Pirjo Korpilahti

Neurophysiologic correlates of deficient phonological representations and object naming in prematurely born children.

OBJECTIVE The aim of this follow-up study was to evaluate the development of object naming ability and auditory processing in prematurely born children. Furthermore, we investigated whether the mismatch negativity (MMN) parameters at the age of 4 years correlate with the MMN parameters and naming ability at the age of 6 years. METHODS Twelve very low birth weight (VLBW) preterm children (mean age 5 years 7 months) and matched controls were studied. Object naming was measured by the Boston naming test. Auditory event-related potentials (ERPs), especially the MMN, were recorded for Finnish syllables (standard /taa/; deviants /ta/ and /kaa/) in an oddball paradigm. RESULTS VLBW preterm children scored significantly lower in the object naming test than their controls. The MMN amplitude for consonant change was significantly smaller in the preterm group compared to the controls. The MMN amplitude at the age of 4 years correlated with the MMN amplitude at the age of 6 years. Furthermore, absence of the MMN at the age of 4 years predicted naming difficulties at the age of 6 years. CONCLUSIONS VLBW preterm children with a difficulty to preattentively discriminate changes in syllables, as indexed by the diminished change detection response, MMN, seem to have sustained naming difficulty. Therefore, it is reasonable to record the MMN along with the language development from infancy, in order to identify the children at risk for language deficiencies and to provide appropriate rehabilitation.

Similarities in the phenotype of the auditory neural substrate in children with Asperger syndrome and their parents

Asperger syndrome (AS) is a developmental disorder of brain function characterized by deficits in social interaction including difficulties in understanding emotional expressions. Children with AS share some of the behavioural characteristics with their parents and AS seems to run particularly in the male members of the same families. The aim of the present study was to determine whether similarities could be found between children with AS and their parents at central auditory processing. It was found that in children with AS the sound encoding, as reflected by the exogenous components of event‐related potentials, was similarly abnormal as in both their mothers and fathers. However, their abnormal cortical auditory discrimination, as indexed by the prolonged latency of the mismatch negativity, resembled that of their fathers but not that of their mothers. The present results suggest that complex genetic mechanisms may contribute to auditory abnormalities encountered in children with AS.

Auditory discrimination and memory functions in SLI children: A comprehensive study with neurophysiological and behavioural methods

Event-related potential (ERP) measures, in particular, the mismatch negativity (MMN), were combined with behavioural tests to examine auditory discrimination and memory functions in school-age children with specific language impairment (SLI). The MMN component is an integrated response to echoic memory representation of the standard stimulus and new afferent elements of the deviant stimuli. Neural activation was recorded for frequency differences in pure tones. Four tests were used to assess the auditory discrimination at behavioural level, two tests in pure tones and two in phonemes. A battery of 7 language tests was given to the SLI children. In the SLI group, the frequency MMN was weaker than in the reference group. The automatic memory recall in mismatch situation was found to reflect other information processes than conscious auditory perception.

Intervention for childhood apraxia of speech: A single-case study:

The underlying nature and diagnosis of childhood apraxia of speech (CAS) still requires clarification. However, the label ‘CAS’ or ‘suspected CAS’ continues to be assigned to a group of children with speech problems, and speech and language therapists need to be aware of effective treatment for these children. The aim of this study was to assess the effectiveness of the combination of two motor intervention methods, Melodic Intonation Therapy (MIT) and the Touch-Cue Method (TCM), on a child with CAS. SS, a girl aged 4 years and 7 months (4;7) whose speech characteristics fulfilled the criteria of CAS received a 6-week treatment with MIT, and following a 6-week treatment-free period, a 6-week treatment period with TCM. Speech sound errors decreased and sequencing abilities increased significantly after the MIT period, and the positive progression continued during the TCM period. SS made substantial gains in producing whole words correctly during the TCM block. Improvement was maintained during the 12-week follow-up. Our findings suggest that the combination of MIT and TCM was an effective way to address the child under study.

