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Dyslexia, dysgraphia and agnosia: types of reading and recognition disorders
Reading rests on two routes — a lexical route that recognises a known word as a whole and a non-lexical route that converts letters into sounds — and before both on orthographic-visual analysis; each dyslexia type reflects damage to a different component, while agnosia is a visual recognition problem, not a language problem.
Why it matters in the exam
Questions give reading examples in Hebrew and ask for the dyslexia type: a reader who reads real words but fails on nonwords; one who sounds out each word by the conversion rules and gets another word (escape read as "pool"); one who swaps the order of middle letters (caregiver read as "caressing"); and one who drops or changes the start or end of the word (wheel read as "wave"). In unpointed Hebrew, surface dyslexia stands out because one written word can have several readings.
Another part deals with recognition problems: visual agnosia, in which the patient does not recognise a picture or object by sight but names it when he touches it or is given a definition; and pure word deafness, in which speech is fluent and normal but auditory word comprehension is impaired, while reading and writing are preserved. Writing in aphasia is asked about too: the common errors are substitution, omission and addition of letters.
Key points
- Two reading routes: lexical and non-lexical.
- Phonological: nonwords fail; surface: reading by conversion rules and word confusions.
- Letter position: middle letters swap; neglect: errors on one side of the word.
- Visual agnosia: no recognition by sight, but naming through another channel.
- Pure word deafness: impaired auditory comprehension, speech and reading preserved.
Summary table
| Type | What is damaged | What it looks like | Exam example |
|---|---|---|---|
| Phonological dyslexia | The non-lexical route (letter-to-sound conversion) | Known words are read; nonwords fail | Difficulty with a pair of nonwords |
| Surface dyslexia | The lexical route | Reading by conversion rules, confusing words with the same letters | Escape read as "pool", writes read as "spelling" |
| Letter position dyslexia | Letter position coding in orthographic analysis | Middle letters swap places, giving another word | Caregiver read as "caressing" |
| Neglect dyslexia | Visual attention to one side of the word | Omission, substitution or addition on one side | Wheel read as "wave", duck read as "ducks" |
| Visual agnosia | Visual recognition of objects | Cannot name a picture, but names by touch or from a definition | "What do we call the object used for cutting bread?" |
| Pure word deafness | Auditory analysis of speech | Fluent normal speech, impaired auditory comprehension, reading preserved | Does not understand spoken questions but answers written ones |
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Sources
- Coltheart et al., Psychological Review, 2001 — DRC: a dual route cascaded model of visual word recognition and reading aloud
- Friedmann & Coltheart, Handbook of Communication Disorders, 2018 — Types of developmental dyslexia
- Whitworth, Webster & Howard, A Cognitive Neuropsychological Approach to Assessment and Intervention in Aphasia, 2nd edition (2014) — Reading and writing
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.