This is a really good question-I've wondered about this since I was initially diagnosed with ET. Anyway, I learned that there are four recognized types of Parkinsonian tremor. -Laura

See the following link:

http://www.rewritetomorrow.eu.com/pd...or-parkinsons/

In the Consensus Statement of the Movement Disorder Society on Tremor 3, four types of Parkinsonian tremor are described:

1. type I – classical Parkinsonian tremor, that is a rest tremor and postural/kinetic tremor at the same frequency, i.e. the rest tremor in this group persisting as a postural tremor
2. type II - rest, postural and kinetic tremors at different frequency
3. type III - pure postural kinetic tremor. This is seen particularly where there is rigidity. This tremor is very similar to the more common ET (See also: Diagnosis)
4. type IV - the monosymptomatic rest tremor, that is a pure tremor at rest which reduces with movement.