What happens to the EEG instrument's recording when changing the time constant from 0.05 seconds to 0.10 seconds?

When the time constant of an EEG instrument is changed from 0.05 seconds to 0.10 seconds, the recording becomes more sensitive to slower frequencies. The time constant is a parameter that dictates how the EEG amplifier responds to incoming signals. A longer time constant allows the amplifier to integrate and respond more slowly to the rapid changes in electrical signals, thereby diminishing its sensitivity to higher frequency components. This results in an enhancement of slower brain wave activities, as the system has more time to average out the quicker oscillations.

In clinical and research settings, this adjustment can be crucial when analyzing specific frequency bands, particularly when slow waves, such as delta or theta waves, are of interest. With a longer time constant, these slower frequencies become more prominent in the recording. Hence, changing the time constant effectively alters the frequency sensitivity of the EEG recording, giving more importance to low-frequency activities over high-frequency ones.