Patricia L. Davies

Development of response-monitoring ERPs in 7- to 25-year-olds.

In a target discrimination task, trials with incorrect responses elicit event-related potentials (ERPs) that include an error-related negativity (ERN or Ne) and a later error-positivity (Pe). Substantial evidence points to the anterior cingulate cortex as the source generator of the ERN. We examined the development of ERP component morphology, amplitude and latency to processing of correct and incorrect responses in 124 children, 7 to 18 years of age, and 27 adults, 19 through 25 years of age. The ERN and Pe were recorded during a standard 480-trial visual flanker task. As expected, response times decreased significantly with age. The ERN amplitude in error trials increased with age, although this was qualified by a nonlinear change as well. The Pe amplitude did not change with age. In correct trials, most participants produced a small negativity corresponding to the timing of the ERN in error trials. This correct-response negativity (CRN) amplitude was larger in children than in adults. Results are discussed with respect to continued maturation of the anterior cingulate cortex and prefrontal cortex into young adulthood.

Charting the Maturation of the Frontal Lobe: An Electrophysiological Strategy.

Tracking the functional development of specific regions of the prefrontal cortex in children using event-related potentials (ERPs) is challenging for both technical and conceptual reasons. In this paper we outline our strategy for studying frontal lobe development and present preliminary results from children aged 7-17 years and young adults using ERPs functionally associated with anterior cingulate and prefrontal cortex, especially the orbitofrontal, ventral, and medial portions. Our analysis of contingent negative variation, error-related negativity, and novelty P300 data show that the ERPs associated with these regions are still maturing into late adolescence, and that their amplitude has significant correlations with behavioral capacities.

Error negativity and response control

Error trials are associated with faster responses than correct trials in simple discrimination tasks suggesting that errors result from impulsive responding. We investigated the relationship between error negativity (Ne/ERN), an event-related potential associated with error detection, and two behavioral indices of response control: response time (RT) differences between incorrect and correct trials (an index of impulsivity) and percentage of errors. Response-locked ERPs were collected from 17 young adults during a visual flanker task. Consistent with previous findings, participants were significantly faster on error trials. However, participants who exhibited larger Ne/ERN peak amplitudes had significantly smaller RT differences, suggesting a more controlled response strategy. Furthermore, Ne/ERN latencies were positively associated with percentage of errors. These findings are consistent with the view that the Ne/ERN reflects the activity of a monitoring system that is closely linked to remedial systems responsible for individual differences in response control or impulsive behavior.

Error-negativity and positivity as they relate to other ERP indices of attentional control and stimulus processing

We compared individual differences in the ERP associated with incorrect responses in a discrimination task with other ERP components associated with attentional control and stimulus discrimination (N2, P3, CNV). Trials with errors that are detected by the subject normally produce a negativity (N(E)) immediately following the response followed by a positivity (P(E)). The morphology of the N(E) and the P(E) is similar to that of the standard N2-P3 complex on correct discrimination trials. Our findings suggest that the P(E) is a P3 response to the internal detection of errors. The N(E), however, appears to be distinct from the N2. Finally, even though both the contingent negative variation (CNV) and the N(E) are associated with prefrontal cortex and the allocation of attention to response accuracy, the N(E) and CNV did not relate to one another.

Motor Skills of Typically Developing Adolescents

To identify sex differences and developmental trends in motor performance and coordination across three stages of development: prepubertal, pubertal and postpubertal, 60 participants, 30 males and 30 females, were assessed on 13 motor tasks. Physical characteristics that accompany puberty were used to classify the participants into the stages. Analysis of variance and covariate analyses demonstrated that motor performance improves throughout adolescence in both males and females and that sex differences exist in motor performance, males performing better than females. The magnitude of the stage and sex differences were demonstrated by large effect sizes (?2). The motor tasks of long jump, running speed, and throwing a ball principally distinguished between the males and females. Female performance differed less from male performance after puberty. Results showed no evidence of impaired coordination or awkwardness at puberty for either sex. Implications for rehabilitation specialists include creating awareness to possible sex differences when evaluating childrens motor skills and awareness for the need for further study of motor performance during puberty in children with disabilities.

Development of Error‐Monitoring Event‐Related Potentials in Adolescents

Abstract: In order to study the maturation of neurobehavioral systems involved in affect regulation and behavioral choices during adolescence, we examined brain activity associated with response monitoring and error detection using event‐related potentials (ERPs). In a visual flanker test, trials with incorrect responses elicit ERP components including an error‐related negativity (ERN) and a later error‐positivity (Pe). We examined the amplitude and latency of the ERN and Pe of incorrect responses in 124 children from 7 to 18 years of age. The ERN amplitude in error trials increased with age although this was qualified by a nonlinear change. The quadratic distribution of the ERN indicated an initial drop in amplitude (lowest at age 10 for girls; age 13 for boys) with a subsequent rise through adolescence. The Pe amplitude did not change with age. Results are discussed with respect to continued maturation of the anterior cingulate cortex and possible influences on adolescent behaviors.

