Some Physiologic Aspects of the Averaged Vertex Response in Humans

The averaged vertex response evoked by pure tone stimuli was studied in awake human beings between the ages of 2 months and 76 years, and the following conclusions were reached: There was no linear relationship between age and vertex response latency or amplitude. For yet unknown reasons, an occasional child, particularly in the 2- to 3-year age range, has a vertex response that is longer in latency and larger in amplitude than the latency and amplitude usually encountered in the vertex response of patients in the age range from 2 months to 5 years and in the adult population. The characteristics of the averaged vertex response are not altered by distracting the subject's attention from the stimuli; neither are they altered in patients with functional impairment of hearing. Vertex response thresholds determined in patients with functional loss of hearing correlate accurately with their true organic thresholds of hearing. The vertex off-response is a most inconsistent phenomenon in the normal population. When present, the amplitude of the off-response was approximately a third of the amplitude of the on-response and was characterized n most subjects by a large positive components (P2) and a minor negative component (N1).