Journal: Brain Communications

Article Title: Delta-gamma phase-amplitude coupling as a biomarker of postictal generalized EEG suppression

doi: 10.1093/braincomms/fcaa182

Figure Lengend Snippet: State classification of iEEG recordings using a four-state HMM. ( A ) State classification of an example iEEG trace from Patient 2 (reference electrode—FCz), where S2 is a seizure-like state, and S3 is PGES-like state. ( B ) Comparison of HMM-driven S3 state classification to the visually estimated PGES durations, with the overall correlation of 0.77 ( P = 0.009). ( C ) Histogram of S2 durations, with a gamma function fitted to the data. The shape parameter of the gamma function—alpha—was calculated to be 3.54 (95% CI 1.59–7.89), which is consistent with the average alpha for seizure duration distributions from Suffczynski et al. (2006) of 3.03 and from Bauer et al. (2017) of 2.66. ( D ) Histogram of S3 durations, with gamma function fitted to the data with alpha parameter calculated to be 2.21 (95% CI 1.01–4.82) which is consistent with alpha for PGES duration distributions from Bauer et al. (2017) of 1.54. This can also be compared to alpha value of 1.83 (95% CI 1.04–3.20) obtained from distribution of visually estimated PGES durations (not shown). These shape parameters suggest that the transitions (to and from seizure states) occur not according to Poisson process, but rather that the probability of transition varies with time. For both sections ( C ) and ( D ), n = 11.

Article Snippet: HMM-derived ictal and postictal state duration distributions were also fitted using a gamma function ( gamfit in the MATLAB package): (8) y = λ α x α - 1 e - λ x Γ ( α ) , where α is the shape parameter and λ is the rate parameter.

Techniques: Comparison

Journal: Brain

Article Title: Dynamics of convulsive seizure termination and postictal generalized EEG suppression

doi: 10.1093/brain/aww322

Figure Lengend Snippet: Gamma distributions of ictal, postictal and normal period durations in the model. Histograms and fitted gamma functions for the distributions of the ‘seizure’ (top) and ‘postictal’ (bottom) durations as simulated using the model. The estimation of the shape parameter α for the fitted gamma-distribution as well as the 95% CIs are presented in the text boxes. The data were obtained using the standard MatLab® function gamfit.

Article Snippet: The three numbers in the legends give the parameter α (from Equation 3 ) for the fitted gamma-distribution and the corresponding 95% CI as obtained from the standard MatLab® function gamfit .

Techniques:

Journal: Brain

Article Title: Dynamics of convulsive seizure termination and postictal generalized EEG suppression

doi: 10.1093/brain/aww322

Figure Lengend Snippet: Gamma distribution of ictal and PGES period durations in human EEG data. Histograms and fitted gamma functions (solid lines) for the distributions of the seizure (top) and PGES (bottom) durations as visually detected from the human EEG recordings. The three numbers in the legends give the parameter α (from Equation 3) for the fitted gamma-distribution and the corresponding 95% CI as obtained from the standard MatLab® function gamfit.

Article Snippet: The three numbers in the legends give the parameter α (from Equation 3 ) for the fitted gamma-distribution and the corresponding 95% CI as obtained from the standard MatLab® function gamfit .

Techniques: