title: Salivary α-amylase reflects change in attentional demands during postural control: comparison with probe reaction time.
abstract: OBJECTIVE
  The influence of attention on postural control and the relationship between attention and falling has been reported in previous studies. Although a dual-task procedure is commonly used to measure attentional demand, such procedures are affected by allocation policy, which is a mental strategy to divide attention between simultaneous tasks. Therefore, we examined the effectiveness of salivary α-amylase, which is a physiological method for measuring attentional demand during postural control.
  
  
  METHODS
  Sixteen healthy participants performed a postural-control task using the Balance System, which is a device that can be calibrated to a specific stability level ("Level 1 = least stable" to "Level 8 = most stable"). Levels 1, 2, and 3 were used for this study. Dependent variables measured were overall stability index, which represents the variance of platform displacement in degrees from a horizontal plane; probe reaction time, which was measured using a sound stimulator and recorder; and salivary α-amylase, which was measured using a portable salivary amylase analyzer.
  
  
  RESULTS
  As stability level of the test task decreased, both stability index and probe reaction time significantly increased. In addition, we identified a positive moderate correlation between probe reaction time and salivary α-amylase.
  
  
  CONCLUSIONS
  Our results suggest that salivary α-amylase and probe reaction time reflect the change in attentional demands during a postural-control task and that salivary α-amylase may be an effective tool for evaluating attentional demands during postural control because it is noninvasive and simple to perform.
authors.affiliation: a Ibaraki Prefectural University of Health Sciences.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Akizuki
authors.forename: Yukari
authors.initials: Y
authors.lastname: Ohashi
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011930:Reaction Time; D055291:Salivary alpha-Amylases / Q000032:analysis*; D013647:Task Performance and Analysis; D055815:Young Adult
chemical_list: D055291:Salivary alpha-Amylases
keywords: dual-task procedure; motor control; physiological index