EEG Measurements Questions And Answers

Amplitude - is an indicator of the voltage of the wave. EEG Voltage is measured in - microvolts - uv Low Voltage - 5-20uv Low-Medium Voltage - 20-40uv Medium Voltage - 40-80 uv Medium-High Voltage - 80-160uv High Voltage - >160uv Sensitivity - the control on the EEG machine that allows us to determine how large or small the wave will appear on the screen. standard setting is 7uv/mm Voltage per millimeter of deflection - top to bottom of the wave Voltage Formula - multiply the sensitivity in uv/mm by the amplitude (deflection/height) in millimeters(mm) V (uv) = S (uv/mm)x A (mm) Determining Voltage - multiply the measurement by the sensitivity of the machine setting and the answer will be the voltage in microvolts. Legend - used to determine the voltage of a selected wave Determining Sensitivity - divide voltage by amplitude(height)- sensitivity (uv/mm)= voltage(uv) /amplitude(mm) Frequency - refers to how many times an event will occur in a given time period EEG frequency - is the number of waves per second (or cycles per second) and is expressed in hertz (hz) Duration - is the length (in terms of ''time'') of an event Duration of a wave - is the time a wave persists and is measured in seconds(milliseconds) Each second of the EEG recording is a - composite of many waveforms and multiple frequencies.