The dichotomy between low frequency and delta waves in human sleep: A reappraisal

Publication date: Available online 2 October 2017
Source:Journal of Neuroscience Methods
Author(s): Jean-Pol Lanquart, Pasquale Nardone, Philippe Hubain, Gwénolé Loas, Paul Linkowski
BackgroundWe present the results of an analysis of the low frequency (LF) (0.25–1Hz) and delta (1–4Hz) waves during human sleep. Our objective was to investigate whether LF and delta waves should be considered as separate entities.MethodsThe slow-wave electroencephalogram (EEG) activity of 2 sets of 10 young, healthy volunteers was analysed utilising the rarely-used Lomb-Scargle periodogram. This method has advantages over the more commonly-used Fast Fourier Transform analysis.ResultsDuring the night, the frequencies of the most powerful waves are concentrated in the 0.5–2Hz range and show a continuous tendency to shift towards slower frequencies during sleep.Comparison with existing methodsWhen considering the frequency dynamics of slow-wave activity below 3Hz, the unifying theory of LF and delta waves is more parsimonious than the idea that there is a different origin and regulation for the two sub-bands.ConclusionsThe unifying theory of LF and delta waves is the simplest explanation for the slow-wave activity of the EEG below 3Hz. This finding is important for the clinical use of slow-wave activity.



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