Deficits in auditory temporal and spectral resolution in language-impaired children

Between 3 and 6 per cent of children who are otherwise unimpaired have extreme difficulties producing and understanding spoken language. This disorder is typically labelled specific language impairment. Children diagnosed with specific language impairment often have accompanying reading difficulties (dyslexia), but not all children with reading difficulties have specific language impairment. Some researchers claim that language impairment arises from failures specific to language or cognitive processing. Others hold that language impairment results from a more elemental problem that makes affected children unable to hear the acoustic distinctions among successive brief sounds in speech. Here we report the results of psychophysical tests employing simple tones and noises showing that children with specific language impairment have severe auditory perceptual deficits for brief but not long tones in particular sound contexts. Our data support the view that language difficulties result from problems in auditory perception, and provide further information about the nature of these perceptual problems that should contribute to improving the diagnosis and treatment of language impairment and related disorders.     

Subjective effects of peak clipping and compression limiting in normal and hearing-impaired children and adults

Despite many advances in hearing-aid signal processing, compression limiting and peak clipping are still used. To date, perceptual studies have been conducted only with adults. The current study was designed to investigate the clarity of peak-clipped and compressed speech for both adults and children. Subjects were 30 normal-hearing and 30 hearing-impaired individuals in three age ranges (7-9, 10-12, and 16-50 years). Stimuli were processed at 60, 70, 75, and 80 dB SPL using peak clipping and at 80 dB SPL using compression limiting. Paired-comparison measures were used to assess the clarity of sentences, and a signal-to-distortion ratio (SDR) based on a measure of coherence between input and output was computed for each condition. For the peak-clipping conditions, there was a decrease in perceived clarity as the input increased from 60 to 80 dB SPL. This perceptual continuum was most apparent for the normal-hearing adults. The normal-hearing 10-12 year olds and the hearing-impaired adults showed a similar, but less pronounced, pattern. In contrast, the remaining three subject groups showed minimal differences in perceived clarity across conditions. Surprisingly, only the two oldest normal-hearing groups showed a clear preference for compression limiting over peak clipping at the highest input level, and only their results were consistent with the pattern of coherence across stimuli. Judgments of clarity by the normal-hearing subjects correlated best with the SDR in the 500-2000-Hz range, while clarity judgments of the hearing-impaired subjects correlated best with the SDR below 1000 Hz.     

Auditory inspection time and intelligence: What is the direction of causation?

Inspection time (IT) is an index of speed of perceptual processing that correlates at moderate levels with tests of mental ability. A key issue has been the question of the direction of causation: is IT causal to individual differences in intellectual ability, or is a fast IT a consequence of having a high IQ? The direction of causation was assessed by administering auditory inspection time (AIT) tests and tests of verbal and nonverbal ability to 104 school children at age 11, and 2 years later at 13 years. Three competing structural equation models were tested by using the cross-lagged panel data: that AIT at age 11 causes later IQ; that IQ at age 11 causes later AIT; and that there is equal reciprocal causation. Various goodness-of-fit indexes indicated that the first model was the most acceptable. AIT accounted for about 6% of the variance in cognitive ability 2 years later. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The specific relation between perception and production errors for place of articulation in developmental apraxia of speech

Developmental apraxia of speech is a disorder of phonological and articulatory output processes. However, it has been suggested that perceptual deficits may contribute to the disorder. Identification and discrimination tasks offer a fine-grained assessment of central auditory and phonetic functions. Seventeen children with developmental apraxia (mean age 8:9, years:months) and 16 control children (mean age 8:0) were administered tests of identification and discrimination of resynthesized and synthesized monosyllabic words differing in place-of-articulation of the initial voiced stop consonants. The resynthetic and synthetic words differed in the intensity of the third formant, a variable potentially enlarging their clinical value. The results of the identification task showed equal slopes for both subject groups, which indicates no phonetic processing deficit in developmental apraxia of speech. The hypothesized effect of the manipulation of the intensity of the third formant of the stimuli was not substantiated. However, the children with apraxia demonstrated poorer discrimination than the control children, which suggests affected auditory processing. Furthermore, analyses of discrimination performance and articulation data per apraxic subject demonstrated a specific relation between the degree to which auditory processing is affected and the frequency of place-of-articulation substitutions in production. This indicates the interdependence of perception and production. The results also suggest that the use of perceptual tasks has significant clinical value.     

