title: Transcranial magnetic stimulation in sleep fragmentation: a model to better understand sleep disorders.
abstract: OBJECTIVE
  To investigate practice-dependent plasticity and cortical inhibition/excitability in good sleepers after a night of sleep fragmentation (SF), by means of transcranial magnetic stimulation (TMS).
  
  
  METHODS
  In basal condition (BC), after a full night of spontaneous sleep, and in fragmented condition (FC), after a fragmented night of sleep, motor evoked potential (MEP) amplitude, motor threshold (MT), silent period (SP), and intracortical inhibition were assessed. In both conditions subjects performed, also, a bimanual motor task: MEPs were recorded before and after exercise, and after rest. We evaluated the presence of post-exercise facilitation and delayed facilitation. Subjects reported their alertness level (Stanford Sleepiness Scale-SSS).
  
  
  RESULTS
  MT and SSS were significantly increased in SF. Instead, no significant differences for MEP amplitude or SP or intracortical inhibition were found. In both conditions post-exercise facilitation and delayed facilitation were present.
  
  
  CONCLUSIONS
  SF produces disruption of nocturnal sleep and increases daytime sleepiness. Confirmatory features of this clinical behaviour could be that in FC we observed a significant increase in SSS and in MT. SF was unable to modify cortical inhibition\excitability and\or to influence plasticity-related parameters. These results seem inconsistent with some of TMS alterations observed in sleep deprivation (SD) and restless legs syndrome (RLS). We suggest that SD and SF represent different phenomena that can depend on various networks acting on motor cortex. We speculate that alterations in cortical excitability found in RLS are intrinsically related to the underlying disease itself and are not instead directly associated with the SF present in RLS.
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy. Electronic address: annascalise@libero.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Scalise
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy.
authors.forename: Italo
authors.initials: I
authors.lastname: Pittaro-Cadore
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Serafini
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Simeoni
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy.
authors.forename: Lara
authors.initials: L
authors.lastname: Fratticci
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Ecoretti
authors.affiliation: Center of Sleep Medicine, Neurology Clinic, University-Hospital S. Maria della Misericordia, Udine, Italy.
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Gigli
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D004569:Electroencephalography; D006801:Humans; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology; D017286:Polysomnography; D012148:Restless Legs Syndrome / Q000503:physiopathology / Q000628:therapy; D012890:Sleep / Q000502:physiology; D012892:Sleep Deprivation / Q000503:physiopathology* / Q000628:therapy; D050781:Transcranial Magnetic Stimulation; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
keywords: Cortical plasticity; Delayed facilitation; Restless legs syndrome; Sleep; Sleep deprivation; Sleep disorders; Sleep fragmentation; Transcranial magnetic stimulation