Neuropsychological Assessment in the School Setting Stephen R. Hooper, Ph.D. Carolina Institute for Developmental Disabilities University of North Carolina School of Medicine Chapel Hill, NC. North Carolina School Psychology Association Fall Conference, October 3, 2011

Objectives To increase participants’ understanding of neuropsychological assessment versus other types of assessment. To increase participants’ understanding of various approaches to neuropsychological assessment with children, with a specific focus on the flexible battery approach. To examine various applications of neuropsychological assessment in the school setting, with a specific focus on writing problems in early elementary school children.

Assessment: A Definition Assessment is a goal directed problem solving process that uses various measures within a theoretical framework. It is a variable process that depends on the questions asked, the type of student, and a myriad of social, developmental, and contextual factors. It cannot be reduced to a finite set of steps or rules.

Neuropsychology: A Definition Clinical Neuropsychology is an applied science concerned with the behavioral expression of brain function/dysfunction. It is the study of the relationship between brain function and subsequent behavior.

Goals of Neuropsychological Assessment Determine spared versus impaired abilities. Understanding impact of injury and/or a neurodevelopmental problem (e.g., LD). Assist in localization of function and dysfunction.

Goals of Neuropsychological Assessment Assist in determining whether to remediate or to compensate. Generate suggestions for remediation and compensation. Growing base of evidence-based interventions. Suggestions for monitoring and tracking of progress in school setting.

When to Consider a Referral Documented brain injury/insult Suspected brain injury or insult Neurodevelopmental disorder Unusual psychological profile Positive neurological findings Severe behavior problems Treatment needs

The Development of Neuropsychological Assessment

Development of the Field Referred children appear more complex. Improvements in medical science have decreased mortality, but increased morbidity. Contributions by child development. New measurement techniques. Specific training guidelines for the field. Steady evolution over past 60-70 years.

Stage I: Single Test Approach (mid-1940s to mid-1960s) Goal: Global differentiation of children with brain damage from normals. Features: Use of general, all-purpose measures of “organicity.” Brain damage as a unitary construct. Strictly empirical and atheoretical.

Stage II: Test Battery/Lesion Specification (early 1960s to mid-1970s) Goal: Detection and differentiation of brain lesions. Features: Use of varied battery of tests (e.g., Halstead-Reitan Battery) Greater appreciation for the variability of brain damage Continued emphasis on maximizing hit- rates in categorical diagnosis

Stage III: Functional Analysis (1970s to 1980s) Goals: Specifying the behavioral effects of cerebral lesions Identifying the underlying components of impaired performance Features: De-emphasis on the use of neuropsychological tests to make inferences regarding brain lesions “Re-Psychologizing” of neuropsychology Emphasis on neuropsychological description

Stage IV: Ecological Analysis (early 1980s to present) Goals: Relating assessment results to the child’s everyday life and future potential Specifying conditions for maximizing adaptive functioning Features: Emphasis on neuropsychological prescription and, most recently, evidence-based practice Evaluation of deficits relative to developmental and environmental demands Biopsychosocial framework

Stage V: Integrative Approach (mid-1990s to present) Goal: A more precise integration of brain structures with corresponding brain function Features: Use of more sophisticated neuroradiologic assessment procedures (fMRI, MRS) Requires concomitant measurement of neurobehavioral functioning A 21st century merger of neurology and psychology

Neurological versus Psychological Assessments

Neurological Examination Components Station and gait Motor tone and strength Cranial nerve functions Sensory-perceptual functions Mental status Neurostructural/neurophysiological measures (not routine)

Largely assesses lower, and some higher, cerebral functions Major Features Time efficient Largely assesses lower, and some higher, cerebral functions Typically not standardized or normed Typically viewed as a screening procedure

Psychological Examination Components Intellectual Selected aspects of cognitive functioning (e.g., visual-perceptual) Achievement Personality/Social-Behavioral

Largely assesses higher cognitive functions Major Features Largely assesses higher cognitive functions Rarely includes measures of lower cerebral measures Usually adequately normed and standardized Requires extended time

Neuropsychological Assessment Neuropsychological assessment represents a combination of the neurological and psychological assessment strategies. It uses assessment methods that tap both higher and lower cerebral functions in an effort to provide a comprehensive view of brain function.

