Dynamics of the wrist in patients with Myoclonus Dystonia. Measurements on the reflexive feedback system.

Myoclonus Dystonia is a movement disorder with autosomal dominant inheritance
and clonically characterized by myoclonic jerks and dystonic postures or
movement of the upper body, combined with psychiatric phenomena such as
obsessive compulsive disorder.

The measurements involve a wrist manipulator. This is a device with which
spinal reflexes can be exactly quantified. It consists of a handhold which the
subject must hold onto. The subject has to keep his/her hand as motionless as
possible, while the wrist manipulator will apply a (small) dynamic force. The
subject is presented the deviation and the zero-position of the handle through
visual feedback. The EMG, EEG, as well as the deviation and force of the
handhold are recorded.

The modulation of spinal reflexes is the reflexive counter-force applied bu the
subject, as a function of the frequency of movement of the wrist manipulator.
It is an exact measurable quantity for the quality of the reflexive feedback
system.

The aim of this study is to gain understanding of the functioning of spinal
reflexes in patients with MD, using a new method involving EMG, EEG and the
wrist manipulator.

Ten controls are matched to ten patients with MD with regards to age and
gender. Measurements are taken to examine the functioning of spinal reflexes in
all twenty subjects. Differences between patients and controls are examined;
these differences will be investigated with the help of a model for the
workings of spinal refleses.

na: The investigation is completely non-invasive