Quantitative analysis of MEG using modified sLORETA for clinical application.
Clin Neurophysiol 2008;
119:1917-1922. [PMID:
18571466 DOI:
10.1016/j.clinph.2008.04.008]
[Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2007] [Revised: 03/10/2008] [Accepted: 04/04/2008] [Indexed: 11/21/2022]
Abstract
OBJECTIVE
To determine whether standardised low-resolution brain electromagnetic tomography modified for a quantifiable method (sLORETA-qm) can be used for quantitative analysis in magnetoencephalography (MEG).
METHODS
Somatosensory evoked fields (SEFs) were obtained from 10 hemispheres of five healthy volunteers stimulated on the median nerve at 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 x threshold of thenar muscle twitch (TMT). N20 m intensity changes were analysed quantitatively using sLORETA-qm. Then, SEFs were measured with stimulation on the median nerve at 1.5 x TMT from 47 hemispheres in 24 subjects. sLORETA-qm intensity and the equivalent current dipole (ECD) moment of N20 m were calculated, and relationships between the values were evaluated.
RESULTS
sLORETA-qm intensity increased linearly with stimulus intensity between 0.75 and 1.5 x TMT, and tended to reach a plateau or decrease at higher stimulus intensities. The distribution of sLORETA-qm intensity after natural logarithmic transformation was normal and a close correlation was found between the ECD moment and sLORETA-qm intensity (r(s)=0.91, p<0.001).
CONCLUSIONS
The results of this study focusing on N20 m suggested that sLORETA-qm is reliable for quantitative analysis of MEG as well as ECD models.
SIGNIFICANCE
sLORETA-qm appears promising for quantitative analyses of MEG for which ECD models are inappropriate.
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