Virginia W. Berninger & H. Lee Swanson
Overview of chapter
This chapter begins with discussion of longstanding debates about defining and treating specific learning disabilities (SLDs). The chapter continues with review of programmatic research over three decades in which the chapter co-authors collaborated, with focus on SLDs in written language (SLDs-WL), that is, literacy learning (reading and writing) for which oral language (listening and expression) is also relevant. Issues covered in the chapter are related to (a) defining, identifying, and differentially diagnosing SLDs-WL and (b) teaching affected individuals with SLDs-WL. Rather than drawing on diagnostic manuals designed for use in medical and clinical settings, in contrast, this interdisciplinary, programmatic research was designed and conducted for the goals of preventing, identifying, and remediating SLDs-WL in school settings and translating the research into practice by interdisciplinary teams in school settings (Berninger, 2015).
To begin with, the authors explain how the construct of levels of language (increasing units of received or produced language) has informed this research on both language acquisition and the role of verbal Working Memory in supporting language learning. Next, research is presented on the three word forms that may be coded into Working Memory for temporary storage and processing, the two loops for interactions between internal codes and acts in the external environment, and the Executive Functions for mental government of the components of Working
Memory as they support language learning. Then a model is presented in which multi-component Working Memory supports the language learning mechanism as it functions in the present (current input and output) with connections with both the past (long-term memory) and future (goals, plans). Finally, SLDs-WL, which may include disabilities at multiple levels of language, are defined and research-supported instructional design principles are reviewed for preventing, diagnosing, and treating SLDs-WL. The chapter ends with discussion of ongoing controversies about whether literacy instruction or Working Memory instruction or literacy instruction informed by Working Memory components in the language learning mechanism best supports literacy achievement in students with SLDs-WL.
Diagnostic features
Although several issues related to SLD have been debated in the literature, this chapter focuses on just two, which are relevant to making the case for the approach that is featured in this chapter. The first issue is whether cognitive abilities of the learner are relevant to identification of SLDs. Some studies suggest that full scale intellectual functioning is irrelevant to defining SLDs (e.g., for review, see Stanovich & Siegel, 1994; see Hoskyn & Swanson, 2000). These conclusions are based on findings showing that poor readers with low full scale cognitive ability do not differ significantly from readers whose reading achievement is discrepant from their full scale cognitive ability (e.g., for review, see Hoskyn & Swanson, 2000).
Swanson (2011) proposed a reason for these findings, namely that procedures used to assess cognitive abilities may not place high demands on Working Memory or Executive Fun ctions and SLDs are related to weaknesses in Working Memory and Executive Fun ctions. In this chapter, another approach, which is evidence-based, is described in which a specific kind of cognitive ability, verbal reasoning, is used to predict expected reading or writing achievement and it is conceptualized as a measure of higher-level Executive Function for translating cognitions into oral language that is relevant to literacy learning as supported by the multiple components of verbal Working Memory. As will be explained, an SLD is not defined by subtracting a single reading achievement score from a full scale cognitive ability score to identify a discrepancy; however, one kind of cognitive ability—verbal reasoning, which is interpreted as high level Executive Function—is relevant to predicting expected achievement, when measures of Working Memory components are also included.
The second issue is related to whether the neurocognitive characteristics of the learner are relevant to planning and implementing instruction, and evaluating response to instruction. A number of studies have suggested that the cognitive or neuropsychological characteristics of the sample with SLD have minimal influence on effective treatment procedures (e.g., Burns et al., 2016; Stuebing, Fletcher, Branum-Martin, & Francis, 2012). Likewise some studies have suggested that using response to instruction (RTI) as the criterion for differentiating students who have SLD from other students tends to use a “one-size-fits-all” approach to designing,
implementing, and evaluating intervention and the non-responders may or may not have SLD (e.g., Balu, Zhu, Doolittle, Schiller, Jenkins, & Gersten, 2015; Tran, Sanchez, Arrelano, & Swanson, 2011). In this chapter an approach, based on behavioral assessment, genetics, and brain research, is described in which SLDs are identified by assessing profiles of reading and writing skills and components of Working Memory supporting language learning. This approach informs individual - izing instruction in literacy (reading and writing) for variations in SLDs-WL and evaluating response to that intervention related to the nature of the specific literacy or Working Memory impairments.
What is Specific Learning Disability in written language?
