20Q: Neuroscience Applications for Differential Diagnosis and Intervention in School-Aged Children

From the Desk of Ann Kummer

Neuroscience involves the study of the nervous system, which includes the brain, spinal cord, and the peripheral nervous system. A branch of neuroscience called cognitive neuroscience involves the study of conscious intellectual activity in humans, such as thinking, problem-solving, reasoning, memory, and, of course, the use of speech and language to communicate. Unfortunately, many speech-language pathologists (SLPs) are unaware of recent neuroscience research that shows how therapy changes the function of the brain to enhance communication skills. Therefore, I invited Dr. Martha S. Burns, the author of the book entitled Cognitive and Communication Interventions: Neuroscience Applications for Speech-Language Pathologists, to enlighten us about this research in this 20Q article.

Dr. Martha S. Burns is the Director of Neuroscience Education at Carnegie Learning Corporation and served as an Adjunct Associate Professor at Northwestern University in the Department of Communication Sciences and Disorders for over 25 years. Dr. Burns is a Fellow of the American Speech-Language-Hearing Association and has received honors from Northwestern University, Evanston Hospital Corporation, the American Speech Language Hearing Foundation and St. Xavier University. She has authored 4 books and over 100 book chapters and articles. As previously mentioned, Dr. Burns is the author of the 2020 Plural Publications neuroscience textbook Cognitive and Communication Interventions. Dr. Burns is a consultant to many school districts around the world. She presents many invited in-services, keynotes, webinars, and continuing education courses worldwide each year on neuroscience applications to language and reading intervention.

This course provides a brief overview of newer research on human brain development with applications to the differential diagnosis of neurodevelopmental differences that affect the acquisition of speech, language, and communication. It reviews prevalence and comorbidities of developmental language disorders with other neurodevelopmental disorder diagnoses and provides general guidelines for assessment and intervention based on the newer neuroscience research.

Now…read on, learn, and enjoy!

Ann W. Kummer, PhD, CCC-SLP, FASHA, 2017 ASHA Honors
Contributing Editor 

Browse the complete collection of 20Q with Ann Kummer CEU articles at www.speechpathology.com/20Q

20Q: Neuroscience Applications for
Differential Diagnosis and Intervention in School-Aged Children

Learning Outcomes

After this course, readers will be able to: 

• Describe neurodevelopmental factors that contribute to brain development
• Discuss types, causes, and prevalence of Neurodevelopmental Disorders (NDDs) that affect acquisition of speech, language, and communication.
• Identify speech, language, and communication assessments for accurate differential diagnosis of neurodevelopmental disorders of speech, language, and communication.

Martha S. Burns 

1. Can you begin by explaining why it is important for speech and language practitioners to understand neuroscience?

There are several reasons neuroscience research is important for clinicians working with school-aged children who exhibit speech, language and communication issues. All significant developmental differences reflect variations in brain maturation (neurodevelopment). Understanding the measurable behavioral differences and the neurodevelopmental processes involved aids diagnostic specification and informs best therapeutic practices.  Neuroscience research helps guide clinical assessment by prioritizing critical aspects of developmental differences that differentiate typical from atypical brain maturation and, from there, identifying the most effective evidence-based intervention approaches, strategies, sequences, and goal hierarchies.  

2. Are there specific speech, language and/or communication diagnoses that are considered neurodevelopmental?

Although there is variable diagnostic terminology commonly in use for school-age children with speech, language and communication differences, all diagnoses fall under a general diagnostic rubric of Neurodevelopmental Disorders (NDDs). Depending on whether services are provided in schools under district IEP guidelines or in clinical/medical settings where DSM-5 and ICD-11 terminology and coding are required, diagnostic terms in use may include Specific Language Impairment (SLI), Speech Sound Disorder (SSD), Developmental Language Disorder (DLD), Communication Disorder (CD) and Social Pragmatic Communication Disorder (SPCD).  All diagnoses refer to differences in the speech/language acquisition or communication development process and are long-standing. Although some of the diagnoses (SLI and DLD) are recommended to be used when there is no known causal condition like Down Syndrome (McGregor et al., 2020), many speech, language, and communication differences do co-occur with other Neurodevelopmental Disorders (NDDs) such as Autism Spectrum Disorder (ASD). This co-occurrence will be discussed under another question.  Because the emphasis of this 20Q course is on the application of neurodevelopmental research to speech, language, and communication disorders, Developmental Language Disorders (DLDs) will be used unless the research cited uses a different term or a specific subtype of speech, language, or communication disorder is being discussed.

