined in seven healthy subjects and five postacute traumatic brain inju red (TBI) subjects. Analysis showed that the cortical potential P1-N1 was similarly affected by condition in both the control and TBI groups . Although TBI subjects showed smaller P1-N1 amplitudes (Go = 2.91uV; No-Go = 3.95uV; p < .03) relative to control subjects (Go = 4.82uV; No -Go = 6.03uV; p < .03), both groups showed larger amplitudes in the No -Go condition. A bipolar lead (C3'-C3'') over the sensorimotor cortex showed a reversal of polarity between Go and No-Go conditions which wa s synchronized with the EMG activity in all control subjects, This sig nal reversal and timing of potentials was absent in four of the five T BI subjects' waveforms, suggesting difficulty in sensorimotor processe s associated with movement control. In addition, TBI subjects displaye d a number of atypical stimulus-locked waveforms, which are discussed relative to the specific functional impairments of individual subjects . The results highlight the potential usefulness of such paradigms as the Go/No-Go procedure in the analyses of electroencephalographic wave forms and of the effects of TBI.