{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T01:23:04Z","timestamp":1791508984420,"version":"4.3.4"},"update-to":[{"DOI":"10.12688\/wellcomeopenres.9869.1","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T00:00:00Z","timestamp":1627430400000}}],"reference-count":49,"publisher":"F1000 Research Ltd","license":[{"start":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T00:00:00Z","timestamp":1627430400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Research Council","award":["694189"],"award-info":[{"award-number":["694189"]}]},{"DOI":"10.13039\/100010269","name":"Wellcome Trust","doi-asserted-by":"crossref","award":["082498, WT100229MA"],"award-info":[{"award-number":["082498, WT100229MA"]}],"id":[{"id":"10.13039\/100010269","id-type":"DOI","asserted-by":"crossref"}]},{"name":"ESRC Deafness Cognition and Language Research Centre","award":["RES-620-28-0002"],"award-info":[{"award-number":["RES-620-28-0002"]}]},{"name":"MEXT Grants-in-Aid for Scientific Research","award":["JP24720187"],"award-info":[{"award-number":["JP24720187"]}]}],"content-domain":{"domain":["wellcomeopenresearch.org"],"crossmark-restriction":false},"short-container-title":["Wellcome Open Res"],"abstract":"<ns3:p>\n                    <ns3:bold>Background<\/ns3:bold>\n                    : Lateralised language processing is a well-established finding in monolinguals. In bilinguals, studies using fMRI have typically found substantial regional overlap between the two languages, though results may be influenced by factors such as proficiency, age of acquisition and exposure to the second language. Few studies have focused specifically on individual differences in brain lateralisation, and those that have suggested reduced lateralisation may characterise representation of the second language (L2) in some bilingual individuals.\n                  <\/ns3:p>\n                  <ns3:p>\n                    <ns3:bold>Methods<\/ns3:bold>\n                    : In Study 1, we used functional transcranial Doppler sonography (FTCD) to measure cerebral lateralisation in both languages in high proficiency bilinguals who varied in age of acquisition (AoA) of L2. They had German (N = 14) or French (N = 10) as their first language (L1) and English as their second language. FTCD was used to measure task-dependent blood flow velocity changes in the left and right middle cerebral arteries during phonological word generation cued by single letters. Language history measures and handedness were assessed through self-report. Study 2 followed a similar format with 25 Japanese (L1) \/English (L2) bilinguals, with proficiency in their second language ranging from basic to advanced, using phonological and semantic word generation tasks with overt speech production.\n                  <\/ns3:p>\n                  <ns3:p>\n                    <ns3:bold>Results<\/ns3:bold>\n                    : In Study 1, participants were significantly left lateralised for both L1 and L2, with a high correlation (r = .70) in the size of laterality indices for L1 and L2. In Study 2, again there was good agreement between LIs for the two languages (r = .77 for both word generation tasks). There was no evidence in either study of an effect of age of acquisition, though the sample sizes were too small to detect any but large effects.\u00a0\n                  <\/ns3:p>\n                  <ns3:p>\n                    <ns3:bold>Conclusion<\/ns3:bold>\n                    : In proficient bilinguals, there is strong concordance for cerebral lateralisation of first and second language as assessed by a verbal fluency task.\n                  <\/ns3:p>","DOI":"10.12688\/wellcomeopenres.9869.2","type":"journal-article","created":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T03:45:07Z","timestamp":1627443907000},"page":"15","update-policy":"https:\/\/doi.org\/10.12688\/wellcomeopenres.crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["Cerebral lateralisation of first and second languages in bilinguals assessed using functional transcranial Doppler ultrasound"],"prefix":"10.12688","volume":"1","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2448-4033","authenticated-orcid":false,"given":"Dorothy V. M.","family":"Bishop","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Clara R.","family":"Grabitz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7085-3672","authenticated-orcid":false,"given":"Sophie