Thursday, July 11, 2019

Working memory profiles of children with dyslexia, developmental language disorder, or both

Gray et al. (2019). Working memory profiles of children with dyslexia, developmental language disorder, or both. JSLHR, 62, 1839-1858.

The ability to briefly hold information in mind and manipulate it is referred to as Working Memory. Working memory supports the completion of complex cognitive tasks in the moment. As we complete a task, we often have to remember some piece of information and add to it or change it as we go. Working memory supports this kind of work. It has been suggested that working memory supports both language learning and reading skills. Evidence showing an association with working memory has been demonstrated for both those with deficits in language learning known as Developmental Language Disorder (DLD) and those with dyslexia, a reading disorder usually attributed to a phonological processing deficit. Nevertheless, not all children with these disorders have been found to have a working memory impairment.

The purpose of this study was to systematically explore the relationship between working memory functioning and profiles of DLD and dyslexia. Children in grade 2 who either had DLD, dyslexia, both DLD and dyslexia, or typical development completed standardized tests of language, vocabulary, word reading, nonverbal intelligence, and others. The participants also completed a battery of working memory measures tapping storage and manipulation of information with auditory nonverbal, visual nonverbal, and number-based stimuli. The working memory battery also included storage-only tasks with either verbal or nonverbal stimuli, and tasks requiring binding of material that was either phonological or visuo-spatial, or both. Findings revealed that working memory profiles were not consistently associated with diagnostic category. That is, low (and high) working memory profiles occurred in children in the typically developing group, as well as in the DLD, dyslexia, and DLD/dyslexia group.

The authors argued that assessing working memory could contribute to the understanding of an individual child’s profile of strengths and weaknesses, which could help to direct intervention.

Blogger: Lisa Archibald

Thursday, May 30, 2019

Rehearsal Effects in Adult Word Learning

Kaushanskaya, M., & Yoo, J. (2011). Rehearsal effects in adult word learning. Language and Cognitive Processes, 26(1), 121-148. doi:10.1080/01690965.2010.486579

Imagine you were trying to learn some useful Spanish words before travelling to Spain. You might start rehearsing the phrase ‘buenos días’ over and over again. This is one type of strategy people automatically use when learning new (foreign) words. By rehearsing the words, the novel phonological word form (speech sounds) is kept active in our minds using what’s called, ‘working memory’. Eventually, the word form is encoded (entered and stored) in long-term memory. There are two ways we might rehearse a word: (1) subvocal rehearsal (i.e., silent), that is just saying it in your head but not aloud and not moving your mouth, and (2) vocal rehearsal, that is saying the word out loud.  One of the goals of this study was to better understand how each of these processes support the learning of new words. Further, foreign words may contain sounds and/or sound structures that do not occur in English, such as /x/ in the Spanish word ‘ojo’ (meaning ‘eye’). Another goal of the study was to investigate how English-like words would benefit from rehearsal differently than words that contain non-native sounds. The also study wanted to examine how meaning is associated with learning novel words. This is important because learning a new word involves knowing both the phonological form and its associated meaning. Returning to the ‘buenos días’ example, it might be helpful to know that this means ‘good morning’ in English so that you can use it to greet people in the morning and not at night.

Across two experiments, adults who spoke only English learned novel words that followed the English structure (phonologically familiar) in Experiment 1 and novel words that contained non-native sounds (phonologically unfamiliar) in Experiment 2. Each word was paired with an English translation. Within each experiment, half of the words were learned through vocal rehearsal and the other half through subvocal rehearsal. Learning was assessed indirectly, that is, participants would hear the novel word and had to recall the English translation (recall task) or choose the correct English translation from five alternative words (recognition task). Testing was done immediately and one week later.

