Amplification and transmission of the EEG

In long-term monitoring of the EEG in epilepsy, the recording conditions are usually such that a technique must be used which allows EEG recording from patients who are engaged in behavioral activities. The technique employed basically consists of the use of a miniaturized EEG amplifier at the site of the patient and the transmission of the amplified EEG to the recording apparatus. As regards the quality of the recording, the use of miniaturized amplifiers involves various problems, particularly those related to the choice of the fixed amplifier characteristics. Depending on the recording conditions, the transmission is commonly carried out whether by cable telemetry or by radio telemetry. Various techniques for multi-channel data transmission can be used for both telemetry methods. The choice of any particular transmission technique will mainly depend on the characteristics of the EEG data transmitted and on specific requirements on the quality of the recording.