Methodological Issues in Neuroimaging studies of Skilled Reading and Reading Disability: Establishing brain/behavior links.

Examining Reading Development and Reading Disability in English Language Learners: Potential Contributions from Functional Neuroimaging

Kenneth R. Pugh

Yale University School of Medicine, New Haven, CT; Haskins Laboratories, New Haven, CT

Rebecca Sandak, Stephen J. Frost, Dina Moore, and W. Einar Mencl

Haskins Laboratories, New Haven, CT

Neuroimaging studies have suggested that across different written languages, skilled reading behavior is supported by similar, largely left hemisphere (LH), networks. In addition, recent studies of reading disability (RD) in monolingual readers, conducted in several languages, suggest a common neurobiological signature for this syndrome (disruption of LH posterior regions that support fluent reading). Thus, at the neurobiological level of analysis, reading

and its disorders appear to be more similar than dissimilar across languages. In this article, we consider the neurobiology of reading development and RD in English language learners (ELL). There is some evidence suggesting that fluent bilingual readers tend to engage primarily overlapping circuits for both L1 and L2. There is, however, a paucity of neurobiological research

on both reading development and RD in this population. Using the existing research on RD as a starting point, we consider in this article how developmental neuroimaging techniques might be applied to (1) help identify RD readers in the ELL populations, and (2) provide �neurobiological outcome measures to help evaluate the efficacy of different approaches to the

teaching of reading in English.

The acquisition of literacy skill is a major cognitive challenge for any child, and in any population significant numbers of children will fail to obtain age-appropriate reading levels (Adams, 1990). For English language learners (ELL), especially those children with limited English proficiency (LEP), the challenge can be all the more acute, and the incidence of reading difficulties in this population is alarmingly high. The National Assessment of Educational Progress (NAEP, 2000) reports that LEP students, especially Hispanic students, lag far behind their White and Asian peers in reading performance.

While socioeconomic factors clearly contribute to this reading crisis, the linguistic and cognitive challenges associated with learning to read in a nonprimary language are likely to be contributing factors as well (August & Hakuta, 1998; Snow, Burns, & Griffin, 1998). Using standard diagnostic criteria, we would certainly classify many of these children as reading disabled (RD).

Although RD, as a gene-linked syndrome, likely occurs with similar frequency in all populations and across all written languages (Grigorenko et al., 1997), because of the struggles inherent in learning to read in a second language, the

tendency for misdiagnosis in ELL children looms. In this article, we are charged with addressing two questions. First, can neuroimaging techniques be used to help identify reading problems that are of a congenital origin? This kind of information, if obtainable, could be useful in helping us to distinguish

true RD from the reading problems associated with the Requests for reprints should be sent to Kenneth R. Pugh, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510.

Electronic inquiries may be sent to [email protected]. myriad of environmental and linguistic factors that challenge many ELL children. Second, how might these techniques be employed in assessing the efficacy of different approaches to the teaching of reading in ELL children? Recent neuroimaging

studies of English monolinguals have begun to reveal the neurobiological signatures of successful training and remediation programs (Shaywitz et al., 2004; Simos, Breier et al., 2002; Temple et al., 2003); it would be desirable, we think, to make similar use of neuroimaging in evaluating effects of contrasting approaches to reading instruction for ELL children.

While a good deal of neuroimaging research has been conducted on reading development, reading disability, and effects of intensive intervention, many of these studies have examined only monolingual speakers of English (for a review, see Pugh, Mencl, Jenner et al., 2000; Sandak, Mencl, Frost, & Pugh, 2004). Good progress has been made though, both in mapping out neurobiological trajectories (i.e., the development of a left hemisphere [LH] circuitry for fluent reading) in typically developing children (Shaywitz et al., 2002; Turkeltaub, Gareau, Flowers, Zeffiro, & Eden, 2003), and in

isolating the neurobiological markers of RD (cf. Brunswick, McCrory, Price, Frith, & Frith, 1999; Pugh, Mencl, Shaywitz et al., 2000; Rumsey et al., 1997; Shaywitz et al., 1998, 2002).