Levels of language in functional language systems and Working Memory
Despite the widely used phrase “language, reading, and writing”, reading and writing are also language; and what is referred to as language is both aural (heard) and oral (spoken). That is, there are four language systems: language by ear (listening), language by mouth (oral expression involving speech but many other processes as well), language by eye (reading), and language by hand (writing), all of which are separable in development and their brain bases yet learn to work together (Berninger, 2015). For example, learning to write draws on (a) what is learned through listening to conversation with others (informal language register) and instructional talk by teachers (academic register); (b) what is generated by thinking aloud while planning or translating or in covert speech before producing written language; or (c) what is shared by an author orally reading for others what was has been written as in author’s chair and discussing one’s writing with peers (Berninger, 2000). Learning to write is also highly related to connections between common subword level and word level units of language in spoken/heard and read/written words and to reading what one has written as one reviews what is written and may revise (Berninger, Abbott, Abbott, Graham, & Richards, 2002; Berninger, Abbott, Jones, et al., 2006a).
Each of the four language systems is multi-leveled, that is, has multiple units of language of increasing size. Analyses of language profiles of developing writers in cross-sectional studies of typical language learners in elementary school showed intra-individual differences in relative strengths and weaknesses across these cascading levels of language on word tasks, sentence tasks, and text tasks (Whitaker, Berninger, Johnston, & Swanson, 1994).
In a subsequent overlapping cohorts longitudinal study of typical language learners, language profiles were assessed when the first cohort was in second grade and again in fourth grade and the second cohort was in fourth grade and again in sixth grade (Berninger et al., 2010). Also administered were measures of Working
Memory organized by levels of language which required storage and processing of words or storage and processing of sentences (Swanson, 1995a,b,c). First the unit of language was presented, then a question was posed to assess processing, and then the task was to repeat the word or sentence to assess storage. Structural equation modeling with two Working Memory factors (word-level of language and sentence-level of language) and separate literacy outcome factors (word reading, reading comprehension, handwriting, word spelling, and composition) were used to examine the relationships between Working Memory at two different levels of language and literacy outcomes. Results showed that (a) word-level Working Memory explained unique variance in each reading or writing outcome in second grade; (b) word-level Working Memory explained unique variance in all word reading and all writing outcomes, and sentence-level Working Memory explained unique variance in reading comprehension in fourth grade (when the two cohorts overlapped); and (c) word-level Working Memory explained unique variance in word reading and word spelling, and sentence-level Working Memory explained unique variance in reading comprehension in sixth grade, but both Working Memory predictors were highly correlated in predicting handwriting and composing and neither explained unique variance in these writing outcomes.
Prior cross-sectional research on typically developing writers had also documented a relationship between handwriting (referred to as a transcription skill) and composing (referred to as a translation skill) (Abbott & Berninger, 1993) and the importance of handwriting in beginning and developing writing (Berninger &
Swanson, 1994). A synthesis of a number of studies showed that composing benefits from transcription skills (handwriting in particular) being automatic to free up limited Working Memory resources for the more demanding tasks of planning, translating, reviewing, and revising (Berninger, 1999; Berninger, Whitaker, Feng, Swanson, & Abbott, 1996). Further studies provided additional, converging evidence for individual differences in Working Memory being related to individual differences in children’s writing (Berninger et al., 2006b; Swanson & Berninger, 1996a, 1996b).
Concurrent with this cross sectional and longitudinal research on typical language learners, research studies were initiated on SLDs-WL, first by screening for the lowest achieving writers and readers in school settings, then by partnering with schools to refer their struggling writers and readers to the university for summer or after school intervention programs, and finally through a multigenerational family genetics study of dyslexia followed by a study of persisting SLDs-WL—writing and reading—in upper elementary and middle school despite earlier interventions.
Through these research studies we initially studied the word-level coding of Working Memory and more recently the syntax-level coding of Working Memory, the loops of Working Memory that enable internal Working Memory to interact with the external environment that nurtures language learning, and the mental government that regulates the multiple components of Working Memory. What was learned is presented next to provide a conceptual framework for current research on defining and treating SLDs-WL. This framework is specific to language (verbal
Working Memory) and not other kinds of learning such as quantitative concepts and visual spatial dimensions of math.