Structure-Function Continuum Neurostructural Measures Neurophysiological Measures Neurobehavioral Measures PSYCH NEURO NEUROPSYCH PET EEG ERP RCBF MRI CT fMRI

Neuropsychological Assessment: Approaches and Models

Approaches to Assessment Fixed Battery Approach Eclectic/Flexible Battery Approach Boston Process Approach Qualitative Approach

Fixed Battery Approach: Characteristics Aims to provide a comprehensive assessment of brain function using an invariant set of validated test procedures. Major emphases placed on standardization and quantification.

Fixed Battery Approach: Advantages Serves to assure a consistently broad-based assessment. Replicability. Provides a standard data base for comparative studies (clinical and scientific).

Fixed Battery Approach: Disadvantages Generally does not provide an in-depth analysis of selected aspects of function. Inflexibility. Assumes a relatively high degree of patient compliance and no handicapping conditions that might interfere with task administration.

Flexible Battery Approach: Characteristics Generally there is at least an implicit outline of the relevant neuropsychological constructs that should be assessed. Any of a variety of validated tests may be selected to assess each functional area. Psychometric properties and complementarity are usually key selection features.

Flexible Battery Approach: Advantages Preserves the quantitative aspects of neuropsychological assessment. Potential for a balanced and broad-based assessment if tests are selected according to key constructs. Flexibility with respect to adapting it to different applications. Flexibility with respect to upgrading.

Flexible Battery Approach: Disadvantages Possible constraints on replicability and comparability. Problems in making comparisons among measures that may differ in terms of norms, test construction, etc. Variable composition may preclude validation studies on the battery as a whole.

A Construct-Driven Approach to Neuropsychological Assessment

Neuropsychological Constructs: Reitan/Rourke Tactile perception Visual perception Auditory perception/language-related Problem solving, concept formation, reasoning Motor and psychomotor Other (e.g., attention)

Neuropsychological Constructs: Fletcher Language Visual-spatial and constructional Somatosensory Motor-sequential Memory and learning Attention [Fletcher suggests designing the battery around the characteristics of the disorder]

Neuropsychological Constructs: Luria Clinical Model Motor Sensory Attention Visual Language Memory Intellectual

Neuropsychological Constructs: Wilson Clinical Model Language Auditory integration Auditory cognition Auditory short-term memory Visual Visual-spatial Visual cognition Visual short-term memory Motor Fine-motor Graphomotor

Neuropsychological Constructs Motor Sensory perceptual Attention Language Visual processing Memory and Learning Executive Functions Related Domains Intellectual Achievement Adaptive behaviors Social-emotional Family School environment

Motor Components Gross motor strength Basic fine-motor speed Complex fine-motor speed Motor coordination and planning Spatial-based movement Oral-motor Balance

Sensory-Perceptual Abilities Most evaluations typically assess the tactile, visual, and auditory modalities. The modalities of olfaction and taste are tapped less routinely, although olfaction can be disrupted in many traumatic brain injuries or neurological processes affecting the prefrontal cortex.

Attention Abilities Selective Attention (Focus/Execute) Modality specific Alertness and Disinhibition Sustained Attention (Vigilance, Span) Encoding Attentional Set Shifting Divided Attention Stabilize/Readiness Need to distinguish between attention as a process versus attention as a disorder.

Expressive Language Communicative intent Oral-motor fluency Naming Word and phrase repetition Organization of output Vocal tone and prosody Pragmatics

Receptive Language Phonemes Word and phrase comprehension Conflictual and comparative statements Vocal tone and prosody Speed of processing Pragmatics

Visual Processing Visual recognition (faces, colors, objects) Visual discrimination Visual closure Visual-spatial (2-dimensional) Visual-spatial (3-dimensional) Visual organization and planning Visual problem solving and efficiency

Memory and Learning Modality Time Retrieval Strategies for retrieval

Memory Components - Modality Visual Verbal Language Non-verbal auditory Somatosensory/Tactile Taste Smell Multisensory

Memory Components - Time Immediate/Short-Term – Information that you need once or for a few seconds. Long-Term – Information that you need to retrieve at a later time. Remote Recall – A special condition of long-term recall

Memory Components - Retrieval Recognition Automatic Episodic vs. Nonepisodic Memory Contextualized recall Declarative vs. Procedural Memory Facts vs. procedures Strategies for retrieval Multiple repetitions Semantic cues Phonemic cues Associative learning

Executive Functions (Luria, 1966) Executive function is defined as the ability to maintain an appropriate problem-solving set for attainment of a future goal. This set can involve (a) an intention to inhibit a response or to defer it to a later, more appropriate time; (b) a strategic plan of action sequences and/or; (c) a mental representation of the task, including the relevant stimulus information encoded in memory and the desired future goal-state.