If this body of evidence is going to provide a reasonable framework fromwhich to begin to exploreRDinELLpopulations we must address the following question: Can we expect the cognitive and neurobiological characteristics of reading

acquisition (and RD) in ELL children to be similar or dissimilar to monolingual English-speaking children studied to date?

Pugh et al.: examining reading development and reading disability in ells 25

In this article, e examine several domains of research that may be relevant to this question.We broadly consider the evidence from studies of monolingual readers in different languages (and different writing systems) for language-invariant or language-specific circuits, along with the current evidence for language-invariant neurobiological signatures of RD. In addition, we consider the existing evidence for overlapping or distinct spoken language and written language systems for L1 and L2 fluent bilinguals. This research can help to frame our expectations and hypotheses as we further explore reading acquisition (at both the behavioral and neurobiological levels-of-analysis) in ELL children.

Spoken and written language circuits in different languages

Both historically and ontologically, spoken language capacity develops prior to the derived abilities of reading and writing. While brain organization for spoken language perception and production is, to a large degree at least, a biological specialization, reading by contrast is almost certainly not (Liberman, 1992). Indeed, reading skill, unlike speech communication skills, must be explicitly taught, and failure is more likely in the print modality than in the spoken modality. Given the biological constraints on spoken language development (and processing), it would seem likely that, despite differences in

morphological and syntactic principles, different languages would tend to have similar neurobiological foundations. Data from both lesion studies, and functional neuroimaging studies of speech perception and production in multiple languages (cf. Indefrey & Levelt, 2004) are broadly consistent with this

expectation. LH temporal and frontal (perisylvian) language zones are uniformly activated for tasks tapping spoken language processes in both alphabetic and nonalphabetic languages (Indefrey & Levelt, 2004).

However, this general pattern of overlapping circuits across various spoken languages does not imply the absence of any language-specific variation at all. For instance, Valaki et al. (2004), using magneto-encephalography (MEG), compared Spanish, English, and Mandarin speakers performing a spoken word (memory) processing task. While all three groups showed largely overlapping LH activation patterns, relative to the first two cohorts, Chinese speakers showed reliably greater contributions from the right hemisphere (RH)

during performance of this task. The authors speculate that increased demands on prosodic coding in tonal languages such as Chinese, may promote a heightened RH involvement.

Thus,while the general claim that speech perception and production in different languages has a largely uniform neurobiological organization seems to have been clearly established at this point, we should remain cognizant of potential differences. It is conceivable that the process of building the neural circuitry for spoken and then written English might subtly differ in ELL children with Chinese, as opposed to Spanish, as the native language. We need to remember that the ELL child, especially one with LEP, is not merely coping with the challenges of learning to read English, but also is still at a fairly early stage in developing a bilingual brain circuitry for spoken language. The

neurobiological mechanisms associated with becoming bilingual are actively being investigated in many domains, and many populations at present (e.g., Dehaene et al., 1997; Kim, Relkin, Lee, & Hirsch, 1997; Perani et al., 1998). Some general findings have emerged (see Abutalebi, Cappa, & Perani,

2001, for a discussion) that might help provide some context for our work with ELL children. Whereas most studies have reported largely overlapping systems for the spoken forms of L1 and L2 in fluent bilinguals, the degree of overlap appears to depend heavily upon factors such as age of acquisition, and

perhaps most importantly, degree of proficiency in L2 (see Abutalebi et al., 2001, for a discussion). Highly proficient speakers of L2 show greater integration of L1 and L2 in the brain than less proficient speakers (Kim et al., 1997; Klein, Milner, Zatorre, Meyer, & Evans, 1995; Perani et al., 1998).

