Print Font & Dyslexia
Across a wide range of print sizes that a dyslexic child is exposed to when attempting to read, his or her attempt does not follow the same curve shape as a skilled readers ability.
When reading, at a constant reading rate is monitored for a child across large print sizes there is a sharp decline in the reading rate of the given text below a critical print size.
The main challenge is to help an impaired child and to find ways that allow this child with dyslexia to read more words in less time, because reading more is undisputedly the most efficient intervention for dyslexia. The significance of helping a child with dyslexia learn how to read better and fluidly can be understood when we appreciate that a dyslexic child reads in 1 year the same number of words a proficient and fluid reading efficient child reads in 2 days. Commercially available tuition even in renowned clinics and hospitals in India typically target the general component skills of reading with no emphasis on specificity or a structured statistically competent monitoring screening system. Even if such a system is able to bring the child up to a stage where the component skills of the child have improved, the main challenge remains (that is, reading deficits must be treated by reading more—a vicious circle for a dyslexic child)
One of the issues that the Dyslexia Association of India™ is noticing amongst the children who are being screened by the association, is that a dyslexic reader requires larger critical print sizes to attain his maximum reading speed, and this requirement may be arising from the letter position-coding deficit.
Dyslexia is a learning disability specific to reading and affects a substantial number of children in Indian schools. Accurate reading requires the child to process both the visual information from the page being read and the linguistic information that the print represents.
Evidence is accumulating that shows that subtle impairments in visual processing of text that is to be read characterize some children with dyslexia.
Impaired processing is being noticed in dyslexic children for low spatial and high temporal frequency visual stimuli and this may indicate a particular problem with visual motion processing.
Low spatial frequency, high temporal frequency and motion information are carried primarily via one of the two parallel retino-cortical pathways in the human visual system. These visual deficits represent a correlate of reading problems such as dyslexia and other learning deficits and are mostly neurological in origin. However- a direct causal link between vision and dyslexia can be observed where reading under demanding visual conditions, such as with small font and print, leads to a decline in reading performance by a child with dyslexia.
Reading errors do decrease in some children when they are presented with a larger print font size, which suggests a causal link between a stressed visual system and the accompanying reading impairment. The potential effect of print size, where dyslexic readers are given larger print fonts than normal readers to achieve a maximum reading speed has been noticed and this ‘print font size effect’ is observable between children where the particular groups difference in reading speed is greatest with text which is in small print. This link between seeing the text in print and that too in a size that is readable and the prevalence of dyslexia is important to keep in mind in its own right because learning disorders are a confluence of neurological issues and the interaction in a human brain between highly interwined systems is still a complex mystery.
It is possible that at a certain stage of cognitive functioning a larger print font size facilitates a child with dyslexia to read accurately and without hiccups as it may increase the visibility of spatial frequencies, which are critical for letter recognition or reading.
In addition, it is possible that dyslexic readers require a wider spatial-frequency bandwidth for reading – which means that with larger letters, more distinguishing letter features may be available within the critical bandwidth for reading.
Sometimes a child with a reading disorder can be less efficient at picking up visual information than a skilled reader because his memory store of letter templates available to match to the incoming information from the text he is reading is less well established and this may result in him requiring either more or a different set of features to distinguish between the letters within the words.
Factors that could be ameliorated by giving a dyslexic child larger print in the text he has to read may include lateral masking (‘crowding’) effects, that may be greater in the impaired child, as could be the possibility of variability in the visual span of the affected child. An alternative account of observed print size effects on dyslexic children is that they could result from a deficit, which has been proposed to interfere with letter position coding pathways that carry information about an object's position in space.
For accurate reading, fidelity of the channel that helps to localize correctly the serial position of letters within words is important, and a dysfunction within a dyslexic child’s brain could lead to improper letter localization and therefore reading errors. In this case, it may be the relative position within words that is affected by the size of the letters. It could be that deficient position signals have a bigger impact for very small letters whose relative position is harder to identify, by the child and so may result in poorer reading performance with small print font size.
This can in simple terms be called a deficit in visual attention but it does propose a specific problem with serially focusing attention, either through rapid attentional capture or with attentional disengagement. If it is a problem with attentional focusing then it probably is contributing to anomalies in - relative position coding - in dyslexia. Accurate - symbol string recognition - in some dyslexic children is negatively affected by adjacent symbol reversals. Thus, while attentional disturbances (taken in isolation) could affect reading, visual attention deficits may manifest as - letter position coding errors - for an impaired child.
So can we (Parents or Teachers) continue to increase the print font size of the text that a child should be given if we believe that he may be reading disabled - i.e. would there be a monotonic increase in reading rates for a dyslexic child with continuously increasing print size? Reading words with very small letters may prove difficult for a dyslexic child either because the letters are hard to identify or because it is hard to determine where they appear in the word as both letter identification and letter position coding play important roles in word identification and slow, inaccurate word identification with small letters could be due to either compromised letter identification or letter position coding for the impaired child.
Letter recognition and reading normally require a critical spatial frequency bandwidth. The idea that a dyslexic child needs larger print to compensate for a higher or broader spatial frequency bandwidth for reading is quite simplistic as one would expect reading performance to keep improving with increasing print size. But this is not the case. Likewise, the idea that a dyslexic child may have a particular print size where reading performance peaks, due to differential sensitivity to specific spatial frequencies, is also not correct as there are no points above critical print font size where reading is more efficient for the dyslexic child.