Mild hearing loss in children with communication disorders

The prevalence of MHL in 202, 1 to 6 year-old children with communication disorders who visited our clinic in 1991 was investigated. 1) 31% of the subjects had MHL bilaterally. The prevalence of MHL was 44% at age 1 year, 20% at age 2 years, 36% at age 3 years, 24% at age 4 years, 39% at age 5 years, 33% at age 6 years. 2) 88% of children with MHL had OME, 10% had mild sensorineural hearing loss, and 2% had cerminous plug. 3) The prevalence of MHL in children with mental retardation and autistic disorders was 9%, that with stuttering was 9%, that of OME accompanied by moderate and severe hearing disorders was 6%. 4) The primary causes in 191, except for those with stuttering, were as follows; the prevalence of MHL was 30%, that of mental retardation and autistic disorders was 24%, and that of articulation disorders was 28%. 5) On the other hand, the prevalence of MHL in children with retarded language development and articulation disorders was 30%, which was significantly higher than that of the other communication disorders. Accordingly, the results of this study suggest that MHL in early childhood greatly influences communication disorders.     

Intersensory experience and early perceptual development: Postnatal experience with multimodal maternal cues affects intersensory responsiveness in Bobwhite Quail Chicks.

Unlike the other sensory modalities of precocial infants, the visual modality does not normally become functional until after birth or hatching. Despite this unique developmental status, the role of emerging visual experience on postnatal perceptual organization remains unclear. In this study, bobwhite quail hatchlings were reared in conditions that manipulated postnatal experience with maternal visual cues, either alone or in conjunction with maternal auditory cues. Results revealed that bobwhite chicks require postnatal exposure to both maternal auditory and visual cues following hatching to demonstrate species-specific perceptual preferences. Chicks that received temporally disparate maternal auditory and visual cues or experience with only maternal visual or maternal auditory cues failed to show species-typical perceptual responsiveness. These results suggest that developmental mechanisms involving both visual and auditory sensory experience underlie the emergence of early intersensory integration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pediatric and psychiatric comorbidity. Part I: The future of consultation-liaison psychiatry

This study was conducted to investigate the influence of high-frequency aircraft noise on the function of the auditory system of school-age children. A total of 228 students attending a school near an airport (school A) and 151 students attending a school far from an airport (school B) were analyzed. Audiometry and brainstem auditory evoked potential (BAEP) detection were performed in all subjects to evaluate cochlear and retrocochlear function. The results of audiometry indicated that hearing ability was significantly worse in the children of school A, which was located under the flight paths. The values of pure tone average, high pure tone average, and threshold at 4 kHz were all higher in children who were frequently exposed to aircraft noise. There was no consistent difference in BAEP latencies between the two schools. These results indicate that central transmission is not affected in children who have been exposed to aircraft noise for several years. The results of the present study showed a significant association between aircraft noise exposure and prevalence of noise-induced hearing loss. Although damage to peripheral cochlear organs was confirmed in school-age children, involvement of the central auditory pathway could not be verified.     

Differences in begging behaviour between barn swallow, Hirundo rustica, nestlings

Studies comparing children's and adults' labeling of speech stimuli have repeatedly shown that children's phonological decisions are more strongly related to portions of the signal that involve rapid spectral change (i.e., formant transitions) and less related to other signal components than are adults' decisions. Such findings have led to a model termed the Developmental Weighting Shift, which suggests that children initially assign particularly strong weight to formant transitions to help delimit individual words in the continuous speech stream but gradually modify these strategies to be more like those of adults as they learn about word-internal structure. The goal of the current study was to test a reasonable alternative: that these apparent age-related differences in perceptual weighting strategies for speech are instead due to age-related differences in auditory sensitivity. To this end, difference limens (DLs) were obtained from children (ages 5 and 7 years) and adults for three types of acoustic properties: dynamic-spectral, static-spectral, and temporal. Two testable hypotheses were offered: Labeling results could reflect either absolute differences in sensitivity between children and adults or relative differences in sensitivity within each group. Empirical support for either hypothesis would indicate that apparent developmental changes in perceptual weighting strategies are actually due to developmental changes in auditory sensitivity to acoustic properties. Results of this study contradicted predictions of both hypotheses, sustaining the suggestion that children's perceptual weighting strategies for speech-relevant acoustic properties change as they gain experience with a native language.     