Thus, spoken language proficiency in L2, by virtue of its effects on brain organization for speech, might impact the ways in which reading circuits develop as literacy skills are taught. This may be an important individual difference dimension to keep in mind as we begin to map out neurobiological trajectories for reading and RD in ELL children. Additionally, as noted above, differences in hemispheric distributions of activation have been reported for Chinese (Valaki et al., 2004), and the unique demands of being bilingual are associated with the need to develop brain mechanisms to cope with

the demands of language switching and suppression (Price, Green, & von Studnitz, 1999). All these types of variables will need to be examined as we begin to chart the neurobiological changes as ELL children learn to master both speech and reading in L2.

We now turn to the issue of reading in different languages. All orthographies code the phonology of the spoken language, but the manner in which this is represented varies across written languages. For example, in alphabetic

orthographies graphemes code-specific consonants and vowels, whereas in syllabaries (such as compose part of the Japanese and Korean writing systems) each grapheme represents a complete syllable. In contrast, Chinese characters

provide limited information about the phonological forms of the words they represent, though some information relevant to phonological form is contained in the phonetic component of compound characters (DeFrancis, 1989; Hung & Tzeng, 1981; Perfetti, 1985). Moreover, even within alphabetic orthographies

there are differences in the consistency with which individual letters correspond to particular phonemes.

Finnish, for example, is considered to be a “transparent” orthography because it displays a consistent mapping between letter and sound, with each letter mapping onto one and only one consonant or vowel and vice versa. English,

by contrast, is an “opaque” orthography; the mapping in English is considerably less consistent (Frost, Katz,&Bentin, 1987).

Our read of cross-language studies of word recognition in skilled adult readers suggests to us that lexical access does not differ in any fundamental manner in transparent versus opaque orthographies (Frost, 1998; Lukatela&Turvey, 1994;

Perfetti, 1985). For instance, Lukatela and Turvey (1994) and Lukatela, Savic, Urosevic, and Turvey (1997) used a variety of priming tasks and observed similar and robust effects of sublexical phonological processes on word identification

Special series: learning disabilities in English language learners

Latencies for both English and Serbo-Croatian (Serbo-Croatian employs a very transparent orthographic system relative to English). Language differences have been reported relative to types (or grain size) of the phonological units relevant to lexical access (e.g., see the German/English comparison

study of Ziegler, Perry, Jacobs, & Braun, 2001), but, in general, sublexical phonological influences appear to be strongly influencing word perception across languages. Indeed, there is even some accumulating evidence that readers of Chinese are sensitive to sublexical phonological information

contained in the phonetic components of compound words (Liu, Chen, & Sue, 2003; Perfetti, Zhang, & Berent, 1992), suggesting certain parallels with lexical access mechanisms identified in alphabetic writing systems. To summarize,

while reading will not be entirely uniform in all of aspects across different orthographies, and this is an active research domain with many outstanding disagreements and debates (see Coltheart, Rastle, Perry, Langdon, & Ziegler,

2001; Harm & Seidenberg, 2004), we would argue, along with Perfetti (1985) and Frost (1998), that word recognition in reading develops on very similar cognitive principles in very different orthographies. In our view, this is so because of the universal requirement to develop fast and efficient access to already well-learned phonological forms, this requirement pressures the reader to be maximally sensitive to sublexical phonological variables in order to facilitate this process (Frost, 1998; Van Orden, Pennington, & Stone, 1990).

Accordingly, wewould predict that the brain circuit that develops to support reading behavior is necessarily quite similar across languages. The functional neuroanatomy of word recognition (and sentence processing) in reading has been investigated in a variety of languages (which employ both alphabetic and nonalphabetic writing systems) in recent years (e.g., Chee, Tan,

& Thiel, 1999; Fiebach, Friederici, Mueller, & von Cramon, 2002;Kuo et al., 2003; Paulesu et al., 2000; Salmelin, Service, Kiesila, Uutela, & Salonen, 1996). Neuroimaging studies of alphabetic languages implicate a set of LH cortical regions including occipitotemporal, temporoparietal, and inferior frontal networks; these networks are almost always engaged in reading irrespective of the specific language and/or writing system under investigation. Language-specific differences appear to be most a matter of degree, not of kind. That

is, in one language, a given neural network might be more or less activated than in another language, but the general circuit appears similar in its taxonomic organization (Paulesu et al., 2000). It has been suggested that these relative differences in the “weighting” of one or another network within the broad reading circuit might be associated with variation in processing demands associated with factors such as the orthographic depth of the writing system (Paulesu et al., 2000).

