Some symptoms are often common in dyslexia, and researchers have identified several types of dyslexia. Using the term dyslexia primarily distinguishes between genetic and acquired forms of dyslexia.
Acquired dyslexia
Occurs later in life and is usually not the result of genetic or hereditary causes. It often follows an injury or brain damage – such as dementia or stroke – that affects the language areas of the brain that are responsible for processing skills.
Developmental dyslexia
This type of dyslexia is usually most prominent in academic settings. Developmental dyslexia is not caused by any kind of brain damage or accident, but is present from birth. There are many different types of dyslexia included in this one classification, but we will focus on the types of dyslexia that affect brain processing and function: Visual dyslexia, phonological dyslexia and mixed type dyslexia.
Surface dyslexia
The most commonly acquired form of developmental dyslexia. Children with surface dyslexia do not show significant difficulties with reading. This type of dyslexia is associated with poor information processing in the visual, lexical or direct neural pathways, meaning that children can probe words well, even nonsensical words, but need to break them down into fragments or syllables to read them. It becomes more troublesome when the words do not follow the pronunciation or when there are exceptions.
Phonological dyslexia
The most common type of dyslexia, synonymous with dyslexia itself. Mainly a type of developmental dyslexia, but in some cases it can be acquired, e.g. after a stroke or Alzheimer’s disease. Children with phonological dyslexia experience extreme difficulty reading long, unfamiliar or rare words. They are, however, able to read familiar words correctly. This type of dyslexia is linked to weak areas of the brain associated with processing the sounds of language, meaning that children with this disorder often read lexical or visual pathways but have problems with auditory processing.
Profound dyslexia
Is an acquired form of dyslexia. One of the most severe forms of dyslexia, as individuals lose their existing ability to read. Profound dyslexics have problems with both sounding out words and recognising whole words because both, phonological and visual, neural pathways are damaged.
Sources:
- M. Dąbrowska: Dysleksja w ujęciu psycholingwistycznym. Przegląd badań. Psychologia Wychowawcza Nr 4 1995 r.
- https://zdrowie.radiozet.pl/Ciaza-i-dziecko/Zdrowie-dziecka/Dysleksja-rozwojowa-na-czym-polega-to-zaburzenie?
- M. Bogdanowicz, A. Borkowska, Model rozpoznawania specyficznych trudności w czytaniu i pisaniu
- M.B. Pecyna (red.), Dysleksja rozwojowa. Fakt i tajemnica w diagnostyce psychologiczno-pedagogicznej
