# mne.preprocessing.nirs.scalp_coupling_index¶

mne.preprocessing.nirs.scalp_coupling_index(raw, l_freq=0.7, h_freq=1.5, l_trans_bandwidth=0.3, h_trans_bandwidth=0.3, verbose=False)[source]

Calculate scalp coupling index.

This function calculates the scalp coupling index 1. This is a measure of the quality of the connection between the optode and the scalp.

Parameters
rawinstance of Raw

The raw data.

l_freq

For FIR filters, the lower pass-band edge; for IIR filters, the lower cutoff frequency. If None the data are only low-passed.

h_freq

For FIR filters, the upper pass-band edge; for IIR filters, the upper cutoff frequency. If None the data are only high-passed.

l_trans_bandwidth

Width of the transition band at the low cut-off frequency in Hz (high pass or cutoff 1 in bandpass). Can be “auto” (default) to use a multiple of l_freq:

min(max(l_freq * 0.25, 2), l_freq)


Only used for method='fir'.

h_trans_bandwidth

Width of the transition band at the high cut-off frequency in Hz (low pass or cutoff 2 in bandpass). Can be “auto” (default in 0.14) to use a multiple of h_freq:

min(max(h_freq * 0.25, 2.), info['sfreq'] / 2. - h_freq)


Only used for method='fir'.

verbose

If not None, override default verbose level (see mne.verbose() and Logging documentation for more). If used, it should be passed as a keyword-argument only.

Returns
sci

Array containing scalp coupling index for each channel.

References

1

Luca Pollonini, Cristen Olds, Homer Abaya, Heather Bortfeld, Michael S Beauchamp, and John S Oghalai. Auditory cortex activation to natural speech and simulated cochlear implant speech measured with functional near-infrared spectroscopy. Hearing research, 309:84–93, 2014.