original_query: What is the purpose of the 10-20 system in EEG exams and polysomnograph sleep studies?
query: What is the purpose of the 10-20 system in EEG exams and polysomnograph sleep studies?
answer: The 10-20 system is an internationally recognized method for standardizing the placement of scalp electrodes during EEG exams and polysomnograph sleep studies.  This ensures that study outcomes can be consistently compiled, reproduced, and analyzed across different studies and subjects.