Hyperactive and hypoxic children: Signal detection, sustained attention, and behavior.

Two parameters from signal detection theory—perceptual sensitivity and decision criterion cutoff scores—were used in the analysis of vigilance performance of 30 hyperactive (mean age 8.5 yrs), 30 hypoxic (mean age 9 yrs), and 47 normal (mean age 8.8 yrs) children. Signal detection analyses of 3 Continuous Performance Test conditions indicated that with increasing age, Ss obtained significantly more hits, fewer false alarms, higher perceptual sensitivity, and responded with greater caution. Overall deficits in signal discrimination (perceptual sensitivity level) were obtained for both the hyperactive and hypoxic Ss when compared to normal age-mates. Whereas the hypoxic Ss demonstrated additional decrements in sustaining attention (sensitivity decrement over time), the hyperactive Ss were impaired by low-response caution, reflecting difficulty inhibiting impulsive responses. Possible differences in hyperactive sample characteristics across studies and time-related recovery factors following hypoxia are discussed. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disturbances of loudness perception

This article reviews information on some auditory disorders that have in common a disturbance in loudness perception. The perceptual disturbances in these disorders have interchangeably been labeled "hyperacusis," "dysacusis," or "phonophobia." Our question concerns whether the loudness disturbances associated with these auditory disorders are sufficiently different as not to justify the equivalence implied by the labelling. Emphasis is placed on those articles that have given clear accounts of the phenomenology of the disturbed perceptual experience and have offered testable hypotheses about the mechanisms underlying it. Hypotheses about the origins of disturbed loudness perception are compared with independent experimental and clinical evidence on those mechanisms. The disturbances of loudness perception that occur in cochlear hearing loss, facial nerve paralysis and stapedectomy, and in more "central" disorders are phenomenologically different, have different underlying mechanisms, and merit different labels that most of them do not currently receive.     

Effects of visual and auditory distractors on learning disabled and normal children's recognition memory performance.

Investigated whether distractibility in learning disabled (LD) children could be predicted on the basis of diagnosed visual and auditory learning deficits. 26 children in Grades 2–4 were classified as having visual or auditory reading disorders on the basis of the Illinois Test of Psycholinguistic Abilities. They and 17 normally achieving children from the same grades performed visual and auditory recognition memory tasks with visual or auditory distractors presented on 80% of the trials. Analysis of error frequencies revealed that with distractors, Ss in the 2 LD groups made more errors and did not improve over trials as much as control Ss. However, the predicted interaction between learning disability modality and task or distractor modality did not obtain. Rather, all 3 S groups made more errors when task and distractor were in the same modality. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequential stream segregation in the absence of spectral cues

This paper investigates the cues used by the auditory system in the perceptual organization of sequential sounds. In particular, the ability to organize sounds in the absence of spectral cues is studied. In the first experiment listeners were presented with a tone sequence ABA ABA ..., where the fundamental frequency (f0) of tone A was fixed at 100 Hz and the f0 difference between tones A and B varied across trials between 1 and 11 semitones. Three spectral conditions were tested: pure tones, harmonic complexes filtered with a bandpass region between 500 and 2000 Hz, and harmonic complexes filtered with a bandpass region chosen so that only harmonics above the tenth would be passed by the filter, thus severely limiting spectral information. Listeners generally reported that they could segregate tones A and B into two separate perceptual streams when the f0 interval exceeded about four semitones. This was true for all conditions. The second experiment showed that most listeners were better able to recognize a short atonal melody interleaved with random distracting tones when the distracting tones were in an f0 region 11 semitones higher than the melody than when the distracting tones were in the same f0 region. The results were similar for both pure tones and complex tones comprising only high, unresolved harmonics. The results from both experiments show that spectral separation is not a necessary condition for perceptual stream segregation. This suggests that models of stream segregation that are based solely on spectral properties may require some revision.     

