Electroencephalogram Technology Synopsis

Electroencephalogram (EEG) source is within the cerebral cortex, large neural populations, all synchronized together to summate at the scalp surface. EEG signal recorded is the summation of the various neuronal populations beneath it and is a composite of various frequencies, designed Δ (0-3.5 Hz), θ (4-7 Hz), α (8-13 Hz) and β (13+ Hz). EEG is analyzed according to voltage, frequency, location, degree of symmetry and coherence between left and right hemispheres and specific waveform morphology and patterns. The International 10-20 System of Electrode Placement was introduced by Herbert Jasper in 1958 and adopted by the International Federation of EEG Societies and is currently in widespread use. Evoked Potentials (EP) are time-locked to the stimulus. Testing modalities and EP test types include: Auditory (BAER and AER), Visual (VER), Somatosensory (SER) and Cognitive (ERP). Quantified EEG includes Topographic Brain Mapping (TBM, BEAM) and Fast Fourier Transform (FFT) to analyze both EEG and EP data.