This overlap is perhaps not surprising given the evidence for similar demands on subword processing. Even in languages with orthographies as distinct as Chinese broadly similar activation has been reported at occipitotemporal, temporoprietal, and inferior frontal sites (Kuo et al., 2003). Some differences

have been reported for Chinese reading at both superior parietal (Kuo et al., 2003), and left middle frontal regions (Tan et al., 2001), but overall the reading networks are largely similar to those observed for alphabetic writing systems (Kuo et al., 2003).

These similarities across languages, at both the behavioral and brain levels-of-analysis, would lead us to anticipate a highly integrated reading circuitry for L1 and L2 in fluent bilingual readers; though a good deal of pressure on the brain

for both integration and for maintaining distinctions would follow from this common neural system (Price et al., 1999).

Bilingual reading studies appear to reinforce this expectation, at least for readers proficient in L1 and L2 (e.g., Chee et al., 1999; Illes et al., 1999; Price et al., 1999).

What type of guidance can the research reviewed here provide as we begin to investigate reading development and RD in ELL readers? In the most general sense, the broad principles of brain organization for speech and reading appear

to be largely uniform across languages. This implies, we think, that there are pervasive, perhaps universal, biological (and cognitive) constraints on how and where in the brain the reading circuit will be developed. For this reason, and especially given the existing evidence on the reading circuitry in skilled bilingual readers for L1 and L2, we suspect that the development of a reading circuitry in children will follow similar broad principles in any population of readers whether bilingual or monolingual. Differences between ELL and monolingual children learning to read English are likely to manifest in variables such as rate of acquisition; fundamental differences in functional brain organization are not

anticipated.We now turn for guidance to the extant developmental neuroimaging literature on reading development, RD, and remediation in non-ELL populations.

Neurobiological studies in English: the posterior and anterior reading

circuitry in typical development and RD

Substantial converging evidence suggests that visual word identification involves a LH posterior cortical reading system with ventral, dorsal, and anterior components (Pugh, Mencl, Jenner et al., 2000). The dorsal system includes the

angular gyrus and supramarginal gyrus in the inferior parietal lobule, and the posterior aspect of the superior temporal gyrus (Wernicke’s area). This region seems to be involved in mapping visual percepts of print onto the phonological

and semantic structures of language (Black & Behrmann, 1994; Geschwind, 1965; Price, 2000). In skilled readers, temporoparietal aspects of the dorsal system (particularly the supramarginal gyrus) respond with greater activity to pseudowords and low-frequency words than to familiar words

(Simos, Fletcher et al., 2002; Xu et al., 2001). Indeed, in beginning readers who will eventually become skilled readers, our studies suggest that the dorsal system predominates as it first learns to decode print; in RD readers this system

is disrupted (Pugh, Mencl, Shaywitz et al., 2000; Shaywitz et al., 1998, 2002). This is consistent with behavioral studies that implicate skill in the phonological analysis of speech (measured by phonological awareness tasks and pseudoword reading) as critical predictors of success in early reading

Pugh et al.: examining reading development and reading disability in ELLS 27 acquisition (Bradley & Bryant, 1985; Wagner & Torgesen,

1987).

Together, these findings suggest that the dorsal system is associated with decoding and is critical for extracting and learning the relationships between the orthography and its phonological forms (O . P), and connecting these to morphological and semantic information (Price, 2000). An anterior system centered in posterior aspects of the inferior frontal gyrus (IFG) appears to be associated with phonological recoding during reading, among other functions

(e.g., phonological memory, syntactic processing); the more anterior aspects of IFG seem to play a role in semantic retrieval (Poldrack et al., 1999). The phonologically relevant components of this multifunctional system have been

found to function in silent reading and in naming (see Fiez & Peterson, 1998 for review) and, like the temporoparietal system, are more strongly engaged by low-frequency words and pseudowords than by high-frequency words (Fiebach

et al., 2002; Fiez & Peterson, 1998), and by low-frequency words with inconsistent orthographic-to-phonological mappings (e.g., “pint”) relative to consistent words (“mill”). We have speculated that this anterior system operates in close conjunction with the temporoparietal system to decode new words during normal reading development (Pugh, Mencl, Jenner et al., 2000).

