Objective: To compare the efficacy, safety, energy efficiency and quality of life (QoL) of bilateral PSA-DBS versus bilateral VIM-DBS in the treatment of essential tremor (ET).

Background: Deep brain stimulation (DBS) is an alternative treatment for disabling and refractory ET. Although DBS of the ventral intermediate nucleus (VIM) has shown a beneficial effect, some evidence suggests DBS in the posterior subthalamic area (PSA) may be more efficacious. Differences in clinical, electrical and QoL outcomes of VIM-DBS and PSA-DBS need to be better characterised.

Method: Randomized double-blind crossover clinical trial in patients with disabling and refractory ET treated by DBS. Bilateral octopolar leads (Boston Vercise™ PC DB1416) were implanted with a trajectory covering VIM (proximal contacts) and PSA (distal contacts). They were randomly assigned to group 1 (PSA-VIM) or group 2 (VIM-PSA), receiving stimulation on each target for 3 months. The primary endpoint was measuring improvement in ET using Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS) total and arm-items scores. Secondary endpoints were measurement of improvement in QoL measured by Visual Analogue Scale (VAS-QoL), detection of possible adverse events (AE) and evaluation of energy requirements.

Results: Eleven patients (6F/5M, mean age of 63±7.6 years) were randomized to group 1 (n=5) or group 2 (n=6). No evidence of period or sequence effect was obtained. Both PSA-DBS and VIM-DBS significantly reduced tremor severity and improved QoL. However, the improvement in FTM-TRS total and arm-items scores was significantly better with PSA-DBS than VIM-DBS, with a mean paired difference of -4.82 points (p=0.032) and -1.27 points (p=0.027), respectively. No statistically significant differences were found in stimulation amplitudes (mean difference -0.23 mA, p=0.386), in VAS-QoL (mean difference 0.91 points, p= 0.211) or AE (neither frequency nor type, p= 0.7124). There were no serious complications or sequelae related to DBS.

Conclusion: Our randomized trial shows that both PSA-DBS and VIM-DBS are effective and safe in treatment of essential tremor, however PSA-DBS elicited a better response in terms of tremor suppression than VIM-DBS. Moreover, our study shows a trend towards lower stimulation amplitudes needed with PSA-DBS.

« Back to 2024 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/a-double-blind-randomized-crossover-clinical-trial-comparing-vim-vs-psa-deep-brain-stimulation-for-disabling-essential-tremor/