title: Variables in P300 recording: task type and electrode position.
abstract: OBJECTIVE
  To analyze the latency and amplitude of P300 responses obtained with electrodes positioned at Cz and Fz and in different tasks of infrequent stimulus identification in normal hearing individuals.
  
  
  METHODS
  Forty adults of both genders participated in the study. Three recordings with three different tasks were obtained for the identification of the infrequent stimulus; simultaneous recordings were obtained from Cz and Fz positions.
  
  
  RESULTS
  Cz position showed significantly greater amplitudes and lower latencies than Fz. Regarding the three tasks, only "pronouncing the word 'thin'" was different from "raising a finger", with lowest latencies for the verbal task. Regarding amplitude, significantly higher values were observed for "raising a finger", followed by "pronouncing the word 'thin'" and mental counting.
  
  
  CONCLUSIONS
  Cz obtained the best values, highest amplitude and lowest latency. Lowest latencies were obtained for the task of "pronouncing the word 'thin'" and the highest amplitudes were obtained for "raising a finger".
authors.affiliation: Universidade de São Paulo - USP - Ribeirão Preto (SP), Brazil.
authors.forename: Humberto de Oliveira
authors.initials: Hde O
authors.lastname: Simões
authors.affiliation: Universidade Estadual Paulista - UNESP - Marília (SP), Brazil.
authors.forename: Ana Cláudia Figueiredo
authors.initials: AC
authors.lastname: Frizzo
authors.affiliation: Universidade de São Paulo - USP - Ribeirão Preto (SP), Brazil.
authors.forename: Sthella
authors.initials: S
authors.lastname: Zanchetta
authors.affiliation: Universidade de São Paulo - USP - Ribeirão Preto (SP), Brazil.
authors.forename: Miguel Ângelo
authors.initials: MÂ
authors.lastname: Hyppolito
authors.affiliation: Universidade de São Paulo - USP - Ribeirão Preto (SP), Brazil.
authors.forename: Ana Cláudia Mirândola Barbosa
authors.initials: AC
authors.lastname: Reis
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation / Q000379:methods*; D000293:Adolescent; D000328:Adult; D003071:Cognition / Q000502:physiology; D004566:Electrodes; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods*; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D055815:Young Adult