C.","family":"Harte","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kate E.","family":"Watkins","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miho","family":"Sasaki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6569-2138","authenticated-orcid":false,"given":"Eva","family":"Gutierrez-Sigut","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mair\u00e9ad","family":"MacSweeney","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0462-6791","authenticated-orcid":false,"given":"Zoe V. J.","family":"Woodhead","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3140-4297","authenticated-orcid":false,"given":"Heather","family":"Payne","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2560","published-online":{"date-parts":[[2021,7,28]]},"reference":[{"key":"ref-1","doi-asserted-by":"publisher","first-page":"769-774","DOI":"10.3171\/jns.1982.57.6.0769","article-title":"Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries.","volume":"57","author":"R Aaslid","year":"1982","journal-title":"J Neurosurg."},{"key":"ref-2","first-page":"497-515","article-title":"What can functional neuroimaging tell us about the bilingual brain?","author":"J Abutalebi","year":"2005"},{"key":"ref-3","doi-asserted-by":"publisher","first-page":"242-275","DOI":"10.1016\/j.jneuroling.2006.10.003","article-title":"Bilingual language production: The neurocognition of language representation and control.","volume":"20","author":"J Abutalebi","year":"2007","journal-title":"J Neurolinguistics."},{"key":"ref-55","article-title":"NTT database series, Nihongo-no Goitokusei: Lexical properties of Japanese.","volume":"1","author":"S Amano","year":"1999"},{"key":"ref-6","doi-asserted-by":"publisher","first-page":"2161","DOI":"10.3791\/2161","article-title":"Assessment of cerebral lateralization in children using functional transcranial Doppler ultrasound (FTCD).","author":"D Bishop","year":"2010","journal-title":"J Vis Exp."},{"key":"ref-7","doi-asserted-by":"publisher","first-page":"587-590","DOI":"10.1016\/j.neuropsychologia.2008.09.013","article-title":"An efficient and reliable method for measuring cerebral lateralization during speech with functional transcranial doppler ultrasound.","volume":"47","author":"D Bishop","year":"2009","journal-title":"Neuropsychologia."},{"key":"ref-9","article-title":"Bilingual FTCD","author":"D Bishop","year":"2021a"},{"key":"ref-10","article-title":"Lateralisation in bilinguals","author":"D Bishop","year":"2021"},{"key":"ref-11","first-page":"307-310","article-title":"Statistical methods for assessing agreement between two methods of clinical measurement.","volume":"1","author":"J Bland","year":"1986","journal-title":"Lancet."},{"key":"ref-12","doi-asserted-by":"publisher","first-page":"1504-1511","DOI":"10.1111\/epi.12757","article-title":"Language dominance assessment in a bilingual population: Validity of fMRI in the second language.","volume":"55","author":"M Centeno","year":"2014","journal-title":"Epilepsia."},{"key":"ref-54","doi-asserted-by":"publisher","first-page":"208-216","DOI":"10.1016\/j.bandl.2013.05.007","article-title":"Language-specific cortical activation patterns for verbal fluency tasks in Japanese as assessed by multichannel functional near-infrared spectroscopy.","volume":"126","author":"H Dan","year":"2013","journal-title":"Brain Lang."},{"key":"ref-13","doi-asserted-by":"publisher","first-page":"3809-3815","DOI":"10.1097\/00001756-199712010-00030","article-title":"Anatomical variability in the cortical representation of first and second language.","volume":"8","author":"S Dehaene","year":"1997","journal-title":"Neuroreport."},{"key":"ref-56","doi-asserted-by":"publisher","first-page":"7565-7574","DOI":"10.1073\/pnas.1811513116","article-title":"Redefining bilingualism as a spectrum of experiences that differentially affects brain structure and function.","volume":"116","author":"V DeLuca","year":"2019","journal-title":"Proc Natl Acad Sci U S A."},{"key":"ref-50","doi-asserted-by":"publisher","first-page":"147-154","DOI":"10.1016\/s0165-0270(97)00067-8","article-title":"AVERAGE: a Windows program for automated analysis of event related cerebral blood flow.","volume":"75","author":"M Deppe","year":"1997","journal-title":"J Neurosci Methods."},{"key":"ref-14","doi-asserted-by":"publisher","first-page":"1124-1146","DOI":"10.1016\/j.neuroimage.2003.10.016","article-title":"The investigation of functional brain lateralization by transcranial Doppler sonography.","volume":"21","author":"M Deppe","year":"2004","journal-title":"Neuroimage."