Objective: To gain insights into brain areas associated with stimulation-induced dysarthria (SID) and to predict stimulation-induced worsening of intelligibility in essential tremor (ET) patient with thalamic deep brain stimulation (DBS).
Background: Thalamic DBS is an effective treatment for patients with medically refractory ET. However, stimulation-induced side-effects, especially SID interfere severely with quality of life. (1)
Method: Monopolar reviews were conducted in 14 ET patients with bilateral thalamic DBS by increasing the stimulation amplitude contact-wise until (i) a maximum of 10mA, (ii) the occurrence of intolerable side effects, or (iii) the onset of SID. Speech assessments included intelligibility ratings when reading a German standard text and a fast syllable repetition task. To detect brain areas associated with SID, a functional connectivity difference image of volumes of tissue activated (VTAs) causing SID, and VTAs not causing SID was created. Addtionally, discriminative fibers for stimulation-induced worsening of intelligibility in individual “ON” stimulation setting were identified in a structural connectome using linear mixed effect models.
Results: A total of 111 contact assessments were included. The functional connectivity difference image indicated stronger connectivity of VTAs causing SID (N=51) to the precentral gyrus with a positive medio-lateral gradient, parts of the inferior and medial frontal gyrus, the supramarginal gyrus, the superior temporal gyrus, as well as the superior and the inferior cerebellar lobules, and the vermis. In the DBS-target region, discriminative fibers for stimulation-induced worsening of intelligibility were located antero-lateral to fibers associated with tremor control, as published by Al-Fatly et al. (2019). The overlap of clinical “ON” stimulation settings with these fibers explained 33.2% of the respective intelligibility outcome variance in a leave-one-out design.
Conclusion: This study demonstrates that SID in ET patients is related to a modulation of the functional connectome of speech production by thalamic DBS. In spite of the proximity of functional and structural connectivity patterns for tremor control (2) and deterioration of speech we were able to derive a fiber-based atlas structure, that might help to avoid stimulation induced dysarthria in essential tremor patients.
References: 1) Flora ED, Perera CL, Cameron AL, Maddern GJ. Deep brain stimulation for essential tremor: a systematic review. Mov Disord 2010; 25(11): 1550-9. 2) Al-Fatly B, Ewert S, Kübler D, Kroneberg D, Horn A, Kühn AA. Connectivity profile of thalamic deep brain stimulation to effectively treat essential tremor. Brain 2019.
To cite this abstract in AMA style:
J.N Petry-Schmelzer, H. Jergas, T. Thies, J. Steffen, P. Reker, H. Dafsari, D. Mücke, G. Fink, V. Visser-Vandewalle, T. Dembek, M. Barbe. Cortical network fingerprint and prediction of deep brain stimulation-induced speech impairment in essential tremor [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/cortical-network-fingerprint-and-prediction-of-deep-brain-stimulation-induced-speech-impairment-in-essential-tremor/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/cortical-network-fingerprint-and-prediction-of-deep-brain-stimulation-induced-speech-impairment-in-essential-tremor/