Automated Frequency Analysis of Synchronous and Diffuse Sleep Spindles.

Background: Sleep spindles have different properties in different localizations in the cortex. Objectives: First main objective was to develop an amplitude-independent multi-channel spindle detection method. Secondly the method was applied to study the anteroposterior frequency differences of pure synchronous (visible bilaterally, either frontopolarly or centrally) and diffuse (visible bilaterally both frontopolarly and centrally) sleep spindles. Methods: A previously presented spindle detector based on the fuzzy reasoning principle and a level detector were combined to form a multi-channel spindle detector. Results: The spindle detector had a 76.17% true positive rate and 0.93% false-positive rate. Pure central spindles were faster and pure frontal spindles were slower than diffuse spindles measured simultaneously from both locations. Conclusions: The study of frequency relations of spindles might give new information about thalamocortical sleep spindle generating mechanisms. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]