Dissociation of sensitivity and response bias in children with attention deficit/hyperactivity disorder during central auditory masking

Sensory white noise improves reading skills and memory recall in children with reading disability

BACKGROUND

Reading disability (RD) is characterized by slow and inaccurate word reading development, commonly reflecting underlying phonological problems. We have previously shown that exposure to white noise acutely improves cognitive performance in children with ADHD. The question addressed here is whether white noise exposure yields positive outcomes also for RD. There are theoretical reasons to expect such a possibility: a) RD and ADHD are two overlapping neurodevelopmental disorders and b) since prior research on white noise benefits has suggested that a central mechanism might be the phenomenon of stochastic resonance, then adding certain kinds of white noise might strengthen the signal-to-noise ratio during phonological processing and phoneme-grapheme mapping.

METHODS

The study was conducted with a group of 30 children with RD and phonological decoding difficulties and two comparison groups: one consisting of skilled readers (n = 22) and another of children with mild orthographic reading problems and age adequate phonological decoding (n = 30). White noise was presented experimentally in visual and auditory modalities, while the children performed tests of single word reading, orthographic word recognition, nonword reading, and memory recall.

RESULTS

For the first time, we show that visual and auditory white noise exposure improves some reading and memory capacities "on the fly" in children with RD and phonological decoding difficulties. By contrast, the comparison groups displayed either no benefit or a gradual decrease in performance with increasing noise. In interviews, we also found that the white noise exposure was tolerable or even preferred by many children.

CONCLUSION

These novel findings suggest that poor readers with phonological decoding difficulties may be immediately helped by white noise during reading. Future research is needed to determine the robustness, mechanisms, and long-term practical implications of the white noise benefits in children with reading disabilities.

Perception in attention deficit hyperactivity disorder

A large body of research demonstrated that individuals with attention deficit hyperactivity disorder (ADHD) suffer from various neuropsychological deficits. In contrast, less is known and only divergent evidence exists on perceptual functions of individuals with ADHD. This is problematic as neuropsychological and perceptual functions are closely interrelated and are often difficult to disentangle in behavioral assessments. This study presents the conduct and results of a systematic literature review on perceptual functions in children and adults with ADHD. This review considers studies using psychophysical methods (objective measurements) and self- and informant reports (subjective measurements). Results indicate that individuals with ADHD have altered perceptual functions in various domains as compared to typically developing individuals. Increased perceptual functions in individuals with ADHD were found with regard to olfactory detection thresholds, whereas reduced perceptual functions were evident for aspects of visual and speech perception. Moreover, individuals with ADHD were found to experience discomfort to sensory stimuli at a lower level than typically developing individuals. Alterations of perceptual functions in individuals with ADHD were shown to be moderated by various factors, such as pharmacological treatment, cognitive functions, and symptom severity. We conclude by giving implications for daily life functioning and clinical practice.

Different effects of adding white noise on cognitive performance of sub-, normal and super-attentive school children

OBJECTIVES

Noise often has detrimental effects on performance. However, because of the phenomenon of stochastic resonance (SR), auditory white noise (WN) can alter the "signal to noise" ratio and improve performance. The Moderate Brain Arousal (MBA) model postulates different levels of internal "neural noise" in individuals with different attentional capacities. This in turn determines the particular WN level most beneficial in each individual case-with one level of WN facilitating poor attenders but hindering super-attentive children. The objective of the present study is to find out if added WN affects cognitive performance differently in children that differ in attention ability.

METHODS

Participants were teacher-rated super- (N = 25); normal- (N = 29) and sub-attentive (N = 36) children (aged 8 to 10 years). Two non-executive function (EF) tasks (a verbal episodic recall task and a delayed verbal recognition task) and two EF tasks (a visuo-spatial working memory test and a Go-NoGo task) were performed under three WN levels. The non-WN condition was only used to control for potential differences in background noise in the group testing situations.

RESULTS

There were different effects of WN on performance in the three groups-adding moderate WN worsened the performance of super-attentive children for both task types and improved EF performance in sub-attentive children. The normal-attentive children's performance was unaffected by WN exposure. The shift from moderate to high levels of WN had little further effect on performance in any group.

SIGNIFICANCE

The predicted differential effect of WN on performance was confirmed. However, the failure to find evidence for an inverted U function challenges current theories. Alternative explanations are discussed. We propose that WN therapy should be further investigated as a possible non-pharmacological treatment for inattention.