Patients'' views on residual blood use for research purposes

OBJECTIVE: This study assessed the effect of nocturnal hypoglycemia on well-being cerebral function, and physical fatigue the next day in 10 subjects with IDDM. RESEARCH DESIGN AND METHODS: After an exercise test to determine work-loads corresponding to 30 and 60% VO2max, volunteers were studied twice, 4 weeks apart. Blood glucose was lowered one night to 2.3-2.7 mmol/l for 1 h, and at the control visit, hypoglycemia was avoided. The next morning, well-being was assessed using the minor symptom evaluation profile (MSEP), and cerebral function was assessed with the paced auditory serial addition test, the digit symbol substitution test, trail making part B, four-choice reaction time, and auditory P300 latency. Subjects then exercised at predetermined workloads corresponding to 30% VO2max for 30 min and 60% VO2max until exhaustion. Fatigue was assessed every 10 min using the Borg scale for rating of perceived exertion. RESULTS: All three components of the MSEP scored higher (indicating more symptoms) after the hypoglycemic night compared with the control night (P < 0.01 contentment, sleep; P < 0.001 vitality). None of the cerebral function tests performed the next day was affected by hypoglycemia. Exercise capacity was similar at both visits, but subjects were more fatigued after the hypoglycemic night (P < 0.01, analysis of variance). There were no differences in potassium, catecholamine, glucose, or lactate concentrations between visits either before or during exercise. CONCLUSIONS: One hour of hypoglycemia at night affects a subject's sense of well-being, but not cerebral function, the next day. The greater fatigue after the hypoglycemic night cannot be explained by the biochemical parameters measured.     

Information processing by school-age children with specific language impairment: evidence from a modality effect paradigm

School-age children with specific language impairment (SLI) and age-matched controls were tested for immediate recall of digits presented visually, auditorily, or audiovisually. Recall tasks compared speaking and pointing response modalities. Each participant was tested at a level that was consistent with her or his auditory short-term memory span. Traditional effects of primacy, recency, and modality (an auditory recall advantage) were obtained for both groups. The groups performed similarly when audiovisual stimuli were paired with a spoken response, but children with SLI had smaller recency effects together with an unusually poor recall when visually presented items were paired with a pointing response. Such results cannot be explained on the basis of an auditory or speech deficit per se, and suggest that children with SLI have difficulty either retaining or using phonological codes, or both, during tasks that require multiple mental operations. Capacity limitations, involving the rapid decay of phonological representations and/or performance limitations related to the use of less demanding and less effective coding and retrieval strategies, could have contributed to the working memory deficiencies in the children with SLI.     

Spatial Working Memory Deficits in Children at Ages 3-4 Who Were Low Birth Weight, Preterm Infants.

The aim of this study was to investigate attention and perceptual and spatial working memory abilities in preterm, low birth weight preschool children without evident brain disorders as determined by normal cerebral ultrasound findings and normal motor development. The authors evaluated 19 preterm and 19 typically developing children who were matched for IQ and chronological age. Results indicated that children born prematurely without major neurological deficits and with a normal cognitive level may have specific difficulty in sustained attention, visuospatial processing, and spatial working memory when evaluated at ages 3-4. This finding is relevant for understanding the qualitative aspects of cognitive development in preterm children and the neurobiological substrate underlying this development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual adjustment to highly compressed speech: Effects of talker and rate changes.

This study investigated the perceptual adjustments that occur when listeners recognize highly compressed speech. In Experiment 1, adjustment was examined as a function of the amount of exposure to compressed speech by use of 2 different speakers and compression rates. The results demonstrated that adjustment takes place over a number of sentences, depending on the compression rate. Lower compression rates required less experience before full adjustment occurred. In Experiment 2, the impact of an abrupt change in talker characteristics was investigated; in Experiment 3, the impact of an abrupt change in compression rate was studied. The results of these 2 experiments indicated that sudden changes in talker characteristics or compression rate had little impact on the adjustment process. The findings are discussed with respect to the level of speech processing at which such adjustment might occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychophysical judgment: electro-cortical and heart rate correlates of accuracy and uncertainty

