Middle Latency Response In Children Research Articles

Auditory Lateralization Training Effects on Binaural Interaction Component of Middle Latency Response in Children Suspected to Central Auditory Processing Disorder.

Many children with central auditory processing disorder (C)APD suffer from spatial processing disorder and benefit from binaural processing training including auditory lateralization training. There are subjective tests for evaluating auditory training effects in children with (C)APD but they rely on patient's attention and cooperation so there is a need for appropriate objective tests. The aim of present study was investigating effects of auditory lateralization training on binaural interaction component (BIC) of middle latency response (MLR). This study was an analytical interventional study. Sixty children suspected to (C)APD (40 boys and 20 girls) were selected based on inclusion criteria and were divided into two groups: control and training group. Auditory lateralization training included 12 formal sessions under headphone by using interaural time difference and performed as a game. MLR (monaural right ear, monaural left ear and binaural) and monaural selective auditory attention test (mSAAT) tests were performed in all the cases. BIC was calculated by subtracting binaural response from summed monaural responses. Covariance test showed that BIC latency decreased and BIC amplitude increased significantly and mSAAT score increased significantly in training group after auditory lateralization training (p value ≤0.001). In present study BIC of MLR had potential to show underlying neurophysiologic changes after auditory lateralization training in children suspected to (C)APD objectively. It is in agreement with behavioral improvements after training (mSAAT improvements).

Binaural Interaction Component of Middle Latency Response in Children Suspected to Central Auditory Processing Disorder.

Binaural processing disorder is an important deficit in children with (C)APD so binaural processing evaluations are crucial. There are subjective and objective tests for assessing binaural processing. Subjective tests require patient attention and active so objective evaluation of binaural processing is important. The aim of present study was investigating binaural interaction component (BIC) of middle latency response (MLR) in children suspected to (C)APD. Sixty 8-12year-old children suspected to (C)APD and sixty normal children were selected based on inclusion criteria. Both groups were matched in terms of sex (40 boys and 20 girls) and age (9.05±1.25years old). MLR test (monaural right ear, monaural left ear and binaural) was performed in all the cases and BIC was calculated by subtracting binaural response from summed monaural responses. Independent t test showed that latency of Pa and Na (ms), Pa-Na amplitude (µv), BIC latency (ms) and amplitude (µv) were significantly different from normal subjects (p value ≤0.001). Present study showed that MLR and BIC of MLR are clinically available and objective tests that can be used to determining children suspected to (C)APD. These tests might have the potential to separating normal children from children with (C)APD objectively.

Potencial Evocado Auditivo de Média Latência (PEAML) em crianças e adolescentes brasileiros: revisão sistemática

RESUMO Objetivo: Revisar sistematicamente a literatura científica sobre a realização do Potencial Evocado Auditivo de Média Latência (PEAML) em crianças e adolescentes brasileiros. Estratégia de pesquisa: Foram pesquisados artigos publicados a partir de 2009, em português, inglês ou espanhol, nas bases de dados eletrônicas MEDLINE, SciELO, BIREME e LILACS. Os artigos selecionados envolveram a realização do PEAML em crianças e/ou adolescentes brasileiros. Após triagem, os artigos foram analisados segundo a iniciativa “Strengthening the Reporting of Observational Studies in Epidemiology” (STROBE). Critérios de seleção: Foram excluídos artigos repetidos nas bases de busca e também os relatos de caso. Resultados: A busca inicial identificou 1315 artigos, dos quais oito foram selecionados para compor a revisão. Verificou-se predomínio de estudos observacionais transversais (75%); estimulação tipo click (100%), com velocidade até 11/s (100%) e intensidade de 70 dBNA (88%); uso de filtro passa-alta de 10 Hz (50%) e passa-baixa de 200 Hz (75%); montagem dos eletrodos em C3/C4 (ativos) A1/A2 (referências), e Fpz (neutro) (88%); amplitude Na-Pa, como principal parâmetro de comparação e normalidade; e uso do teste ANOVA (63%) para análise estatística. Nos estudos revisados, a média da latência da onda Pa e da amplitude Na-Pa em crianças e adolescentes normo-ouvintes foi de 32 milissegundos e 1,57 microvolts, respectivamente. Conclusão: Não há consenso quanto aos parâmetros de registro do PEAML em crianças e adolescentes brasileiros. Ainda assim, a média de latência de Pa e amplitude Na-Pa encontrada em crianças e adolescentes brasileiros normo-ouvintes, avaliados nos oito artigos desta revisão, concorda com os parâmetros de normalidade já estabelecidos internacionalmente.

