Reliability of P50 auditory event-related potential indices of sensory gating


  • This work was supported by an Ohio State University Seed Grant to S. B. Scheatzkopf. We thank Brian Burriss and Jennifer Hirt for their assistance with data collection and scoring. John T. Cacioppo, Ann M. Kring, Corinne M. Mar. John M. Neale, and Harvey G. Shulman for fecdback on a prelininary version of the manuscript, David L. Lozano for technical assistance, and the Ohio State University Psychophysiology Reading Group for their periodie feedback on this line of research.

Address reprint requests to: Dr. David A. Smith, Department of Psychology, Ohio State University, 142 Townshend Hall, 1885 Neil Avenue Mall, Columbus, OH 43210-1222. E-mail: DASMITH+@OSU.EDU.


We examined the reliability of three traditional P50 auditory event-related potential indices under paired-click conditions: (a) the conditioning response (C), (b) the testing response (T), and (c) the testing to conditioning suppression ratio (T/C). Three alternative indices, (a) the (C−T) difference, (b) the (C−T)/(C+T) adjusted difference, and (c) the (T−T) residualized difference, where T′ is the regression of T on C, were also studied. The N 100 wave was used as a generalizability check. Although C and T amplitudes were reliably were reliably measured by traditional means, the T/C suppression ratio was not. for psychometric reasons that are described, the reliability of the suppression ratio is undermined principally by the correlation between C and T. The C−T difference score is a promising alternative to the unreliable T/C suppression ratio. Theoretical consequences of changed metrics are discussed.