3. I have read that there are no known causal connections to DLDs; is that true when they occur in association with other developmental disorders?

As with speech, language, and communication diagnoses, there are no specific known causes of many NDDs.  However, atypical variations in speech, language, and communication in school-aged children do often co-occur alongside other cognitive and/or behavioral issues associated with NDDs, such as Autism Spectrum Disorder (ASD) and Attention Deficit and Hyperactivity Disorder (ADHD). If the full cognitive and behavioral spectrum of developmental differences, including speech and language issues, are not effectively identified and treated, this may lead to severe adulthood impairments of function (Straub et al., 2022). The field of neuroscience seeks to identify neurodevelopmental factors that contribute to differences across all aspects of school-aged development and thereby help with differential diagnosis as well as selection and use of efficient evidence-based interventions (Burns, 2020).

4. What do neuroscientists currently understand about the neurodevelopmental processes that might contribute to atypical development?

Healthy, typical brain development is extraordinarily complex. The human brain has over 90 million neurons that become interconnected in multiple ways during development. Each neuron will make more than 1000 connections during development, which ultimately leads to approximately 60 trillion neuronal connections in the adult brain. The developmental processes that enable these trillions of connections involve cellular and structural changes that proceed in a specified sequence (Pakkenberg & Gundersen, 1997). The developmental sequence is impacted by a complex interplay of many factors, including genetics, diet, environmental exposures, and experience (Schwarzenberg et al., 2018). For the past quarter century, developmental neuroscientists have been working to better understand these brain developmental processes to help prevent and/or mitigate neurodevelopmental processes that may go awry.  For example, the observation that developmental speech, language and reading differences often run in families (Volkers, 2018) is clarified by research on neurogenetics, helping to better understand factors that contribute to familial prevalence. That knowledge can lead to earlier identification and intervention of speech and language issues in those children with a family history, as well as identify dyslexia risk before reading problems present and interfere with other aspects of behavioral development or lead to academic failure.

5. With the human brain so complex, is there a high prevalence of developmental difficulties other than those that affect speech, language, and communication in school-age children?

Yes, by later adolescence, nearly a third of children in the U.S. will receive a diagnosis of some type of neurodevelopmental disorder. Two recent studies published since 2022 provide the most current information on the prevalence of neurodevelopmental disorders in children and adolescents. The first cohort study of over three million publicly and privately insured children in the US revealed that 17.5% of insured children in the U.S. had received a diagnosis of one or more neurodevelopmental disorders by 8 years of age (Straub et al., 2022). A second study, conducted by Francés and colleagues, also published in 2022, indicated the incidence of diagnosed neurodevelopmental disorders in school-age children significantly increases to 28% by age 18.  Straub et al. (2022) caution that their reported incidence figures represent an under-diagnosis of neurodevelopmental disorders, especially among publicly insured children under 8 years of age.  That may explain, in part, why the incidence increases so dramatically in the upper-elementary, middle, and high school years.

6. How many of the children who receive an NDD diagnosis exhibit speech, language, and communication disorders, and does it vary by demographics of any kind?

In the Straub et al., 2022 database of insured children up to 8 years of age, the incidence of speech-language disorder diagnosis was 3.3% - 5.3% among privately insured children and 8.3% vs 8.1% among publicly insured children. There was also variability in prevalence among children born to young mothers (aged 24 years of age or younger) - 3.3% compared to 5.3% diagnosed with mothers 35 years or older. However, the speech or language disorders more commonly diagnosed in children born to older mothers in the privately insured group were not evident in the publicly insured group. It is not clear why the incidence of speech-language disorders is less among younger mothers, as there were no clear differences by maternal age seen for other neurodevelopmental disorders (Straub et al., 2022). And it should be noted that ongoing studies of post-Covid outcomes may reveal additional increases in academic difficulties as well as neurodevelopmental diagnoses among school-age children (Deoni, Beauchemin, Volpe, & D’Sa, 2021).