The ventral system appears to be late developing and appears to support fluent reading performance subsequent to initial instruction (Booth et al., 2001; Shaywitz et al., 2002). It includes a LH inferior occipitotemporal/fusiform area and extends anteriorly into the middle and inferior temporal gyri. It has been suggested that occipitotemporal components of this ventral system function as a presemantic visual word form area by some researchers (cf. Cohen et al., 2002, but see Price, Winterburn, Giraud, Moore, & Noppeney, 2003 for an alternative account). More anterior foci within the ventral system extending into the middle to inferior temporal gyri appear to be semantically tuned (Fiebach et al., 2002; Simos, Breier et al., 2002; Tagamets, Novick, Chalmers, &

Friedman, 2000). The ventral system, particularly the more occipitotemporal aspect, is also fast acting in response to linguistic stimuli in skilled readers, but not in RD individuals (Salmelin et al., 1996; Tarkiainen, Cornelissen, & Salmelin, 2003). Indeed, recent studies examining both timing and

stimulus-type effects suggest that moving anteriorly through this system, subregions respond to word and word-like stimuli in a progressively abstracted and linguistic manner (Tarkiainen et al., 2003).

For both children and adults with reading disabilities, there are marked functional differences with regard to activity generated in the dorsal, ventral, and anterior systems during reading (Brunswick et al., 1999; Paulesu et al., 2001; Pugh, Mencl, Shaywitz et al., 2000; Rumsey et al., 1997; Salmelin et al., 1996; Shaywitz et al., 1998, 2002). Specifically, RD readers tend to underengage the LH posterior dorsal and ventral systems used by nonimpaired readers in word and pseudoword reading; this disruption is also evident as reduced functional

connectivity among these regions during reading (Horwitz, Rumsey, & Donohue, 1998; Pugh, Mencl, Shaywitz et al., 2000). Instead, they tend to show evidence of two, apparently compensatory, responses to their LH posterior dysfunction: an increased functional role for RH posterior sites (Sarkari et al., 2002; Pugh, Mencl, Shaywitz et al., 2000; Shaywitz et al., 1998, 2002) and increased bihemispheric IFG activation (Brunswick et al., 1999; Shaywitz et al., 1998, 2002).

In our cross-sectional developmental study, we examined changes in the LH circuitry in nonimpaired and RD cohorts ranging in age from 7 through 17 (Shaywitz et al., 2002). Multiple regression analyses were employed to examine correlations between activation at different brain regions and reading skill (measured by performance on standard reading tests). The critical finding for typically developing children was that the higher the reading skill, the stronger the response in the LH ventral cortex (with several RH regions showing

age- and skill-related reductions). Thus, we argued that a beginning reader on a successful trajectory employs a widely distributed cortical system including RHtemporoparietal and frontal regions. As reading skill increases, these regions still play some role, but importantly, the LH ventral system appears to become the critical support for fluent recognition of printed (word) stimuli (see Booth et al., 2001; Turkeltaub et al., 2003 for similar findings). In contrast, for children who are RD, this pattern of ventral development is disrupted. This disruption is characterized neurobiologically by (1) poorly developed LH dorsal and ventral function, (2) increased reliance with age on the anterior system, and (3) an increased tendency with age to engage RH homologues to the dysfunctional LH posterior circuits (Sarkari et al., 2002; Shaywitz et al., 2002).

