title: Salivary biomarkers of HPA axis and autonomic activity in adults with intellectual disability with and without stereotyped and self-injurious behavior disorders.
abstract: Salivary levels of biomarkers for the hypothalamic-pituitary-adrenal axis (HPA; cortisol) and sympatho-adreno-medullary system (SAM; α-amylase) were measured in 51 adults (57% male) with neurodevelopmental disorders associated with intellectual disability (i.e., mental retardation) and chronic self-injurious behavior (SIB) and compared with matched controls without SIB. Cortisol levels differed significantly (p < 0.01) between the SIB and control group (SIB > control). Within-group analyses showed significant differences (p < 0.05) in levels of salivary α-amylase between individuals with SIB and those with SIB meeting criteria for stereotyped movement disorder (SMD; SIB + SMD > SIB). Salivary α-amylase was significantly correlated with frequency of stereotypy among the SIB group (r = 0.36, p < 0.05). These preliminary findings warrant further exploration into the role of the SAM system in the pathophysiology of SIB and related repetitive behaviors among individuals with neurodevelopmental disorders associated with intellectual disability.
authors.affiliation: Department of Educational Psychology, Center for Neurobehavioral Development, University of Minnesota, Education Science Building, 56 River Road, Minneapolis, MN, 55455, USA, symon007@umn.edu.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Symons
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Wolff
authors.forename: Laura S
authors.initials: LS
authors.lastname: Stone
authors.forename: Tony K Y
authors.initials: TK
authors.lastname: Lim
authors.forename: James W
authors.initials: JW
authors.lastname: Bodfish