The relationship between perceptual accuracy and physiological response amplitude was investigated in an auditory pitch discrimination experiment. Confidence ratings were obtained from all subjects following each trial. The stimulus set consisted of three tones of different frequencies spaced in a manner to provide both easy and difficult discriminations. Heart rate, EEG and vertical eye movement were recorded throughout the experiment. The results of the experiment indicated that the largest evoked cardiac rate response was elicited by the stimulus which produced the fewest errors in judgment; larger auditory evoked potentials, particularly the late positive component (P300), were associated with the 'easy' stimulus; greater cortical negativity was associated with the difficult stimuli. Eye activity was found to covary with judgmental accuracy; cortical slow wave activity was particularly sensitive to the confidence, or 'uncertainty' parameter. A 'decision tree' model was hypothesized to describe the processing mechanism involved in solving the discrimination problem.     

Now you see it, now you don't: Evidence for age-dependent and age-independent cross-modal distraction.

Age-related deficits in selective attention have often been demonstrated in the visual modality and, to a lesser extent, in the auditory modality. In contrast, a mounting body of evidence has suggested that cross-modal selective attention is intact in aging, especially in visual tasks that require ignoring the auditory modality. Our goal in this study was to investigate age-related differences in the ability to ignore cross-modal auditory and visual distraction and to assess the role of cognitive control demands thereby. In a set of two experiments, 30 young (mean age = 23.3 years) and 30 older adults (mean age = 67.7 years) performed a visual and an auditory n-back task (0 ≤ n ≤ 2), with and without cross-modal distraction. The results show an asymmetry in cross-modal distraction as a function of sensory modality and age: Whereas auditory distraction did not disrupt performance on the visual task in either age group, visual distraction disrupted performance on the auditory task in both age groups. Most important, however, visual distraction was disproportionately larger in older adults. These results suggest that age-related distraction is modality dependent, such that suppression of cross-modal auditory distraction is preserved and suppression of cross-modal visual distraction is impaired in aging. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Physical health of 7-year-old children. An epidemiological study of school entrants and a comparison with their preschool health

At 7 years of age, all 649 7-year-old children in a school district underwent a physical examination, a vision screening and an auditory screening. 210 of the children were previously examined in an extensive health control at 4 years of age. The purpose of the present study was to describe the children's health situation and to evaluate the special health control performed at 4 years of age. In 15% of the children, functionally important health problems were found. Visual defects were most common, comprising 7.5%, then came physical health problems such as motor disturbances, obesity, bacteriuria in 6.5%, and hearing defects in 1%. About half of the important health problems were previously known. Children who had passed the special health control at 4 years of age had fewer newly detected important health problems and more previously known ones than other children, which means that many children with above all visual defects but also motor disturbances, bacteriuria and testis retention, were detected and treated earlier than would have happened without the special control at 4 years. It is concluded that the "ordinary" preschool Child Health Services did fulfill their purpose to detect handicapping disorders in an acceptable way; by the introduction of the special health control at 4 years of age, this function was further improved.     

Effect of compression point load on the path and life of fatigue crack growth in mixed mode loading

In this study, fatigue crack growth of edge crack in plate made from 5083 aluminum alloy under mixed mode fracture was numerically investigated. Effect of various parameters include initial crack direction angle (30°, 60°, 90°), initial crack length (20 and 25 mm) and load ratio (R=0 and 0.25) were considered. We also consider the effect of point compression load on crack growth life with 20 mm initial crack length under 30°, 60°, 90° at various parts of crack growth path. Mentioned models were simulated using the finite element softwares, ABAQUS and FRANC2D and their results were compared together. For validation we compare the numerical results for a specimen with its experimental data. Numerical results show good agreement with the experimental data for fracture path. It is observed that the point compression load can affect the path and life of crack growth in fatigue loading. If this load was applied in the first cycles of crack growth, its effect is more than another cases. For instance in the crack growth with initial angle 30o applying point load in 5, 10 and 15 mm of crack growth length, increase the life 79.4%, 18.9% and 6.2% respectively.