Takashi Shibata1, Hiroshi Otsubo2. 1. Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada. 2. Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: hiroshi.otsubo@sickkids.ca.
Abstract
INTRODUCTION: Delta brushes are an indicator of brain maturity on a neonatal EEG. We investigated phase-amplitude coupling (PAC) between slow delta waves and superimposed alpha-beta activity in delta brushes to elucidate the spatiotemporal developments of the delta brush with post-menstrual weeks (PMW). METHODS: The subjects were 18 neurologically intact patients (seven girls). We analyzed EEG within 42 PMW. Patients were divided into four age groups as follows: PMW ≤30w; 31-34 w; 35-38 w; and 39-42 w. We selected up to three epochs of 2-minute EEG segments including delta brushes. We calculated the modulation index (MI), direct mean vector length (dMVL), and mean of phase angle of coupling by PAC between slow waves (0.5-1.5 Hz) and fast activities (8-25 Hz) in four regions (F: Fp1 and Fp2, C: C3 and C4, T: T3 and T4, O: O1 and O2). RESULTS: We collected data from 18 patients and 31 epochs between 29 and 42 PMW, which comprised one, four, five, and eight patients, and two, seven, eight, and 14 epochs in the ≤30w, 31-34 w, 35-38 w, and 39-42 w groups, respectively. There were significant differences in the dMVL between the four regions in age groups ≤30w (P = 0.033) and 31-34w (0.017). Both MI and dMVL showed that delta brushes became higher in the occipital region from 32 to 36 PMW. The mean phase angle of coupling concentrated around either 0° or 180° for all age groups. CONCLUSIONS: PAC analysis revealed the spatiotemporal relations of alpha-beta activities that are modulated by slow delta waves in neonatal delta brushes. The delta brushes appeared to be at a maximum around 32-36 PMW with the predominant occipital distribution. The PAC of the delta brush might represent the cortical neuronal fast activity that is modulated by slow delta waves of subcortical regions during a particular neonatal period.
INTRODUCTION: Delta brushes are an indicator of brain maturity on a neonatal EEG. We investigated phase-amplitude coupling (PAC) between slow delta waves and superimposed alpha-beta activity in delta brushes to elucidate the spatiotemporal developments of the delta brush with post-menstrual weeks (PMW). METHODS: The subjects were 18 neurologically intact patients (seven girls). We analyzed EEG within 42 PMW. Patients were divided into four age groups as follows: PMW ≤30w; 31-34 w; 35-38 w; and 39-42 w. We selected up to three epochs of 2-minute EEG segments including delta brushes. We calculated the modulation index (MI), direct mean vector length (dMVL), and mean of phase angle of coupling by PAC between slow waves (0.5-1.5 Hz) and fast activities (8-25 Hz) in four regions (F: Fp1 and Fp2, C: C3 and C4, T: T3 and T4, O: O1 and O2). RESULTS: We collected data from 18 patients and 31 epochs between 29 and 42 PMW, which comprised one, four, five, and eight patients, and two, seven, eight, and 14 epochs in the ≤30w, 31-34 w, 35-38 w, and 39-42 w groups, respectively. There were significant differences in the dMVL between the four regions in age groups ≤30w (P = 0.033) and 31-34w (0.017). Both MI and dMVL showed that delta brushes became higher in the occipital region from 32 to 36 PMW. The mean phase angle of coupling concentrated around either 0° or 180° for all age groups. CONCLUSIONS: PAC analysis revealed the spatiotemporal relations of alpha-beta activities that are modulated by slow delta waves in neonatal delta brushes. The delta brushes appeared to be at a maximum around 32-36 PMW with the predominant occipital distribution. The PAC of the delta brush might represent the cortical neuronal fast activity that is modulated by slow delta waves of subcortical regions during a particular neonatal period.
Authors: Réjean M Guerriero; Michael J Morrissey; Maren Loe; Joseph Reznikov; Michael M Binkley; Alex Ganniger; Jennifer L Griffith; Sina Khanmohammadi; Robert Rudock; Kristin P Guilliams; ShiNung Ching; Stuart R Tomko Journal: J Clin Neurophysiol Date: 2021-02-10 Impact factor: 2.590