},{"key":"ref-15","article-title":"Boston naming test","author":"H Goodglass","year":"1983"},{"key":"ref-16","first-page":"197-218","article-title":"Neural basis of lexicon and grammar in L2 acquisition: The convergence hypothesis","author":"D Green","year":"2003"},{"key":"ref-17","doi-asserted-by":"publisher","first-page":"256-269","DOI":"10.1002\/brb3.56","article-title":"Does cerebral lateralization develop? 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Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2\/xml","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2\/iparadigms","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,8,12]],"date-time":"2021-08-12T05:05:50Z","timestamp":1628744750000},"score":1,"resource":{"primary":{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,7,28]]},"references-count":49,"URL":"https:\/\/doi.org\/10.12688\/wellcomeopenres.9869.2","relation":{"has-review":[{"id-type":"doi","id":"10.21956\/wellcomeopenres.18790.r45183","asserted-by":"subject"},{"id-type":"doi","id":"10.21956\/wellcomeopenres.18790.r45183","asserted-by":"object"}]},"ISSN":["2398-502X"],"issn-type":[{"value":"2398-502X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,7,28]]},"assertion":[{"value":"Indexed","URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2#article-reports","order":0,"name":"referee-status","label":"Referee status","group":{"name":"current-referee-status","label":"Current Referee Status"}},{"value":"10.21956\/wellcomeopenres.18790.r45183, Marc Brysbaert, Department of Experimental psychology\u00a0, Ghent University, Ghent, Belgium, 12 Aug 2021, version 2, indexed","URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2#referee-response-45183","order":0,"name":"referee-response-45183","label":"Referee Report","group":{"name":"article-reports","label":"Article Reports"}},{"value":"10.21956\/wellcomeopenres.10640.r18023, David W. Green, Tom Hope, Experimental Psychology, Faculty of Brain Sciences, University College London, London, UK, 05 Dec 2016, version 1, 1 approved, 1 approved with reservations, 1 not approved","URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v1#referee-response-18023","order":1,"name":"referee-response-18023","label":"Referee Report","group":{"name":"article-reports","label":"Article Reports"}},{"value":"<b>Dorothy Bishop<\/b>; \n<i>Posted: 24 Jun 2021<\/i>; \n<i>Comments under Rationale<\/i> We thank the reviewers for providing an overview of the literature on microcircuitry, which we now mention in the Discussion  \n<i>Usually desirable to report objective measures of language proficiency<\/i> Please see response to reviewer 1. We did not have such measures for Study 1, but we do for study 2.  \n<i>Given the experimenter spoke English all the time, how was the transition to the word generation task managed, in particular the switch from describing a picture in L1 to the naming task?\u2019<\/i> Alas, this was not noted at the time of data collection for Study 1 and we do not have a record of how this was handled, though we do state that the examiner used English throughout. For Study 2, the experimenter switched instruction languages according to the tested languages.  \n<i><b>Data analysis. <\/b>The word generation task involved an interval for the silent generation of words in response to a cued letter (15 secs) followed by a 5 second recall interval. Although this interval is short and so constrains information on relative difficulty, it is of interest to know the mean scores and their variance. If there is variance, does such variance have detectable effects on the signal?&nbsp;<\/i> We were not sure we had interpreted this correctly; in Study 1 words were generated covertly, therefore we did not have a record of responses. However, in previous studies with monolinguals, we have specifically considered whether varying task difficulty affects laterality. Where difficulty is varied by constraining the task (requiring words starting with 2 specific letters rather than one), this reduced performance but did not affect the LI. (Badcock, N. A., Nye, A., &amp; Bishop, D. V. M. (2012). Using functional transcranial Doppler ultrasonography to assess language lateralisation: Influence of task and difficulty level. Laterality, 17(6), 694\u2013710. https:\/\/doi.org\/10.1080\/1357650X.2011.615128). In Study 2 subjects generated words overtly and we report data on number of words produced.