Working Memory (WM) and related Executive Function (EF) deficits
Three word forms for storage and processing in verbal Working Memory
English is a morphophonemic orthography (Venezky, 1970, 1999; Henry, 2010;
Nunes & Bryant, 2006). That is, words that are heard or spoken can be coded into Working Memory as phonological word-forms for storage and processing;
phonological word forms can be assessed using normed measures for listening to pronounced pseudowords without meaning and then reproducing them by saying them with all sounds, stress patterns, and the intonation correct. Words that are read or written can be coded into Working Memory as orthographic word-forms for storage and processing. Orthographic word forms can be assessed using normed measures for viewing a briefly displayed written word or letter string and then answering questions about the ordering of all the letters, a letter in a designated position, or a letter group in a designated position; none of the letters have a single corresponding sound or any sound so answers depend on specific letters. Both phonological and orthographic word-forms may also have morphological codes, that is, affixes after the base word that mark number or tense or grammar function or before the base word that qualify meaning; morphological word-forms can build bridges (connections) between phonological and orthographic codes because they occur in each. Each of the three word forms has also been assessed with tasks participants perform during brain imaging.
Because English is a morphophonemic orthography, it is not surprising that both the behavioral assessment with normed measures and brain imaging findings provided converging evidence that there are phonological, orthographic, and morphological codes for single words in Working Memory (Berninger & Richards, 2010; Richards et al., 2006). In addition, the studies provided evidence for a pattern analyzer in the episodic buffer that abstracts phonotactic, orthotactic, and morphotactic knowledge about identity, position, and sequence of component letters of these word forms (Berninger, Fayol, & Alamargot, 2012).
Storage and processing for accumulating words and syntactic structures
Words accumulate over time and are syntactically coded for order, which is language specific. Syntax coding also differentiates content words, for example, nouns, verbs, adjectives, and adverbs that correspond to cognitive constructs, and function words, such as prepositions, conjunctions, pronouns, and articles that have no meaning of their own but contribute to sentence meaning via the relationships
they create among the other words in the sentence. Coding multiple syntactic units over time is coordinated by Executive Functions of Working Memory that sustain processing over time and coordinate the cross-domain translation processes of language into cognition and vice versa (see Berninger, Swanson, & Griffin, 2014).
Both behavioral studies (Abbott, Berninger, & Fayol, 2010; Berninger & Abbott, 2010) and brain imaging studies (Richards, Nagy, Abbott, & Berninger, 2016) have provided evidence for syntax as well as word level skills.
Neurological profile
Two loops for interactions of internal codes with acts in the external environment
Building upon the seminal insights of Baddeley, Gathercole, and Papagno (1998) that the phonological loop is fundamentally a language learning device, multidisciplinary investigations of the phonological loop, operationalized as rapid automatic naming of rows of letters (RAN) were conducted at the genetics level of analysis (Rubenstein, Raskind, Berninger,, Matsushita,, & Wijsman, 2014), behavioral level of analysis (Brooks, Berninger, Abbott, & Richards, 2011), and brain level of analysis (Richards & Berninger, 2008). RAN assesses the ability to name (integrating internal code for names for output through language by mouth at the word level of language with internal code received through sensory input from the external environment via language by eye).
The orthographic loop, operationalized as rapid automatic alphabet writing (Alphabet 15 seconds), that is, the number of legible letters in alphabet order in the first 15 seconds of writing the alphabet from memory, was also investigated at the genetics level of analysis (Abbott, Raskind, Matsushita, Richards, Price, &
Berninger, 2017), behavioral level of analysis (Berninger & Richards, 2010; Brooks et al., 2011), and the brain level of analysis (Richards, Berninger, & Fayol, 2012).
The brain studies showed that letter writing is not a pure motor skill but rather involves internal orthographic coding (the mind’s eye) (Richards, Berninger, Stock, Altemeier, Trivedi, & Maravilla, 2011). The internal orthographic codes are integrated alone or together with internal codes for letter names or sounds received from the external world through language by ear with the internal codes for motor output via language by hand of letter forms. Importantly, it is motor planning for sequential finger movements involved in letter formation stroke by stroke that also plays an important role in orthographic loop function along with orthographic coding (Richards, Berninger, Stock, Altemeier, Trivedi, & Maravilla, 2009a). Both the phonological and orthographic loops may thus play important roles in the integration of incoming sensory input with motor coding for output via the mouth and/or hand for written language codes and thus learning to read and write. Only when both the phonological loop and the orthographic loop were exercised during instruction did phoneme processing in brain normalize after intervention (Richards & Berninger, 2008).
Executive functions for mental government of working memory
Swanson provided evidence for the role of Executive Functions in Working Memory in children with reading (e.g., Swanson, 1993a,b; 1999, 2000, 2006;
Swanson, Cochran, & Ewers, 1989; Swanson, Howard, & Sáez, 2006), math (e.g., Swanson & Beebe-Frankenberger, 2004; Swanson & Sachse-Lee, 2001) and writing difficulties (e.g., Hoskyn & Swanson, 2003; Swanson & Berninger, 1996a).
