Category: Dystonia: Pathophysiology, Imaging
Objective: To examined how pallidal activity correlates with symptom severity across dystonic patients.
Background: The internal segment of globus pallidus (GPi) is the most common target for surgical treatment of dystonia. To date, one of the accepted views suggested altered activity patterns and abnormal synchronization of globus pallidus as causes of dystonia.
Method: We have analyzed neural activity of the globus pallidus in 20 patients. Microelectrode recordings were performed during neurosurgeries to implant electrodes for deep brain stimulation (DBS). We simultaneously recorded local field potentials (LFP) and electromyographic signals of the neck and finger flexor muscles. We used Burke-Fahn-Marsden (BFMDRS) rating and the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) for assessing the neurological status of patients.
Results: Analysis of the single unit activity showed that increase in the severity of dystonia correlated with a significant decrease in the firing rate, an increase in frequency variance, as well as an increase in the index of oscillations in the high-frequency gamma range in the internal segment of globus pallidus (GPi). An analysis of the parameters of neuronal activity separately for each pattern (burst, pause, and tonic) of neuronal activity showed that the established differences are significant only for burst neurons.
Analysis of local potentials (LFP) showed that the synchronization of neuronal populations in the alpha range (8-12 Hz) positively correlated with the severity of dystonia according to the TWSTRS scale. At the same time, changes in activity in the alpha range during tests involving the neck muscles become less pronounced with an increase in the severity of dystonia according to the TWSTRS scale. There was a trend towards a decrease in the amplitude of high beta frequencies (20-30 Hz) with an increase in dystonia severity BFMDRS scores. Using multifractal analysis, we also obtained evidence that the characteristics of the multifractal spectrum of pallidal LFP correlate with the BFMDRS scores.
Conclusion: We found that pallidal firing rate and alpha oscillations correlate with the severity of clinical symptoms in patients with dystonia.
This study was supported by Russian Science Foundation (18-15-00009) and Russian Foundation for Basic Research (20-015-00438).
To cite this abstract in AMA style:U. Semenova, R. Medvednik, A. Tomskiy, V. Popov, A. Sedov. Pallidal firing rate and alpha oscillations correlate with the severity of clinical symptoms in patients with dystonia [abstract]. Mov Disord. 2022; 37 (suppl 2). https://www.mdsabstracts.org/abstract/pallidal-firing-rate-and-alpha-oscillations-correlate-with-the-severity-of-clinical-symptoms-in-patients-with-dystonia/. Accessed March 4, 2024.
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MDS Abstracts - https://www.mdsabstracts.org/abstract/pallidal-firing-rate-and-alpha-oscillations-correlate-with-the-severity-of-clinical-symptoms-in-patients-with-dystonia/