gms | German Medical Science

64th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

26 - 29 May 2013, Düsseldorf

Taste disturbances in bilateral thalamic (Vim) deep brain stimulation for essential tremor – an underestimated yet common side effect caused by differences in individual fiber anatomy

Meeting Abstract

  • Bastian E. A. Sajonz - Stereotaxie und Funktionelle Neurochirurgie, Klinik für Neurochirurgie, Universitätsklinikum Bonn
  • Burkhard Mädler - Stereotaxie und Funktionelle Neurochirurgie, Klinik für Neurochirurgie, Universitätsklinikum Bonn
  • Stephan Herberhold - Klinik für Hals-Nasen-Ohrenheilkunde, Universitätsklinikum Bonn
  • Sebastian Paus - Klinik für Neurologie, Universitätsklinikum Bonn
  • Niels Allert - Neurologisches Rehabilitationszentrum „Godeshöhe“ e.V., Bonn
  • Volker A. Coenen - Stereotaxie und Funktionelle Neurochirurgie, Klinik für Neurochirurgie, Universitätsklinikum Bonn

Deutsche Gesellschaft für Neurochirurgie. 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Düsseldorf, 26.-29.05.2013. Düsseldorf: German Medical Science GMS Publishing House; 2013. DocP 051

doi: 10.3205/13dgnc468, urn:nbn:de:0183-13dgnc4688

Published: May 21, 2013

© 2013 Sajonz et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: An inquiry among 16 patients treated with bilateral thalamic (Vim: Nucleus ventralis intermedius thalami) deep brain stimulation (DBS) for essential tremor revealed that the majority (10/16) suffered from stimulation induced taste disturbances. An evaluation of diffusion tensor (DTI) neuroimaging studies was performed to exemplify potential causes.

Method: Two of four selected patients reported stimulation induced hypogeusia while the other two did not. Tremor symptoms were assessed with the essential tremor rating scale (ETRS) in the stimulation on and off state. A subjective gustometry was conducted with deactivated, unilateral left/right and bilateral stimulation. Using preoperative DTI and the postoperative helical cranial computed tomography, effective contact positions (EC) were determined in relation to the medial lemnisci (ML) and the dentato-rubro-thalamic tracts (DRT).

Results: The patients showed a tremor improvement on average by 80 % on the ETRS comparing deactivated with bilateral stimulation. The subjective gustometry confirmed the stimulation induced hypogeusia in the two patients that had reported taste disturbances previously. One of the remaining two patients showed minimal taste reductions while the other showed stable results in the gustometry. The EC of all patients are situated within the DRT, which enters the thalamus from below close to Vim and Vop (Nucleus ventralis oralis posterior thalami). The two patients with considerable stimulation induced hypogeusia show a pattern of fiber anatomy with DRT and ML converging within immediate proximity of the EC. In the patient without hypogeusia the converging point of DRT and ML is situated more cranial to the EC. The patient with minimal taste reductions during unilateral right and bilateral stimulation shows an adjacency of DRT and ML at the EC on the right but not on the left.

Conclusions: Tremor reduction is explained through electrode location in the DRT. Stimulation induced taste disturbances seem to be common rather than exceptional side effects of bilateral Vim-DBS. The exact course of the gustatory tract cannot be defined by DTI-fiber tracking most likely because of its small volume. However, from lesion studies a posteromedial course within proximity of the ML can be inferred. Individual fiber anatomy of DRT and ML with a converging point near the stimulation target site seems to be the cause of stimulation induced hypogeusia by current spread, necessary to cover DRT fibers for tremor reduction.