Magnetically-invoked motor evoked potentials (MEPs); an assessment of the errors in measuring latencies


Hovey C. F. J. , Griffiths I. W. , Mccarthy P. W.

9th WSEAS International Conference on Simulation, Modelling and Optimization, Budapest, Hungary, 3 - 05 September 2009, pp.122-123 identifier

  • Publication Type: Conference Paper / Full Text
  • City: Budapest
  • Country: Hungary
  • Page Numbers: pp.122-123

Abstract

Magnetic stimulation is extensively used in research of the intra-cortical connections of the human brain, but there is relatively little evidence of its reliability in terms of generating repeatable Motor Evoked Potentials (MEPs) which are often used as a means of establishing the appropriate power output of the stimulator for an individual subject. The amplitude of cortically evoked responses has long been known to be very variable, but latency has been considered to be a reliable measure, while this measurement of latency could be subject to a number of errors; we report a total error of less than 5% of the measured latency. Although coil sizes and geometries may also affect latency, we confirm that the use of surface or needle electrodes does not appear to affect latency measurement.