FREQUENCY ANALYSIS OF ELECTROENCEPHALOGRAPHIC RHYTHMS IN HUMANS EXPOSED TO HIGH INTENSITYINTERMITTENT AUDITORY INPUTS

Abstract

Summary.-Through binaural earphones, 10 Ss were presented with intermittent auditory stimuli ranging from 3 to 15 pps at intensities from 100 to 130 db. EEGs were taken and the occipital or temporal output was analyzed with a frequency analyzer. Only one of 10 Ss showed EEG following at most input frequencies. When the data from all Ss were combined, it was discovered that the introduction of auditory inputs at 10 pps produced an inhibition of the loips alpha rhythm. The data imply a limited interaction between the visual and auditory modalities. Although a number of studies have reported the measurement of evoked auditory responses in humans (e.g., Geisler, Frishkopf, & Rosenblith, 1958; Geisler & Rosenblith, 1962; Sato, et al., 1961), only two reports have described auditory driving of the EEG in humans using lncermlttent auditory inputs. Goldman (1952) mentioned the possibility in a brief abstract, while Neher (1961) reported measuring auditory driving wich the aid of a frequency analyzer. Unfortunately, the auditory pulses in the latter study were produced by having someone beat on a snare drum, a method which admittedly did not permit careful control of the stimuli. The scarcity of reports of auditory driving in contrast to the large number dealing with photic driving suggests the possibility that different mechanisms may be involved. Since none of the previous reports examined a wide range of input frequencies or intensities, it was decided to investigate the problem of auditory driving using a wide range of input conditions and a frequency analyzer.