7. How does the prevalence of DLDs compare with other neurodevelopmental disorder diagnoses in the later school years?

By age 18, Frances et al. (2022) reported a prevalence of communication disorders (CD) diagnoses as 1-3.42% in individuals up to 18 years of age, while other neurodevelopmental diagnoses contributed to the increases observed in older children. The specific incidence of other neurodevelopmental disorders reported by the authors was: intellectual disability (ID), 0.63%; attention-deficit/hyperactivity disorder (ADHD), 5–11%; autism spectrum disorder (ASD), 0.70– 3%; specific learning disorder (SLD), 3–10%; and motor disorders (MDs) add another 0.76–17%.)

8. With this high prevalence of NDDs in general, do other neurodevelopmental differences often overlap or co-occur with speech or language issues?

Yes, in fact, there is ample new research indicating frequent comorbidity of communication disorders with other diagnoses (Astle, Holmes, Kievit & Gathercole, 2022). The comorbidities of speech, language, and/or other disorders with other neurodevelopmental disorders besides ADHD include those that usually manifest in specific domains, namely specific learning disorder (SLD), with difficulties in reading, writing, and mathematics and autistic spectrum disorder (ASD).

9. What are the other specific neurodevelopmental diagnoses that may co-occur with DLDs?

Table 1 below, adapted from Astle, Holmes, Kievit, & Gathercole, 2022, lists the moderate (*) and strong (**) shared behavioral associations associated with different speech, language and communication disorder diagnoses and other neurodevelopmental diagnoses.

Table 1

Possible overlapping behavioral manifestations of NDD’s in School-age Children (adapted from Astle, Holmes, Kievit, & Gathercole, 2022). Note: the authors did not include dyspraxia because of a lack of research on cognitive/behavioral dimensions)

10. Has neuroscience identified specific features of brain development that contribute to neurodevelopmental differences?

In a seminal paper clarifying our understanding of factors that have a major impact on brain development of infants and young children, Schwarzenberg and colleagues (2018) [associated with the American Academy of Pediatrics Committee on Nutrition CON)] have described two major developmental processes that can dramatically alter brain maturation and lead to developmental disorders. One is the sequence with which specific brain pathways develop, and the second is a hierarchy of scaffolding stages where one developmental process depends on the successful completion of a prior stage.

11. Can you give an example of how the changes in the sequence of brain pathway development would affect speech or language development?

Recall from question 4 above that during brain development, over time, each of our 80 billion neurons will make more than 1000 connections. Those connections ultimately lead to approximately 60 trillion neuronal connections by the time a person reaches adulthood. Recall also that the developmental processes that enable these trillions of connections involve changes in the neurons themselves (cellular changes) as well as changes in brain structure that proceed in a very specific sequence (Pakkenberg & Gundersen, 1997). So, a developmental process that appears to go awry in some children with developmental disorders is the sequence with which brain pathways form. As an example, we know that there are important primary developmental pathways in the brain that handle rapidly changing information. Stein (2023), in a review of theories of dyslexia, explains these pathways are referred to as magnocellular. In the auditory system, the magnocellular pathways enable a baby or young child to perceive the rapidly changing phonemes in a speech signal, which will, in turn, enable the development of phonological pathways. Evidence now indicates that if those magnocellular pathways fail to develop as the first sequential component of language acquisition, then other pathways that depend on phonological processing, from morphology to sentence structure to decoding a written word, will subsequently fail to develop adequately as well (Heim, Keil, Choudhury, Friedman & Benasich, 2013; Stein, 2023). Hence, this underlying brain maturational sequence explains why much of the research on intervention with language disorders, as well as dyslexia, shows the value and importance of beginning with phonological interventions (Burns, in press).

12. Can you give an example of a hierarchy of scaffolding stages where one developmental process depends on the successful completion of a prior stage?

During postnatal development, the primary cortical brain regions that support hearing, somatosensory, and visual capacities become shaped and fine-tuned through interactions with the physical and social world. Cortical development is thus partly a competitive process in which specific exposures allow cortical networks to specialize. An example familiar to those of us who work with developmental speech and language is how a child’s phonological and language system will evolve and specialize based on the initial language(s) the child is exposed to during infancy and early preschool years. Early in development, the child’s brain will specialize to perceive, understand and speak any language system the child is adequately exposed to, but once specialized, later in development, the cortex becomes much less adept at learning another language (Johnson, 2011; Wilson & Prescott, 2021). These early optimal periods are considered “sensitive periods” for specific types of cortical development. For example, a child who learns a tonal language like Mandarin will have built a cortical system that will have more difficulty perceiving than learning a non-tonal language like English, and vice-versa. Thus, the initial language exposure during the brain’s sensitive period for language acquisition will shape how the cortex specializes in perceiving other languages, tonal or alphabetic, after the sensitive period ends. A related feature of the hierarchy of scaffolding is the known negative impact of limited language exposure during the early preschool years (Burns, 2020). Finally, new research suggests that sensitive periods for language acquisition may vary in children with neurodevelopmental disorders. For example, Vyshedskiy, Venkatesh & Khokhlovich (2024) reported on data from 31,000 individuals with ASD, stating that those individuals have a significantly shorter sensitive period of language acquisition than typically developing children.

