Analyzing an Electroencephalography Report (Eeg)…
Christine Medeiros
BIOL.2401.S2L
Roland Tay, M.D., M.A.
30 July 2012
Analyzing an Electroencephalography Report (EEG)…
The importance of complete and well recorded data in analyzing an EEG
The summary of findings is only as detailed as the data reported.
Introduction
The electroencephalogram, also known as the EEG is the recording of electrical activity of the brain in various states of rest or stimulation. The test is performed using the electroencephalography machine which records the brainwaves in Hz or cycles per second. The characteristics of normal brainwave have been established. Their frequency is typically between 1 and 30 hertz, having a dominant rhythm of 10 HZ and average amplitude (the height of the wave) of 20 to 100 micro volts. Not surprising, the different areas of the brain demonstrate varied frequencies. For example, the waves of the occipital lobe (processes visual stimuli) have a lower frequency than the frontal and parietal lobes (process cognitive function, speech and language and soma sensory processes, respectfully). There are four waves which are typically studied in humans. The Alpha waves which have a frequency range of 8 to 13 HZ and are seen when the subject is in a relaxed state with eyes closed.
The Beta waves range 14 to 30 HZ, have lower amplitude and are generally seen when the subject is in an attentive or alert state.
The Delta wave is a very large wave (high amplitude) with a frequency of 4 HZ or less and is found when the subject is in deep sleep.
Theta waves are also large with a frequency of 4 to 7 Hz; normal in children, but abnormal in adults.
In the ADI activity the Alpha waves were the focus for analysis. The EEG was performed using the ADI system to look at the effect of various interfering signals, examine the effect on alpha waves caused by opening and shutting the eyes, how alpha waves are affected by performing simple math equations as well as the effects on the brainwaves while listening to rock
BIOL.2401.S2L
Roland Tay, M.D., M.A.
30 July 2012
Analyzing an Electroencephalography Report (EEG)…
The importance of complete and well recorded data in analyzing an EEG
The summary of findings is only as detailed as the data reported.
Introduction
The electroencephalogram, also known as the EEG is the recording of electrical activity of the brain in various states of rest or stimulation. The test is performed using the electroencephalography machine which records the brainwaves in Hz or cycles per second. The characteristics of normal brainwave have been established. Their frequency is typically between 1 and 30 hertz, having a dominant rhythm of 10 HZ and average amplitude (the height of the wave) of 20 to 100 micro volts. Not surprising, the different areas of the brain demonstrate varied frequencies. For example, the waves of the occipital lobe (processes visual stimuli) have a lower frequency than the frontal and parietal lobes (process cognitive function, speech and language and soma sensory processes, respectfully). There are four waves which are typically studied in humans. The Alpha waves which have a frequency range of 8 to 13 HZ and are seen when the subject is in a relaxed state with eyes closed.
The Beta waves range 14 to 30 HZ, have lower amplitude and are generally seen when the subject is in an attentive or alert state.
The Delta wave is a very large wave (high amplitude) with a frequency of 4 HZ or less and is found when the subject is in deep sleep.
Theta waves are also large with a frequency of 4 to 7 Hz; normal in children, but abnormal in adults.
In the ADI activity the Alpha waves were the focus for analysis. The EEG was performed using the ADI system to look at the effect of various interfering signals, examine the effect on alpha waves caused by opening and shutting the eyes, how alpha waves are affected by performing simple math equations as well as the effects on the brainwaves while listening to rock