PMID- 21071268
OWN - NLM
STAT- MEDLINE
DCOM- 20110517
LR  - 20110309
IS  - 1872-8952 (Electronic)
IS  - 1388-2457 (Linking)
VI  - 122
IP  - 4
DP  - 2011 Apr
TI  - The routine circular coil is reliable in paired-TMS studies.
PG  - 784-8
LID - 10.1016/j.clinph.2010.10.027 [doi]
AB  - OBJECTIVE: Motor cortex excitability can be measured by transcranial magnetic 
      stimulation (TMS) using different coil types, but paired-TMS was originally 
      devised with a figure-of-eight coil. We asked whether the most popular, circular 
      coil was suited to the every-day assessment of cortical excitability, 
      particularly paired-TMS indexes, and if it reduced the measurement error. 
      METHODS: We studied 12 right-handed, healthy subjects (34+/-7.6 years). Resting 
      motor threshold (MT), cortical silent period (CSP), short-interval intracortical 
      inhibition (SICI) at the 2, 3, 4 and 5 ms interstimulus intervals (ISIs) and 
      intracortical facilitation (ICF) at the 14 and 16 ms ISIs were measured. 
      Intrinsic variability of these indexes was evaluated in terms of Coefficients of 
      Variation, to estimate the measurement error. This sequence was carried out both 
      using a figure-of-eight coil over the hand motor area and a circular coil centred 
      at the vertex. Testing was repeated 8-13 months later. RESULTS: On average, MT, 
      SICI and ICF did not show any statistically significant difference (p>0.05) when 
      studied with the figure-of-eight as compared with the circular coil. CSP was 
      significantly shorter (p=0.007) with the figure-of-eight coil. Using either coil 
      did not affect measurement variability. There was no significant 
      session-to-session group difference at any of the variables using either coil 
      type. CONCLUSIONS: Except for the CSP duration, the TMS testing and retesting of 
      cortical excitability, particularly the paired-pulse indexes, did not vary 
      significantly as a function of the coil used. SIGNIFICANCE: Routine circular 
      coils can be used reliably in paired-TMS studies designed to measure longitudinal 
      changes in cortical excitability though they do not reduce the measurement error.
CI  - Copyright (c) 2010 International Federation of Clinical Neurophysiology. Published 
      by Elsevier Ireland Ltd. All rights reserved.
FAU - Badawy, Radwa A B
AU  - Badawy RA
AD  - Department of Neurology, Austin Health, Heidelberg, Victoria, Australia.
FAU - Tarletti, Roberto
AU  - Tarletti R
FAU - Mula, Marco
AU  - Mula M
FAU - Varrasi, Claudia
AU  - Varrasi C
FAU - Cantello, Roberto
AU  - Cantello R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20101110
PL  - Netherlands
TA  - Clin Neurophysiol
JT  - Clinical neurophysiology : official journal of the International Federation of 
      Clinical Neurophysiology
JID - 100883319
SB  - IM
MH  - Adult
MH  - Data Interpretation, Statistical
MH  - Electromyography
MH  - Electronics
MH  - Equipment Design
MH  - Evoked Potentials, Motor/physiology
MH  - Female
MH  - Hand/innervation
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Motor Cortex/*physiology
MH  - Neural Pathways/physiology
MH  - Reproducibility of Results
MH  - Transcranial Magnetic Stimulation/*instrumentation
EDAT- 2010/11/13 06:00
MHDA- 2011/05/18 06:00
CRDT- 2010/11/13 06:00
PHST- 2010/05/08 00:00 [received]
PHST- 2010/10/14 00:00 [revised]
PHST- 2010/10/17 00:00 [accepted]
PHST- 2010/11/13 06:00 [entrez]
PHST- 2010/11/13 06:00 [pubmed]
PHST- 2011/05/18 06:00 [medline]
AID - S1388-2457(10)00766-2 [pii]
AID - 10.1016/j.clinph.2010.10.027 [doi]
PST - ppublish
SO  - Clin Neurophysiol. 2011 Apr;122(4):784-8. doi: 10.1016/j.clinph.2010.10.027. Epub 
      2010 Nov 10.