&nbsp; There was no relationship between number of words generated and LI.&nbsp;  \n<i><b>Estimates of reliability <\/b>The authors nicely use odd-even trials to estimate signal reliability for the asymmetry index. This estimate proved significant for the production task in the native language (L1) but not for the second language, English (L2). If there is no asymmetry difference then shouldn\u2019t there be a significant correlation when alternate trials are taken from different language runs?&nbsp;<\/i> We were also puzzled by the differing estimates of split half reliability - as it turns out when we reanalysed the data for this version, using our current analysis scripts, the estimate of split half reliability was more similar for the two languages: for L2, the original analysis gave r = .28. With our new method, one participant met criteria as an outlier and was excluded, and we also used Spearman rather than Pearson correlation, and based the LI on the mean rather than peak of the difference waveform; this gives r = .60. Please note: the analytic decisions leading to these changes were made a priori: we used the scripts and outlier exclusion criteria that we documented in Woodhead et al (2019), and list here how each modification of the method affected the correlation: - Discarding one participant with noisy data (participant 14), R = 0.44 - Using Spearman\u2019s correlations instead of Pearson\u2019s, R=0.49 - Using mean LI method instead of peak, R=0.60 We feel this provides further justification for basing analyses on mean rather than peak values: the latter can be more noisy, especially if the data do not show a single pronounced peak.","URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2#referee-comment-4673","order":2,"name":"referee-comment-4673","label":"Referee Comment","group":{"name":"article-reports","label":"Article Reports"}},{"value":"10.21956\/wellcomeopenres.10640.r20237, Andreas Jansen, Verena Schuster, Laboratory for Multimodal Neuroimaging (LMN), Department of Psychiatry, University of Marburg, Marburg, Germany, 20 Mar 2017, version 1, 1 approved, 1 approved with reservations, 1 not approved","URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v1#referee-response-20237","order":3,"name":"referee-response-20237","label":"Referee Report","group":{"name":"article-reports","label":"Article Reports"}},{"value":"<b>Dorothy Bishop<\/b>; \n<i>Posted: 24 Jun 2021<\/i>; \n<i>\u2018explain why the authors assessed in particular hemispheric dominance\u2019 \u2013 many reasons for differences in L1 and L2: recruitment of brain regions, strength of brain activity, connectivity between language regions<\/i>  We now make it clear that we recognise that there are potentially many ways in which language processing may differ for the two languages in bilinguals, but we do not think that invalidates a decision to look specifically at brain lateralisation, which has previously been discussed as potentially differing between languages.  \n<i>State why it was anticipated that language lateralization is stronger for a bilingual persons L1 than for L2.. &nbsp; Explain what the authors would have concluded when they had found significant differences between the lateralisation of L1 and L2. Explicitly state how strong the LI would expected to differ between L1 and L2.<\/i>  We now go into more detail regarding predictions from prior literature. The prediction of discrepant laterality between languages was not strong: In the literature, there are reports of both the same strength of lateralisation for L1 and L2 and also reduced lateralisation for L2.&nbsp; A finding of significant difference in lateralisation between L1 and L2 would have lent further support to one side of this debate.&nbsp;  \n<i>What is a minimal difference that would have been considered as relevant? There are issues with interpreting non-significant findings.<\/i>  As well as reporting Bayes Factors for mean comparisons, we have now conducted further analysis using the Bland-Altman method, which is specifically designed to address this issue.  \n<i>It is also not clear whether the authors intended to assess differences between L1 and L2 on a group level or in individual subjects? What would be the putative role of interindividual differences?