How to compare NIRS spectra between each other?

[groot44]

What would be the best practices for comparing multiple NIRS spectra between each other? I’m working with NIRS data of multiple samples from different subjects, measured with the same measurement setup. The aim is in the end to analyse correlation between signals and anatomical differences between subjects.

Based on what I have found so far, I’m considering either absolute power or absolute intensity of the spectrum (not sure if they are the same or not). I’m fairly new with NIRS signal analysis and thus wanted to ask for opinions with the matter. Thanks in advance!

 

[berkeman]

What would be the best practices for comparing multiple NIRS spectra between each other? I’m working with NIRS data of multiple samples from different subjects, measured with the same measurement setup. The aim is in the end to analyse correlation between signals and anatomical differences between subjects.

Based on what I have found so far, I’m considering either absolute power or absolute intensity of the spectrum (not sure if they are the same or not). I’m fairly new with NIRS signal analysis and thus wanted to ask for opinions with the matter. Thanks in advance!

Welcome to PF.

What does your typical spectra data look like as a function of time and subject task? I'm not familiar with the bandwidth of the NIRS spectrum -- how wide is it, and what is the significance of the different regions in the spectrum?

What tasks do you have the subjects performing, and are the recordings synchronized? Or are the scans just resting scans and you want to compare them?

I've worked with EEG and EKG pads and recordings a fair amount -- Is hair an issue with NIRS sensing, or do you shave the probe sites?

https://cortechsolutions.com/product/ni-br-sym54/

 

[DrDu]

You could, for example do a PCR.

 

[groot44]

Welcome to PF.

What does your typical spectra data look like as a function of time and subject task? I'm not familiar with the bandwidth of the NIRS spectrum -- how wide is it, and what is the significance of the different regions in the spectrum?

What tasks do you have the subjects performing, and are the recordings synchronized? Or are the scans just resting scans and you want to compare them?

I've worked with EEG and EKG pads and recordings a fair amount -- Is hair an issue with NIRS sensing, or do you shave the probe sites?

View attachment 282060
https://cortechsolutions.com/product/ni-br-sym54/

Thanks for the answer! I haven't worked with EEG yet but hopefully in the future. To answer your question about hair, I believe it could be issue but we used light sources on forehead to avoid the issue.

The bandwidth is given as electromagnetic spectrum from approximately 300nm to 1200nm (wavelength), measurement done by spectrometer utilising charge-coupled device (CCD). The most important wavelengths are 830nm and 905nm due to oxyhemoglobin and deoxyhemoglobin absorption qualities.

The integration time of the samples is same. These are only resting measurements and would like to further analyse them for correlation. So I have been considering how to quantify the results.

 

[groot44]

You could, for example do a PCR.

What is PCR? Or do you mean principle component analysis PCA?

 

[DrDu]

What is PCR? Or do you mean principle component analysis PCA?

I tell you if you tell me what NIRS means

 

[DrDu]

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/abs/10.1002/cem.1180020207

 

[groot44]

I tell you if you tell me what NIRS means

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/abs/10.1002/cem.1180020207

Interesting, hadn't heard about PCR! Thank you, I'll look into it.