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Doctoral dissertation project of Tabea Thies

The influence of levodopa and deep brain stimulation on speech dynamics of patients with Parkinson’s disease (working title)

Patients with Parkinson’s disease (PwPD) suffer from a neurodegenerative disorder of the nervous system. Due to a progressive loss of dopaminergic cells in the substantia nigra PwPD develop problems with motor and non-motor functions. Therefore, not only gross motor but also cognitive abilities are impaired. Furthermore, the speech system gets affected which often leads to dysarthric speech impacting the phonation, articulation and the respiratory system.

At early stages of the disease a drug treatment with levodopa is efficient. But as the disease progresses the medication gets less effective. In advanced stages of the disease a deep brain stimulation (DBS) is another treatment option: electrodes get implanted in the patient’s brain stimulating a specific brain area. Both treatments can improve the motor functions. However, it is unclear whether these treatments improve speech motor control as well. Many studies tried to investigate the influence of levodopa and neurostimulation on speech production, but the results are striking.

My dissertation project aims to investigate the speech production of PwPD completing different tasks in different conditions. Whereas, preoperative recordings (before the implantation of DBS) investigate the levodopa response on speech production, postoperative recordings determine the influence of DBS. For capturing speech dynamics according to the treatments, acoustic and articulatory speech data will be analysed within the framework of articulatory phonology (Browman & Goldstein, 1986), in which speech production is defined as a self-organized system which adapts to changing requirements (H&H model, Lindblom, 1990). According to this, I expect that patients adapt to drug administration, neurostimulation and motor impairment. Within a discourse, speakers modulate speech parameters to produce a communicative or situation-adequate output (e.g. they speak louder in noisy environments). However, in deteriorated speech systems it is unclear, whether these mechanisms of regulation remain. Therefore, I want to investigate whether PwPD adapt to requirements of speech discourses and how much variability is allowed in the production of prosodic-linguistic constituents until the speech motor systems gets instable.


Short biography

Tabea Thies studied Linguistics and Phonetics at the University of Cologne where she received her master’s degree in 2018. Her research is focused on pathological speech especially investigating the speech production of patients with movement disorders. While attending university, she worked as a research assistant at the Phonetics Lab of the Department of Linguistics. After finishing her masters, she worked as research associate at the Neurology Department of the University Hospital in Cologne. Currently she is a doctoral student collaborating between the Phonetics Lab and Neurology Department in Cologne.

Contact: tabea.thies(at)

Profile on the Phonetics Lab website



Hermes, A., Mücke, D., Thies, T., & Barbe, M. T., “Coordination patterns in Essential Tremor patients with Deep Brain Stimulation: Syllables with low and high complexity”, in: Laboratory Phonology: Journal of the Association for Laboratory Phonology 10, 6, 2019, pp. 1–20, DOI:

Thies, T., Röhr, C.T., Baumann, S. & M. Grice, “Prosodic Marking of Information Status in Picture Story Descriptions”, in: Proceedings of the Conference on Phonetics & Phonology in German-Speaking Countries, P&P 13, 28-29 Sept, HU: Berlin, 2017, pp. 193–196.

Röhr, C. T., Thies, T., Baumann, S. & M. Grice, “Prosodic Marking of Information Status in Task-Oriented Dialogues”, in: Proceedings of the Conference on Phonetics & Phonology in German-Speaking Countries, P&P 12, München, Germany, 2016, pp. 168–171.

Thies, T., Hermes, A. & D. Mücke, “Coordination Deficits in Essential Tremor Patients with Deep Brain Stimulation”, in: Proceedings of the Conference on Phonetics & Phonology in German-Speaking Countries, P&P 12, München, Germany, 2016, pp.204–206.



2016: The University of Cologne’s Faculty of Arts and Humanities Prize for the B.A. thesis titled: „Eine akustisch-artikulatorische Analyse der Sprechmotorik bei Essentiellen Tremorpatienten mit Tiefer Hirnstimulation.“


Cover photo: Human brain (Pixabay License, // Portrait photo: Patric Fouad