The results indicate that vocal rehearsal was beneficial for phonologically familiar words while subvocal rehearsal was beneficial for phonologically unfamiliar words when tested immediately. Interestingly, there was no difference at delayed testing, with weak rehearsal effects at minimum. The authors conclude that different rehearsal strategies may support learning in different ways. When saying aloud novel phonologically familiar words, this may highlight similarities between structures of novel words and English, and thereby, increase the learner’s ability to rely on native-language knowledge during learning. In contrast, saying aloud novel phonologically unfamiliar words may highlight differences and deter learning. Instead, silent rehearsal of phonologically unfamiliar words might be beneficial as it may not make such differences salient, and thereby, increase reliance on native-language knowledge. Findings from this work serves as an important first step into understanding mnemonic strategies that can potentially lead to better word learning and help create stronger links with long-term memory. Results must be interpreted with caution, however, given that the effects were observed for immediate but not long-term recall.

Blogger: Theresa Pham is a student in the combined SLP MClSc/PhD program, supervised by Dr. Lisa Archibald.

Learning and Overnight Retention in Declarative Memory in Specific Language Impairment

Lukács, Á., Kemény, F., Lum, J. A., & Ullman, M. T. (2017). Learning and overnight retention in declarative memory in specific language impairment. PloS one, 12(1), e0169474.

Memory is divided into a long-term memory system and a working memory system. Research has demonstrated that children with developmental language disorder (DLD; also referred to as specific language impairment) have poor working memory which means they have difficulty holding and manipulating information in mind that they have just received. There has been less research examining the long-term memory system in children with DLD. The long-term memory system has two types of memory; procedural and declarative memory.  Procedural long-term memory is our knowledge of how to do something such as ride a bike or tie our shoes and declarative memory is a type of long-term memory used for recalling facts, knowledge, events, and words.
The present study examined the role of declarative memory in children with DLD. The researchers assessed both immediate learning (10-minute delay) and retention (1-day delay) using nonverbal stimuli (seeing pictures of objects) and verbal stimuli (hearing words). Children who were typically developing and children with DLD were asked to complete a recognition task that was used to assess declarative memory. The recognition task was a judgement task where the participants had to indicate if they had seen or heard the item before. Participants first completed an encoding phase where they were presented with 32 real and 32 novel items. This was completed for both nonverbal and verbal stimuli. They completed the judgement task 10-minutes after the encoding phase and again 1-day after the encoding phase.

The researchers found that for nonverbal stimuli the typically developing children showed no change in accuracy between the 10- minute delay and the 1-day delay but children with DLD were significantly more accurate at the 1-day delay compared to the 10-minute delay. The typically developing children performed significantly better than the children with DLD when tested after the 10-minute delay but there was no difference between groups at the 1-day delay. This result indicates that after some consolidation the children with DLD were more accurately able to identify nonverbal items seen before. For verbal items, typically developing children performed better than children with DLD and they did not find the same trend of better performance in the DLD group at the 1-day delay. This result was not surprising since children with DLD are known to have difficulty with word learning.

These results would suggest that children with DLD have consolidation strengths in declarative memory, specifically for non-verbal items. This finding demonstrates the importance of consolidation and sleep for learning new objects. It would suggest that time for consolidation might be important when determining what a child with DLD has learned.

Blogger: Meghan Vollebregt is a student in the combined SLP MClSc/PhD program working under the supervision of Dr. Lisa Archibald.

Tuesday, April 30, 2019

Mathematical thinking in children with developmental language disorder: the role of pattern skills and verbal working memory

Fyfe, E.R., Matz, L.E,, Hunt, K.M., & Alibali, M.W. (2019). Mathematical thinking in children with developmental language disorder: the role of pattern skills and verbal working memory. Journal of Communication Disorders, 77, 17-30.

This paper examines the role of pattern skills and verbal working memory in mathematics performance in children with developmental language disorder (DLD). Growing evidence suggests that children with DLD have difficulty on mathematics tasks such as counting and arithmetic (see Cross, Joanisse & Archibald, 2019, for a review). Working memory and pattern skills are both known to be associated with mathematical abilities. Some previous studies have identified difficulties with verbal working memory in children with DLD, as well as difficulties learning implicit patterns in statistical learning tasks. The aim of the study was to examine how working memory and pattern skills might contribute to differences in mathematics performance in children with DLD and typically developing (TD) children.

