title: Early-onset alcohol dependence increases the acoustic startle reflex.
abstract: BACKGROUND
  Hyperreactivity and impaired sensory gating of the acoustic startle response in alcohol dependence has been suggested to reflect a residual effect of previous detoxifications, increasing the severity of subsequent withdrawal episodes. Previous studies on the acoustic startle only included early-onset alcohol-dependent patients. The observed abnormalities may therefore also be specific for this subtype of alcohol dependence. We investigated the acoustic startle response in alcohol-dependent patients and healthy controls and hypothesized that (i) early-onset alcohol-dependent patients show increased acoustic startle responses compared with late-onset alcohol-dependent patients and healthy controls, and (ii) the duration of alcohol dependence or the number of prior detoxifications would not explain the differences in the acoustic startle between early- and late-onset alcohol dependence.
  
  
  METHODS
  The acoustic startle reflex was assessed in detoxified, male alcohol-dependent patients (N = 83) and age-matched healthy male controls (N = 86). Reflex eye blink responses to an auditory startle stimulus were measured by means of electromyographic recordings over the right orbicularis oculi muscle. Reflex amplitudes and levels of prepulse inhibition (PPI) were analyzed.
  
  
  RESULTS
  There was no association between number of previous withdrawals and the startle response or PPI. Early-onset alcohol-dependent patients showed higher acoustic startle amplitudes compared with late-onset alcohol-dependent patients and healthy controls [75/105 dB: F(2, 166) = 9.2, p < 0.001; 85/105 dB: F(2, 166) = 12.1, p < 0.001; 95 dB: F(2, 166) = 8.2, p < 0.001; 105 dB: F(2, 166) = 9.7, p < 0.001], and there were no differences in PPI.
  
  
  CONCLUSIONS
  Increased acoustic startle response in detoxified early-onset alcohol-dependent patients may reflect a trait marker specifically involved in early-onset alcohol dependence. The findings of the current study do not support the hypothesis that the increased startle response is a residual state marker.
authors.affiliation: Department of Psychiatry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. a.f.a.schellekens@psy.umcn.nl
authors.forename: Arnt F A
authors.initials: AF
authors.lastname: Schellekens
authors.forename: Peter C R
authors.initials: PC
authors.lastname: Mulders
authors.forename: Bart
authors.initials: B
authors.lastname: Ellenbroek
authors.forename: Cor A J
authors.initials: CA
authors.lastname: de Jong
authors.forename: Jan K
authors.initials: JK
authors.lastname: Buitelaar
authors.forename: Alexander
authors.initials: A
authors.lastname: Cools
authors.forename: Robbert-Jan
authors.initials: RJ
authors.lastname: Verkes
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D017668:Age of Onset; D000437:Alcoholism / Q000503:physiopathology*; D001767:Blinking / Q000502:physiology*; D016022:Case-Control Studies; D002492:Central Nervous System Depressants / Q000009:adverse effects*; D004576:Electromyography; D000431:Ethanol / Q000009:adverse effects*; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D013216:Reflex, Startle / Q000502:physiology*; D055139:Sensory Gating / Q000502:physiology*; D013375:Substance Withdrawal Syndrome
chemical_list: D002492:Central Nervous System Depressants; D000431:Ethanol