Developmental Science 10:5 (2007), pp 576– 587 DOI: 10.1111/j.1467-7687.2007.00620.x REPORT Blackwel PublishingLtd Atypical long-latency auditory event-related potentials in a subset of children with specific language impairment Dorothy V.M. Bishop,1 Mervyn Hardiman,1 Ruth Uwer2 and Waldemar von Suchodoletz2 1. Department of Experimental Psychology, University of Oxford, UK 2. Department of Child and Adolescent Psychiatry and Psychotherapy, University of Munich, Germany Abstract It has been proposed that speciﬁc language impairment (SLI) is the consequence of low-level abnormalities in auditory per- ception. However, studies of long-latency auditory ERPs in children with SLI have generated inconsistent ﬁndings. A possible reason for this inconsistency is the heterogeneity of SLI. The intraclass correlation (ICC) has been proposed as a useful statistic for evaluating heterogeneity because it allows one to compare an individual’s auditory ERP with the grand average waveform from a typically developing reference group. We used this method to reanalyse auditory ERPs from a sample previously described by Uwer, Albrecht and von Suchodoletz (2002). In a subset of children with receptive SLI, there was less correspondence (i.e. lower ICC) with the normative waveform (based on the control grand average) than for typically developing children. This poorer correspondence was seen in responses to both tone and speech stimuli for the period 100–228 ms post stimulus onset. The effect was lateralized and seen at right- but not left-sided electrodes. Introduction Speciﬁc language impairment (SLI), also known as developmental language disorder, is diagnosed when a child has difﬁculty in producing or understanding spoken language for no apparent reason. According to ICD-10 criteria (World Health Organization, 1993), the diagnosis is made when language development is out of keeping with other aspects of development, and possible explanatory causes have been excluded. Prevalence ﬁgures vary depending on how stringently such criteria are applied, and whether the focus is just on receptive language impairment, or is extended to include those with primarily expressive language difﬁculties. In an extensive epidemiological study in the USA, Tomblin, Records, Buckwalter, Zhang, Smith and O’Brien (1997) Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation. estimated the prevalence in 5- to 6-year-olds at around 7%, although the percentage of children whose problems attract clinical concern is lower than this. Over the past few decades, considerable progress has been made in understanding the etiology of SLI, and it is now widely recognized that the causes are predomi- nantly neurobiological rather than sociocultural, with genes playing a substantial role (see Bishop, 2002, for review). Nevertheless, we have made remarkably little progress in understanding the neurological basis of SLI. In part this may be because the number of studies using direct measures of neurological structure or function is small, but another reason is the heterogeneity of the disorder. Traditionally, SLI has been subdivided into expressive vs. expressive-receptive subtypes (American Psychiatric Association, 1994), though this gross con- trast may be inadequate for capturing the full range of clinical variation (Bishop, 2004). It seems likely that different etiologies are implicated in different subtypes of SLI. Certainly, there is wide variation in results from Address for correspondence: Dorothy V.M. Bishop, Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK; e-mail: dorothy.bishop@psy.ox.ac.uk © 2007 The Authors. Journal compilation © 2007 Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA.