Detect whether the mouse is touching the ground or if it is in the air

My sister and me are writing a program to help people, that suffer from tremor (trembling in hands).

The program recognizes if the mouse cursor is getting slower and then makes the cursor easier controllable and slower to make using a mouse with trembling hands easier.

The program works so far and there is only one problem: if the user lifts the mouse to another position, the speed is 0 for a short span of time. The program assumes that the cursor has to be slowed down, but this should not happen.

Is there any way to detect whether the mouse is touching the mouse pad/ground?

We are programming in C#.