When to use this hub
Open the domain tab you are evaluating. Use the Differential tab when a student presents with mixed patterns — co-occurring dyslexia and dysgraphia is the rule rather than the exception, and dyscalculia frequently co-occurs with both. The differential view is built to keep the three pathways distinguishable in your thinking and in your FIE prose.
Reading
Dyslexia
Phonological-based reading disability. Decoding, word reading, fluency, and spelling are affected out of proportion to other language skills.
- PA, PM, RAN — the three deficits
- Orthographic mapping theory
- Simple View of Reading
- Dyslexia vs. DLD differential
Writing
Dysgraphia
Written expression disability with two distinct pathways — graphomotor and orthographic processing — each presenting differently and calling for different supports.
- Two-pathway framework
- Copy-vs.-dictation clinical move
- Alphabet fluency interpretation
- WM cognitive load cascade
Math
Dyscalculia
Mathematics learning disability affecting number sense, calculation automaticity, and/or reasoning. Differentiated from math anxiety and language-mediated math difficulty.
- Schreuder TEDA 2026 five domains
- mAMAS for anxiety differentiation
- KeyMath-3 + cognitive subtests
- Differential diagnosis table
Eligibility Domains
SLD Domain Reference
Educational and eligibility logic for Oral Language, Reading Comprehension, Written Expression (composition), and Math Problem Solving — the domains not fully covered by named disability patterns.
- Listening Comprehension + Oral Expression
- RC vs. Basic Reading differential
- WE composition vs. transcription pathways
- Language-mediated MPS vs. dyscalculia
Frameworks shared across all three domains
State Policy
Texas Dyslexia Handbook (2024)
The SBOE Handbook is the authoritative state document. Figure 4.1 defines the dyslexia three-question framework; Figure 5.3 defines the dysgraphia equivalent. Dyscalculia is not addressed in the Handbook and relies on TEDA and research-based frameworks.
Evaluation Methodology
C-SEP (Schultz & Stephens)
Comprehensive Evaluation Process for SLD identification. Review → Plan → Assess → Decide. Emphasizes legally defensible FIEs grounded in mechanism-then-score-then-implication narrative sequencing.
TEDA 2026 Speakers
Integrated Frameworks
Schreuder (dyscalculia five-domain framework, mAMAS), Stanley (language difference vs. disorder), Garcia-Prats (impact statement structure), Codding (CBM-Math research), Schultz (C-SEP clinical framing) — each integrated into the relevant domain reference.
Professional Judgment Required — These references are clinical aids, not substitutes for professional judgment or the individual clinical references they point to. Always refer to the full domain reference and assessment manuals. Aligned to the Texas Dyslexia Handbook (2024), IDEA, TAC §89.1040, and TEDA 2026 frameworks.
Dyslexia — Key Identification Concepts
📖 Three Required Questions (Figure 4.1)
All three must be addressed when dyslexia is suspected (Texas Dyslexia Handbook, 2024, p. 43).
- Characteristics present? Difficulty with accurate and/or fluent word recognition, poor decoding and/or poor spelling.
- Phonological mechanism? Deficit in PA, phonological memory, and/or RAN.
- Unexpected? Unexpected for age and ability given effective instruction.
The three-question model is a structuring frame for the FIE narrative, not a checklist — all three questions must be answered with data.
⚠️ Reeval Persistence Rule
When a prior eligibility included dyslexia and current reading scores are at or above 85, this reflects intervention success — not resolution of the underlying processing differences.
- Phonological processing and RAN differences are neurobiological and persist.
- Accommodations remain warranted even when achievement scores normalize.
- Document PA, PM, and RAN data at reeval regardless of achievement score levels.
FIE language: "Current reading scores in the average range reflect the student's response to structured literacy intervention and continued access to accommodations, not resolution of the underlying phonological processing differences."
🔊 PA — Phonological Awareness
The ability to detect, identify, and manipulate sound units in spoken language (phonemes, syllables, onset-rime).
- Assessed by: CTOPP-2 Phonological Awareness Composite, TAPS-4 Phonological Awareness
- Deficit: Below-average performance on blending, segmenting, elision tasks
🧠 PM — Phonological Memory
The ability to store phonological information in short-term (working) memory for processing.
- Assessed by: CTOPP-2 Phonological Memory Composite, WISC-V Digit Span
- Deficit: Difficulty with nonword repetition, digit span tasks
⚡ RAN — Rapid Automatized Naming
Speed and automaticity of retrieving phonological codes from long-term memory.
- Assessed by: CTOPP-2 Rapid Symbolic Naming Composite, TAPS-4 Processing Speed
- Deficit: Slow naming speed on letters, digits, colors, objects
Dysgraphia — Key Identification Concepts
✍️ Three Required Questions (Figure 5.3)
The Texas Dyslexia Handbook Figure 5.3 defines the parallel three-question framework for dysgraphia.
- Characteristics present? Difficulty with handwriting, spelling, and/or written expression that is significant and persistent.
- Mechanism? Difficulty in graphomotor processing and/or orthographic processing underlies the writing difficulty.
- Unexpected? Unexpected for the student's age and other abilities given effective instruction.
🔀 Two Distinct Pathways
- Graphomotor pathway: Breakdown in the motor planning and execution of letter formation. Copy and dictation are both impaired. Handwriting is the primary complaint. OT is often relevant.