A body of evidence is accumulating suggesting that there are many commonalities in theways inwhich reading disability manifests across languages (e.g., early problems in metalinguistic processing and phonological decoding; Wimmer, 1993; Ziegler, Perry, Ma-Wyatt, Ladner, & Schulte-Korne, 2003). Given this behavioral evidence, and given the evidence for common circuits in different written languages, we might expect language-invariant neurobiological signatures to be associated with reading disability as well. The evidence to date from alphabetic languages is supportive of this expectation (Paulesu et al., 2001; Salmelin et al., 1996; Shaywitz et al., 2002). Functional disruptions in LH posterior cortex (particularly the occipiotemporal region) in RD individuals performing reading tasks during neuroimaging have been found in several languages varying in orthographic depth (English, Finnish, German, French, Italian). This common neurobiological signature, within a largely language invariant circuitry for reading in the LH, reinforces the need to understand reading development and reading remediation from a cross-linguistic perspective.

A recent study of Chinese RD readers (Siok, Perfetti, Jin, & Tan, 2004) reported a language-specific difference in the RD signature

(specifically diminished activation of middle frontal regions for RD readers relative to controls). This finding has not been reported in alphabetic languages. However, these authors also found diminished activation in RD readers at the same LH occipitotemporal region previously reported by Paulesu and others in RD within alphabetic languages (Brunswick et al., 1999; Paulesu et al., 2001; Salmelin et al., 1996; Shaywitz et al., 2002). More studies need to be done in nonalphabetic writing systems to examine the implications of both the similarities and the differences with respect to RD; such studies will be critical in establishing the generality neurobiological profiles of RD.

Special series: learning disabilities in English language learners

identifying RD in ELL populations

To the question of how neuroimaging might help to identify markers of RD within ELL populations we begin by considering the language-invariant disruption of LH ventral cortex reported thus far (e.g., Paulesu et al., 2001; Rumsey et al., 1997; Salmelin et al., 1996; Shaywitz et al., 1998, 2002).

However, because this ventral system, critical in fluent reading skills, appears to be relatively late-emerging for typically developing readers (Shaywitz et al., 2002), for beginning ELL readers (or any population of reading novices) patterns of activation in this region might not be terribly diagnostic of RD at the onset of literacy instruction. But, by measuring success or failure in training-up this system (over time) and determining how this varies with type of reading instruction focus on the ventral system might provide a means of better understanding individual differences in developmental trajectories within ELL cohorts.

The apparent disruption of LH temporoparietal regions with the corresponding RH shift during language tasks (Sarkari et al., 2002; Shaywitz et al., 2002; Simos et al., 2000) might be more diagnostic of RD, even in beginning

ELL readers, and this should be investigated carefully. The disruption of those LH temporoparietal regions critical for learning to integrate orthography, phonology, and semantics, has been observed even in beginning readers (Simos, Fletcher et al., 2002) and is evident even during performance of spoken language tasks (Rumsey et al., 1992; Temple et al., 2003). Thus, a RH shift within the temporoparietal system for L1 and/or L2 might be diagnostic of RD in ELL children even during the earliest stages of reading instruction (Simos

et al., 2002). Indeed, the degree to which adequate integration and distinctiveness is developed for the spoken forms of L1 and L2, likely depends on intact temporoparietal function from the outset; therefore, we hypothesize that anomalies in activation patterns in this system might be the key

neurobiological variable predicting success or failure in developing an optimized LH reading circuitry over time in these children. Longitudinal studies will be crucial in testing this hypothesis.

With a goal of identifying latent RD in ELL children diagnostic markers for RD outside of the language domain should be examined as well. For example, several studies have observed anomalous responses to simple visual motion detection in MT/V5 for RD readers (Demb, Boynton, & Heeger, 1998; Eden et al., 1996). This type of nonlanguage neurobiological marker might help to identify at risk children early on, even for populations where matching on language experience is not possible. In addition, many technologies are

available to examine structural and neurochemical factors in RD, and many intriguing findings and some RD markers have been reported at these levels of analysis (Klingberg et al., 2000; Habib, 2000). These sorts of neurophysiological

indices might be extremely helpful in identifying latent RD in struggling populations of ELL children, where functional imaging is complicated by performance variation.

