Phonological deficit
Encyclopedia
The phonological deficit hypothesis is a prevalent neurological explanation for the cause of reading difficulties and dyslexia
. It stems from evidence that individuals with dyslexia tend to do poorly on tests which measure their ability to decode nonsense words using conventional phonetic rules, and that there is a high correlation between difficulties in connecting the sounds of language to letters
and reading delays or failure in children.
The basic hypothesis is that reading failure or dyslexia stems from a functional or structural deficit in left hemispheric
brain areas associated with processing the sounds of language. Some researchers have studied the structure and function of neural pathways in the language areas
of the brain
. Others have focused on the perception of short or rapidly varying sounds of language, positing that the core deficit is one of timing rather than of overall function.
In the past two decades, the phonological deficit hypothesis has been the dominant explanation favored by researchers as to the probable cause of dyslexia, but it is only one of several competing theories. Critics of the phonological hypothesis point out that it fails to account for symptoms of dyslexia unrelated to phonetic decoding difficulties, such as problems with short-term memory, visual processing issues, or difficulties with balance and small motor coordination that are common to many dyslexic children and adults. They also argue that much of the evidence for the theory is based on circular reasoning, in that phonological weakness is seen as both a defining symptom of dyslexia and as its underlying cause.
Dyslexia
Dyslexia is a very broad term defining a learning disability that impairs a person's fluency or comprehension accuracy in being able to read, and which can manifest itself as a difficulty with phonological awareness, phonological decoding, orthographic coding, auditory short-term memory, or rapid...
. It stems from evidence that individuals with dyslexia tend to do poorly on tests which measure their ability to decode nonsense words using conventional phonetic rules, and that there is a high correlation between difficulties in connecting the sounds of language to letters
Phonemic awareness
Phonemic awareness is a subset of phonological awareness in which listeners are able to hear, identify and manipulate phonemes, the smallest units of sound that can differentiate meaning...
and reading delays or failure in children.
The basic hypothesis is that reading failure or dyslexia stems from a functional or structural deficit in left hemispheric
Lateralization of brain function
A longitudinal fissure separates the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. The sides resemble each other and each hemisphere's structure is generally mirrored by the other side. Yet despite the strong anatomical similarities, the functions of each...
brain areas associated with processing the sounds of language. Some researchers have studied the structure and function of neural pathways in the language areas
Language center
The term language center refers to the areas of the brain which serve a particular function for speech processing and production.- Current scientific consensus :...
of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
. Others have focused on the perception of short or rapidly varying sounds of language, positing that the core deficit is one of timing rather than of overall function.
In the past two decades, the phonological deficit hypothesis has been the dominant explanation favored by researchers as to the probable cause of dyslexia, but it is only one of several competing theories. Critics of the phonological hypothesis point out that it fails to account for symptoms of dyslexia unrelated to phonetic decoding difficulties, such as problems with short-term memory, visual processing issues, or difficulties with balance and small motor coordination that are common to many dyslexic children and adults. They also argue that much of the evidence for the theory is based on circular reasoning, in that phonological weakness is seen as both a defining symptom of dyslexia and as its underlying cause.
See also
- PhonologyPhonologyPhonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
- ReadingReading (process)Reading is a complex cognitive process of decoding symbols for the intention of constructing or deriving meaning . It is a means of language acquisition, of communication, and of sharing information and ideas...
- PhonemePhonemeIn a language or dialect, a phoneme is the smallest segmental unit of sound employed to form meaningful contrasts between utterances....
| Phonemic awarenessPhonemic awarenessPhonemic awareness is a subset of phonological awareness in which listeners are able to hear, identify and manipulate phonemes, the smallest units of sound that can differentiate meaning...
| PseudowordPseudowordA pseudoword is a unit of speech or text that appears to be an actual word in a certain language , while in fact it is not part of the lexicon. Within linguistics, a pseudoword is defined specifically as respecting the phonotactic restrictions of a language... - PhonicsPhonicsPhonics refers to a method for teaching speakers of English to read and write that language. Phonics involves teaching how to connect the sounds of spoken English with letters or groups of letters and teaching them to blend the sounds of letters together to produce approximate pronunciations...
| Synthetic phonicsSynthetic phonicsSynthetic phonics is a method of teaching reading which first teaches the letter sounds and then builds up to blending these sounds together to achieve full pronunciation of whole words...