Auditory brainstem responses of children with developmental language disorders

The impact of maternal smoking on fast auditory brainstem responses

Deficits in auditory processing have been posited as one of the underlying neurodevelopmental consequences of maternal smoking during pregnancy that leads to later language and reading deficits. Fast auditory brainstem responses were used to assess differences in the sensory processing of auditory stimuli among infants with varying degrees of prenatal cigarette exposure. Maternal report of consumption of cigarettes and blood samples were collected in the hospital to assess exposure levels and participants were then seen at 6-months. To participate in the study, all infants had to pass the newborn hearing exam or a clinically administered ABR and have no known health problems. After controlling for participant age, maternal smoking during pregnancy was negatively related to latency of auditory brainstem responses. Of several potential covariates, only perinatal complications and maternal alcohol use were also related to latency of the ABR responses and maternal smoking level accounted for significant unique variance after controlling for these factors. These results suggest that the relationship between maternal smoking may lead to disruption in the sensory encoding of auditory stimuli.

Contralateral Suppression of Otoacoustic Emissions in Children with Specific Language Impairment

OBJECTIVE

The purpose of the investigation was to determine whether a group of children with specific language impairments (SLI) have reduced peripheral auditory processes thought to be associated with speech-in-noise intelligibility.

DESIGN

Transient evoked otoacoustic emissions (TEOAE) and their suppression by the efferent activity of the medial olivocochlear system (MOCS) in response to contralateral acoustic stimulation were used to compare these processes in 18 children with SLI and 21 controls.

RESULTS

The results revealed no group difference in TEOAE suppression effect or left/right asymmetry of TEOAE suppression effect.

CONCLUSIONS

These results suggest that children with SLI do not have auditory processing problems at this peripheral level casting doubt on a hypothesized relationship between strength of MOCS activity and language impairment.

Sensory processing of backward-masking signals in children with language-learning impairment as assessed with the auditory brainstem response

The purpose of this study was to examine the possible contribution of sensory mechanisms to an auditory processing deficit shown by some children with language-learning impairment (LLI). Auditory brainstem responses (ABRs) were measured from 2 groups of school-aged (8-10 years) children. One group consisted of 10 children with LLI, and the other group (control) consisted of 10 children with normally developing language. The ABR was elicited with a brief tone burst presented either alone (no-masking condition) or immediately followed by a longer duration noise burst (backward-masking condition). The primary dependent variable was the latency of wave V of the ABR. The mean latencies were not significantly different for the 2 groups in the no-masking condition. However, in the backward-masking condition, the mean latency for the LLI group was significantly increased relative to the mean latency for the control group. Thus, the presence of successive sounds delay the neural response in children with LLI. The explanation for this delay at the level of the brainstem is not known, but it may be due to disruption of synchrony, activation of alternate (less direct) pathways, increased inhibition, or some combination of these (or other) factors.

Brainstem auditory-evoked potentials of 8-year-old preterm children in relation to their psycholinguistic abilities and MRI findings

BACKGROUND

Brainstem auditory potential (BAEP) has been used to demonstrate brainstem damage and to provide prognosis for the outcome for newborn children. There are contradictory results of its power to predict problems in language development or problems at school. It is well known that preterm children experience an excess of these problems.

AIM

To study if BAEP findings of 8-year-old preterm children differ from those of the full-term born control children and whether there is correlation to their linguistic problems or to the findings in magnetic resonance imaging (MRI).

STUDY DESIGN

Population-based cohort study.

SUBJECTS

Forty-two preterm children aged 8 years born with birth weight <1750 g and their matched full-term control children with birth weight >2500 g, 24 of whom had BAEP recordings and MRI.

OUTCOME MEASURES

Differences in BAEPs between the preterm and the control children. Correlation of BAEPs with linguistic problems and with MRI findings.

RESULTS

No differences were found in the absolute latencies nor in the interpeak intervals and in the I/V amplitude ratio. Nor did the results differ even when cerebral palsy disabled preterm children, preterm children with mild neurodevelopmental dysfunction or healthy preterm children were compared to each other or to the control children. No correlation to the linguistic problems or to the findings of periventricular leukomalacia (PVL) in MRI or to the different measurements of the brainstem were found.

CONCLUSION

If hearing impairment does not exist, BAEP does not give further information on neurodevelopmental nor linguistic problems of the preterm children.

Voice, speech and language characteristics of children with Prader-Willi syndrome

Eleven individuals with Prader-Willi syndrome (PWS), aged between 4 and 25 years, were compared with II non-PWS children of the same sex, age, body mass index and IQ level. Voice, speech and language skills were generally impaired in subjects with PWS. Oral motor function, pitch level and resonance were specifically disordered and clearly differentiated the two groups from each other. Certain biological perinatal factors separated subjects with PWS from other obese children and adolescents, but did not differentiate within the group with PWS and could not account for the speech/language problems. Underlying cerebral dysfunction, combined with a characteristic anatomy of the mouth and larynx in PWS, contributes to altered voice, speech and language function.

Auditory evoked potentials in young patients with Down syndrome. Event-related potentials (P3) and histaminergic system

Subjects with Down syndrome exhibit various types of cognitive impairment. Besides abnormalities in a number of neurotransmitter systems (e.g. cholinergic), histaminergic deficits have recently been identified. Brainstem auditory evoked potentials (BAEPs) and auditory event-related potentials (ERPs), were recorded from 10 children (aged 11-20 years) with Down syndrome and from 10 age- and sex-matched healthy control subjects. In Down subjects, BAEPs revealed shortened latencies for peaks III and V with shortened interpeak latencies I-III and I-V. ERPs showed a delay of components N1, P2, N2 and P3. In addition, subjects with Down syndrome failed to show P3 amplitude reduction during repeated stimulation. To evaluate the cognitive effects of histaminergic dysfunction, ERPs were recorded from 12 healthy adults (aged 20-28 years) before and after antihistaminergic intervention (pheniramine) compared to placebo. Whereas components N1, P2, N2 remained unchanged after H1-receptor antagonism, P3 latency increased and P3 amplitude showed no habituation in response to repeated stimulation. The results suggest that the characteristic neurofunctional abnormalities present in children with Down syndrome must be the consequence of a combination of structural and neurochemical aberrations. The second finding was that antihistaminergic treatment affects information processing tested by ERPs similar to that seen with anticholinergic treatment.

Clinical interest of brainstem auditory evoked potentials in 72 children with inadequate language development

The present study is of brainstem auditory evoked potentials (BAEP) in 72 children, of 2 to 13 years of age, showing inadequate language development. The age of the children was mainly below the age of 4 (39 cases = 54%), peaking between 3 and 4 years of age (33 cases = 46%). Even so, 82% of our patients were 3 years old or over: 64% were boys, 36% girls, the proportion of boys falling off with age 26% (19 cases) of BAEPs recorded were normal, 74% (53 cases) pathological. High prevalence of undiagnosed hearing loss was found. Physiopathological BAEP classification showed endocochlear impairment in 68% (36 cases), conductive impairment in 21% (11 cases) and retrocochlear impairment in 11% (6 cases) of subjects. Unilateral impairment (20 cases = 28%) cannot account for inadequate language development; but, in the 8 cases (11%) of total bilateral hearing loss, and the 15 cases (21%) of partial bilateral impairment, hearing loss more or equal to 50 dB HL, impaired hearing would play a role in the retardation.