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Prestimulation-induced startle modulation in attention-deficit hyperactivity disorder and nocturnal enuresis
E M Ornitz1, G L Hanna, J de Traversay
1Department of Psychiatry, University of California, Los Angeles.
Insights
Enuresis, or bedwetting, is linked to deficient startle inhibition in boys, suggesting a maturational delay. Attention-deficit hyperactivity disorder (ADHD) did not impact this startle modulation.
Area of Science:
- Neuroscience
- Developmental Psychology
- Pediatrics
Background:
- Startle modulation, a measure of sensorimotor gating, is crucial for processing stimuli.
- Attention-deficit hyperactivity disorder (ADHD) and enuresis are common childhood conditions with potential neurodevelopmental underpinnings.
- Previous research suggests altered startle responses in ADHD, but the link with enuresis requires further investigation.
Purpose of the Study:
- To investigate the effect of enuresis and ADHD on startle modulation in boys.
- To examine how prestimulation intervals influence startle responses in these groups.
- To explore potential maturational aspects of startle inhibition deficits.
Main Methods:
- A study involving 43 boys with ADHD (some with enuresis), 17 enuretic boys without ADHD, and 42 controls (ages 6-11).
- Startle modulation was assessed using 60-ms and 120-ms prestimulation intervals followed by a continuous tone.
- Multivariate analysis examined the impact of enuresis and ADHD on startle amplitude modulation.
Main Results:
- Enuresis significantly affected startle amplitude modulation, primarily by reducing inhibition after a 120-ms prestimulation interval.
- This reduction in startle inhibition in enuretic boys was comparable to that of 5-year-old normal children, indicating a maturational delay.
- Attention-deficit hyperactivity disorder (ADHD) did not show a significant effect on startle modulation by prestimulation.
Conclusions:
- Deficient startle inhibition is a characteristic associated with enuresis, suggesting a maturational component in neurophysiological processing.
- The observed dysfunction in startle inhibition in enuresis, but not ADHD, may involve mesopontine reticular mechanisms related to preattentive processing and bladder control.
- These findings highlight distinct neurophysiological pathways potentially underlying enuresis and ADHD.
Abstract:
Startle modulation was induced by prestimulation in 43, 6-11 year old boys with attention-deficit hyperactivity disorder (ADHD), 13 of whom were or had been enuretic, 17 age-matched enuretic boys, and 42 age-matched normal boys, using 60-ms and 120-ms prestimulation intervals and a 4000-ms continuous tone. There was a significant multivariate effect of enuresis on startle amplitude modulation. This effect was attributed primarily to the reduction of amplitude inhibition following the 120-ms prestimulation interval regardless of whether or not enuresis was associated with ADHD. There was no effect of ADHD on startle modulation by prestimulation. The inhibition following the 120-ms prestimulation interval in the enuretic boys was reduced to the level of 5-year-old normal children, suggesting a maturational component of the deficient startle inhibition. The neurophysiologic dysfunction underlying the deficient startle inhibition in enuresis, but not ADHD, is discussed in terms of a possible dysfunction of mesopontine reticular mechanisms mediating preattentive processing of signals associated with spinal reflexes involved in urinary bladder control.