The effects of thalamic and posterior subthalamic deep brain stimulation on speech in patients with essential tremor - A prospective, randomized, doubleblind crossover study.

To prospectively evaluate the effect of PSA- and VIM DBS on speech in ET patients. Leads were implanted bilaterally with contacts placed in both VIM and PSA. Thirteen patients were analyzed pre- and postoperatively. Preoperative speech of ET patients was compared to healthy controls. PSA- and VIM-DBS were evaluated in a randomized, double-blind crossover phase. At preoperative baseline, we found reduced intelligibility. Differences in acoustic and VAS data ('ability to speak') compared to controls were gradient. Articulation rate could be predicted by disease duration. Decreased articulation rate, spirantization and voicing were found for PSA- and VIM-DBS. Targets did not differ in terms of speech deterioration. Speech in ET patients without DBS can be impaired, dependent on patient's individual characteristics. Both PSA- and VIM-DBS affect speech in a comparable way. Thus, the PSA can be considered an alternative DBS target in ET without higher risk of dysarthria.