If a 150μV spike is recorded at a sensitivity of 10μV/mm, how much deflection occurs?

To determine the deflection on the EEG recording paper due to a spike, one needs to use the relationship between the amplitude of the spike, the sensitivity of the machine, and how this translates into physical deflection on the paper.

In this case, a spike of 150μV needs to be represented on paper with a sensitivity setting of 10μV/mm. Sensitivity indicates how many microvolts correspond to each millimeter of deflection. Therefore, with a sensitivity of 10μV/mm, every 10μV of the spike will cause a deflection of 1mm.

To find out the total deflection for the spike:

1. First, calculate how many units of 10μV are in the 150μV spike:

[

\text{Number of 10μV units} = \frac{150μV}{10μV/mm} = 15

]

2. Since each unit of 10μV results in a 1mm deflection, the total deflection will be equal to the number of 10μV units identified:

[

\text{Total deflection} = 15 \text{ mm}

]

Thus