ALFF and RSFA are the same or different

Hi all,

I want to implement Amplitude of Low-Frequency Fluctuations (ALFF) and Resting‐State Fluctuation Amplitude (RSFA) measures. But I am a bit confused about the difference between them. This paper by Golestani, Wei and Chen uses both measures and compares them as proxies for cerebrovascular reactivity. This implies that they are different measures, albeit related.

However the following two descriptions seem to say that they are equivalent if not exactly the same.

RSFA in Tsvetanov et al. in the section “fMRI Acquisition and Preprocessing” and ALFF described the CONN toolbox page as “alternative/equivalent formulation”.

Briefly, both say take preprocessed time series, band-pass filter it [0.01-0.08] and take the SD.

Are they the same? And if not then what is the difference and which source is correct?

Thank you very much.

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