title: Increased whole-body auditory startle reflex and autonomic reactivity in children with anxiety disorders.
abstract: BACKGROUND
  Young patients with anxiety disorders are thought to have a hypersensitive fear system, including alterations of the early sensorimotor processing of threatening information. However, there is equivocal support in auditory blink response studies for an enlarged auditory startle reflex (ASR) in such patients. We sought to investigate the ASR measured over multiple muscles (whole-body) in children and adolescents with anxiety disorders.
  
  
  METHODS
  Between August and December 2006, we assessed ASRs (elicited by 8 consecutive tones of 104 dB, interstimulus interval of about 2 min) in 25 patients and 25 matched controls using a case-control design and in 9 nonaffected siblings. We recorded the electromyographic activity of 6 muscles and the sympathetic skin response. We investigated response occurrence (probability %) and response magnitude (area under the curve in microV x ms) of the combined response of 6 muscles and of the single blink response.
  
  
  RESULTS
  In patients (17 girls, mean age 12 years; 13 social phobia, 9 generalized anxiety, 3 other), the combined response probability (p = 0.027) of all muscles, the combined area under the curve of all muscles (p = 0.011) and the sympathetic skin response (p = 0.006) were enlarged compared with matched controls. The response probability (p = 0.48) and area under the curve (p = 0.07) of the blink response were normal in patients compared with controls. The ASR pattern was normal with normal latencies in patients compared with controls. In nonaffected siblings, the sympathetic skin response (p = 0.038), but not the combined response probability of all muscles (p = 0.15), was enlarged compared with controls.
  
  
  CONCLUSIONS
  Limitations are the sample size and restricted comparison to the psychophysiological ASR paradigm.
  
  
  CONCLUSIONS
  The results point toward a hypersensitive central nervous system (fear system), including early sensorimotor processing alterations and autonomic hyperreactivity. The multiple muscle (whole-body) ASR is suggested to be a better tool to detect ASR abnormalities in patients with anxiety disorders than the blink response alone. Abnormalities in ASR serve as a candidate endophenotype of anxiety disorders.
authors: Department of Neurology and Clinical Neurophysiology, Academic Medical Centre, University of Amsterdam, The Netherlands.
authors: Mirte J
authors: MJ
authors: Bakker
authors: Marina A J
authors: MA
authors: Tijssen
authors: Johan N
authors: JN
authors: van der Meer
authors: Johannes H T M
authors: JH
authors: Koelman
authors: Frits
authors: F
authors: Boer
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000375:Aging; D001008:Anxiety Disorders / Q000503:physiopathology*; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001767:Blinking / Q000502:physiology; D016022:Case-Control Studies; D002648:Child; D004576:Electromyography / Q000706:statistics & numerical data*; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D008297:Male; D013216:Reflex, Startle / Q000502:physiology*; D012727:Sex Characteristics; D035781:Siblings