Participants were 36 children aged 6 to 13 years old, eighteen of whom had been identified with DLD. Children completed a battery of tasks assessing verbal working memory, pattern extension, math calculation, and knowledge of math concepts. Verbal working memory was assessed using the Competing Language Processing Task, in which children answered yes/no questions about sentences while also holding the last word of each sentence in memory. In the pattern extension task, children were given 7 elements which varied in shape and size and were asked to identify the 8th shape and explain their reasoning for selecting that shape. The math tasks consisted of math problems involving standard arithmetic (e.g. 2 + 4 + 5 + 2 = __ ), inversion ( e.g. 4 + 7 – 7 = __ ), and equivalence (e.g. 3 + 4 + 6 = 3 + __ ). For each math problem children were asked to explain their strategy, and the authors coded these responses based on whether they demonstrated conceptual understanding of inversion and equivalence.

The authors first used logistic regression to examine differences between the TD and DLD groups on each of the behavioural tasks. They found that, relative to the TD group, the group with DLD performed more poorly on each type of math problem and on the verbal working memory task, but performed similarly on the pattern extension task. A hierarchical regression was then used to examine how math calculation and knowledge of math concepts might each be predicted by pattern extension and working memory. Working memory accounted for some differences in calculation and concepts scores however it did not uniquely predict variance beyond the variance predicted by the group variable. Pattern extension performance did not predict concept scores but uniquely predicted calculation scores, above and beyond the variance predicted by group, age, non-verbal IQ, and working memory.

Overall, these findings suggest that some aspects of poor math performance in DLD may be related to verbal working memory capacity. Additionally, the ability to recognize patterns may support recognition of rules in number sequences, facilitating calculation skills in both TD children and children with DLD. Importantly, the authors acknowledge that their regression models accounted for less than half of the variance in calculation skills and concept knowledge, which suggest there any many other factors that may be contributing to development of mathematics knowledge. In general, these findings highlight that the linguistic and working memory-related factors in DLD can impact performance in many academic areas, despite other intact cognitive processes, including patterning.

Blogger: Alex Cross is an M.Cl.Sc. and Ph.D. Candidate in Speech-Language Pathology, supervised by Dr. Lisa Archibald and Dr. Marc Joanisse.

Tuesday, February 12, 2019

Describing language assessment for school-aged children: A Delphi study

Denman, D., Kim, J., Munro, N., Speyer, R., & Cordier, R. (2018). Describing language assessment for school-aged children: A Delphi study. International Journal of Speech-Language Pathology, 1-11.

The recent CATALISE studies reported a consensus for identification and terminology for children with persistent language difficulties with a significant functional or educational impact. A number of important questions follow on from the consensus statement. The purpose of this statement was to investigate the different types or purposes of language assessments completed by speech-language pathologists (SLPs).

Informed by current evidence and conversation, the researchers developed a taxonomy for assessment that included (1) modality/domain, (2) purpose, (3) delivery, and (4) form. A group of 55 Australian SLPs agreed with this taxonomy on each of 2 rounds of a Delphi survey. In rounds 2 and 3 of the survey, participants were also asked to assign categories based on the taxonomy for 2 case studies. Although lower, agreement for these categorizations reached the established consensus target. SLPs often went beyond the details of the case to explain how one aspect of assessment could fit different categories.

The taxonomy reveals the multiple purposes and types of assessments completed by SLPs. SLPs often move flexibly across assessment purposes and types in order to address questions arising in an assessment.

Blogger: Lisa Archibald

Sunday, January 20, 2019

The Role of Nonverbal Working Memory in Morphosyntactic Processing by Children with Specific Language Impairment and Autism Spectrum Disorders

Weismer, S. E., Davidson, M. M., Gangopadhyay, I., Sindberg, H., Roebuck, H. & Kaushanskaya, M. (2017). The role of nonverbal working memory in morphosyntactic processing by children with specific language impairment and autism spectrum disorders. Journal of Neurodevelopmental Disorders, 9(28). doi: 10.1186/s11689-017-9209-6.

