INTRODUCTION
Dyslexia is a specific reading disability that literally means inadequate of verbal language. Developmental dyslexia was first reported in children in 1896 but was originally noted in adults before children. It is one of the major learning disabilities and a language disorders that is characterized by difficulty in decoding of similar looking words such as d and b. It is manifested in the form of difficulty in reading and acquiring skill in spelling and writing. It was initially thought that the problem was in the visual system of the brain as child had difficulties in recognizing letter and not seeing them backwards but the significant difficulty was there in naming the letter. Thus the problem was concluded to be linguistic than verbal
HISTORY
Dyslexia was first identified by Oswald Berkhan in 1881 but the term was coined by an ophthalmologist “Rudolf Berlin” in 1887 practicing in Germany.
1896—Morgan reported developmental dyslexia
1897—Deferine suggested that the posterior brain region is critical for reading
1892—Deferine also suggested another posterior brain area that is more central to the occipitotemporal area was also critical for reading
1920—Dyslexia was believed to be a visual defect rather than a verbal defect.
DEFINING DYSLEXIA
According to Tracy L Tanner it is a noncurable, life-long disorder that affects an individual’s ability to process information as applied to reading, spelling, writing, and maths. There exists a discrepancy between what the individuals does and what the individual is capable of doing. Dyslexics are a heterogeneous group and no two individual affected are the same by the many characteristics associated with dyslexia. Treatment for dyslexia is only possible after the strengths and weaknesses of the dyslexic are assessed.
According to New Zealand Ministry of Education (2008): Dyslexia is a spectrum of specific learning difficulties and is evident when accurate and/or fluent reading and writing skills, particularly phonological awareness, develop incompletely or with great difficulty. This may include difficulties with one or more of reading, writing, spelling, numeracy or musical notation. These difficulties are persistent despite access to learning opportunities that are effective and appropriate for most other children.
Dyslexia is a persistent, chronic condition that exists or stays with the person for lifetime and does not represent a transient developmental lag. It is both familial and heritable providing opportunities for early identification in children and adults. Family history plays an important role in diagnosis of dyslexia as maximum children (65%) appear to have a dyslexic parent, 40% of dyslexia sibling. Replicate linkage studies on dyslexia implicate loci on chromosome 2, 3, 6, 15, 8. However, the difference of genetic loci will give rise to the same phenotypes or different types of dyslexia is still under.
TYPES OF DYSLEXIA
Early indicators of dyslexia
- Uneven developmental profile
- Delay in speech development
- Difficulty in learning simple pattern
- Difficulties with fine/gross motor skills
- High distraction/poor concentration
- A child who can converse intelligently but presents with difficulty in writing his name
- Draw well but difficulty in rhymes.
PATHOPHYSIOLOGY
Wide range of studies shows that dyslexic children have disruptions in the left hemisphere posterior reading system mainly in left temporoparietal occipital brain region along with increased activation in frontal region in dyslexic children (Figs 31.1A and B). These neural signals that are widely distributed relates spoken Let’s say the language system can be seen as a hierarchical series of components, i.e. letter—words— sentence—language i.e. the functional unit of language is phonemic/letter, i.e. the word mat will consist three phonemes such as m/a/t. To read this word at the beginner level, the child must be able to divide the word such as m-a-t. To speak out the read word as child will retrieve the word from his internal lesion, assemble all the broken phonemes and utter a word. Phonemic awareness, i.e. the art of pulling away (decoding) the word into a phoneme is deficient in dyslexic children. Reading has two components decoding and comprehension. Phonologic module impaired the ability to decode which is a lower order, this deficit is domain specific and independent of nonphonologic linguistic ability that are well developed, i.e. the dyslexic children are otherwise intelligent but experience great difficulty in reading. This lower order linguistic function blocks the higher order process and thus an inability to conclude a meaning from the word. Therefore, the affected child cannot use his higher order skills to access the meaning of printed word until he has decoded the word.
Brain activation of (A) Normal brain; (B) Dyslexic brain
General Appearance
- Bright, intelligent; high spirited personality but sufficiently poor verbal skills such as unable to read, write, spell as per age.
- High IQ yet may not perform academically
- Performs orally better but not in written
- Portrays careless attitude and behaves immaturely
- Poor self-esteem as compared to other children
- Day dreamer and lacks track of time
- Reads slowly and hesitantly
- Looses orientation easily while reading
- Unable to spell the word correctly
- Omits or adds suffixes or prefixes
- Poor comprehension
- Poor retention of already taught things
- Spell words as they sound, e.g. knife spelled as nife
- Omits punctuations
- Poor at copying from board
- Learns best through hands on, demonstration and visual aids
- Talented in extracurricular activities such as art, drama, music, etc.
Educational Effects of Dyslexia
- Reading and perpetual difficulties
- Errors in oral reading
- Difficulty in comprehending from reading material
- Slow reading
- Omission of words
- Loss of orientation while reading
- Distortion of text (words may float)
- Visual irritating glare from white paper.
Writing Skills
- Illegible handwriting Inconsistencies
- Spelling mistakes
- Mixture of cases
- Unfinished letters
- Directional confusion
- Sequential difficulties
- Unusual pencil grip
- Can be ambidextrous
- Awkward handwriting and slow speed
- Unmatched difference between oral and written skill.