MATURATION OF SENSORY GATING PERFORMANCE IN CHILDREN WITH AND WITHOUT SENSORY PROCESSING DISORDERS

Recent interest in sensory gating in children with and without neuropsychological disorders has resulted in a number of studies and the results regarding the developmental trajectory of sensory gating are inconsistent. We investigated the maturational course of sensory gating in samples of typically developing children and children with sensory processing deficits (SPD) and compared their performance to adults. Besides gating ratios, we also examined the brain responses to conditioning and test click stimuli in the sensory gating paradigm separately to clarify if the changes in click amplitudes could explain the maturational change in the T/C ratio in children. Eighteen adults with no known disorders, 25 typical children, and 28 children with SPD participated in this study. The children ranged in ages between 5 and 12 years. The three groups differed in their P50 and N100 ERP components. Both child groups displayed significantly less gating than the adults. Children with SPD demonstrated significantly less gating and more within-group variability compared to typical children. There were significant relationships between age and T/C ratios and between age and peak-to-peak amplitude of the conditioning click in typical children but not in children with SPD. Typical children demonstrated significantly smaller brain response amplitudes to the clicks as compared to adults. These findings suggest that there is a maturational course of sensory gating in typical children and if there is a maturational trajectory in children with SPD it appears to be different than typical children. In addition, children with SPD were found to be lacking in their ability to filter out repeated auditory input and failed to selectively regulate their sensitivity to sensory stimuli.

Validation of School Function Assessment with Elementary School Children.

The present study was conducted to examine the validity of the School Function Assessment (SFA). The study sample consisted of 64 children: 29 in general education (GEN) without disabilities, 18 with learning disabilities (LD), and 17 with cerebral palsy (CP). Convergent validity was supported by the significant correlation (r values ranged from .56 to .72) found between the scores on the Vineland Adaptive Behavior Scales (classroom edition) to comparable scales of the SFA. Construct validity of the SFA using the known groups method was also supported. Significant differences in SFA scores among the 3 groups were found using the Kruskal-Wallis analysis of variance and multiple comparisons. The GEN group differed from the LD group in cognitive/behavioral subtests, the CP group differed from the GEN group in all areas of the SFA, and the LD and CP groups differed on the physical domain of the SFA. Finally, the discriminant analysis of scores on the SFA showed the high percentage of participants being correctly classified in the respective groups (93.1% for GEN, 55.8% for LD, and 88.2% for CP). These results provide new evidence for the validity of the SFA using methodologies not previously reported in the literature. Given the unique features as well as the provided psychometrical properties of the SFA, this recently developed functional assessment should be considered a valid instrument for use in school settings.

Psychometric properties of the Young Children's Participation and Environment Measure.

OBJECTIVE To evaluate the psychometric properties of the newly developed Young Childrens Participation and Environment Measure (YC-PEM). DESIGN Cross-sectional study. SETTING Data were collected online and by telephone. PARTICIPANTS Convenience and snowball sampling methods were used to survey caregivers of children (N=395, comprising children with [n=93] and without [n=302] developmental disabilities and delays) between the ages of 0 and 5 years (mean age±SD, 35.33±20.29 mo) and residing in North America. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The YC-PEM includes 3 participation scales and 1 environment scale. Each scale is assessed across 3 settings: home, daycare/preschool, and community. Data were analyzed to derive estimates of internal consistency, test-retest reliability, and construct validity. RESULTS Internal consistency ranged from .68 to .96 and .92 to .96 for the participation and environment scales, respectively. Test-retest reliability (2-4 wk) ranged from .31 to .93 for participation scales and from .91 to .94 for the environment scale. One of 3 participation scales and the environment scale demonstrated significant group differences by disability status across all 3 settings, and all 4 scales discriminated between disability groups for the daycare/preschool setting. The participation scales exhibited small to moderate positive associations with functional performance scores. CONCLUSIONS Results lend initial support for the use of the YC-PEM in research to assess the participation of young children with disabilities and delays in terms of (1) home, daycare/preschool, and community participation patterns; (2) perceived environmental supports and barriers to participation; and (3) activity-specific parent strategies to promote participation.

Multisensory integration in children: A preliminary ERP study

The spatio-temporal scalp distribution of multisensory auditory-somatosensory integration was investigated in typically developing children ages 6-13. Event-related potentials were recorded from 32 scalp electrodes while participants watched a silent cartoon. Three types of sensory stimulation were presented pseudo-randomly: auditory clicks, somatosensory median nerve electrical pulses, or simultaneous auditory and somatosensory stimuli. No behavioral responses were required of the participant. To examine integration, responses to simultaneous auditory and somatosensory stimulation were compared to the sum of unisensory auditory plus unisensory somatosensory responses for four time-windows: (60-80 ms, 80-110 ms, 110-150 ms and 180-220 ms). Results indicated significant multisensory integration occurred in central/post-central scalp regions between 60-80 ms in the hemisphere contralateral to the side of somatosensory stimulation and between 110-150 ms in the hemisphere ipsilateral to the side of somatosensory stimulation. Between 180-220 ms, significant multisensory integration was evident in central/post-central regions in both hemispheres as well as midline scalp regions. This study suggests that children exhibit differential processing of multisensory compared to unisensory stimuli, as has previously been reported in adults.