The grammar of a language refers to the rules for how we put words and sentences together. One part of grammar is called morphology and refers to the smallest units of meaning in a language. Take, for example, the word ‘jumped’. Jumped has 2 meaningful units or morphemes – the action, jump, and the past tense marker that tells us the action is already over, -ed. Morphemes like ‘-ed’ are called inflectional morphemes, and there are a lot of them in the English language. Like ‘-ed’, some are bound to verbs to signal tense (when something is happening) or agreement (between the subject and verb of a sentence as in he jumps vs. they jump). Others mark nouns as plural (e.g., cups), possessive (e.g., Jill’s), etc. Children with a developmental language disorder (DLD; also known as specific language impairment) have difficulty learning these inflectional morphemes. Some studies also suggest that children with autism spectrum disorder (ASD) have the same kind of trouble with learning morphology.

Both children with DLD and ASD are also reported to have poor working memory. Working memory is a difficulty holding and manipulating information you’re thinking of in the moment. According to one theory, having poor working memory might make it difficult to learn language. If that’s the case, we would expect language tasks to be harder when more language is involved, for example, when sentences are long or complex. If a language error happens early in a sentence when there’s not much to hold in memory, it would be easy to detect the error even if working memory is poor. If a language error happens late in the sentence, however, someone with poor working memory would have a hard time remembering the whole sentence and catching the error. There’s another theory, though, that says that understanding the ends of sentences might be easier. According to the ‘wrap up’ theory, errors occurring later in a sentence will be more easily detected because there is more information or context available later in a sentence to help the child process and notice errors in grammar.

In this study, children who were typically developing or had DLD or ASD completed tests of working memory (for information unrelated to language) and grammar. The grammar test was a “grammatical judgement task” and involved the children listening to a sentence and deciding if that sentence contained any errors in grammar or not. The grammar errors were either close to the beginning or the end of the sentence. The researchers found that the typically developing, DLD and ASD groups did not differ on the test of working memory. On the grammatical judgement task, the researchers found that children with typically developing language skills were better at detecting grammar errors than children with DLD. This result is not surprising considering that children with DLD are known to have difficulty learning the inflectional morphemes that were used as the grammatical errors. As well, all children were better and faster at detecting grammatical errors late in a sentence than those occurring early in a sentence. This finding supports the “wrap-up” account. It suggests that the information in a sentence may help a child to make sense of that sentence and to notice any errors that may exist.

The results of this study suggest that context helps. That is, important details are best provided once a child understands the topic or context being discussed. It might suggest that the strategy of ‘Keep It Short and Simple’ may not be the best strategy for all children. Some children might benefit from having sufficient information to support their understanding.

Blogger: Alyssa Kuiack is a M.Cl.Sc./PhD candidate, in speech-language pathology, working under the supervision of Dr. Lisa Archibald.

Friday, December 7, 2018

Strategy use fully mediates the relationship between working memory capacity and performance on Raven’s matrices

Gonthier, C., & Thomassin, N. (2015). Strategy use fully mediates the relationship between working memory capacity and performance on Raven’s matrices. Journal of Experimental Psychology: General, 144, 916-924.

Working memory capacity (WMC) refers to the amount of information that can be held briefly in mind for processing. Working memory capacity is closely associated with fluid intelligence, the ability to think logically and solve problems in novel situations. It has been suggested that working memory capacity and fluid intelligence are related because they both rely on controlled attention, the ability to direct one’s attention to relevant information and away from irrelevant information. It may be, however, that the ability to use strategies to support working memory drives the relationship between working memory capacity and fluid intelligence. Strategies are procedures that facilitate the achievement of a higher level goal or task.

The purpose of this study was to examine the extent to which strategy use may influence performance on a common fluid intelligence measure. In the fluid intelligence task, the person is shown an incomplete matrix that follows logical rules along with 8 possible pieces to complete the matrix. The person chooses the piece that completes the matrix. One effective strategy that can be used to complete this task, constructive matching, is to create a mental representation of the answer and then look for a match among the alternatives. A less effective strategy, response elimination, consists of comparing the features of the problem and each alternative response until one answer is identified. In study 1, university students were asked to complete the matrix reasoning task either without instruction (control) or after receiving instruction on the use of the constructive matching strategy. It was hypothesized that if strategy use accounts for the relationship between working memory capacity and fluid intelligence, then the relationship between these two constructs should decrease when participants are not using their strategy of choice. The results were consistent with this hypothesis in that the relationship between WMC and matrix reasoning was lower in the group instructed on a particular strategy. In study 2, participants were asked about their strategy use after completing the task (which was completed without instruction on strategy use). Results revealed that the relationship between WMC and matrix reasoning was mediated by strategy use.