Training children with ADHD to minimize impulsivity in auditory contralateral masking

OBJECTIVE

Impulsivity and distractibility are among the important symptoms of attention deficit hyperactivity disorder (ADHD). In this study, impulsivity is operationally measured using false-alarm rates in an auditory, contralateral-masking task. Intensive auditory training was attempted to decrease false alarm rates.

METHODS

In contralateral masking there is a distracting noise in one ear on every trial and a threshold-level tone in the other ear on half of those trials. Participants indicated whether the tone was present or not and received immediate feedback. The intensity of the masked tone was adaptively varied to track threshold. False alarms are the error of commission, saying that a stimulus is present when it is not. Seven school-aged children with ADHD (ages 10-16) and four adults without ADHD were trained on this task for 900 trials per day over four consecutive days.

RESULTS

False alarms from the children with ADHD decreased over the four days of training, beginning at the high level and ending at the low level expected from previous studies. There was no generalization to a different masking task. Results from the four adults were unexpected: soon after the training began they behaved no differently than the children with ADHD.

CONCLUSION

Children with ADHD can be trained to become less impulsive in an auditory detection task.

Attention-deficit/hyperactivity disorder: a neuropsychological perspective towards DSM-V

Neuropsychological methods and techniques have much to offer in the evaluation of the individual suspected as having Attention-Deficit/Hyperactivity Disorder (ADHD). After a review of the historical evolution of the ADHD concept, incidence and prevalence, and DSM-IV criteria for diagnosis, especially as regards omission related to gender differences, and other associated cultural, familial, socioenvironmental, and subject influences, this paper describes a number of dilemmas and obstacles encountered in clinical practice. Included are the confounds associated with the wide range of possible comorbidities, the insufficiency of current DSM-IV criteria, the emergence of subtype differentiation and its impact on diagnosis and treatment. The complex relationship between neuropsychological constructs and ADHD, and obstacles to valid assessment are also addressed. The complexities associated with a thorough ADHD evaluation are viewed within an impressive and expansive existing scientific framework and recommendations are made for future directions.

Effects of the neonatal intensive care unit on auditory attention and distraction

A theory is proposed that attention to acoustic signals is important for normal development and varies with background masking sounds. Specifically, the theory states that distractibility increases with decreasing predictability of the acoustic environment and with decreasing age. Literature from premature neonates, normal infants, preadolescent children, children with attention deficit disorders, and adults is reviewed. One conclusion is that an environment perceived by adults as predictable may be distracting for preterm infants. One recommendation for future research is to include measures of background acoustic predictability as independent variables or covariates in developmental studies.

Continuum of impulsiveness caused by auditory masking

OBJECTIVE

Impulsivity is a hallmark of attention deficit/hyperactivity disorder (ADHD). Various auditory masking procedures can quantify the impulsivity caused by distracting background sounds. This study compares the impulsiveness and distraction caused by informational masking (unpredictable tones) with previously published data on central masking (contralateral noise) in children with and without ADHD.

METHODS

Twenty-six normal and 14 children diagnosed as having ADHD (combined type), all between the ages of 7 and 13, indicated whether they heard a 512-ms, 500-Hz pure tone in a single-interval task under conditions of informational masking and in quiet. The masker consisted of 10 randomly selected frequencies between 1,000 and 2,500 Hz presented simultaneously at an overall level of 60 dB SPL. A maximum-likelihood method estimated thresholds and false alarm rates.

RESULTS

There were no differences due to ADHD in thresholds or false alarm rates either with informational masking or in quiet. With informational masking, normal children had high false alarm rates, similar to those from children with ADHD under central masking. With informational masking, all children tended to say a stimulus was present when it was not.

CONCLUSIONS

All children behave impulsively under some conditions. Pediatric patients with attention disorders can thus be reassured that impulsiveness with unpredictable background sounds is normal, to some extent. Response biases of children with ADHD may only diverge from normal in situations where distracting external stimuli have an intermediate level of predictability. A previous study showed that with central masking, children with ADHD are more impulsive than normal. There appears to be a limit to the uncertainty in auditory masking that can be tolerated by children. Children with ADHD become impulsive at lower levels of uncertainty than normal. Increasing the predictability of distracting background sounds may thus improve the performance of children with ADHD. Informational masking may, for normal listeners, mimic something of what it is like to have an attention deficit. ADHD can be profitably studied with auditory tasks.