What is the modified 10-20 system?
The 10–20 system or International 10–20 system is an internationally recognized method to describe and apply the location of scalp electrodes in the context of an EEG exam, polysomnograph sleep study, or voluntary lab research.
Why do we use the international 10-20 system?
Conclusion: Using the 10-20 system for TMS positioning is applicable at low cost and may reach desired cortex regions reliably on a larger scale level. For finer grained positioning, possible interindividual differences, and therefore the application of neuroimaging based methods, are to be considered.
What is the frequency range of normal EEG signal?
However, the most frequently used method to classify EEG waveforms is by the frequency, so much so, that EEG waves are named based on their frequency range using Greek numerals. The most commonly studied waveforms include delta (0.5 to 4Hz); theta (4 to 7Hz); alpha (8 to 12Hz); sigma (12 to 16Hz) and beta (13 to 30Hz).
How do you find an Inion?
Starting at the nape of the neck, run a finger up the back of the participant’s head until a bony ridge, or bump, can be felt. Having the participant move his/her head up and down may help you to identify this bony ridge. The slight hollow just beneath this bony ridge is the inion.
What is a normal EEG result?
Most waves of 8 Hz and higher frequencies are normal findings in the EEG of an awake adult. Waves with a frequency of 7 Hz or less often are classified as abnormal in awake adults, although they normally can be seen in children or in adults who are asleep.
What do the numbers 10 and 20 mean in EEG measurements?
The “10” and “20” refer to the fact that the actual distances between adjacent electrodes are either 10% or 20% of the total front–back or right–left distance of the skull. For example, a measurement is taken across the top of the head, from the nasion to inion.
How do you write numbers on a number line?
Choose number lines labelled with whole numbers, fractions, decimals, or negative numbers. Or use a blank number line, with or without tick marks. Describe intervals between points on the line using forward or backward jumps above and below the line.
How is the 10-10 system used in EEG?
EEG electrode positions in the 10-10 system using modified combinatorial nomenclature, along with the fiducials and associated lobes of the brain. When recording a more detailed EEG with more electrodes, extra electrodes are added using the 10% division, which fills in intermediate sites halfway between those of the existing 10–20 system.