How much deflection will occur if a 100uV spike is recorded at a sensitivity of 10uV/mm?

To calculate the amount of deflection on the EEG trace for a spike of 100 microvolts (uV) recorded at a sensitivity of 10 microvolts per millimeter (uV/mm), you would use the formula:

Deflection (mm) = Amplitude (uV) / Sensitivity (uV/mm).

Plugging in the values given:

Deflection = 100 uV / 10 uV/mm = 10 mm.

This means that the spike will deflect by 10 millimeters on the EEG recording paper or screen. The choice indicating 10 mm correctly reflects this calculation.

Understanding this principle is essential for interpreting EEG tracings, as sensitivity translates the voltage levels into a visual format that can be read and analyzed. A higher sensitivity value would lead to more deflection for the same voltage, while lower sensitivity would result in less deflection, making it crucial to know the sensitivity setting to accurately interpret the amplitude of waves recorded.