Electrophysiological correlates of cross-linguistic semantic integration in hearing signers: N400 and LPC

We explored semantic integration mechanisms in native and non-native hearing users of sign language and non-signing controls. Event-related brain potentials (ERPs) were recorded while participants performed a semantic decision task for priming lexeme pairs. Pairs were presented either within speech or across speech and sign language. Target-related ERP responses were subjected to principal component analyses (PCA), and neurocognitive basis of semantic integration processes were assessed by analyzing the N400 and the late positive complex (LPC) components in response to spoken (auditory) and signed (visual) antonymic and unrelated targets. Semantically-related effects triggered across modalities would indicate a similar tight interconnection between the signers׳ two languages like that described for spoken language bilinguals. Remarkable structural similarity of the N400 and LPC components with varying group differences between the spoken and signed targets were found. The LPC was the dominant response. The controls׳ LPC differed from the LPC of the two signing groups. It was reduced to the auditory unrelated targets and was less frontal for all the visual targets. The visual LPC was more broadly distributed in native than non-native signers and was left-lateralized for the unrelated targets in the native hearing signers only. Semantic priming effects were found for the auditory N400 in all groups, but only native hearing signers revealed a clear N400 effect to the visual targets. Surprisingly, the non-native signers revealed no semantically-related processing effect to the visual targets reflected in the N400 or the LPC; instead they appeared to rely more on visual post-lexical analyzing stages than native signers. We conclude that native and non-native signers employed different processing strategies to integrate signed and spoken semantic content. It appeared that the signers׳ semantic processing system was affected by group-specific factors like language background and/or usage.

Event-Related Potentials Reflect Deficits in Lexical Access: The N200 in Prematurely Born School-Aged Children

Objectives: Children born preterm have a high prevalence of neurocognitive deficits early in life. We examined whether the neural correlates of lexical access are atypical in 9-year-old children born preterm, and whether the findings of acoustic mapping correlate with language- and attention-related skills. Patients and Methods: The subjects were fourteen 9-year-old children born preterm and 14 full-term, typically developing controls. Two auditory event-related potential (ERP) components, the N200 and the N400, were used to assess discrimination response and word recognition. A set of behavioral tests (naming ability, auditory attention, phonological processing, pseudoword repetition, and comprehension of instructions) was performed, and the results were compared with the amplitudes, latencies, and scalp distribution of the ERP results. Results: In prematurely born children, neurophysiological deficits were associated with difficulties in auditory discrimination. The N200 amplitude correlated significantly with auditory attention and pseudoword repetition. The scalp distribution of both the N200 and the N400 was broader in children born preterm than in the controls. Low scores in the neuropsychological tasks referred to difficulties in auditory processing and memory. Conclusions: Children born preterm have difficulties in lexical access together with memory- and attention-related processes, which may have a longstanding impact on their school outcomes and academic skills.

Semantic representation of speech and signing in codas and interpreters: Behavioral patterns of interaction

Abstract Lexical representation of natural signed language in interrelation to speech was explored by analyzing hearing signers’ and non-signers’ behavioral response patterns to a within- and across-language semantic decision task. Native hearing signers, non-native sign language interpreters and sign-naïve controls had to decide whether two lexical items (speech-speech or speech-sign) were antonymic or not. Aim of this study was to examine whether sign language and speech are interacting with each other on the semantic level. Response patterns indicate semantic effects on within-language conditions in all three groups, whereas clear semantically motivated responses to cross-language conditions were only apparent in the two signing groups, though with different functional distribution. Our data demonstrate how tightly signing and speech can be interconnected at the semantic level. This linkage is at least partly learned and connected with language usage.

Recurrent respiratory tract infections or acute otitis media were not a risk factor for vocabulary development in children at 13 and 24 months of age

This study examined associations between recurrent respiratory tract infections (RTI) and acute otitis media (AOM) during the first one and two years of life and vocabulary size at 13 and 24 months of age.

Children born preterm have high risk for central auditory processing deficits, as indexed by the auditory brain event-related potentials (ERPs)

Resumen Una parte importante del desarrollo cerebral y de las redes neuronales se produce durante las ultimas 6 semanas de gestacion. Por consiguiente, el cerebro inmaduro es muy susceptible a las consecuencias del nacimiento prematuro y a un desarrollo atipico de los procesos neurobiologicos. Se ha observado que el nacimiento pretermino afecta con mayor frecuencia a la maduracion del cerebro en las areas frontal, temporal media y parietooccipital, que son importantes para los procesos auditivos, linguisticos y cognitivos y para la integracion de la informacion recibida. Muchos ninos prematuros presentan deficiencias en el procesamiento auditivo central (PAC) a nivel de la codificacion de los rasgos sonoros. Nuestros estudios de seguimiento muestran que los ninos prematuros tambien presentaban deficit en la discriminacion auditiva central, medida a traves del potencial de disparidad (MMN, del ingles mismatch negativity). Ademas, los deficit en la discriminacion auditiva central se correlacionaban con la adquisicion del lenguaje. Estos deficit persisten, con frecuencia, desde la primera infancia hasta la edad escolar. Por estos motivos, se deberia evaluar el PAC desde una edad temprana para poder organizar una rehabilitacion oportuna y especifica para este tipo de trastorno.