Deep brain stimulation (DBS) in the treatment of advanced Parkinson´s disease with motor complications, dystonia and Parkinson and essential tremor has been a main clinical and research area since the first DBS treatment took place in the department and in Denmark in 1996.
At first, the research focus was on clinical effect, long-term follow-up, gait analysis and patient and spouse experiences of being treated with DBS. Treatment with DBS results in impressive improvement of cardinal motor symptoms and motor fluctuations. Parkinson medication is reduced by approximately 50% and quality of life is significantly improved (for references see pumed.com/, author Ostergaard K or Østergaard K).
In our research group, the DBS effect mechanism has recently been explored by means of sophisticated research tools such as magnetoencephalography (MEG) and diffusion-weighted MR tractography. During DBS on and off, with and without levodopa intake cortical recordings by MEG demonstrated differentiated effects of DBS and levodopa treatments on early somatosensory cortical processing (Kousik Sarathy Sridharan PhD dissertation, 2017 “Neuromagnetic investigations of mechanisms and effects of STN-DBS and medication in Parkinson's disease”. This is one step towards an understanding of the DBS mechanism.
DBS treatment in nucleus subthalamicus (STN) for Parkinson motor fluctuations can cause increase of impulsivity and reduced verbal fluency. In a current postdoc project, behaviour and language are explored during DBS and recording of cortical activity while performing a go/no-go task and a verbal fluency task. The results are expected to map the cortical areas involved in STN DBS side effects mentioned above. The question is if change of the STN stimulation area and thereby avoidance of unwanted stimulation of cortical areas involved in behaviour and cognition can reduce such sideeffects (Postdoc Andreas Højlund, project “Explaining impairment of verbal fluency and increase of impulsivity due to STN-DBS in Parkinson’s disease – using magnetoencephalography (MEG”).
MR diffusion tensor imaging and fiber-tracking have been implemented by the DBS team through a recent PhD study. (Mikkel V. Petersen PhD dissertation, 2016 “Tractography and neurosurgical targeting in deep brain stimulation”, link: goo.gl/iASQAq).
By MR tractography we have been able to -1) optimize precision of electrode implantation in DBS, and by continuation of these studies we expect to -2) gain new knowledge of the treatment effective pathways and pathways contributing to side effects, and to -3) gain new insight into the unknown mechanism of action in DBS. These studies are ongoing in a current postdoc project (postdoc Mikkel V. Petersen “Investigating brain structural connectivity in advanced Parkinson’s disease to optimize treatment with Deep Brain Stimulation (DBS)”).
The DBS/MEG/MR group
Karen Østergaard, Professor, e-mail: firstname.lastname@example.org
Andreas Højlund, Postdoc,e-mail: email@example.com
Mikkel V. Petersen, Postdoc, e-mail: firstname.lastname@example.org