Deficits in auditory sensory discrimination among children with attention-deficit/hyperactivity disorder

Needle in a haystack: localising the long-term neuronal changes from early-life exposure to general anaesthesia

Narrowing down the histopathological changes in the brain after early-life exposure to general anaesthesia has presented a consistent challenge for preclinical models of anaesthetic neurotoxicity. Using resting-state functional magnetic resonance imaging, in this issue of the journal Neudecker and colleagues demonstrated in vivo connectivity changes in the brain following a seed-based analysis that was derived from previously reported histopathology in the same animals. The combination of neurohistology and neuroimaging should help focus future preclinical studies investigating the developmental consequences of early exposure to general anaesthesia.

Gender Differences in Auditory and Visual Attentional Performance in Children with and without ADHD

OBJECTIVE

Despite the relatively high prevalence of attention deficit hyperactivity disorder (ADHD), the impairment of ADHD in women is underestimated due to the different ways the phenomenon manifests compared to traditional male symptoms. In order to close the gender gap in diagnosis and treatment, this study aims to explore the impact of gender on auditory and visual attention in children with and without ADHD.

METHOD

A total of 220 children with and without ADHD participated in this study. Their auditory and visual attention performances were analyzed by comparative computerized auditory and visual subtests.

RESULTS

Auditory and visual attention performance in children with and without ADHD did affect by gender, including typically developing (TD) boys are better than TD girls at distinguishing visual targets from non-target stimuli. When performing attention tasks, TD girls generally maintained a cautious response, which was different from TD boys, who generally adopted positive response methods. ADHD girls suffered from more serious auditory inattention problems than ADHD boys; however, ADHD boys suffered from more auditory and visual impulsive problems than ADHD girls. The internal attention problems of female ADHD children were broader than that of their male ADHD peers and were also more severe, especially in problems of auditory omission and auditory response acuity.

CONCLUSIONS

ADHD children had a significant gap in auditory and visual attention performance compared to TD children. The research results support the impact of gender on the performance of auditory and visual attention in children with and without ADHD.

[Application of Preschool Auditory Processing Assessment Scale in children with attention deficit hyperactivity disorder]

OBJECTIVES

To investigate the characteristics of auditory processing (AP) in preschool children with attention deficit hyperactivity disorder (ADHD) using Preschool Auditory Processing Assessment Scale (hereafter referred to as "auditory processing scale").

METHODS

A total of 41 children with ADHD and 41 typically developing (TD) children were assessed using the auditory processing scale, SNAP-IV rating scale, and Conners' Kiddie Continuous Performance Test (K-CPT). The auditory processing scale score was compared between the TD and ADHD groups. The correlations of the score with SNAP-IV and K-CPT scores were assessed.

RESULTS

Compared with the TD group, the ADHD group had significantly higher total score of the auditory processing scale and scores of all dimensions except visual attention (P<0.05). In the children with ADHD, the attention deficit dimension score of the SNAP-IV rating scale was positively correlated with the total score of the auditory processing scale (rs30=0.531, P<0.05; rs27=0.627, P<0.05) as well as the scores of its subdimensions, including auditory decoding (rs=0.628, P<0.05), auditory attention (rs=0.492, P<0.05), and communication (rs=0.399, P<0.05). The hyperactivity-impulsivity dimension score of the SNAP-IV rating scale was positively correlated with the hyperactivity-impulsivity dimension score of the auditory processing scale (rs=0.429, P<0.05). In the children with ADHD, the attention deficit dimension score of the K-CPT was positively correlated with the total score (rs30=0.574, P<0.05; rs27=0.485, P<0.05) and the hyperactivity-impulsivity dimension score (rs=0.602, P<0.05) of the auditory processing scale.

CONCLUSIONS

Preschool children with ADHD have the risk of AP abnormalities, and the auditory processing scale should be used early for the screening and evaluation of AP abnormalities in children.

A mechanistic model of ADHD as resulting from dopamine phasic/tonic imbalance during reinforcement learning

Attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children. Although the involvement of dopamine in this disorder seems to be established, the nature of dopaminergic dysfunction remains controversial. The purpose of this study was to test whether the key response characteristics of ADHD could be simulated by a mechanistic model that combines a decrease in tonic dopaminergic activity with an increase in phasic responses in cortical-striatal loops during learning reinforcement. To this end, we combined a dynamic model of dopamine with a neurocomputational model of the basal ganglia with multiple action channels. We also included a dynamic model of tonic and phasic dopamine release and control, and a learning procedure driven by tonic and phasic dopamine levels. In the model, the dopamine imbalance is the result of impaired presynaptic regulation of dopamine at the terminal level. Using this model, virtual individuals from a dopamine imbalance group and a control group were trained to associate four stimuli with four actions with fully informative reinforcement feedback. In a second phase, they were tested without feedback. Subjects in the dopamine imbalance group showed poorer performance with more variable reaction times due to the presence of fast and very slow responses, difficulty in choosing between stimuli even when they were of high intensity, and greater sensitivity to noise. Learning history was also significantly more variable in the dopamine imbalance group, explaining 75% of the variability in reaction time using quadratic regression. The response profile of the virtual subjects varied as a function of the learning history variability index to produce increasingly severe impairment, beginning with an increase in response variability alone, then accumulating a decrease in performance and finally a learning deficit. Although ADHD is certainly a heterogeneous disorder, these results suggest that typical features of ADHD can be explained by a phasic/tonic imbalance in dopaminergic activity alone.

Multi-level evidence of an allelic hierarchy of USH2A variants in hearing, auditory processing and speech/language outcomes

Language development builds upon a complex network of interacting subservient systems. It therefore follows that variations in, and subclinical disruptions of, these systems may have secondary effects on emergent language. In this paper, we consider the relationship between genetic variants, hearing, auditory processing and language development. We employ whole genome sequencing in a discovery family to target association and gene x environment interaction analyses in two large population cohorts; the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK10K. These investigations indicate that USH2A variants are associated with altered low-frequency sound perception which, in turn, increases the risk of developmental language disorder. We further show that Ush2a heterozygote mice have low-level hearing impairments, persistent higher-order acoustic processing deficits and altered vocalizations. These findings provide new insights into the complexity of genetic mechanisms serving language development and disorders and the relationships between developmental auditory and neural systems.

Peter Perrino et al. identify variants in USH2A linked to a dominant language disorder in a human family and find that these variants are also associated with low-frequency hearing at the population level. They investigate the function of USH2A variants in mice, showing that mutations in this gene are responsible for hearing loss.