title: Automatic identification of Cyclic Alternating Pattern (CAP) sequences based on the Teager Energy Operator.
abstract: The Cyclic Alternating Pattern (CAP) is a periodic cerebral activity prevalent during Non-Rapid Eye Movement (NREM) sleep-stages. The CAP is composed by A-phases that are related to a change in amplitude, frequency or both from the background activity epochs, called B-phases. Depending on the type of increase the A-phase could be classified as A1, A2 or A3 subtype. This paper proposes the usage of the Teager Energy Operator (TEO) to analyze the amplitude changes in the different frequency-bands to detect A-phases subtypes. The TEO classification performance is compared with the performance of a state-of-the art EEG feature, applied previously for CAP scoring and referred as the macro-micro structure descriptor (MMSD). In general, the TEO is the best feature and the improved results were obtained in the delta band for the A1 and A2 sub-types. More precisely, a sensitivity and specificity of 80.31% and 82.93% were obtained for the A1 subtype, respectively. A2 phases were detected with 76.96% of sensitivity and 73.22% of specificity. The two features detected A3 subtype with approximately the same sensitivity (approx. 70%) and specificity (approx. 75%), however the results were improved by considering the highest frequency band. These results are consistent with the frequency content of the different sub-phases.
authors.forename: Fátima
authors.initials: F
authors.lastname: Machado
authors.forename: Francisco
authors.initials: F
authors.lastname: Sales
authors.forename: Conceição
authors.initials: C
authors.lastname: Bento
authors.forename: António
authors.initials: A
authors.lastname: Dourado
authors.forename: César
authors.initials: C
authors.lastname: Teixeira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001331:Automation; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D017286:Polysomnography; D012815:Signal Processing, Computer-Assisted; D012895:Sleep, REM / Q000502:physiology*; D055815:Young Adult