Projects

Akustische und artikulatorische Analyse stimulationsinduzierter Dysarthrie bei Patienten mit essentiellem Tremor und tiefer Hirnstimulation im Bereich des Nucleus ventralis intermedius (VIM)

Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) is commonly performed to suppresses medically resistant essential tremor (ET). It is a highly effective treatment and usually leads to a tremor reduction of 60-80%. However, stimulation-induced dysarthria (SID) is one of the most common side effects in ET patients treated with DBS in the VIM. In fact, in up to 75% of the patients, speech deterioration has been reported, inducing a severe impact on quality of life and social functioning: To date, the exact pathogenesis of SID in VIM-DBS treated ET patients is unknown. It might be either the stimulation of the target area itself disturbing physiological processes of speech production or collateral effects through current spread to neighbouring structures, such as the laterally located corticobulbar fibre tracts of the internal capsule.

This idea is supported by the fact that more laterally placed electrodes are associated with more severe SID. However, stimulation induced dysarthria due to too medial or ventral stimulation has also been reported. This leads to the dilemma of choosing suboptimal stimulation parameters to avoid SID at the cost of less tremor suppression. Some of our patients even frequently switch between stimulation settings, according to the priority of motor skills required (less impaired speech vs. better tremor suppression).

The goal of our project “Akustische und artikulatorische Analyse stimulationsinduzierter Dysarthrie bei Patienten mit essentiellem Tremor und tiefer Hirnstimulation im Bereich des Nucleus ventralis intermedius (VIM)” is to combine interdisciplinary (clinical, acoustic, articulatory, logopedic) methods to work out pathophysiological concepts, therapeutic and maybe even preventive intervention options. Up to now, acoustic studies were only able to make indirect statements about speech motor control. By means of articulatory measurements, we might be able to show how articulation is disturbed by VIM-DBS. Possibly, our findings can be expanded to other neurologic speech disorders and can be used to identify pre-operative markers for the risk of stimulation induced dysarthria.