- Orthographic processing pathway: Deficit in the ability to store and retrieve complete visual word forms. Spelling is the primary complaint. Copy may be intact; dictation is impaired. Often co-occurs with dyslexia.
Clinical move: Compare copy performance to dictation performance. Intact copy with impaired dictation = orthographic pathway. Both impaired = graphomotor pathway (or both).
Dyscalculia — Key Identification Concepts
🔢 Schreuder TEDA 2026 — Five Domains
Dyscalculia is evaluated across five domains (Schreuder, TEDA 2026). A pattern of weakness across multiple domains — not a single score — drives identification.
- Automaticity: Math fact retrieval speed and accuracy
- Calculation: Written computation procedures
- Number Sense: Magnitude understanding, number line, estimation
- Mathematical Reasoning: Problem solving, applied math
- Cognitive Factors: WM, processing speed, fluid reasoning contributions
😰 mAMAS — Math Anxiety Differentiation
Math anxiety can produce a profile that mimics dyscalculia. The Modified Abbreviated Math Anxiety Scale (mAMAS) helps differentiate.
- High mAMAS + intact fact retrieval on untimed/low-stakes tasks → math anxiety primary
- High mAMAS + deficits present on untimed tasks too → dyscalculia, anxiety secondary
- Document anxiety data in the FIE regardless of primary conclusion
Anxiety and dyscalculia frequently co-occur. Ruling out anxiety as the sole explanation is the goal — not ruling out anxiety entirely.
Cross-Domain Differential — Distinguishing the Three Pathways
Co-occurring SLD presentations are common. Dyslexia and dysgraphia co-occur frequently because both involve orthographic processing. Dyscalculia may co-occur with either when language-based or executive function deficits are present. Use this table to keep the profiles distinguishable in your data analysis and FIE prose.
| Feature | Dyslexia | Dysgraphia | Dyscalculia |
|---|---|---|---|
| Core mechanism | Phonological processing deficit (PA, PM, RAN) | Graphomotor and/or orthographic processing deficit | Number sense / math fact retrieval / procedural deficit |
| Primary complaint | Word reading, decoding, spelling, reading fluency | Handwriting, spelling, written output quantity/quality | Math facts, calculation, number magnitude, math reasoning |
| Spelling pattern | Phonetically plausible errors; relies on sound not visual memory | Orthographic errors; visual word form not retained | Spelling usually unaffected unless co-occurring dyslexia |
| Reading profile | Decoding and/or fluency below achievement composite | Reading often intact; deficit is output-specific | Reading usually unaffected unless co-occurring dyslexia |
| Writing profile | Spelling errors, reduced output due to decoding demands | Handwriting, letter formation, spelling; output quantity reduced | Writing usually unaffected; may struggle with word problems |
| Math profile | Math usually unaffected; may struggle with word problems due to reading | Math alignment, written calculation layout may be affected | Fact retrieval, calculation, number sense, estimation deficits |
| Key cognitive markers | Low PA, PM, and/or RAN; Phonological Processing composite | Graphomotor: fine motor, visual-motor; Orthographic: visual WM, coding | Low WM, processing speed, fluid reasoning; number line tasks |
| Anxiety overlap | Reading anxiety secondary to avoidance; not the primary cause | Writing avoidance common; not the primary cause | Math anxiety must be actively differentiated (mAMAS) |
| Reeval rule | Scores ≥85 = intervention success, not resolution; accommodations persist | Handwriting may improve with OT; orthographic deficits typically persist | Math fact automaticity deficits typically persist; scaffolding success ≠ resolution |
| Texas policy hook | TX Dyslexia Handbook Fig. 4.1; HB 3928; TAC §89.1040 | TX Dyslexia Handbook Fig. 5.3; TAC §89.1040 | No Handbook section; TEDA 2026 + research-based framework; TAC §89.1040 |
Mixed presentations — FIE framing guidance
📚✍️ Dyslexia + Dysgraphia (most common co-occurrence)
Co-occurring dyslexia and dysgraphia reflect shared orthographic processing demands. Both involve word-level encoding — reading direction and writing direction of the same deficit.
- Document phonological processing data (PA, PM, RAN) for dyslexia prong
- Document graphomotor vs. orthographic pathway separately for dysgraphia prong
- Per Garcia-Prats: write one combined impact paragraph for both (dyslexia + BR/RF combined; dysgraphia + WE combined)
- Eligibility: student can qualify for both SLD-Basic Reading and SLD-Written Expression under the same evaluation
Do not subsume dysgraphia into the dyslexia write-up. Keep pathways distinct in the FIE even when both are present.
🔢 + 📚 or ✍️ Dyscalculia Co-occurring with Reading/Writing SLD
Dyscalculia may co-occur with dyslexia when language-based deficits affect word problem comprehension, or when shared working memory and processing speed weaknesses drive both profiles.
- Distinguish reading-mediated math difficulty (word problems) from number-sense dyscalculia (fact retrieval, calculation, magnitude)
- Calculation subtests (not applied problems) are the cleaner dyscalculia measure when reading is also impaired
- Document cognitive profile across all three SLD areas — WM and PSI are often the shared substrate
A student can qualify for SLD in all three areas. Each eligibility area requires its own mechanism documentation in the FIE.