Letter recognition alone is not sufficient for word identification and reading; rather inter-letter effects also need to be taken into account. Knowing the position of a letter relative to the other letters in a word is necessary for correct word identification; for example, distinguishing the logic behind the spelling of ‘trap’ versus ‘tarp’ or ‘part’ requires correctly locating the spatial arrangement of the letters in the word.
There is a brain channel for all children whether dyslexic or non-dyslexic, which may carry a code for the relative position of each letter in the word the child, is reading. This channel probably has a heavy traffic of noise or may contain more “noise” in a dyslexic child, so the number position for the letter ‘r’ and ‘a’ in ‘trap’ ‘tarp’ and ‘part’ may come with some uncertainty with what a dyslexic child sees. Does he see the ‘r’ in a greater proportion or does he see ‘a’ in a higher proportion. Relative letter position information - is contained within an intermediate spatial scale of the visual stimulus (i.e. the print), while information about whole words and letter features is carried by coarse and fine scales, respectively.
For very tiny print, the fine spatial scale for a dyslexic child becomes too small to resolve critical features, so letters cannot be identified and the acuity limit is reached. Just above this point, letters can be resolved but may not be ordered correctly because of spatial uncertainty in the codes for spatial position. Therefore hypothetically, greater relative - position noise - in dyslexia may contribute to slow reading in general, and could cause a dyslexic child trying to read to be more susceptible to deterioration with small print: meaning the dyslexic child’s reading will have slower maximum reading speeds and higher critical print sizes.
Other related aspects of inter-letter effects on word reading that are noticed include crowding, visual attention and visual span. Crowding, or lateral masking, refers to the hindering of letter recognition when other letters flanks a letter.
The difference in the reading accuracy between a normal child and a dyslexic child could be because of greater susceptibility to crowding effects, especially if their recognition of isolated letters is already inaccurate or slow. Similarly we find greater interference between far flankers than near ones for dyslexic children, which are attributed to differences in visual attentional filtering.
Critical print font size decreases with age, suggesting younger children need larger print to optimize reading performance. This is the reason that reading materials for early, very young readers generally have larger print than texts for older children. But there is a negative correlation between reading speed and critical print size, which shows that in general slower non-dyslexic readers require larger print size to support their maximum reading speed. The fact that dyslexic readers require larger print font size to attain their maximum reading speed has implications for the type of print that parents select for their children, but the key is not to overdo it. Increasing the print font size to 18 will make no difference if the impaired child does not know the basics of reading, the phonic strategies behind the articulation of the alphabet and the rules of the language. Print font size can be useful, and it is possible to use it as a conjunct application for a child with dyslexia. Hoping that larger words translate into more information going into the brain is very simplistic, as sense has to be made of the information going into the brain.
Behavioral evidence showing that dyslexic children are affected by crowding or lateral masking can play an important role in helping some children using a complementary approach where we try to focus on the accessibility of the reading material by manipulating the physical properties of print. Crowding as explained above is a perceptual phenomenon with detrimental effects on letter recognition that is modulated by the spacing between letters. The key aspect here in not print font size, but the interference of flanking letters on the recognition of target letters. For some reading disabled children recognition of text gets impaired when letters are closer than a certain level of critical spacing, which is proportional to eccentricity but independent of print font size.
It is the peripheral vision in normal adult readers, which is the area affected, but it also affects central vision in school-aged children. There is mounting evidence that children with dyslexia and reading disorders are more influenced by crowding than their peers in the same class even when optimal viewing conditions are provided to the dyslexic children. Letter identification is a fundamental step in visual word recognition and reading aloud and parsing of a letter string into its constituent graphemes is a key component of phonological decoding, which in turn, is fundamental for reading acquisition in competent readers. Crowding in a dyslexic brain might not only slow down reading speed but also induce reading errors, because crowding is accompanied by a jumbled percept that is thought to reflect pooling of features from the target and the flankers. Extra-wide inter letter spacing in words should reduce crowding and ameliorate reading performance in dyslexic children, but this again is a complementary strategy and not a solution of the problem as both reduction and increase in spacing have a detrimental effect on reading performance with reading speed in skilled adult readers being slowed when letter spacing is doubled. Therefore the key is a judicious application of the intervention where each child develops an idea of what will help him to focus on aspects of reading text so that the same page does not need to be read a dozen times over and still make no sense of what is being read.
The Dyslexia Association of India™ works with its children to teach them how the manipulation of spacing influences the letter identification stage, which is identical across different alphabetic languages they have to learn in school. Developing a specialized neural system for visual word recognition demands optimized processing to handle parallel independent identification of letters in the extreme crowding condition of printed words in school based text that a dyslexic child is faced with constantly. Improving a sluggish visuospatial attention system in dyslexic children diminishes crowding by improving accuracy of target identification or reducing the critical spacing. In fact at risk children or pre readers in nursery and classes I who have been observed to have a sluggish spatial attention span and these children grow up to become dyslexic.
Combined with the Neuroplasticity T.R.A.I.N™ programme of the Dyslexia Association of India™ the effect of print font size can be integrated into understanding the critical print font size that has to be used by each child. The way the human brain functions, no two individuals even if they are identical twins will process information entering their brains in the same manner and before parents start to zerox or photocopy school text books into larger more readable fonts, please spare some time and effort to have your child assessed for the underling problem that may be the cause of his academic problems
The Dyslexia Association of India™ can be contacted on email@example.com or on phone at 88260-22886 for further information and it would be or endeavor to attempt to resolve any query or concern that you may have about your child.