White matter asymmetry in the human brain: a diffusion tensor MRI study

Language ability and handedness are likely to be associated with asymmetry of the cerebral cortex (grey matter) and connectivity (white matter). Grey matter asymmetry, most likely linked to language has been identified with voxel-based morphometry (VBM) using T(1)-weighted images. Differences in white matter obtained with this technique are less consistent, probably due to the relative insensitivity of the T(1) contrast to the ultrastructure of white matter. Furthermore, previous VBM studies failed to find differences related to handedness in either grey or white matter. We revisited these issues and investigated two independent groups of subjects with diffusion-tensor imaging (DTI) for asymmetries in white matter composition. Using voxel-based statistical analyses an asymmetry of the arcuate fascicle was observed, with higher fractional anisotropy in the left hemisphere. In addition, we show differences related to handedness in the white matter underneath the precentral gyrus contralateral to the dominant hand. Remarkably, these findings were very robust, even when investigating small groups of subjects. This highlights the sensitivity of DTI for white matter tissue differences, making it an ideal tool to study small patient populations.     

Comprehension of humor in primary agenesis of the corpus callosum

Individuals with agenesis of the corpus callosum (ACC) can, in some cases, perform normally on standardized intelligence tests. Nevertheless, recent studies suggest that individuals with ACC and normal IQ scores have deficits in domains of fluid and social intelligence. Anecdotal reports from families suggest diminished appreciation of the subtleties of social interactions, and deficits in the comprehension of jokes and stories. In this research, both the cartoon and narrative joke subtests of a humor test (developed by Brownell et al. [Brownell, H., Michel, D., Powelson, J., & Gardner, H. (1983). Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients. Brain and language, 18(1), 20-27] and Bihrle et al. [Bihrle, A. M., Brownell, H. H., Powelson, J. A., & Gardner, H. (1986). Comprehension of humorous and non-humorous materials by left and right brain-damaged patients. Brain and Cognition, 5(4), 399-411]) were given to 16 adults with complete ACC (all with IQs>80) and 31 controls of similar age and IQ. Individuals with ACC performed worse than controls on the narrative joke subtest (p<.025) when VIQ was controlled. However, on the cartoon subtest the two groups were not significantly different. Covarying age, forms of IQ, narrative memory, set-switching, and literal language comprehension did not substantially alter the group difference. However, covarying comprehension of nonliteral language and proverbs eliminated the difference, suggesting a common origin for the comprehension of jokes, nonliteral language, and proverbs, most likely related to capacity for understanding second-order meanings.     

Book Reviews

Books Reviewed:
M. Bennett Developmental Psychology: Achievements and Prospects.
L. Balter & C. S. Tamis-LeMonda. Child Psychology. A Handbook of Contemporary Issues.
Ann Clarke and Alan Clarke. Jessica Kingsley Early Experience and the Life Path.
B. Lask & R. Bryant-Waugh. Anorexia Nervosa and Related Eating Disorders in Childhood and Adolescence (2nd ed.).
Susan Harter. The Construction of the Self.
J. Solomon & C. George. Attachment Disorganization.
L. H. Willey. Pretending To Be Normal. Living with Asperger's Syndrome.
D. M. Fergusson & P. E. Mullen. Childhood Sexual Abuse: An Evidence Based Perspective.
M. Weiss, L. Trokenberg Hechtman, & G. Weiss. ADHD in Adulthood. A Guide to Current Theory, Diagnosis, and Treatment.
T. M. Levy. Handbook of Attachment Interventions.
Carol S. Dweck. Self-theories: Their Role in Motivation, Personality and Development.
P. Howlin, S. Baron-Cohen, & J. Hadwin. Wiley Teaching Children with Autism to Mind Read: A Practical Guide.
M. Barrett. The Development of Language.
D. Cicchetti, & S. L. Toth. Developmental Approaches to Prevention and Intervention: Rochester Symposium on Developmental Psychology,
P. T. Slee & K. Rigby. Children's Peer Relations.
David Messer & Stuart Miller. Exploring Developmental Psychology: From Infancy to Adolescence.     

Can severe language disability be identified in three‐year‐olds? Evaluation of a routine screening procedure

This study evaluates the predictability of a new language screening procedure in 3-y-olds. It is used in several Child Health Centres (CHC) in Sweden and has the character of a field study involving more than 60 CHC nurses. The main questions concern the (i) development in 3-y-olds assessed as severely language delayed and (ii) whether there are any earlier unknown severely disabled children identified at 4 y of age. Ninety-six percent of the original study population participated in the follow-up. The calculations are based on results from 2237 children. A well-established screening routine, which has been shown capable of predicting the risk of not being able to follow expected schooling, and case records were used as an acceptable proxy outcome measure, pending a better gold standard. In the group of severely disabled 3-y-olds, sensitivity, specificity and positive predictive values were 86, 99 and 43%, respectively. Finally, three false-negatives were identified. In light of the present results, continued application of the 3-y screening is discussed.     

Crossed aphasia. An update

The aim of this article is to present an update of a rare but interesting problem: crossed aphasia. This term indicates the presence of aphasia after unilateral cerebral lesion of the hemisphere ipsilateral to the patient's dominant hand. We report two cases, review the most relevant literature, and analyze clinical, neuroanatomical, and neurophysiological aspects, taking in consideration the various interpretations proposed to explain this unusual language disorder.     