Auditory middle latency response in children with learning difficulties.

Summary Introduction: This is an objective laboratory assessment of the central auditory systems of children with learning disabilities. Aim: To examine and determine the properties of the components of the Auditory Middle Latency Response in a sample of children with learning disabilities. Methods: This was a prospective, cross-sectional cohort study with quantitative, descriptive, and exploratory outcomes. We included 50 children aged 8–13 years of both genders with and without learning disorders. Those with disorders of known organic, environmental, or genetic causes were excluded. Results and Conclusions: The Na, Pa, and Nb waves were identified in all subjects. The ranges of the latency component values were as follows: Na = 9.8–32.3 ms, Pa = 19.0–51.4 ms, Nb = 30.0–64.3 ms (learning disorders group) and Na = 13.2–29.6 ms, Pa = 21.8–42.8 ms, Nb = 28.4–65.8 ms (healthy group). The values of the Na-Pa amplitude ranged from 0.3 to 6.8 ìV (learning disorders group) or 0.2–3.6 ìV (learning disorders group). Upon analysis, the functional characteristics of the groups were distinct: the left hemisphere Nb latency was longer in the study group than in the control group. Peculiarities of the electrophysiological measures were observed in the children with learning disorders. This study has provided information on the Auditory Middle Latency Response and can serve as a reference for other clinical and experimental studies in children with these disorders.

Auditory middle latency responses in children with specific language impairment

Auditory-evoked potentials represent the response of the auditory pathway to an auditory stimulus. Specific language impairment (SLI) children have delayed language development with difficulties in both understanding and producing spoken language. Hence, the purpose of this study was to determine whether a group of children with SLI had abnormal changes in the auditory middle latency response (AMLR). AMLR was obtained for 19 SLI children and they were studied and compared to normal. Audiological assessment and speech language tests were done for the study group. The results revealed no significant statistical differences between SLI children and the normal with regard to AMLR (P > 0.05). Our results suggest that children with SLI do not have abnormal auditory system response at the level measured by AMLR casting doubt on affection of the hypnotized origin of AMLR, mainly primary auditory cortex, as a cause for delayed language development in those children.

Effect of auditory training on the middle latency response in children with (central) auditory processing disorder

The purpose of this study was to determine the middle latency response (MLR) characteristics (latency and amplitude) in children with (central) auditory processing disorder [(C)APD], categorized as such by their performance on the central auditory test battery, and the effects of these characteristics after auditory training. Thirty children with (C)APD, 8 to 14 years of age, were tested using the MLR-evoked potential. This group was then enrolled in an 8-week auditory training program and then retested at the completion of the program. A control group of 22 children without (C)APD, composed of relatives and acquaintances of those involved in the research, underwent the same testing at equal time intervals, but were not enrolled in the auditory training program. Before auditory training, MLR results for the (C)APD group exhibited lower C3-A1 and C3-A2 wave amplitudes in comparison to the control group [C3-A1, 0.84 microV (mean), 0.39 (SD--standard deviation) for the (C)APD group and 1.18 microV (mean), 0.65 (SD) for the control group; C3-A2, 0.69 microV (mean), 0.31 (SD) for the (C)APD group and 1.00 microV (mean), 0.46 (SD) for the control group]. After training, the MLR C3-A1 [1.59 microV (mean), 0.82 (SD)] and C3-A2 [1.24 microV (mean), 0.73 (SD)] wave amplitudes of the (C)APD group significantly increased, so that there was no longer a significant difference in MLR amplitude between (C)APD and control groups. These findings suggest progress in the use of electrophysiological measurements for the diagnosis and treatment of (C)APD.

Effects of cochlear implant use on the electrically evoked middle latency response in children

The electrically evoked middle latency response (eMLR) reflects central auditory activity in cochlear implant users. This response was recorded repeatedly in 50 children over the first year of cochlear implant use and in 31 children with 5.3 ± 2.9 years of implant experience. The eMLR was rarely detected at the time of implantation in anaesthetized or sedated children and was detected in only 35% of awake children at initial device stimulation. The detectability of the eMLR increased over the first year of implant use becoming 100% detectable in children after at least one year. Acutely evoked responses were more likely to be present in older children despite longer periods of auditory deprivation. Within six months of implant use, most children had detectable eMLRs. At early stages of device use, eMLR amplitudes were lower in children implanted below the age of 5 years compared to children implanted at older ages; amplitudes increased over time in both groups. Latencies after six months of implant use were prolonged in the younger group and decreased with implant use. EMLR changes with chronic cochlear implant use suggest an activity-dependent plasticity of the central auditory system. Results suggest that the pattern of electrically evoked activity and development in the auditory thalamocortical pathways will be dependent upon the duration of auditory deprivation occurring in early childhood.

