Late cortical-evoked responses in clinical use

Area of Science:

• Neuroscience
• Clinical Electrophysiology

Background:

• Direct-current (dc) deflections in electroencephalography (EEG) were previously observed using high stimulus intensities.
• Studies in animals showed evoked dc potentials were localized to specific cortical areas corresponding to sensory modalities.

Purpose of the Study:

• To develop a routine, clinically applicable computerized technique for recording dc shifts in human EEG.
• To simultaneously measure various sensory-evoked potentials and perstimulatory dc shifts.

Main Methods:

• Utilized a fully computerized dc recording averaging system with Beckman electrodes placed at the vertex.
• Applied the technique to record electric responses from the intact human skull to auditory, gustatory, and olfactory stimuli.
• Recorded perstimulatory dc shifts during prolonged click trains.

Main Results:

• Successfully developed and implemented a routine technique for clinical use.
• Demonstrated simultaneous plotting of auditory, gustatory, and olfactory evoked potentials.
• Observed dc shifts, including perstimulatory shifts, in normal and pathological subjects.

Conclusions:

• The developed technique is effective for clinical application in assessing sensory-evoked dc potentials in humans.
• This method provides a comprehensive approach to studying electrophysiological responses to various sensory stimuli.
• Further application in clinical settings (e.g., ENT and pediatric clinics) is supported by the study's findings.