Intermuscular coherence as biomarker for pallidal deep brain stimulation efficacy in dystonia

• Published in: Clinical neurophysiology Vol. 130; no. 8; pp. 1351 - 1357
• Main Authors: Doldersum, E., van Zijl, J.C., Beudel, M., Eggink, H., Brandsma, R., Piña-Fuentes, D., van Egmond, M.E., Oterdoom, D.L.M., van Dijk, J.M.C., Elting, J.W.J., Tijssen, M.A.J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-08-2019
• Subjects: Adult; Biomarker; Deep brain stimulation; Deep Brain Stimulation - methods; Dystonia; Dystonia - diagnosis; Dystonia - therapy; Electroencephalography - methods; Electromyography - methods; Female; Globus Pallidus - physiopathology; Humans; Intermuscular coherence; Male; Middle Aged; Motor Cortex - physiopathology; Muscle, Skeletal - physiopathology; Biomarker; BFMDRS; GPi-DBS; Deep brain stimulation; CBTBC-loop; LFP; CMC; Dystonia; Intermuscular coherence; TWSTRS; IMC
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2019.04.717

•Intermuscular coherence can function as a biomarker for Globus Pallidus interna Deep Brain Stimulation (GPi-DBS) efficacy in dystonia.•GPi-DBS decreases intermuscular coherence in the low frequency band and beta band.•Intermuscular coherence correlates with dystonia symptom severity.
Finding a non-invasive biomarker for Globus Pallidus interna Deep Brain Stimulation (GPi-DBS) efficacy. Dystonia heterogeneity leads to a wide variety of clinical response to GPi-DBS, making it hard to predict GPi-DBS efficacy for individual patients.
EEG-EMG recordings of twelve dystonia patients who received bilateral GPi-DBS took place pre- and 1 year post-surgery ON and OFF stimulation, during a rest, pinch, and flexion task. Dystonia severity was assessed using the BFMDRS and TWSTRS (pre- and post-surgery ON stimulation). Intermuscular coherence (IMC) and motorcortex corticomuscular coherence (CMC) were calculated. Low frequency (4–12 Hz) and beta band (13–30 Hz) peak coherences were studied.
Dystonia severity improved after 1 year GPi-DBS therapy (BFMDRS: 30%, median 7.8 (IQR 3–10), TWSTRS: 22%, median 6.8 (IQR 4–9)). 86% of IMC were above the 95% confidence limit. The highest IMC peak decreased significantly with GPi-DBS in the low frequency and beta band. Low frequency and beta band IMC correlated partly with dystonia severity and severity improvement. CMC generally were below the 95% confidence limit.
Peak low frequency IMC functioned as biomarker for GPi-DBS efficacy, and partly correlated with dystonia severity.
IMC can function as biomarker. Confirmation in a larger study is needed for use in clinical practice.