Electrical middle latency responses in children with cochlear implants

Electrical middle latency responses in children with cochlear implants

Electrical middle latency responses in children with cochlear implants

Electrical middle latency responses in children with cochlear implants

Low-frequency hearing assessment by middle latency responses in children with pervasive developmental disorder

Objective: In this study, we assessed middle latency responses (MLR) in children diagnosed with pervasive developmental disorder (PDD) in order to detect low-frequency auditory thresholds. Methods: 35 children, 25 males and 10 females, aged below 5, diagnosed with PDD were referred to rule out any possible hearing deficit. Audiologic evaluation included free-field testing, tympanometry, and both MLR and auditory brainstem responses. A control group of 15 normal children matched for sex and age were used. Results: In 9 out of 35 children (25%), low-frequency sensory hearing loss was revealed. The hearing loss was unilateral in seven children and bilateral in two, and varied from slight to severe. In four out of the nine cases (44%), parents had not suspected hearing loss, since these children always responded to sound. Conclusions: Among children diagnosed with PDD a significant proportion (25%) was affected by low-frequency sensory hearing loss, detected by MLR. In these children, when low-frequency hearing loss was found bilateral or severe unilateral, aural rehabilitation was initiated in order to improve their responses to auditory stimuli and their impaired communication with the environment. PDD children, even if their reaction to sound is normal, must be referred to thorough audiometric evaluation while low-frequency hearing level should always be tested.

Middle latency response in children with learning disabilities: Preliminary findings

The objective of this investigation was to determine if auditory middle latency responses (MLR) obtained from children with learning disabilities (LD) differ from those obtained from children without LD. Simultaneous recordings of auditory brainstem and middle latency responses were obtained in both vertex-ipsilateral (V-I) and vertex-contralateral derivations (V-C) in 22 children (11 LD and 11 normal) in the age range of eight to twelve years whose peripheral hearing was within normal limits to bilateral. The results indicate that for specific recording conditions, the latencies of middle latency responses differ significantly between children with LD and a normal group of children.

MLRs in children are consistently present during wakefulness, stage 1, and REM sleep.

Auditory middle latency responses (MLRs) were recorded continuously from normal children, ages 4 to 9 years, during natural sleep. Concurrently obtained EEG recordings were used to determine stages of sleep. Wave Pa was consistently present during wakefulness, alpha, stage 1, and REM sleep. Wave Pa detectability was poor during stage 4 sleep. The probability of obtaining wave Pa during stage 4 increased systematically with age. During stages 2 and 3, Pa detectability was variable. The inconsistency of MLRs in children currently limits their clinical use. These data indicate that the occurrence of MLRs in children is not haphazard, and that the MLR in children can be reliably obtained during certain states of arousal. A straightforward clinical application of these findings is that efforts to obtain MLRs be concentrated during periods favorable for recording the response. We suggest practical strategies for detecting optimal sleep stages.

Auditory middle latency responses in children: Effects of age and diagnostic category

The nature of auditory middle latency responses (MLRs) in children has been the subject of considerable debate. In order to study MLRs as a function of age, MLRs were obtained in 217 subjects ranging in age from 6 days to 20 years, all with normal auditory brain-stem responses (ABRs). Subjects were classified into several diagnostic categories: normal; communicative disorders (language delay, learning disability); mentally retarded, multiply handicapped; and post-meningitic. Age effects, the effects of diagnostic category, and possible differences in MLRs of males vs. females and right vs. left ears were examined. The detectability of both Na and Pa was found to increase significantly as a function of age. Detection of these MLR components became similar to adult values (approaching 100% detectability) at approximately 10 years of age. No significant differences were found among diagnostic categories. There were also no significant differences in the detectability of MLRs in males as compared to females, and there were no right vs. left ear differences. The strong age effect which appears to exist in the MLR influences their clinical use. When responses are present, they may be useful indicators of hearing sensitivity, but the absence of MLRs in children cannot be taken as an indication of hearing loss. Similarly, absent or abnormal MLRs cannot be interpreted as a manifestation of auditory pathway dysfunction, since there appears to be little difference in MLRs in normal subjects and MLRs in patients with a wide range of neurologic, cognitive, and speech and language disorders.