We might also begin to search for potential anomalies in the neurobiological circuits supporting more complex cognitive operations such as attentional control, response inhibition, and verbal working memory; these domains are likely critical to success both in language switching and language integration in ELL readers. There is little guidance from the existing studies thus far on how these variables might relate to latent RD, but given the unique demands that bilingualism places on brain systems, research of this sort has real potential to broaden our understanding of ELL development in general.

Finally, beyond the question of identifying RD within LL populations, functional neuroimaging can be particularly helpful in assessing the efficacy of different approaches to the teaching of reading in ELL (Simos, Breier et al., 2002). As seen in recent remediation studies in monolinguals (Simos, Fletcher et al., 2002; Shaywitz et al., 2004; Temple et al., 2003), successful training approaches have profound effects of normalizing LH trajectories in struggling readers. Reduced RH reliance and increased LH activation following training has been seen in all of these remediation studies 1(each compared pre- and post-intervention activation pro- files). These studies converge to indicate that development of the LH posterior reading system constitutes an important

neurobiological outcome variable associated with successful instruction and remediation. Thus, functional neuroimaging might be used in this manner to help in evaluating the sorts of reading instruction that work best for ELL children whether at risk for RD or not. Finding a neurobiological signature of successful intervention/instruction (e.g., LH posterior increases) can help to discriminate between “better or worse” approaches that might all produce some transient gains in reading performance.

In conclusion, the extant cross-language research on the brain organization for speech and reading in monolingual and bilingual populations suggests that, while the rate of acquisition may differ between these populations, the development of an optimal reading circuitry in ELL children should follow a similar trajectory and a predictable course with respect to localization. Moreover, several potential neurobiological markers for RD have been identified (both language and nonlanguage based) which we believe will be helpful in

distinguishing latent RD from environmental factors in ELL children.

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About the Authors

Kenneth R. Pugh is a Research Scientist at Yale University School of Medicine (Pediatrics) and a Senior Scientist at the Haskins Laboratories, New Haven, CT. His primary research interests are in cognitive neuroscience and psycholinguistics, examining language processing for print and speech, and employing combined behavioral and functional magnetic resonance imaging

(fMRI) measures to the study of both skilled reading and reading disability (RD). Current research examines the effects of training and remediation on the developing neurocircuitry associated within reading. Dr. Pugh is director of the Yale Reading Study, an NIH-funded project examining reading development and disability in adolescence.

Rebecca Sandak is a Senior Scientist at Haskins Laboratories, NewHaven, CT. Her research focuses on understanding cognitive processes underlying skilled and impaired reading, reading acquisition, and successful reading instruction and remediation. In recent work, she has employed functional neuroimaging (fMRI) to investigate how learning conditions, reading expertise,

and reading strategies influence the cortical areas that are recruited for reading. She presently directs a research project (in collaboration with the Kennedy-Krieger Institute and ETS) evaluating behavioral and neural effects of several research-driven intervention methods for improving the reading abilities of struggling adolescent readers.

Stephen J. Frost is a Senior Scientist at the Haskins Laboratories, New Haven, CT. His primary line of research combines behavioral and functional neuroimaging methodologies toward the understanding of skilled reading and reading development. A second line of research involves exploring parallels in the processing of spoken and written language across languages and,

the extent to which spoken and written language access common phonological, orthographic, and semantic information.

Dina L. Moore is an Assistant Professor of Psychology at Southern Connecticut State University and a research affiliate at Haskins Laboratories, New Haven, CT. She completed her PhD in developmental psychology at the University of Connecticut and recently completed postdoctoral training at Haskins Laboratories. Her primary research interests are the neurobiology of reading processes and reading disabilities and long-term neuropsychological consequences of childhood trauma specifically related to language functioning.

W. Einar Mencl is a Senior Scientist at the Haskins Laboratories, New Haven, CT. His research focuses primarily on psycholinguistics, including reading, reading disability, and speech perception. He continues to develop analysis techniques to identify neural systems from neuroimaging data.