What Box: A task for assessing language lateralization in young children.

The assessment of active language lateralization in infants and toddlers is challenging. It requires an imaging tool that is unintimidating, quick to setup, and robust to movement, in addition to an engaging and cognitively simple language processing task. Functional Transcranial Doppler Ultrasound (fTCD) offers a suitable technique and here we report on a suitable method to elicit active language production in young children. The 34-second "What Box" trial presents an animated face "searching" for an object. The face "finds" a box that opens to reveal a to-be-labelled object. In a sample of 95 children (1 to 5 years of age), 81% completed the task-32% with ≥10 trials. The task was validated (ρ = 0.4) against the gold standard Word Generation task in a group of older adults (n = 65, 60-85 years of age), though was less likely to categorize lateralization as left or right, indicative of greater measurement variability. Existing methods for active language production have been used with 2-year-old children while passive listening has been conducted with sleeping 6-month-olds. This is the first active method to be successfully employed with infants through to pre-schoolers, forming a useful tool for populations in which complex instructions are problematic.

Language phenotypes in children with sex chromosome trisomies.

Background: Sex chromosome trisomies (47,XXX, 47,XXY and 47,XYY) are known to be a risk factor for language disorder, but typical outcomes are hard to estimate, because many cases are identified only when problems are found. Methods: We recruited children aged 5-16 years with all three types of trisomy, and divided them into a High Bias group, identified in the course of investigations for neurodevelopmental problems, and a Low Bias group, identified via prenatal screening or other medical investigations. Children from a twin sample were used to compare the pattern and severity of language problems: they were subdivided according to parental concerns about language/history of speech-language therapy into a No Concerns group (N = 132) and a Language Concerns group (N = 41). Children were individually assessed on a psychometric battery, and a standardized parent checklist. After excluding children with intellectual disability, autism or hearing problems, psychometric data were available for 31 XXX, 20 XXY and 19 XYY Low Bias cases and 13 XXX, 25 XXY and 32 XYY High Bias cases. Results: Variation within each trisomy group was substantial: within the Low Bias group, overall language scores were depressed relative to normative data, but around one-third had no evidence of problems. There was no effect of trisomy type, and the test profile was similar to the Language Concerns comparison group. The rate of problems was much greater in the High Bias children with trisomies. Conclusions: When advising parents after discovery of a trisomy, it is important to emphasise that, though there is an increased risk of language problems, there is a very wide range of outcomes. Severe language problems are more common in those identified via genetic testing for neurodevelopmental problems but these are not typical of children identified on prenatal screening.

Correction: No population bias to left-hemisphere language in 4-year-olds with language impairment.

[This corrects the article DOI: 10.7717/peerj.507.].

Erratum: Parental phonological memory contributes to prediction of outcome of late talkers from 20 months to 4 years: a longitudinal study of precursors of specific language impairment.

[This corrects the article DOI: 10.1186/1866-1955-4-3.].

No population bias to left-hemisphere language in 4-year-olds with language impairment.

Background. An apparent paradox in the field of neuropsychology is that people with atypical cerebral lateralization do not appear to suffer any cognitive disadvantage, yet atypical cerebral lateralization is more common in children and adults with developmental language disorders. This study was designed to explore possible reasons for this puzzling pattern of results. Methods. We used functional transcranial Doppler ultrasound (fTCD) to assess cerebral blood flow during language production in 57 four-year-olds, including 15 children who had been late-talkers when first seen at 20 months of age. We categorized cerebral lateralization as left, right or bilateral, and compared proportions with each type of laterality with those seen in a previously tested sample of children aged 6-16 years. We also compared language scores at 4 years for those with typical and atypical lateralization, and then looked at the association the opposite way: comparing those with typical or impaired language in terms of their cerebral lateralization. Results. The distribution of types of cerebral lateralization was similar for 4-year-olds to that seen in older children. Overall, cerebral lateralization was not predictive of language level. However, for children who had language difficulties at 20 months and/or 4 years (N = 21), there was no population bias to left-hemisphere language activation, whereas children without language problems at either age showed a pronounced bias to left-sided language lateralization. Nevertheless, many children with right hemisphere language had no indications of language difficulties, confirming that atypical cerebral asymmetry is not a direct cause of problems. Conclusions. We suggest that atypical lateralization at the individual level is not associated with language impairment. However, lack of lateralization at the population level is a marker of risk for language impairment, which could be due to genetic or non-genetic causes.

