The role of the motor cortex in essential tremor

Sarvi Sharifi, F. Luft, T. Heida, W. Mugge, A.C. Schouten, L. Bour, A.F. van Rootselaar

    Research output: Contribution to journalMeeting AbstractOther research output

    Abstract

    Objectives: Essential tremor (ET), the most prevalent hyperkinetic movement disorder, is characterized by an action tremor (4-7 Hz). The role of the sensorimotor cortex in tremor generation is uncertain. Previous corticomuscular coupling studies in ET showed either a cortical drive, an afferent input, or both. In contrast, familial cortical myoclonic tremor with epilepsy (FCMTE) with tremulous movements, clinically resembling ET, is characterized by a cortical drive around 15-20Hz.

    Methods: Corticomuscular directionality was investigated with renormalized partial directed coherence (rPDC) in ET (n=16), FCMTE (n=7), and healthy controls (HC; n=16). EEG-EMG was recorded during 2 minutes of postural tremor (ET and FCMTE right arm outstretched; HC mimicking tremor ±5Hz), and 1 minute of self-paced slow movements <3Hz (ET and HC).

    Results: In ET and HC, predominantly, muscular to cortical directionality was evident around (mimicked) tremor frequency. FCMTE patients revealed a cortical to muscular directionality. During voluntary slow movements, below 3 Hz, corticomuscular coupling was bidirectional in ET and HC.

    Conclusions: Our results indicate cortical activity at (mimicked) tremor frequencies resulting from afferent input in ET and HC, instead of a cortical drive. In FCMTE, rPDC was able to confirm a cortical drive tremulous movement frequencies. Furthermore, our findings indicate direct sensorimotor cortex output during slow voluntary movements. Concluding, tremor in ET seems not to result from a direct cortical drive. Subcortical circuits, possibly normally involved in high paced oscillatory movements, seem to be involved in ET.

    Original languageEnglish
    Pages (from-to)e128
    Number of pages1
    JournalParkinsonism & Related Disorders
    Volume22
    Issue numberSuppl. 2
    DOIs
    Publication statusPublished - Jan 2016
    EventXXI World Congress on Parkinson's Disease and Related Disorders 2015 - Milan, Italy
    Duration: 6 Dec 20159 Dec 2015
    Conference number: 21

    Keywords

    • BSS-Electrical Neurostimulation
    • METIS-320920
    • IR-102657
    • EWI-27534

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