The findings suggest that strategies play a critical role in the relationship between working memory and fluid intelligence. Teaching strategies to support working memory may be effective in supporting reasoning.

Blogger: Lisa Archibald

Thursday, November 8, 2018

Relations Among Socioeconomic Status, Age, and Predictors of Phonological Awareness

McDowell, K. D., Lonigan, C. J., & Goldstein, H. (2007). Relations among socioeconomic status, age, and predictors of phonological awareness. Journal of Speech, Language, and Hearing Research, 50(4), 1079-1092.

There are many individual differences that influence a child’s ability to learn to read. For example, the ability to identify or manipulate sounds in words known as phonological awareness has been found to be strongly related to reading success. McDowell and colleagues consider why phonological awareness skills may differ across individuals by examining two hypotheses. First, the phonological deficit hypothesis which holds that children with poorly established phonological representations will have difficulty with phonological awareness tasks. The second is the lexical restructuring model which describes a child’s phonological awareness skill as a function of their vocabulary. In other words, as a child’s vocabulary grows, they develop more sophisticated spoken word recognition skills, and this allows them to break down a word which makes the phonemic units of the words more accessible. This study involved the examination of the extent to which phonological awareness skills were explained by performance on measures related to these two hypotheses (speech sound accuracy and vocabulary, respectively) as well as the child’s age and socioeconomic status.

Preschool participants between the ages of 2 and 5 years old completed a wide range of speech and language assessments to capture phonological awareness skill, vocabulary and speech sound accuracies. Results revealed that speech sound accuracy, vocabulary, SES, and age each contributed unique variance to the prediction of phonological awareness skill. The authors concluded that since speech sound accuracy and vocabulary both explained phonological awareness that these results support both the phonological deficit hypothesis and the lexical restructuring model. Further analyses revealed that age moderated the relationship between speech sound accuracy and phonological awareness.  These results indicated that as children get older the continued occurrence of speech sound inaccuracies more strongly predicts poor phonological awareness skills.

This research illustrates the complexity that individual differences bring to predicting a child’s ability to learn to read. Further, the results emphasize the need to build both vocabulary knowledge and good quality of phonological representations of known words.

Blogger: Meghan Vollebregt is a student in the combined SLP MClSc/PhD program working under the supervision of Dr. Lisa Archibald.

Tuesday, October 16, 2018

Sequential prediction of literacy achievement for specific learning disabilities contrasting in impaired levels of language in Grades 4 to 9

Sanders, E.A., Berninger, V.W., Abott, R.D. (2017). Sequential prediction of literacy achievement for specific learning disabilities contrasting in impaired levels of language in grades 4 to 9. Journal of Learning Disabilities, 51(2), 137-157.

Do you ever think about your thinking, and try to explain it? The process of ‘translating’ your cognitive or thinking skills using language (or linguistic representations) is known as cognitive-linguistic translation. Cognitive-linguistic translation has been associated with reading and writing outcomes in typically developing children, possibly because reading and writing place demands on both our cognitive and linguistic skills (Niedo et al., 2014).

Working memory refers to the ability to briefly store and manipulate information in mind. Working memory has also been found to be related to reading and writing achievement. This study considers a number of proposed subcomponents of working memory:

  • word-form coding, which involves storing and processing information about the sounds (phonology), written letters (orthography), and meaning units (morphology) of a word 
  • phonological loop, which stores the phonological forms of words, and is important in naming visual objects or reading words (orthographic forms) 
  • orthographic loop, which stores representations of written letters and words (orthography), enabling the sequential finger movements that are required for writing letters or words; 
  • supervisory attention and executive functions, which refers to the ability to focus (or regulate) attention to relevant information and switches the focus of attention as relevance changes.