Executive Functions (Welsh & Pennington, 1988) Executive function is primarily the set maintenance required to achieve a future goal. This set would include the requisite skills of planning, organization, inhibition of maladaptive responses, self-monitoring, and flexibility of strategies contingent on feedback. Goldman-Rakic (1990) would add to this definition the concept of working memory.

A Conceptual Model of Executive Functioning (Denckla, 1993) Delay between stimulus and response Internal representation of schema Internal representation of action plan Response inhibition Efficiency and consistency of response Active strategies and deployment Flexible strategies and deployment

An Empirical Model of Executive Functioning (Welsh et al., 1991) Speeded responding Visual search - achieved at age 6 Verbal fluency - > age 12 Motor sequencing - > age 12 Set maintenance Wisconsin Card Sort - achieved at age 10 MFFT - achieved at age 10 Planning Tower of Hanoi (3 disk) - achieved at age 6 Tower of Hanoi (4 disk) - > age 12

Dorsolateral Prefrontal Cortex (DlPFC) Executive Functions Dorsolateral Prefrontal Cortex (DlPFC) Regions within DlPFC appear to influence: The selection of behaviors Recognition of context-dependent changes between stimuli and behavior Potentiation of sets of stimulus-response contingencies related to behaviors in context Flexible, goal-driven control of behavior

Executive Functions Varying levels of damage to the DlPFC are associated with: Lack of motivation, creativity, or goal-following Difficulty in initiating or flexibly modifying actions, resulting in stereotyped responses Inability to assess others’ mental states – Theory of Mind Perseveration and more random-choice errors than age-matched controls Increased distractibility and problems with sustained attention Impaired working memory Understanding of complex task rules

Ventromedial Prefrontal Cortex (VmPFC) Executive Functions Ventromedial Prefrontal Cortex (VmPFC) The VmPFC is critical for elucidating the relation between stimuli and reinforcers and for explaining the inability of individuals with vmPFC damage to learn reward contingencies.

Executive Functions Damage to the orbitofrontal cortex, consisting of both ventral and medial regions, leads to: Impulsivity Sensitivity to immediate rewards Lack of self-control Disruption of both affective and nonaffective stimuli Individuals with VmPFC damage tend to select behaviors with the highest perceived reward, not the highest perceived utility.

Dorsolateral Prefrontal Cortex Frontal Pole Ventromedial Prefrontal Cortex

Eclectic Battery Framework Key Constructs ______________________________________________ C1 C2 Language C4 C5 Cx SC1 SC2 Speech perception SC4 SC5 SCx Phonology Semantics Morphology Lexicon

Related Domains Intellectual Achievement - critical to placement Reading, Writing, Arithmetic, etc. Skill deficits versus performance deficits Adaptive behavior Social-emotional Psychosocial environment (school, family, social)

Developmental Shifts Rate of information Volume of information Intensity (complexity) of information While important for all children, knowledge of when these shifts may occur become critical for children with special needs because of the mismatch between the curriculum and their respective needs.

School Applications

School Applications Neurodevelopmental Disorders Genetic Disorders Learning Disabilities High Functioning Autism Genetic Disorders Fragile X Syndrome Turner Syndrome Prader Willi Syndrome Psychiatric Disorders Early Onset Schizophrenia Bipolar Affective Disorder Neglect and Maltreatment Post Traumatic Stress Disorder Pediatric Disorders Chronic Kidney Disease Pediatric Hypertension Traumatic Brain Injury Other Conditions and Disorders

School Applications Written Language

Written Language The study of written language as a cognitive process has slowly expanded over the past 30 years. High stakes testing and heightened accountability in writing present new challenges. Research efforts fall well behind reading and math. National Center for Learning Disabilities report, “The State of Learning Disabilities 2009,” doesn’t even mention writing disorders. New guidelines for the DSM-V propose to eliminate Writing Disorder as a diagnostic entity.

Written Language The cognitive origins of written language view it as a problem-solving process whereby authors attempt to produce their declarative knowledge. This is more challenging for preschoolers and early elementary school children as they are just beginning to learn to write. Most prevalent communication disability, with recent estimates being at approximately 15% (Katusic et al., 2009). Writing problems increase with advancing age (e.g., 25% of students are proficient on the NAEP Writing Test) (National Center for Educational Statistics, 2005).

