gms | German Medical Science

Objective: We describe the quantification of bradykinesia and its response to DBS with diadochometry.The effectiveness of deep brain stimulation DBS for the treatment of Parkinsons' disease has been shown in several retrospective and one prospective study. The ratings of these studies however rely on clinical rating scales like the UPDRS as main tools for assessment of motor performance. The limited interrater reliability of these scales impaires the comparison of different studies. Moreover a tool free of the influence of an individual investigator would lend credibility to the merits of DBS. The validity of diadochometry has been demonstrated in previous studies. The parameters measured are movement velocity along with amplitude and frequency of diadochokinesia.

Methods: Rapid alternating forearm supination and pronation was recorded in ten patients with Parkinson’s disease following implantation of electrodes in the STN by a diadochometry device built in our laboratory. The tests were performed in the following treatment conditions: 1 preoperative: medication on/off; 2 postoperative: off stimulation on medication; 3 postoperative: on stimulation on medication. Also, a group of age- and gender-matched control subjects was examined.

Results: DBS increased movement velocity, movement amplitude and movement frequency. The improvement of movement velocity in diadochometry and bradykinesia in UPDRS part III were closely related. The movement velocity of neurological normal control subjects remained significantly higher than the values of patients in the stimulation on condition.

Conclusions: In our study we could quantify preoperative bradykinesia and its significant improvement after DBS. Diadochometry values are closely related to UPDRS motorscores. Diadochometry is a valid, objective and simple to perform diagnostic tool. It should be considered as an additional tool besides established clinical rating scales in future trials on the efficacy of DBS.