Delayed beta synchronization after movement of the more affected hand in essential tremor

• Published in: Neuroscience letters 2006-09, Vol.405 (3), p.246-251
• Main Authors: Tamás, Gertrúd, Pálvölgyi, László, Takáts, Annamária, Szirmai, Imre, Kamondi, Anita
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Analysis of Variance; Beta Rhythm; Biological and medical sciences; Cortical Synchronization; Essential tremor; Essential Tremor - physiopathology; Female; Functional Laterality; Fundamental and applied biological sciences. Psychology; Hand - physiopathology; Humans; Male; Medical sciences; Middle Aged; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Movement - physiology; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Parkinson Disease - physiopathology; Parkinson's disease; Post-movement beta synchronization; Reaction Time - physiology; Self-paced movement; Tremor generators; Vertebrates: nervous system and sense organs
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2006.07.001

To investigate the pathomechanism of parkinsonian tremor (PT) and essential tremor (ET) by studying the correlation between tremor asymmetry and post-movement beta synchronization (PMBS) of the human EEG. We recorded the EEG of 10 patients with ET, 10 patients with Parkinson's disease and 10 controls. Subjects pressed an on-off switch in a self-paced manner with the thumb of their less (T+) and more (T++) tremulous hand. After digitalization of the EEG from the Cz, C3, C4 electrodes the movement reactive beta frequency, its maximum peak power value and its latency triggered to movement offset were determined. In ET tremor intensity did not influence the power of PMBS, however it was significantly delayed after the movement of the more tremulous hand. In Parkinson's disease after the movement of the more tremulous hand PMBS power was decreased, but it was not delayed. In controls the side of movement had no effect on the power and latency of the PMBS. The neuronal mechanisms underlying PMBS generation are differently affected in essential tremor and Parkinson's disease. The increase of PMBS latency after movement of the more affected hand in ET indicates possible cortical mechanisms in essential tremor generation.