Simultaneous Recording of Motor Related Cortical Potentials to Different Basal Components of Voluntary Movements (P4.193)

Objective To compare Motor Related Cortical Potentials (MRCPs) to basic components of voluntary movements in prolonged recording sessions. Background A study addressing the distinctive features and degree of stability in subsequent intra-session determinations of MRCPs to ballistic movement, purposeful activation and relaxation, is lacking. Materials and Method EEG activity (27 electrodes placed over the sensorimotor cortex) was recorded in 10 normal volunteers instructed to continuously perform a sequence of 3 simple self-paced movements with the right index finger, separated by an interval of at least 3-4 sec: 1) rapid, ballistic-type (Bt-) extension with immediate automated return to resting position; 2) rapid extension (Ex-) to reach and maintain a defined target followed by 3) relaxation (Re-) with passive return to resting position. A prolonged recording session (80 minutes) provided, for each task, a sequence of 4 MRCPs resulting from the average of 4 successive blocks of 40-80 artefact-free EEG epochs (3 sec before and 1 sec after onset of individual movements derived from the mechanogram). Recording breaks of about 10-20 seconds, without interruption of motor task, were interposed at intervals of 3-4 minutes. Results No subject reported localized muscle fatigue at the end of session. Pre- and post-movement components were stable in all MRCPs throughout the recording session. All potentials showed a similar onset and duration of pre-movement components with a similar scalp distribution. Clear-cut differences were observed between the 3 MRCPs in the post-movement components probably reflecting different afferent patterns from peripheral effectors. Conclusions/Significance Simultaneous evaluation of different MRCPs to basic components of voluntary movements is the prerequisite to disclose a differential derangement of motor control in movement disorders. Unambiguous demonstration that MRCP does not show habituation in prolonged recording is the necessary methodological premise for a reliable evaluation of MRCP changes induced by any perturbing factor, such as fatigue. Disclosure: Dr. Troni has nothing to disclose. Dr. Boretto has nothing to disclose. Dr. di Sapio has received personal compensation for activities with Biogen-Dompe, Novartis, and Teva Neuroscience as a speaker and consultant and for activities with Merck-Serono, Biogen-Dompe, and Farmades as a reimbursement. Mr. Melillo has received personal compensation for activities with Biogen as a speaker. Dr. Rosalba has nothing to disclose. Dr. Maria Consuelo has nothing to disclose.