Unilateral Stimulation of Prelemniscal Radiations for the Treatment of Acral Symptoms of Parkinson's Disease: Long-Term Results

Background: Prelemniscal radiations (Raprl) have been proposed as a target for the treatment of Parkinson's disease. We evaluated effectiveness of this target through UPDRS-III in patients treated with Raprl deep brain stimulation (Raprl-DBS) and followed from 24 to 48 months.

Methods: Nineteen patients in Hoehn-Yahr stages II-III were implanted with tetrapolar deep brain stimulation electrodes in Raprl contralateral to the extremities with more prominent symptoms. Placement was assisted by MRI/CT/anatomical atlas fusion, microelectrode recording, and micro- and macro-stimulation. The effect on motor symptoms was evaluated in an open label protocol through specific items of the UPDRS-III score, applied pre-operatively and 6, 12, 24, and 48 months after the onset of stimulation in an OFF-medication/ON-stimulation condition. Changes in scores with regard to pre-operative condition were obtained for each symptom in both sides and statistical significance determined through double-tail Wilcoxon test. Influence of demographic variables on outcome was analyzed using linear regression testing.

Results: A greater than 80% decrease in UPDRS score for contralateral symptoms (classified as excellent results) occurred in 14 patients (73.7%), while in the other 5 it decreased from 33 to 79% (considered suboptimal results). These changes remained statistically significant up to 48 months (p < 0.01), while ipsilateral symptoms progressively increased. Suboptimal results were associated with selective improvement of only one symptom.

Conclusion: Raprl-DBS induces a long-term, significant improvement of contralateral acral symptoms of Parkinson's disease.