I keep reading documents about the UPDRS and for example tremor is "measured" by this scale.

What I don't understand and can't seem to find are the instructions on how the examiner determines what "marked amplitude" is and how is "marked amplitude defined" The same goes for some of the other motion tests. Have any of you seen documentation on how doctors are taught to determine these values?

Thanks,
rd42

Like rd42 I've been unable to find detailed instructions. Without those, there is a danger that different people mark differently (my "mild" might be your "moderate").

Moreover, the 5 point scale (0, 1, 2, 3, 4) is restrictive. Can you have a 2.4 for tremor, say?

Does this matter? It depends on the context. As a measure of long term progression, especially where the marking is done by the same person throughout, it's probably reasonable. But, it doesn't help much for the sort of questions that I think many of us have: what exercise/diet minimises my tremor?

Tremor is difficult to measure because it affects different parts of the body differently at different times. That said, I still think we should try to objectively quantify it: e.g. the movement of my left index finger is 1 cm/sec, with a frequency of 6 hz.

Devices exist to do that, some with data logging over an extended period.

As a first step, I'm writing a program which uses a lap top's touchpad to measure finger motion over a 30 second period, say. It will only give a snapshot view.

John