<\/i>  This is a within-subjects study, with each person tested in both their languages, so the differences are evaluated in individual subjects. The correlations that are reported depend on there being individual differences in the extent of lateralisation. The result, therefore, hinges on interindividual differences.  \n<i>Important to know if technique is sensitive to find differences if they exist \u2013 are there methodological studies to assess the sensitivity of fTCD to small differences in lateralisation?&nbsp; ' I have serious doubts that fTCD can be applied for that purpose. The authors expect to find differences between the lateralization of L1 and L2. It is important to know whether the technique is sufficiently sensitive to find differences, if they exist.'<\/i>  Since this study was conducted, we have reported a study of test-retest reliability of laterality indices assessed using fTCD, which we now cite.&nbsp; They are high enough to give confidence that the degree, as well as direction of laterality measured this way, is reasonably stable. See Woodhead, Z. V. J., Bradshaw, A. R., Wilson, A. C., Thompson, P. A., &amp; Bishop, D. V. M. (2019). Testing the unitary theory of language lateralization using functional transcranial Doppler sonography in adults. \n<i>Royal Society Open Science<\/i>, \n<i>6<\/i>(3), 181801. https:\/\/doi.org\/10.1098\/rsos.181801. The reviewers clearly have a very negative impression of fTCD as a measure of laterality, but it's unclear what they prefer. The Wada technique is a blunt instrument that is useful in clinical contexts for making a basic distinction between left, right and bilateral, but it is neither feasible nor useful for measuring degrees of lateralisation. With fMRI one can quantify the LI, but the results will depend on the statistical approach (e.g. height or extent of statistic, %signal change etc), ROI studied and on thresholding. The kinds of individual difference in vasculature that the reviewers mentioned may well affect the observed LI - we now make that point in the Discussion. However, this will be as true for measures from fMRI as for fTCD, and in addition, with fMRI, the issue is complicated by the possibility of individual differences in localisation of language regions.&nbsp; So, while we accept that fTCD is not perfect, neither are other methods, and part of our goal in ongoing research is to use them as complementary methods. Indeed we regard it as a worthwhile endeavour in future to consider how far the LI in fTCD relates to anatomical variation. But we don't see any of these as reasons to dispense with the results we have obtained, which we regard as part of a complex pattern of evidence on these issues.  \n<i>Why did the developers report correlations between fTCD and other techniques (such as fMRI or Wada test) as high as r~0.9, when it is not possible to reproduce these findings even with the same modality?<\/i>  We cannot say why the M&uuml;nster group who developed fTCD reported these correlations.&nbsp; Our work is independent of theirs and we have not used the Average software for some years, though the processing steps we adopt are largely the same. The correlations they originally reported were based on small sample sizes and would have large confidence intervals around them. In addition, language laterality, as conventionally measured,&nbsp; is usually not normally distributed and should be evaluated with a nonparametric correlation coefficient. We hope to obtain data on larger samples in future that will provide more solid evidence on the relationship between lateralisation as assessed by fTCD and fMRI.","URL":"https:\/\/wellcomeopenresearch.org\/articles\/1-15\/v2#referee-comment-4674","order":4,"name":"referee-comment-4674","label":"Referee Comment","group":{"name":"article-reports","label":"Article Reports"}},{"value":"Study 1 was supported by a Wellcome Trust programme grant [082498] and European Research Council Advanced Grant [694189]. Study 2 was supported by funding for the ESRC Deafness Cognition and Language Research Centre (DCAL) [grant number RES-620-28-0002] and MEXT Grants-in-Aid for Scientific Research [grant number JP24720187] for MS. MM was supported by a Wellcome Trust Senior Research Fellowship [grant number WT100229MA].","order":5,"name":"grant-information","label":"Grant Information"},{"value":"This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.","order":0,"name":"copyright-info","label":"Copyright"}]}}