Parental phonological memory contributes to prediction of outcome of late talkers from 20 months to 4 years: a longitudinal study of precursors of specific language impairment.

BACKGROUND: Many children who are late talkers go on to develop normal language, but others go on to have longer-term language difficulties. In this study, we considered which factors were predictive of persistent problems in late talkers. METHODS: Parental report of expressive vocabulary at 18 months of age was used to select 26 late talkers and 70 average talkers, who were assessed for language and cognitive ability at 20 months of age. Follow-up at 4 years of age was carried out for 24 late and 58 average talkers. A psychometric test battery was used to categorize children in terms of language status (unimpaired or impaired) and nonverbal ability (normal range or more than 1 SD below average). The vocabulary and non-word repetition skills of the accompanying parent were also assessed. RESULTS: Among the late talkers, seven (29%) met our criteria for specific language impairment (SLI) at 4 years of age, and a further two (8%) had low nonverbal ability. In the group of average talkers, eight (14%) met the criteria for SLI at 4 years, and five other children (8%) had low nonverbal ability. Family history of language problems was slightly better than late-talker status as a predictor of SLI.. The best predictors of SLI at 20 months of age were score on the receptive language scale of the Mullen Scales of Early Learning and the parent's performance on a non-word repetition task. Maternal education was not a significant predictor of outcome. CONCLUSIONS: In this study, around three-quarters of late talkers did not have any language difficulties at 4 years of age, provided there was no family history of language impairment. A family history of language-literacy problems was found to be a significant predictor for persisting problems. Nevertheless, there are children with SLI for whom prediction is difficult because they did not have early language delay.

dopOSCCI: a functional transcranial Doppler ultrasonography summary suite for the assessment of cerebral lateralization of cognitive function.

We present a description of a new software package, 'dopOSCCI', which summarises data from experimental studies where functional transcranial Doppler ultrasonography (fTCD) is used to compare hemispheric rates of blood flow in order to assess lateralization of a cognitive process. The software provides a graphical user interface to summarise analogue and digital data collected using Multi-Dop Doppler Ultrasound devices (DWL Multidop T2: manufacturer, DWL Elektronische Systeme, Singen, Germany). The unique aspects of dopOSCCI allow multi-file processing, multi-event marker processing, behavioural and multi-session summaries, image file data visualization, and tab-delimited output files which includes split-half, single-trial summaries and data quality variables. The Matlab based software is available under the GNU GPL license and can be accessed online at https://databank.ora.ox.ac.uk/general/datasets/dopOSCCI, the Oxford University DataBank.

Assessment of cerebral lateralization in children using functional transcranial Doppler ultrasound (fTCD).

There are many unanswered questions about cerebral lateralization. In particular, it remains unclear which aspects of language and nonverbal ability are lateralized, whether there are any disadvantages associated with atypical patterns of cerebral lateralization, and whether cerebral lateralization develops with age. In the past, researchers interested in these questions tended to use handedness as a proxy measure for cerebral lateralization, but this is unsatisfactory because handedness is only a weak and indirect indicator of laterality of cognitive functions. Other methods, such as fMRI, are expensive for large-scale studies, and not always feasible with children. Here we will describe the use of functional transcranial Doppler ultrasound (fTCD) as a cost-effective, non-invasive and reliable method for assessing cerebral lateralization. The procedure involves measuring blood flow in the middle cerebral artery via an ultrasound probe placed just in front of the ear. Our work builds on work by Rune Aaslid, who co-introduced TCD in 1982, and Stefan Knecht, Michael Deppe and their colleagues at the University of Münster, who pioneered the use of simultaneous measurements of left- and right middle cerebral artery blood flow, and devised a method of correcting for heart beat activity. This made it possible to see a clear increase in left-sided blood flow during language generation, with lateralization agreeing well with that obtained using other methods. The middle cerebral artery has a very wide vascular territory (see Figure 1) and the method does not provide useful information about localization within a hemisphere. Our experience suggests it is particularly sensitive to tasks that involve explicit or implicit speech production. The 'gold standard' task is a word generation task (e.g. think of as many words as you can that begin with the letter 'B'), but this is not suitable for young children and others with limited literacy skills. Compared with other brain imaging methods, fTCD is relatively unaffected by movement artefacts from speaking, and so we are able to get a reliable result from tasks that involve describing pictures aloud. Accordingly, we have developed a child-friendly task that involves looking at video-clips that tell a story, and then describing what was seen.