Written Language Key theoretical models provide guidance. Hayes and Flower (1980) – Classic recursive model Hayes (1996) – Revised recursive model Kellogg (1996) – Working memory model Berninger & Winn (2006) – Not-So-Simple View of Writing Developmental unfolding of functions to facilitate writing

Hayes (1996) Recursive Model

Kellogg’s (1996) Working Memory Model

The Not-So Simple View of Writing Model (Berninger & Winn, 1996)

Written Language From a neuropsychological perspective, these models suggest the involvement of several key functions: Fine-Motor Language Memory Executive Functions and other regulatory mechanisms

Executive Functions in Good versus Poor Writers Z-scores (M = 0 + 1) Hooper et al.. (2002), Journal of Learning Disabilities

Memory Functions in Good versus Poor Writers Verbal Nonverbal Scaled Scores (M = 10 + 3) Test of Memory and Learning Subtests Hooper et al.. (2011), In Submission

WJ-R Broad Writing Skills Kindergarten Teacher Attention Ratings and Written Language Trajectories 515 510 Average Attention 505 500 WJ-R Broad Writing Skills Low Attention 495 490 485 480 9.5 10.5 11.5 Age Hooper et al. (2010), School Psychology Quarterly

Kindergarten Language Abilities and Written Language Trajectories Hooper et al. (2010), School Psychology Quarterly

Written Language Subtypes (n = 257) Wakely, Hooper, et al. (2006), Developmental Neuropsychology.

Response to Problem Solving Intervention Hooper et al. (2006), Developmental Neuropsychology

Writing Skills Development Project Funded by: Institute for Educational Science; PI - Hooper

Specific Objectives Examine the cognitive underpinnings for the development of written expression. Examine the co-morbidity that is present in children at-risk for writing problems. Examine the response to evidence-based intervention for children at-risk for writing problems.

Research Questions Can we create a measurement model that is relatively stable across early elementary school grades? Do the components of this model relate to written language in early elementary grades? According to the Not-So-Simple View of Writing, we would expect the fine-motor and language functions to correlate the strongest with written language in first and second grades.

Participants N = 205 students ascertained from a single school district in NC. (stratified across 7 elementary schools and associated classrooms). Inclusion/Exclusion criteria: English-speaking Participation in kindergarten Bulk of education in the regular curriculum

Participants Chronological Age Race: 75.1% Caucasian First Grade = 6.54 years Second Grade = 7.54 years Race: 75.1% Caucasian Gender: 57.1% Male Maternal Education: HS+ = 75% IQ = 96.78 (13.09)

Measures Tasks were extracted from the various developmental models of writing and included measures of: Fine-motor Language Attention/Executive Functions Tasks were normatively based, age-appropriate, and readily available to the typical clinician.

Measures Motor Language Attention/Executive Functions PAL Finger Sense Succession-Dominant Hand PAL Finger Sense Succession-Nondominant Hand Language PAL Elision PAL Letters PAL Word Choice Attention/Executive Functions Verbal working memory Visual working memory WJ-III Planning WJ-III Verbal Retrieval Vigil Errors of Omission Vigil Errors of Commission

Neurocognitive Components Model Fine Motor Attention/ Executive Function Language WIAT II Written Expression and Spelling PAL Finger Succession Dominant PAL Finger Succession Non-Dominant Elision/PAL Phonemes PAL Letters PAL Word Choice Visual Working Memory Verbal Working Memory WJ-III Retrieval Fluency WJ-III Planning VIGIL Omissions VIGIL Commissions Hooper et al. (2011), Reading and Writing.

Measures The WIAT-II Written Expression Subtest served as the primary outcome measure. At grades 1 and 2, the Written Expression subtest consists of three tasks: timed alphabet writing, written word fluency, and sentence combining. At grade 3, the student is asked to write a paragraph in accordance with a specific writing prompt. The WIAT-II Spelling Subtest includes items to demonstrate knowledge of written letters, letter groups, and words. The WIAT-II Written Expression Subtest was administered to the entire sample each fall, and at the beginning and ending of the treatment trial to the designated At-Risk students.