Associated Problems
- Speech and language delay: Difficulty in putting thought into words, incomplete sentences, stutter under stress, mispronunciation of words. Requires speech therapy.
- Otitis media common in these children can impact development of phonics in these children.
- High incidence of autoimmune disorders such as asthma, thyroiditis, inflammatory bowel disease and attention deficit hyperactivity disorder (ADHD).
- Oral skill: Although these children articulate fairly well, there is a lack of speech and writing. A delayed response could be due to lapse between hearing and comprehending it.
- Numbers: 60% of the dyslexic children have inaccurate calculations, failure to remember calculations, difficulty in multiplication and weak computation skills.
- Confused with similar looking mathematical signs such as + - ×, ÷ - %, < - >.
- Reversal of number 21–12, 17–71.
- Transposing no. 257–527.
- May not understand difference between terms minus and reduction.
- Problem in telling time.
- Posing difficulties with mental arithmetic.
Social and Emotional Problems
- Stress and high level of anxiety
- Panic attack if unable to cope
- Extremely disordered
- Troublemakers or too quiet in class
- Deep or light sleeper
- Bed wetting beyond age
- Strong sense of justice
- Creating stories and perceptions
- Poor organization skills
- Messy, difficulty in tying shoelace
- Highly creative and vivid imaginations
- Perceive better with pictures rather than words
- May not understand body language and facial expression
- Poor with lateral language (jokes, proverb)
- Poor time management.
- The word that can be perceived in 40 different ways with various letter arrangements, i.e. reverse, upside, downside, sideways. Though their mind works faster but arriving at right conclusion makes them appear slow
ORAL MANIFESTATIONS
As explained above, dyslexia is a learning disability and therefore child is trainable for executing basic routine exercises, however, child has its own apprehension in explaining his difficulties, a dyslexic child has more or less a healthy dentition but needs to be emphasized over. Poor oral hygiene, dental caries and malocclusion are some of the oral features that can be seen. Stress levels are invariably high in these children ultimately leading to habits such as nail biting which consequently leads wearing and notching of incisal edge of the anteriors. Halitosis is another feature of these children which also occurs due to high stress levels, thus proper hygiene instructions should be given and taught
DIAGNOSIS
- Diagnosis at all the stages is clinical diagnosis through history, observation and psychometric assessment.
- Unexpected difficulty in reading with exceptionally bright child
- Associated phonological/ linguistic problem
- Phonological deficit that does not intrude other linguistic problem
- Trouble in recognizing letters
- Visual distortion despite normal visual results
- Dysgraphia along with laborious note taking
- History of language delay
- Complaints often are school centered
- Do the assessment test such as comprehensive test of phonological processing (CTOPP) and test of word reading efficiency (TOWRE)
- Rule out primary sensory impairments
- Sex-linked genetic disorders such as Klinefelter syndrome that may be associated with language and reading problem
- Delayed neurologic examination
- Laboratory measures such as electroencephalography, chromosomal analysis, functional and imaging
MANAGEMENT
- The management of dyslexia demands a lifetime perspective.
- In early years of life, the treatment focuses on the reading problem but as the child matures, emphasis shifts to accommodations.
- Primary goal is to correct the underlying problem of phonemic awareness (PA).
- National reading panel suggests effective intervention that includes:
- Phonemic awareness—ability to focus and manipulate phonemes thus permuting comprehensive, enhancing PA, reading and teaching.
- Children to manipulate phonemes, phonic instruction enhances children success in learning to read fluency refers to ability to read orally with speed, accuracy and proper expression thereby attaining comprehensions. This can be done by guided oral reading.
- Effects of early therapy or intervention have been seen in children as compared to adults.
- Oral tools such as spell checkers, tape recorder in the classroom and recorded books can be used for dyslexics.
- Modified classroom, extra time for work completion.
- Demonstration, hand on, visual aids work better for dyslexic child than conventional methods.
- The child will need approximate amount of patience and teaching to overcome obstacles of dyslexia.
- Emphasis on phonological deficits and easy identification will help the prevention of reading problems.
- Visual treatment such as eye exercise may improve perceptual abilities; giving the right environment will give child a coping ability; home-based programs will also help improving child his capacity in phonological awareness.
DENTAL MANAGEMENT
- Children should have morning appointments as they are most attentive and remain able to seat in the dental chair.
- As children have a lot of comorbidities such as autoimmune disorder, asthma, ADHD and irritable bowel disease, drug interactions should be taken care of.
- Avoid aspirating local anesthesia (LA) to avoid interactions between pressor agents of LA and medications used for dyslexia.
- Avoid aspirin and nonsteroidal anti-inflammatory drugs. LA containing vasoconstrictor and antioxidants should be avoided in asthmatic patient to avoid the images of asthmatic attack.
- Children with hyperthyroidism to receive care in emergency room.
- Rule out the use of corticosteroids in asthma and avoid stress adrenal insufficiency.
- Children with hypothyroidism are hyperresponsive even on smaller amount of drugs.
- Treatment under nitrous oxide can be put to use to avoid stress.
- Oral hygiene exercises such as brushing, flossing and tongue cleaning should be taught regularly to dyslexic children as these kids are poor communicators and do not express easily. This could be one of the reasons that they generally present to dentist only when in pain.
CONCLUSION
The least understood condition presents itself as a challenge in front of the dentist. However, recognizing the condition early in life will prove to be helpful for the child and dentist in rendering treatment.