The aim of the study was to examine the relationship between cognitive-linguistic translation and working memory subcomponents to reading and writing in children with specific learning disabilities, including dysgraphia (handwriting impairment), dyslexia (word reading and spelling impairment), and oral and written language impairment.

Children in grades 4 to 9 completed a large battery of achievement tests measuring multileveled reading, writing, and language achievement, to assign participants to the dyslexia, dysgraphia, and oral/written language impairment groups based on which group best characterized their specific learning disability. Participants also completed a number of tasks measuring cognitive-linguistic translation, word-form coding at the phonological, orthographic, and morphological levels, phonological loop, orthographic loop, and executive functions including focused attention and switching attention.

The authors used a sequential multiple regression to examine how working memory components and cognitive linguistic translation predicted academic achievement. The results showed that while cognitive-linguistic translation accounted for a significant percentage of variation in reading and writing achievement, all of the working memory components accounted for additional unique variance in reading and writing achievement. With respect to writing achievement, a lower percentage of variance was accounted for by the predictor variables, relative to reading achievement. When a variable coding group membership was added to the regression model, there was a small percentage of variance accounted for, suggesting that there are some additional differences in learning disability profiles beyond what was captured by cognitive-linguistic translation and working memory components.

Overall, these findings suggest that cognitive linguistic translation, word-form coding, phonological loop, orthographic loop, supervisory attention, and executive functions all contribute uniquely to reading and writing achievement in children with specific learning disabilities. This highlights the usefulness of considering specific components of working memory and cognitive-linguistic translation when making learning disability diagnoses. Additionally, assessing these cognitive constructs in addition to academic achievement may also assist in individualizing instructional plans to improve academic achievement in children with specific learning disabilities.

Niedo, J., Abbott, R. D., & Berninger, V. W. (2014). Predicting levels of reading and writing achievement in typically developing, English-speaking 2nd and 5th graders. Learning and individual differences, 32, 54-68.

Blogger: Alex Cross is a M.Cl.Sc. and Ph.D. Candidate in Speech-Language Pathology, supervised by Dr. Lisa Archibald and Dr. Marc Joanisse.

Thursday, October 11, 2018

Newly-acquired words are more phonologically robust in verbal short-term memory when they have associated semantic representations

Savill, N., Ellis, A. W., & Jefferies, E. (2017). Newly-acquired words are more phonologically robust in verbal short-term memory when they have associated semantic representations. Neuropsychologia, 98, 85–97.

It is well established that short-term or working memory codes phonological (or speech sounds of a word) information, while long-term memory holds semantic (meaning-based) information. Only recently has there been interest in looking at the effects of storing semantic information in short-term memory. A key question then is whether the learning of new phonological forms can benefit from semantic support.

In this study, participants learned new words that were trained with or without a semantic association. Words that had a semantic association were paired with an object and participants learned facts about that object, while words without semantic support were paired with a blurred image, without a central meaning. Learning was assessed immediately by a series of tests: participants were asked to recall any words they remembered (free recall); recall the words in the order they were presented (serial recall); and label the objects presented. On Day 2, participants were tested again using these tasks and were also asked to decide if the image matched the spoken label.

Overall the results suggest that word learning can benefit from being supported by meaning cues. Semantic effects also occurred immediately. Words paired with semantic cues had a slight advantage, with more phonemes recalled correctly compared to familiar words (i.e., words trained without semantic support) and new words; otherwise, performance for semantically-trained words and familiar words were comparable across all other tasks. Surprisingly, participants were poor at freely recalling items and naming pictures even though they successfully learned to link the word with the object and learned the semantic features about that object at the end of training. This suggests that word form and meaning might be encoded into long-term memory at least somewhat separately. It would follow that future work needs to consider when the link between word and meaning is being learned successfully and established in memory.

Blogger: Theresa is a MClSc/PhD Candidate, supervised by Dr. Lisa Archibald. Theresa’s work examines the learning of phonological (speech sound) and semantic (meaning) aspects of words.