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Deep brain stimulation affects language processing in Parkinson’s disease

A new MEG study by the NeDComm group at CFIN has just been published in Acta Neurologica Scandinavica

17.06.2021 | Henriette Blæsild Vuust

Professor Yury Shtyrov, CFIN

Parkinson’s disease (PD) is a common neurological disorder affecting millions of people worldwide. Although it is best known for its debilitating effects on the motor system, severely affecting people’s ability to move, it also affects different aspects of cognition. Deep brain stimulation of the sub-thalamic nucleus (STN-DBS) is an effective surgical treatment that helps control motor symptoms in patients with advanced PD that cannot be treated with simple drugs. Small battery-driven electrodes are inserted deep into the patient’s brain and constantly deliver small electric currents which help the person’s nervous system function normally even at advanced stages of PD. Although the therapeutic effectiveness of STN-DBS on the motor symptoms is well documented, the impact of this treatment on cognitive functions, such as language, is still controversial.

A group of scientists and clinicians from CFIN and Aarhus University Hospital, led by Professor Yury Shtyrov, investigated the effects of such electrical stimulation on two aspects of language processing in PD patients: processing of verb meaning and morphosyntactic (i.e., word structure) processing. Dr Rasha Hyder, the first author of the study, and her colleagues developed a special language paradigm which was easy to follow even for patients with advance PD, and used magnetoencephalographic (MEG) responses to study the brain’s reactions to different types of words while the patients’ DBS stimulation was changed to different settings.
The results revealed that bilateral and right unilateral stimulation of the sub-thalamic nucleus yielded significant dissociations for the processing of different verb types, with greater brain responses for action-related verbs compared to abstract verbs. For morphosyntax processing, STN-DBS only in the left hemisphere of the brain yielded significant effects, with greater neuromagnetic responses to the incorrectly inflected nouns as compared to the correct inflections suggesting recovery of normal neurolinguistic function.

The results provide a first demonstration of differential effects of unilateral and bilateral STN-DBS on brain activity associated with the processing of spoken language and suggest that different aspects of linguistic information processing in PD patients are affected differently by STN-DBS treatment. This paves the way for better understanding of both PD mechanisms and effects of deep brain stimulation as well as for future therapy developments.

For full details, please see their full paper:

Hyder R, Højlund A, Jensen M, Johnsen EL, Østergaard K, Shtyrov Y. STN-DBS affects language processing differentially in Parkinson's disease: Multiple-case MEG study. Acta Neurol Scand. 2021;00:1–10.

https://doi.org/10.1111/ane.13423


Contact:

Professor Yury Shtyrov
yury@cfin.au.dk    
https://pure.au.dk/portal/en/persons/yury-shtyrov (647ef703-8140-4df2-810d-32b539576368).html

Forskning, Sundhed og sygdom, Videnskabelig medarbejder, CFIN, CFIN, Ph.d.-studerende, Forskningsårsstuderende, Udvekslingsstuderende, Kommende studerende, Teknisk/administrativ medarbejder