title: The effects of delta wave sleep interruption on pain thresholds and fibromyalgia-like symptoms in healthy subjects; correlations with insulin-like growth factor I.
abstract: OBJECTIVE
  To assess the effects of delta wave sleep interruption (DWSI) on pain thresholds and fibromyalgia-like symptoms. To examine the potential correlations between DWSI and serum insulin-like growth factor 1 (IGF-1).
  
  
  METHODS
  Thirteen healthy volunteers were subjected to 3 consecutive nights of DWSI (Group 1). Pain thresholds were measured by dolorimetry and symptoms by visual analog scale. Six subjects not undergoing DWSI served as dolorimetry and symptom controls (Group 2). Serum IGF-1 was measured by competitive binding radioimmunoassay before and after DWSI.
  
  
  RESULTS
  No significant differences in pain thresholds as a function of condition (baseline, DWSI, recovery) or overnight change were detected between or within groups (p>0.05). Morning mean dolorimeter scores were lower than evening scores in both groups during all 3 conditions, and were lower in Group 1 than in Group 2 during DWSI. Group 1 subjects had higher composite symptom scores during DWSI (p< or =0.005), attributed largely to increases in fatigue. Serum levels of IGF-1 from Group 1 subjects showed no significant change after DWSI (p>0.05).
  
  
  CONCLUSIONS
  In our study subjects, 3 nights of DWSI caused no significant lowering of pain thresholds compared with a control group. Subjects appeared to have lower pain thresholds in the mornings, and DWSI appeared to augment this effect. Symptoms were more apparent during DWSI, but were primarily related to fatigue. IGF-1 was not altered by 3 nights of DWSI. The low levels of IGF-1 seen in patients with fibromyalgia syndrome may result from chronic rather than acute DWSI, or may be dependent on factors other than disturbances of delta wave sleep.
authors.affiliation: Department of Medicine, Brooke Army Medical Center, Fort Sam Houston, Texas 78234-6272, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Older
authors.forename: D F
authors.initials: DF
authors.lastname: Battafarano
authors.forename: C L
authors.initials: CL
authors.lastname: Danning
authors.forename: J A
authors.initials: JA
authors.lastname: Ward
authors.forename: E P
authors.initials: EP
authors.lastname: Grady
authors.forename: S
authors.initials: S
authors.lastname: Derman
authors.forename: I J
authors.initials: IJ
authors.lastname: Russell
mesh_terms: D000293:Adolescent; D000328:Adult; D003700:Delta Rhythm; D004569:Electroencephalography; D005260:Female; D005356:Fibromyalgia / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D017288:Pain Threshold / Q000502:physiology*; D012892:Sleep Deprivation / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology
chemical_list: D007334:Insulin-Like Growth Factor I