Beyond the Hypnogram: Multitaper Spectrogram Analysis of Sleep EEG

These tutorials are a companion to:

Prerau MJ, Bianchi MT, Brown RE, Ellenbogen JM, Patrick PL. Sleep Neurophysiological Dynamics Through the Lens of Multitaper Spectral Analysis. Physiology (Bethesda). 2017 Jan;32(1):60-92. Review. PubMed PMID: 27927806.

Move Beyond the Hypnogram

In this set of free online interactive tutorials, we will explain the theory of spectral estimation and demonstrate how a technique called multitaper spectral analysis can create clear, vibrant pictures of brain dynamics during sleep — rich with information beyond what can be seen in traditional clinical hypnogram analyses.


Sleep is a continuous, dynamic neural process involving the complex interaction of many different networks within the brain. Long-standing clinical practice, however, breaks up sleep into discrete sleep stages through time-consuming, subjective, visual inspection of 30-second segments of electroencephalogram (EEG) data. As a result, vital information about brain activity is lost. Multitaper spectral analysis is therefore a powerful tool for finding new insights into the physiological mechanisms underlying sleep and for developing new ways of diagnosing and tracking sleep and diagnosing related disorders.

What is Spectral Estimation? Why is it Useful for Analyzing the Sleep EEG?

Multitaper Spectrogram Tutorial Part 1In Part 1 of this tutorial you will be introduced to spectral estimation, a powerful mathematical tool for analysis of neural oscillations present in the EEG. You will learn the history of characterizing the sleep EEG and why spectral estimation provides an objective, flexible, high-resolution alternative to traditional sleep staging.

The Power of Multitaper Spectral Estimation

Multitaper Spectrogram Tutorial Part 2In Part 2 of this tutorial you will learn the theory behind spectral estimation and common problems that occur when it is not applied in a principled manner. You will then learn about multitaper spectral analysis, a method of spectral estimation that greatly reduces the inaccuracy and noise present in other approaches. Finally, you will learn how to estimate the multitaper spectrogram in a principled manner, based on assumptions about the data you are studying.

The Multitaper Sleep EEG Spectrogram

Multitaper Spectrogram Tutorial Part 2 In Part 3 of this tutorial you will learn how to apply the multitaper spectrogram to the analysis of sleep EEG data. You will learn the different spectral motifs that are hallmarks of the major sleep stages, as well as the spectral signatures of microevents such as spindles and K-complexes. With this knowledge, you should be able to characterize the dynamics and architecture of an entire night of sleep from the multitaper sleep EEG spectrogram alone. You will then learn about potential clinical and experimental applications for the use of the multitaper spectrogram.