Thus, the research on the two brain developmental processes of brain pathway sequences and hierarchy of scaffolding stages is useful in clinical practice because it clarifies a) why early identification and intervention of developmental disorders are so important and b) explains variations in response to speech and language intervention seen in some neurodevelopmental disorders.

13. What does developmental neuroscience research indicate about effective interventions with neurodevelopmental disorders?

Fortunately, the human brain is an experience-dependent organ throughout the human life span, albeit the most sensitive periods for different neurodevelopmental diagnoses may vary with different diagnoses, as mentioned in Question 12 above.  But even in those cases, as long as there is not a degenerative disease process, there is strong evidence that many brain connections can be modified and/or enhanced through effective therapeutic processes long after specific sensitive developmental processes may have ended (Burns, 2020).  

14. How does neuroscience research apply to the differential diagnosis of speech, language, and communication disorders?

Through the two processes described above, sequencing and scaffolding, healthy neurobehavioral development will proceed at biologically defined time points. However, when inhibitory genetic and/or environmental factors interfere, children may present with neurodevelopmental disorders. These often affect speech sound, oral language comprehension and usage, and/or other aspects of communication. Because of the complexity and overlapping surface behaviors associated with any neurodevelopmental disorder, as well as the underlying neurodevelopmental processes that contribute to atypical development, assessment of unitary components of language, communication and/or cognition alone will likely not enable the most effective or efficient intervention. Rather, application of the broader understanding of neurodevelopmental processes enables the diagnostician to delve below surface behaviors during assessment. So, in addition to an assessment of unitary components of language, such as measures of receptive vocabulary or comprehension of specific syntactic structure, research indicates a transdiagnostic, multifactor approach may better serve the large heterogeneous population of youth with neurodevelopmental disorders (Astle, Holmes, Kievit & Gathercole, 2022).

15. What are some of the complications in differential diagnosis of speech, language and communication disorders in school-age children?

Since the more severe neurodevelopmental disorders that affect speech sound development and language are customarily identified and formally assessed prior to school entry, other less obvious difficulties that affect academic attainment, such as behavior and social-communicative interaction, may not be evident until a child is required to sit still, attend, learn and interact in structured instructional settings. Children with Developmental Dyslexia are often not identified by educators until later primary grades after failure to learn to read becomes evident (Burns, in press). Yet, the link between oral and written language, especially with respect to reading comprehension, has been recognized for years (Bishop & Snowling, 2004.; Snowling and Hulme, 2021).  Since early intervention is essential to improve prognosis and early diagnosis (Francés et al., 2022) and difficulties with speech or language acquisition may be initially more obvious, it may fall on the speech and language specialist to alert educators to the possibility of reading problems among K-1 students in their caseload, enabling earlier identification and intervention of dyslexia.

16. Based on the neuroscience research to date, are there some suggestions regarding the first steps in effective differential diagnosis of DLDs and Specific Reading Disorders?

In their review of neurodevelopmental disorders that affect speech, language, communication, and subsequently, reading, Astle, Holmes, Kievit, & Gathercole (2022) emphasize the importance of assessment of phonological processing as a first step in differential diagnosis. This suggestion is consistent with the research on cortical developmental sequences and sensitive periods since phonological acquisition depends on early developing magnocellular pathways that form prior to other pathways associated with language acquisition.  The authors recommend that phonological processing assessments include diagnostic tests of perceptual and cognitive skills necessary for representing and manipulating the sound structure of language. Specifically, their research review supports phonological processing assessment through formal standardized tests of:

• phonological awareness,
• rapid automated naming and
• verbal short-term memory

17. Is there a recommended assessment priority for individuals with speech/language disorders associated with other NDDs like ADHD and autism?

