Coherence analysis of EEG during cataplexy attacks in narcoleptic adult patients

Corresponding Author: F. İrsel Tezer E-mail: irseltezer@yahoo.com.tr ; irsel@hacettepe.edu.tr Submitted: 12 February 2018 Accepted: 28 May 2018 You may cite this article as: Erbil N, Tezer Fİ. Coherence analysis of EEG during cataplexy attacks in narcoleptic adult patients. Neurol Sci Neurophysiol 2018; 35(3): 119-126. Abstract Objective: Cataplexy is defined as episodes of sudden, transient loss of voluntary muscle tone usually triggered by positive emotional stimuli. Due to the triggering factors, involvement of emotion-processing structures such as the amygdala and limbic system was suggested. Although electrophysiologically hypersynchronous paroxysmal slow wave activities were reported during cataplexy attacks, the involved area was not clear. In this study we examined functional couplings by using coherence analysis to investigate electrophysiological data among the involved brain regions during cataplexy attacks in adult patients. Methods: Thirteen of our 31 patients with polysomnography recordings had type I narcolepsy. Seven emotionally triggered cataplectic attacks were recorded during monitoring in three patients. Spectral electroencephalography changes were analyzed and compared during whole attacks and interictal awakening periods with similar duration. The imaginary part of coherence for every electrode with other electrodes was also calculated respectively. Results: The coupling of slow waves increased in temporal regions during the attacks. Coherence between the right side of temporal regions and frontal areas increased in slower waves (<4 Hz). The coherence of other slow waves (4-7 Hz) was pronounced in the left temporal region with almost all over the cortex. Conclusion: Our electrophysiological findings related to the involvement of temporal and frontal lobes during cataplexy attacks supported previous neuroimaging and physiological reports. Further investigations to clarify the neural circuits involved in their manifestation should be considered in future.