M. Althaus et al., Cardiac adaptivity to attention-demanding tasks in children with a pervasive developmental disorder not otherwise specified (PDD-NOS), BIOL PSYCHI, 46(6), 1999, pp. 799-809
Background: Decreases in heart rate variability (HRV) have been repeatedly
demonstrated to be an index of effort allocation to attention-demanding tas
ks. Children with autistic-type problems in social interaction and in adapt
ing to unfamiliar situations (DSM-IV: PDD-NOS) have been shown to have spec
ific attention deficits. These children were hypothesized to exhibit less c
ardiac adaptivity to attention-demanding tasks.
Methods: Two groups of 18 children with PDD-NOS, judged to be hyperactive a
nd nonhyperactive, were compared to 18 healthy children with respect to the
ir performances on a visual attention task and the differences in HRV measu
red during periods of task performance and periods of rest.
Results: Compared to the control group, both clinical groups were found to
have a stronger capacity limitation in processing high loads of information
, and to be less capable of maintaining a stable task performance throughou
t the whole task. Both clinical groups showed significantly less decreases
in HRV during the periods of task performance. The magnitude of rest-task d
ifferences in HRV was found to correlate significantly with a behavioral me
asure of resistance to unexpected changes in daily routines.
Conclusions: Children with PDD-NOS are significantly less flexible in their
autonomic adaptation to attention-demanding tasks. The findings are interp
reted as reflecting a deficiency in the functional organization of those ne
ural pathways that provide cortical control of the visceral efferents. (C)
1999 Society of Biological Psychiatry.