What defines Pen blocking and how can it be resolved?

Pen blocking refers to a phenomenon observed during EEG or similar neurophysiological recordings, where the waveforms appear to demonstrate a flattening effect or have distorted amplitudes. This situation arises when the GAIN setting on the recording equipment is set too high. When GAIN is excessively increased, it amplifies the signal to the point that it exceeds the upper limit of the recording system. This results in waveform distortion, leading to an inaccurate representation of the brain's electrical activity.

To resolve pen blocking, practitioners should adjust the GAIN setting to an appropriate level that allows for optimal signal recording without distortion. Proper calibration ensures that the recordings reflect true brain activity, allowing for accurate interpretation.

In contrast, other causes like poor electrode placement or having electrodes spaced too far apart would not specifically lead to pen blocking. While they might affect the overall quality or clarity of the recorded signals, they do not directly cause the flattening or distortion associated with incorrect GAIN settings.