OBJECTIVES: In a group of patients with Huntington's disease and age-matched controls, we studied the cortical silent period (SP) elicited by single transcranial magnetic stimulation (TMS) pulses. METHODS: We measured the area of the pre-stimulus electromyographic (EMG) activity, the area of the motor evoked potentials (MEPs) and the duration of the SP induced by stimuli delivered at an intensity of 150% of motor threshold with a round coil placed over the vertex. We determined the cortical SP by sampling only the 5 traces containing the shortest SPs and by collecting 10 consecutive unselected traces without selecting trials. RESULTS: Patients and controls had normal EMG background areas, and MEP latencies and areas. Whereas data measured from selected trials gave a normal duration of the SP (patients, 154+/-58 ms; controls, 166+/-22 ms), data from unselected trials yielded a significantly longer SP duration in patients than in controls (356+/-251 vs. 159+/-44 ms) and also a larger variance and range. CONCLUSIONS: We conclude that in Huntington's disease, an abnormal cortical SP is best sought by collecting unselected consecutive traces. We suggest that the prolonged SP in HD originates from a dysfunction of the mechanisms controlling the restart of voluntary movement after TMS.
OBJECTIVES: In a group of patients with Huntington's disease and age-matched controls, we studied the cortical silent period (SP) elicited by single transcranial magnetic stimulation (TMS) pulses. METHODS: We measured the area of the pre-stimulus electromyographic (EMG) activity, the area of the motor evoked potentials (MEPs) and the duration of the SP induced by stimuli delivered at an intensity of 150% of motor threshold with a round coil placed over the vertex. We determined the cortical SP by sampling only the 5 traces containing the shortest SPs and by collecting 10 consecutive unselected traces without selecting trials. RESULTS:Patients and controls had normal EMG background areas, and MEP latencies and areas. Whereas data measured from selected trials gave a normal duration of the SP (patients, 154+/-58 ms; controls, 166+/-22 ms), data from unselected trials yielded a significantly longer SP duration in patients than in controls (356+/-251 vs. 159+/-44 ms) and also a larger variance and range. CONCLUSIONS: We conclude that in Huntington's disease, an abnormal cortical SP is best sought by collecting unselected consecutive traces. We suggest that the prolonged SP in HD originates from a dysfunction of the mechanisms controlling the restart of voluntary movement after TMS.
Authors: V Di Lazzaro; M Dileone; F Pilato; M-F Contarino; G Musumeci; A R Bentivoglio; P A Tonali; J C Rothwell Journal: J Neurol Neurosurg Psychiatry Date: 2006-09 Impact factor: 10.154
Authors: Sven Schippling; Susanne A Schneider; Khailash P Bhatia; Alexander Münchau; John C Rothwell; Sarah J Tabrizi; Michael Orth Journal: Biol Psychiatry Date: 2009-02-07 Impact factor: 13.382
Authors: Tim Wagner; Uri Eden; Felipe Fregni; Antoni Valero-Cabre; Ciro Ramos-Estebanez; Valerie Pronio-Stelluto; Alan Grodzinsky; Markus Zahn; Alvaro Pascual-Leone Journal: Exp Brain Res Date: 2008-01-10 Impact factor: 1.972