A distinction has been made between the Executive Functions that self-regulate Working Memory and the Executive Functions which are supported by Working Memory, as explained next.
Lower-order Executive Functions in Working Memory
Miyake, Friedman, Emerson, Witzki, Howerter, and Wager (2000) contributed to the reframing of the central executive of Working Memory as three separable Executive Functions: inhibition, mental set shifting, and monitoring and updating.
To operationalize inhibition a Stroop test was used which required naming color words printed in ink color inconsistent with the color word name. To operational - ize mental set shifting, Rapid Automatic Switching (RAS) tasks developed by Wolf (1986) that require naming of constantly switching categories of stimuli (letters and numerals) were used. To operationalize monitoring and updating, the number of repetitions during a verbal fluency (word finding) task was assessed as an indicator of break down in self-monitoring. Results showed that individuals with dyslexia varied in which of these Executive Functions they were impaired (Berninger, Abbot, Thompson, et al. 2006b). Genetics studies identified a genetic basis for switching attention (mental set shifting) (Rubenstein et al., 2014). A brain imaging study employing the n-back paradigm, which requires self-monitoring over time (decide if what you saw n slides before is what you are seeing now) showed that students with dyslexia performed significantly worse than the controls without dyslexia on this Working Memory task (Richards et al., 2009b).
Higher-order Executive Functions supported by Working Memory
Berninger et al. (2014) differentiated between lower-level Executive Functions and higher-level Executive Functions. The lower-level Executive Functions provide mental self-government for coordinating the components of Working Memory, which in turn support the higher-order Executive Functions, for example, for integrating reading and writing when taking notes on source material and then writing reports or summaries of those notes (Altemeier, Jones, Abbott, & Berninger, 2006). For writing these higher-order Executive Functions include idea generating, planning, goal setting, reviewing, and revising. Brain scanning during idea generating showed Blood Oxygenated Level Dependent (BOLD) response in middle frontal gyrus, a brain region associated with Working Memory functions (Berninger, Richards, et al., 2009b). All the sensorimotor, language, cognitive, social/affective,
and attention processes involved in writing rely on Executive Functions within Working Memory or are supported by Working Memory to coordinate them (Berninger & Richards, 2012). For example, inhibition is important for not being distracted by nearby written words in order to focus on the relevant target word during a fixation (Yagle et al., 2017). Switching attention is especially important in managing changing focus sequentially across one- and two-letter graphemes in a written word (Thomson et al., 2005). Sustaining attention may be more important in staying on task until a writing assignment is completed (Altemeier, Abbott, &
Berninger, 2008; Amtmann, Abbott, & Berninger, 2008). For those with co- occurring ADHD, which is most common in dysgraphia, strategies are needed for paying attention to sequential components in letter production (Richards, Abbott,
& Berninger, 2016).
Understanding multi-component Working Memory in language learning mechanism
Recent research supports a conceptual framework in which multi-component Working Memory supports the language learning mechanism that underlies development of aural language, oral language, reading, and writing and their interrelationships. Both in typically developing language learners (Niedo, Abbott,
& Berninger, 2014) and those with specific learning disabilities in written language (writing with or without co-occurring reading problems) (Sanders, Berninger, &
Abbott, 2017) the Working Memory components—three word forms, two loops, and lower-level Executive Functions for supervisory attention explained additional variance beyond the Verbal Comprehension Index and more variance than did Verbal Comprehension Index in literacy outcomes across levels of language.
Interventions
Treating SLDs-WL (language by hand and language by eye)
Challenges in defining Specific Learning Disabilities in written language—writing and reading (SLDs-WL)
One approach to defining learning disabilities has been dynamic assessment, that is, first teach the struggling student and then assess how the student responds (Swanson, 1992, 1995c, 1999). Examination of response to instruction for at-risk low achievers in writing and reading supported differential diagnosis of learning disabilities (Berninger, 2008). Comprehensive assessment of learning profiles and phenotype profiles also support differential diagnosis of SLDs-WL (Berninger, Richards, & Abbott, 2015). Molecular genetics research has also shown that three SLDs-WL (dysgraphia dyslexia, and OWL LD), all of which have associated writing impairments differ in genetic markers (alleles) associated with them (Abbott et al., 2017).