title: Early respiratory dysfunction as a biomarker for epileptic encephalopathy.
abstract: OBJECTIVE
  West syndrome is an epileptic encephalopathy starting in infancy with almost continuous interictal epileptic activity, so-called hypsarrhythmia pattern, and therefore is an interesting model for investigating the effect of interictal epileptic activity on autonomic function. It is known that autonomic dysfunction contributes to morbidity and mortality in epilepsy. Our aim is to investigate the effect of interictal epileptic activity in West syndrome on respiratory control.
  
  
  METHODS
  Interictal single-lead ECG signals were extracted from 24-h video-EEG recordings in 10 children suffering from West syndrome and 14 control subjects. RR interval time series were calculated, and respiration was derived from the ECG signal. ECG-derived respiration (EDR) signals were computed and time and frequency domain parameters were extracted to characterize the respiration pattern.
  
  
  RESULTS
  In time domain, the standard deviation of the EDR signal is significantly lower in patients with West syndrome compared to control subjects. This finding is an indication of a less variable respiratory rate. In frequency domain, we analyzed the mean power spectrum for the EDR. In patients with West syndrome, there is more activity at the lower frequencies considered to be a risk factor for apneas. Second, there is an attenuated peak at the higher frequency band where normal respiratory rate is to be found, indicating an abnormal breathing pattern.
  
  
  CONCLUSIONS
  Our results show that there is a clear dysfunction in autonomic respiratory control in patients with West syndrome, in between the typical ictal epileptic spasms, compared to control subjects. Respiration is more fixed and contains a higher risk of apneas.
authors.affiliation: Pediatric neurology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Jansen
authors.forename: C
authors.initials: C
authors.lastname: Varon
authors.forename: S
authors.initials: S
authors.lastname: Van Huffel
authors.forename: L
authors.initials: L
authors.lastname: Lagae
mesh_terms: D015415:Biomarkers; D004562:Electrocardiography; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012127:Respiratory Distress Syndrome, Newborn / Q000209:etiology*; D013036:Spasms, Infantile / Q000150:complications* / Q000175:diagnosis*; D013057:Spectrum Analysis; D013997:Time Factors
chemical_list: D015415:Biomarkers
keywords: ECG; West syndrome; autonomic; epileptic encephalopathy; epileptic spasms; respiration