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Neurophotonics • Open Access

Exploring effective multiplicity in multichannel functional near-infrared spectroscopy using eigenvalues of correlation matrices
Author(s): Minako Uga; Ippeita Dan; Haruka Dan; Yasushi Kyutoku; Y. H. Taguchi; Eiju Watanabe

Paper Abstract

Recent advances in multichannel functional near-infrared spectroscopy (fNIRS) allow wide coverage of cortical areas while entailing the necessity to control family-wise errors (FWEs) due to increased multiplicity. Conventionally, the Bonferroni method has been used to control FWE. While Type I errors (false positives) can be strictly controlled, the application of a large number of channel settings may inflate the chance of Type II errors (false negatives). The Bonferroni-based methods are especially stringent in controlling Type I errors of the most activated channel with the smallest p value. To maintain a balance between Types I and II errors, effective multiplicity (Meff) derived from the eigenvalues of correlation matrices is a method that has been introduced in genetic studies. Thus, we explored its feasibility in multichannel fNIRS studies. Applying the Meff method to three kinds of experimental data with different activation profiles, we performed resampling simulations and found that Meff was controlled at 10 to 15 in a 44-channel setting. Consequently, the number of significantly activated channels remained almost constant regardless of the number of measured channels. We demonstrated that the Meff approach can be an effective alternative to Bonferroni-based methods for multichannel fNIRS studies.

Paper Details

Date Published: 4 February 2015
PDF: 7 pages
Neurophoton. 2(1) 015002 doi: 10.1117/1.NPh.2.1.015002
Published in: Neurophotonics Volume 2, Issue 1
Show Author Affiliations
Minako Uga, Jichi Medical Univ. (Japan)
Chuo Univ. (Japan)
Ippeita Dan, Jichi Medical Univ. (Japan)
Chuo Univ. (Japan)
Haruka Dan, Jichi Medical Univ. (Japan)
Chuo Univ. (Japan)
Yasushi Kyutoku, Chuo Univ. (Japan)
Y. H. Taguchi, Chuo Univ. (Japan)
Eiju Watanabe, Jichi Medical Univ. (Japan)

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