By mean of the analog computer the evoked electroencephalngraphic responses of the vertex (C_z) during barbital sleep in normal young children to acoustic stimuli were obtained with following results:
There were penta-phasic with the components of vertex-positive (P₁), negative (N₁), positive (P₂), negative (N₂) and of vertex positive (P₃).
The peak latencies of these components in children aged 16 days to 3 months were 60 to 80msec (P1), 160 to 210msec (N₁), 250 to 340msec (P₂), 470 to 690msec (N₂) and 820 to 860msec (P₃), while those of children aged 1 to 5 years were about 60msec (P₁), 130 to 190msec (N₁), 270 to 310msec (P₂), 420 to 610msec (N₂) and 730 to 800msec (P₃) respectively.
The evoked responses of the children aged 16 days to 3 months appeared at the intensity of 30 to 60dB SPL and in children aged 1 to 5 years 20 to 50dB SPL.
The amplitude and the peak latencies of the evoked response varied with the stages of sleep. The major difference between the waking stage and the all stages of sleep were the appearance of P₃ and the consistent increase in the peak latencies of N₁, P₂ and N₂ during sleep.

View full abstract

The auditory pathway has been known to have both crossed and uncrossed fibers. It is of interest to note which of them is more important in an anatomico-physiological point of view, and how exists the so-called cerebral dominance in hearing.
These problems are discussed from the results of animal experiments, brain pathology, neurosurgery and central audiology. Although the conclusion is yet incomplete because of the very complexity of the brain mechanism, further approaches can be expected from not only the researches mentioned, but also the psychopathology of speech.

View full abstract

In five normal subjects averaged EEG responses to auditory stimuli were recorded during relaxed and under repetitive. photic stimulation.
Typical auditory responses in relaxed state consisted of early components of 40-100msec and late rather large ones of more than 100msec in latency. When repetitive flashes were given simultaneously, the later components of the average auditory responses were remarkably surpressed. It suggests that the later response may be the discharge of non-specific origin and influenced by visual stimulation.
Problem of central (cortical and reticular system) control of sensory transmission was discussed and facilitatory and inhibitory phenomenon of sensory evoked response under various consciousness was reviewed. The optimal state of subjects to obtain the largest response in EEG audiometry was considered from the psychophysiological point of view.

View full abstract