title: Spontaneous K-Complex Density in Slow-Wave Sleep.
abstract: OBJECTIVE
  To study spontaneous K-complex (KC) densities during slow-wave sleep. The secondary objective was to estimate intra-non-rapid eye movement (NREM) sleep differences in KC density.
  
  
  METHODS
  It is a retrospective study using EEG data included in polysomnographic records from the archive at the sleep research laboratory of the Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, India. The EEG records of 4459 minutes were used. The study presents a manual identification investigation of KCs in 17 healthy young adult male volunteers (age = 23.82±3.40 years and BMI = 23.42±4.18 kg/m2).
  
  
  RESULTS
  N3 had a higher KC density than N2 (Z = -2.485, p = 0.013) for all of the probes taken together. Four EEG probes had a higher probe-specific KC density during N3. The inter-probe KC density differed significantly during N2 (χ2 = 67.91, p < .001), N3 (χ2 = 70.62, p < .001) and NREM (χ2 = 68.50, p < .001). The percent distribution of KC decreased uniformly with sleep cycles.
  
  
  CONCLUSIONS
  The inter-probe differences during N3 establish the fronto-central dominance of the KC density regardless of sleep stage. This finding supports one local theory of KC generation. The significantly higher KC density during N3 may imply that the neuro-anatomical origin of slow-wave activity and KC is the same. This temporal alignment with slow-wave activity supports the sleep-promoting function of the KC.
authors.affiliation: Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India.|Department of Biomedical Science, College of Health Science, Mizan Tepi University, Mizan Teferi, Ethiopia.
authors.forename: Md Dilshad
authors.initials: MD
authors.lastname: Manzar
authors.affiliation: Department of Biochemistry, Institute of Home Economics, University of Delhi, New Delhi, India.
authors.forename: Mohammad Muntafa
authors.initials: MM
authors.lastname: Rajput
authors.affiliation: Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: Wassilatul
authors.initials: W
authors.lastname: Zannat
authors.affiliation: Somnogen Canada Inc., College Street, Toronto, Canada.
authors.forename: Seithikurippu R
authors.initials: SR
authors.lastname: Pandi-Perumal
authors.affiliation: The University Sleep Disorders Center, Department of Medicine, College of Medicine, and NSTIP Strategic Technologies Program, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Ahmed S
authors.initials: AS
authors.lastname: BaHammam
authors.affiliation: Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: M Ejaz
authors.initials: ME
authors.lastname: Hussain
mesh_terms: D000328:Adult; D004569:Electroencephalography; D006801:Humans; D008297:Male; D012894:Sleep Stages / Q000502:physiology*