Comparative findings of voice and speech: language processing at an early ontogenetic age in quantitative EEG mapping

Quantitative EEG mapping in powers of electrical activity, concentration of main powers and area of concentration in relation to the side of presentation (left, right, and bihemisphery) and closer location was done on a 24-day-old infant first, and again when the infant was 2.5 months. EEG responses are analyzed in following acoustic modalities: (1) specific (native language speech of mother and unfamiliar female, unfamiliar female speech of foreign language); (2) unspecific (passive period). Familiar and unfamiliar texts present the contents of speech material. Comparative findings on two different ages showed that the infant maintains the processing scheme of unfamiliar stimulus (passive period, foreign language), and also very similar processing scheme of unfamiliar voice regardless if the text in native language is familiar or unfamiliar. During stimulation with familiar or unfamiliar text in native language, which is read by mother, processing type is significantly changed in relation to the age at the time of examination. While a 24-day-old infant shows a similar scheme in processing the familiar and the unfamiliar voices in native language, at the age of 2.5 months, this scheme of processing is changed, especially for theta rhythm, which now has bihemisphery presentation (at earlier stage it has right-side presentation) in the F–C–P region, what is practically the same region where also delta rhythm is processed. However, the sample of unfamiliar voice in native language observed in subsequent period, when the infant was 2.5 months old, maintains the same processing location as it has at an earlier ontogenetic stage, when the infant was 24 days old, regarding the theta rhythm processed in the F–C–P region with right-side presentation, and delta rhythm processed in C–P region with bihemisphery presentation. Post stimuli periods observed when the infant was 2.5 months old show obviously differentiation of theta and delta rhythms’ samples and their electrophysiological parameters. The samples of familiar and unfamiliar texts in native language when read by mother (familiar voice) begin to differentiate regarding to closer location and number of centers for maximal powers in theta rhythm at subsequent ontogenetic period (2.5-month-old infant). The samples of quantitative EEG mapping for a 2.5-months-old infant show the signs of complex processing of different stimuli types: known/unknown voice, foreign language, with stronger inclusion of parietal regions, bihemisphery and an increase in number of maximal powers' centers, compared to the samples when the infant was 42 days old. Quantitative EEG electrophysiological parameters are discussed in relation to side representation and closer regional location with the aim of explaining the processing of complex speech and language stimulation in relation to certain characteristics in its bases.     

Language skills, peer rejection, and the development of externalizing behavior from kindergarten to fourth grade

Background: Children with poorer language skills are more likely to show externalizing behavior problems, as well as to become rejected by their peers. Peer rejection has also been found to affect the development of externalizing behavior. This study explored the role of peer rejection in the link between language skills and the development of externalizing behavior. Methods: Six hundred and fifteen (615) children were followed from kindergarten to grade 4. Receptive language skills were measured with the Peabody Picture Vocabulary Test in grade 2. Teachers reported externalizing behavior and peer reports of social rejection were measured annually. Results: Children with poorer receptive language skills showed increasing externalizing behavior, while children with better receptive language skills showed decreases in externalizing behavior. Children with poorer receptive language skills experienced peer rejection most frequently. The link between receptive language skills and the development of externalizing behavior was mediated by the development of peer rejection. Findings suggested that this mediational link applied mostly to boys. Conclusion: Children with poorer language skills are at increased risk of becoming rejected by mainstream peers, which adds to the development of externalizing behavior.     

Relation between language, audio-vocal psycholinguistic abilities and P300 in children having specific language impairment

Specific language impairment is a relatively common developmental condition in which a child fails to develop language at the typical rate despite normal general intellectual abilities, adequate exposure to language, and in the absence of hearing impairments, or neurological or psychiatric disorders. There is much controversy about the extent to which the auditory processing deficits are important in the genesis specific language impairment. The objective of this paper is to assess the higher cortical functions in children with specific language impairment, through assessing neurophysiological changes in order to correlate the results with the clinical picture of the patients to choose the proper rehabilitation training program.

Subjects and method

This study was carried out on 40 children diagnosed to have specific language impairment and 20 normal children as a control group. All children were subjected to the assessment protocol applied in Kasr El-Aini hospital. They were also subjected to a language test (receptive, expressive and total language items), the audio-vocal items of Illinois test of psycholinguistic (auditory reception, auditory association, verbal expression, grammatical closure, auditory sequential memory and sound blending) as well as audiological assessment that included peripheral audiological and P300amplitude and latency assessment.The results revealed a highly significant difference in P300 amplitude and latency between specific language impairment group and control group. There is also strong correlations between P300 latency and the grammatical closure, auditory sequential memory and sound blending, while significant correlation between the P300 amplitude and auditory association and verbal expression.

Conclusion

Children with specific language impairment, in spite of the normal peripheral hearing, have evidence of cognitive and central auditory processing defects as evidenced by P300 auditory event related potential in the form of prolonged latency which indicate a slow rate of processing and defective memory as evidenced by small amplitude. These findings affect cognitive and language development in specific language impairment children and should be considered during planning the intervention program.