Results Time Χ2 GFI RMSEA SRMR Grade 1 43.23 .99 .02 .04 Grade 2 54.71 .96 .05 Criteria: Goodness of Fit Index > .95, Root-Mean Squared Error of Approximation < .06, and Standardized Root-Mean Squared Residual < .08

Predictive Relationships Predictive Models Written Expression R2 Spelling R2 1st Grade-1st Grade .48 .74 2nd Grade-2nd Grade .57 .82 1st Grade-2nd Grade .58 .76

Predictive Relationships Predictive Models Written Expression Spelling 1st Grade-1st Grade EF + Gender (male) EF 2nd Grade-2nd Grade EF + Language Reading 1st Grade-2nd Grade EF +Gender (male) EF + Reading

Summary The neurocognitive model works well at each time point and over time. There is strong relationship of the neurocognitive model with written expression (48%-58% of the variance) and spelling (74%-82% of the variance) at each time point. Executive functions and language abilities appear to contribute the most to these relationships. Suggests the foundation for an empirically-based neurocognitive assessment for writing in young children, but reinforces the need to include specific measures.

Summary These relationships provide support for the neurocognitive components espoused by several different theoretical models of writing in young elementary school children. The invariant weighting of the specific constructs in the model at grades 1 and 2 does not support the sequential unfolding of the core neurocognitive functions. The developmental unfolding may occur at a different time point (e.g., does fine-motor happen earlier?). The relative strength of executive functions to written expression was surprising at this age, but highlighted the importance of assessing these functions early in written language development and interventions.

Summary Reflection of the measures used? What will happen when other variables are added to the model (e.g., affect, motivation)? Will model work differently with younger or older children? Children with WD? Heterogeneity of WD? Response to intervention? Need more research to examine evidence-based diagnostic and treatment practices. What about linkages to neuroscience?

The Importance of Cognitive Functions in a Response-to-Treatment Paradigm for Writing

Research Questions Can we show improvement in the writing of at-risk writers using an evidence-based approach to writing? Do specific cognitive variables have any influence on response to treatment? Do selected cognitive subgroups perform differently in their response to treatment?

Participants Second grade participants were screened with respect to their writing skills with the WIAT-II Written Expression scale. This resulted in 138 students deemed at-risk for a written language disorder (i.e., < 25th percentile), and 67 students not at-risk for writing problems. The not at-risk students were selected randomly at the school and classroom levels. Students deemed at-risk were randomly assigned into treatment (n = 68) versus no-treatment (n = 70) conditions.

Measures Employed the same measurement model. The WIAT-II Written Expression Subtest served as the primary outcome measure. At grades 1 and 2, the Written Expression subtest consists of three tasks: timed alphabet writing, written word fluency, and sentence combining. At grade 3, the student is asked to write a paragraph in accordance with a specific writing prompt. The WIAT-II Spelling Subtest includes items to demonstrate knowledge of written letters, letter groups, and words. The WIAT-II Written Expression Subtest was administered to the entire sample each fall, and at the beginning and ending of the treatment trial to the designated At-Risk students.

Procedures Comprehensive assessments were conducted in the fall of first, second, and third grade. Interventions were conducted via small groups (i.e., 3 to 6 students) between January and May of the second grade. Interventions comprised use of the PAL Lesson Plans #4 and #7 (Abbott & Berninger, 2003). Focused on development of alphabetic principle at the subword and word levels, and aspects of text generation. Manualized treatment protocol that is commercially available. Conducted twice a week for 12 weeks at 25 minutes per session. 94% fidelity rate for the second grade intervention. 85% attended at least 75% of the sessions.

Procedures Students assigned to the no treatment at-risk group and the typical group received written language instruction via the regular classroom setting in a Business-As-Usual model. For these students, written language instruction followed a state-wide standard course of study. Writing skills were immersed in daily classroom activities, with little in the way of direct instruction for written expression.

Question 1: Findings All three of the groups demonstrated growth in their writing skills over time. When the contrasts between the three groups are examined, the treatment effect was significant only on the quadratic component of the slope (B Estimate = 1.18, p < .006). The quadratic component represents an acceleration parameter, indicating that the treatment induced acceleration in the rate of writing skill acquisition for treated participants. The growth rate for the treated group begins to accelerate such that by the start of third grade the growth rate for the treated group has significantly exceeded the rate for the untreated at-risk group (B Estimate = 2.79, p < .003). Effect sizes were small.

Hooper et al. (2011), Annals of Dyslexia.

