Quantitative Assessment of Movement Disorders in Clinical Practice

Abstract

Assessment of tremor and dystonia is crucial to characterize their patients' clinical state. Three different devices have been used: (1) PAM, a passive marker based motion analyzer, (2) a digitizing tablet with spiral drawing test, and (3) a 3D accelerometer. PAM fits excellently to testing different kinds of human movements by detecting the displacement. Even the involuntary movements of different regions on the face can be quantitatively assessed. Seventeen disk shaped adhesive markers were attached to the face of two patients with Meige syndrome, presenting blepharospasm and oromandibular dystonia. 20-s recordings were taken with PAM, an inexpensive and clinically easily applicable motion analyzer. The evaluation of the recordings before, and after surgery showed significant reduction of the intensity and rate of uncontrolled movements while the difference between the movement of the left and right cheeks diminished substantially. The paper gives the marker pattern used as well as the evaluation method. Tracking a spiral with a pen on a digitizing tablet is challenging for patients with movement disorders affecting their upper limbs. 68 patients with neural diseases were tested, altogether 544 recordings were made and evaluated. Typical trajectories are shown together with the evaluation. Tremor is present even in healthy subjects. A 3D accelerometer based, clinically applicable tool has been developed. 60-s recordings were taken from ten healthy subjects. Persons held the device in their hand while their wrist was supported. The timefrequency diagrams of the recordings show patient specific characteristics. Based on recordings taken at rest the actual stress level can be estimated. Though not measured generally, this is an important parameter during many clinical tests, especially during blood pressure measurement.