The large (31,000 individuals) cohort study on language disorders associated with ASD by Vyshedskiy, Venkatesh & Khokhlovich (2024) has indicated three neurologically and clinically distinct language comprehension mechanisms that may be more important than vocabulary building for language intervention of ASD as early as possible. The three comprehension clusters the authors recommend preferentially addressing are syntax, modifiers (like size, color, and superlatives), and the ability to follow commands (which may include working memory components). Although this is the largest study of language issues in ASD to date, there are many individual differences in children diagnosed with ASD, so this recommendation should be viewed in a child-centered context.

18. What are assessment priorities for more severe DLDs with problems persisting into upper elementary, middle and high school?

Developmental language disorders that are more severe and persist into higher elementary grades and/or overlap with diagnoses of ASD necessitate a more in-depth assessment of oral language. Certainly, standardized language assessments like the Clinical Evaluation of Language Fundamentals (CELF-5) are a staple for assessment of DLDs, but recent research by Vyshedskiy, A., Venkatesh, R., & Khokhlovich, E. (2024) indicates that sometimes standardized tests overload working memory capacity in school-age children with executive function disorders thereby affecting the validity of information on specific grammatical structures. So, clinicians may want to watch for inconsistencies in language test results of older, more severely impaired school-age children.

19. What other assessment information is important for differential diagnosis and effective intervention?

In addition to a professional diagnosis and differential diagnostic information, Astle, Holmes, Kievit & Gathercole (2022) remind us that a diagnostic label does not characterize a child’s needs. Labels are especially inadequate to predict a child’s cognitive or behavioral difficulties or provide an accurate picture of what to expect in the classroom or the social/emotional needs of any struggling student. They recommend a child-centered approach (as opposed to a diagnostic-centered approach), namely:

• What are the child’s strengths and challenges?
• How can we enable the child to flourish?

To accomplish the child-centered approach, clinicians can consult with parents and teachers, carefully attend to how the child responds to various therapeutic activities during each clinical session, determine effective cuing and/or assistive materials, and observe the student as they interact socially and in the classroom.

20. Of course, it is essential that we use evidence-based interventions shown to improve function in areas identified through the diagnostic process, but how does neuroscience research inform the use of interventions that capitalize on individual strengths and other aspects of intervention, like dosage?

Intervention for children whose behavioral issues overlap diagnostic categories can benefit from compensatory therapeutic approaches – capitalizing on a student’s strengths to support areas of difficulty (Astle, Holmes, Kievit & Gathercole, 2022;). This diagnostic therapy approach generally requires ongoing observation and notation of how the student responds to individual therapeutic tasks, such as visual supports, melody, or physical actions to enhance attention and/or retention. Many of the newer technological intervention approaches are now designed to provide and assess different compensatory approaches and capitalize on their use during instruction and practice. Examples include technological interventions for children with ASD (Grynszpan, Weiss, Perez-Diaz, & Gal, 2014; Kasari et al., 2014) and acoustic modifications for students with auditory processing disorders (Burns, in press). In addition, there is substantial evidence that digital technological supplementary instruction and interventions designed and assessed by neuroscientists can provide opportunities for structured and guided individualized practice as well as an effective means to increase therapeutic dosage (Burns, 2020).

References

Astle, D. E., Holmes, J., Kievit, R., & Gathercole, S. E. (2022). Annual research review: The transdiagnostic revolution in neurodevelopmental disorders. Journal of Child Psychology and Psychiatry, 63(4), 397-417.

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Bishop, D. V., & Snowling, M. J. (2004). Developmental dyslexia and specific language impairment: Same or different? Psychological bulletin, 130(6), 858.

Burns, M. (2020). Cognitive and communication interventions: Neuroscience applications for speech-language pathologists. Plural Publishing.

Burns, M. (in Press). How the brain reads: Language, cognition and auditory processing. In Geffner, D., & Swain, D. (Eds.), Auditory processing disorders: Assessment, management, and treatment; Volume 4. Plural Publishing.

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Volkers, N. (2018). Does an SLI label really restrict services? It all depends who you ask. Or perhaps more importantly, where they live. The ASHA Leader, 23(12), 54–61.

Vyshedskiy, A., Venkatesh, R., & Khokhlovich, E. (2024). Are there distinct levels of language comprehension in autistic individuals–cluster analysis. npj Mental Health Research, 3(1), 19.

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