Question 1: Findings Using curriculum-based measures for the Treatment Group, we also found evidence for significant progress in: Writing Organization as determined by sentence structure and the total number of words correctly sequenced. The number of varied vocabulary words used. The number of words spelled correctly. The total number of words written. Overall holistic score

Question 2: Findings When the interactions between the treatment group were examined, both the attention/executive function and language moderators approached significance. There was no interaction between treatment group and fine-motor speed. For language, this was seen in both the linear (B = -1.42, p < .10) and quadratic (B = -1.95, p < .06) growth curves. For attention/executive functions it was seen for the linear growth function (B = 1.20, p < .08). These findings suggest that moderating effects of different cognitive functions cannot be ruled-out as contributors to the response-to-intervention effects.

WIAT-II Written Expression Moderating Effects of EFs on Treatment Assessment Time Points WIAT-II Written Expression Standard Scores p < .08

Question 3: Findings To construct the latent class groupings, we employed the three latent variables from our measurement model (Fine-Motor, Attention/Executive Functions, Language) for the available 138 students. Findings revealed two empirically-based classes. Specific Deficit Group (n = 90), with average probability of class membership of .93. Low g Group (n = 58), with average probability of class membership of .93.

Question 3: Findings Based on latent class analysis, there were 5 groups: Typically Developing (TD) Specific-Deficit Untreated Specific-Deficit Treated Low-g Untreated Low-g Treated Findings indicated that there was significant change over time on the WIAT-II Written Expression for all 5 groups. When we focused on the treatment effects within the two latent classes, significant treatment effects were observed within both the Specific-Deficit and Low-g classes.

Question 3: Findings For the Specific-Deficit Class, the treatment significantly affects only the quadratic component of the trajectory (B = 1.28, p < .02), although the linear component of the growth trajectory approached significance in the expected direction (B = 0.73, p < .10). In each instance, the students in the treatment groups show a steeper slope than the untreated students following the intervention. In the Low-g Class, the treatment positively and significantly affects both the linear component (B = 1.54, p < .01) and the quadratic component (B = 2.08, p < .002). The Low-g treated group showed a faster rate of gain on the WIAT-II Written Expression score following the intervention.

Hooper et al. (2011), Annals of Dyslexia.

Summary This study provides modest support for the PAL Lesson Plans in the treatment of young elementary school children at-risk for problems in written expression. This change follows only 10 hours of intervention. The rate of growth for the treatment group was superior to the other two groups following intervention. This study also examined moderator effects on intervention for students at-risk for writing disorders. Both language and attention/executive functions approached significance such that lower scores influenced overall performance.

Summary In addition to specific cognitive moderators, when latent class groupings of students were derived, a differential rate of change was noted. These differences were seen in: Students with skill deficits in writing, but with relative strengths in their executive functions. Students with overall lower functioning.

Summary An RTI model and associated curriculum based measures may not be enough for many children to succeed with treatment. Perhaps other variables, such as executive functions, need to be considered and factored into the intervention paradigm. These findings suggest the need for more detailed assessments of many children prior to beginning an RtI paradigm so as to facilitate the effectiveness of instruction.

Conclusions

Conclusions There is a long standing history of the involvement of neuropsychology with educational settings and learning. School Neuropsychology Knowing the differences in how you approach an assessment as an examiner as well as from a consumer perspective is important.

Conclusions From an empirical perspective, under no circumstance is the wholesale use of IQ testing for identification of LD justified, and the same could be said for neuropsychological assessments. Evidence-based hypotheses should guide the assessment process (e.g., spatial abilities in math, phonological awareness in reading, executive functions in writing), and the use of neurocognitive constructs should facilitate this effort. Remember, it is a problem solving process!

Conclusions A comprehensive neuropsychological evaluation probably should be employed for the most severely involved LDs (e.g., the Tier 2-3 cases) and medically involved cases. Subtype X Treatment models remain to be verified, although the findings are mixed at present. Utilization of neurocognitive data in the RtI model has not been fully tested. A comprehensive neuropsychological evaluation also may be useful in younger learners or children with medical difficulties where neurocognitive abilities may be predictive of later learning. Given the high rate of co-morbid conditions in the school setting, these conditions also should be considered in the assessment process. The underlying neurobiological mechanisms may be inter-related (e.g., ADHD and RD).

Questions? Contact Information: stephen.hooper@cidd.unc.edu