title: Daytime vigilance and quality of life in epileptic patients treated with vagus nerve stimulation.
abstract: OBJECTIVE
  The goal of this study was to determine if vagus nerve stimulation (VNS) has any effect on daytime vigilance and perceived sense of well-being.
  
  
  METHODS
  Multiple Sleep Latency Tests (MSLTs) were performed and visual reaction times (VRTs) obtained in eight epileptic patients before and during treatment with VNS. Prior to VNS initiation patients' baseline MSLT and VRT scores were recorded. Six months after VNS was initiated, treatment MSLT and VRT scores were obtained. A group of 12 age-matched healthy subjects served as controls. In addition, there was a global evaluation of well-being at baseline and during a follow-up of 6 months.
  
  
  RESULTS
  As expected, patients evaluated both at baseline and during VNS showed more sleepiness than controls. In this group, baseline sleep latencies on the MSLT were significantly shorter, while VRT latencies were significantly longer than those of controls. After 6 months of VNS, MSLT scores in the eight patients did not change significantly with respect to baseline. However, if the single patient treated with relatively high stimulus intensities (1.75 mA) was excluded from the group and only the seven patients treated with low stimulus intensities (<or=1.5 mA) were considered, a significant effect of chronic VNS on MSLT scores could be observed. In fact, the mean sleep latency (MSL) average of the seven subjects significantly improved from 9.9+/-2.5 minutes during baseline to 10.9+/-2.3 minutes after 6 months of VNS (P<0.05). Conversely, the only patient treated with high stimulus intensities showed increased sleepiness, with MSL decreasing from 14.4 to 9.8 minutes. On the other hand, VRT latencies did not significantly change during VNS. Patients considered as a whole had significant improvements on global evaluation scores of quality of life.
  
  
  CONCLUSIONS
  VNS at low stimulus intensities promotes daytime vigilance in adult epileptic patients and has a positive effect on quality of life.
authors.affiliation: Department of Neurosciences, University of Pisa, via Roma, 67, I-56126 Pisa, Italy. rgalli@neuro.med.unipi.it
authors.forename: Renato
authors.initials: R
authors.lastname: Galli
authors.forename: Enrica
authors.initials: E
authors.lastname: Bonanni
authors.forename: Chiara
authors.initials: C
authors.lastname: Pizzanelli
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Maestri
authors.forename: Ludovico
authors.initials: L
authors.lastname: Lutzemberger
authors.forename: Filippo Sean
authors.initials: FS
authors.lastname: Giorgi
authors.forename: Alfonso
authors.initials: A
authors.lastname: Iudice
authors.forename: Luigi
authors.initials: L
authors.lastname: Murri
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D002540:Cerebral Cortex / Q000503:physiopathology; D002940:Circadian Rhythm / Q000502:physiology*; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis* / Q000453:epidemiology; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000295:instrumentation; D011788:Quality of Life; D011930:Reaction Time / Q000502:physiology; D012720:Severity of Illness Index; D014630:Vagus Nerve / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*