Glossary Of Dyslexia Related Words

Agraphia
loss of the ability to write
Alexia
a form of sensory aphasia resulting in the loss of the ability to read; word blindness
Ambidextrous
possessing the ability to work effectively with either hand
Anterior genu
describes the forward region of the corpus collosum
Aphasia
absence or impairment of the ability to communicate through speech, written, or sign language due to dysfunction of the brain centers
Autoimmune Disease
a disease in which the immune system erroneously attacks self-cells
Cerebral Vascular Accident
a rupture of a blood vessels in the brain
Chromosomes
structures located in the nucleus of the cell that contain DNA which** transmits genetic information; this information contains codes for all human qualities and characteristics
Concordance Rates
Statistical analysis on twin studies which determines the extent to which twins are similar, low rates = not similar (or environmentally influenced), high rates = similar (genetically influenced)
Congenital defects
on abnormality presented at birth
Corpus Collosum
bundle of nerves which run between the left and right lobes and thus, enable to two lobes to communicate
Dizygotic Twins
fraternal twins who stem from two eggs and two sperm
Genetic Predisposition
creates a greater risk of displaying a particular characteristic or a certain disorder due to the inherited genetic composition
Hereditary Traits
genetic characteristic transmitted from parent of offspring
Heterogeneous Condition
a condition caused by more than one chromosome
Interhemispheric Communication
communication between the left and right lobes of the brain
Magnocellular
a layer in the LGN that provides information about form, movement, depth and modulation of contrast sensitivity
Magnocellular Pathway
neuronal pathway that connects the retina (eye) to the occipital and parietal lobes of the brain (regions of the brain that process, in part, visual and auditory information) transfers information pertaining to objects in motion
Monozygotic twins
identical twins who stem from one egg and one sperm
Parvocellular
a layer in the LGN that provides information about colour and fine details
Parvocellular Pathway
coincides with the magnocellular pathway to form the lateral geniculate nucleus; transfers information which describes objects
Posterior
describes the back end of a region
Sensory aphasia
Inability to understand spoken words if auditory centre is affected (auditory aphasia) or the written word if visual centre is affected (visual aphasia)
Strephosymbolia
difficulty in distinguishing between letters that are similar but face opposite directions. Example: p-g and b-d
Vestibullary
sense of balance
Wordblindness
a form of sensory aphasia resulting in the loss of the obi lity to read; alexia

Types of Dyslexia

It has been difficult to isolate distinguishing features that would categories specific dyslexia as a single condition. SLDs have many subtypes with a variety of breakdowns, as suggested by Carlson (1998) G Reid (1999). They suggested two major distinctions of people as follows:

Developmental SLDs:
are caused by biological anomalies, usually genetic, in the brain at various levels (i.e. morphological or synoptic) from prenatal through childhood development.
Acquired SLDs:
are caused by brain trauma that may occur prenatally or later, which leads to similar behavioural characteristics of developmental SLDs.

As mentioned previously, we will focus on dyslexia, which is a general term for reading disorders with many subgroups (i.e. surface, phonological, word-form or spelling and direct). As a quick note, dysgraphia, writing disorders, has similar subgroups (i.e. surface, phonological and direct). Basically writing involves reading with an output expression using visual imagery and phonetics, as well as memory of letter sequence and muscle motor. The dyslexia subgroups can be understood as follows:

Surface
person can read words phonetically but has problems with whole word recognition (i.e. yacht - yatchet).
Phonological
person can read familiar words by using whole word method but has difficulty "sounding out" words that are new or letter-to-sound decoding problems.
Spelling
person can read individual letters that lead to reading words if given enough time but has problems recognising the word as a whole and phonetically (i.e. men - h-e-n).
Direct
person can read aloud without comprehension that is similar to speech comprehension aphasias like anomia.

Since all dyslexics do not possess the some symptoms, it was suggested dividing dyslexia into three categories.

  • visuoapatial difficulties
  • speech sound difficulties
  • correlating difficulties

Persons with visuo-spartical difficulties cannot recognise groups of letters. They may tend to guess words by shape and not by context. People with this form of dyslexia may also confuse reversible letters, transpose letters in syllables and syllables in words and words in phrases. They have trouble reproducing letters in writing and may confuse letter, syllable and word order. They may also read words backwards.

Those with speech sound difficulties have problems in understanding spoken language. Difficulty arises in breaking words into syllables and in forming sentences. Those who have problems correlating are unable to find the appropriate speech sounds for individual letter and sounds in writing (this is seen more commonly with monosyllabic words). Researchers began to standardise the concept of dyslexia as case studies and investigations increased. The divisions below are listed according to the researcher of dyslexia.

Boder's Reading -.Spelling pattern Dysfunction
Boder developed a diagnostic screening tool for developmental dyslexia from which she divided into three subtypes;

Dysphonetic
This is the largest of the three divisions. This is viewed as a disability in associating symbols with sounds. The misspelling typical of this disorder are phonetically inaccurate. The misreading are substitutions based on small clues, and are also semantic.
Dyseidetic
In this group there are deficits in vision and memory of letters and word shapes. The person is unable to develop a sight vocabulary, however they have the ability to acquire adequate phonetic skills.
Alexia or mixed dyseidetic and dysphonetic
This subtype combines the deficit of the first two groups. This person may have a disability in both sight vocabulary and phonetic skills. People with this form of dyslexia are usually unable to read and spell.

Visual and Auditory
Standardised reading tests as well as tests for reading diagnosis. They also identified subtypes of dyslexia.

Visual Dyslexic
Those with visual usually cannot learn words as a whole component. The person has problems with visual discrimination, memory synthesis and sequencing of words. Reversal of words or letters when reading, writing and spelling is common.
Auditory Dyslexia
Auditory dyslexics cannot link the auditory equivalent of a word to the visual component.

Visual Learners, Auditory Learners, Visual and Auditory deficits

  • good visual memory but poor auditory memory
  • good auditory memory but poor visual memory
  • poor visual and auditory. In this case reading disability is severe and difficult to remedy Deficits

What Characteristics Accompany Dyslexic?
Few people with dyslexia exhibit all the signs of the disorder.

Some common signs are:

  • Lack of awareness of sounds in words, rhymes, or sequences of sounds and syllables in words.
  • Difficulty decoding words - word identification
  • Difficulty encoding words - spelling
  • Poor sequencing of numbers, of letters in words, when read or written, e.g. b-d; sing-sign; left-felt; soiled-solid, scared-sacred; 13-31
  • Difficulty expressing thoughts in written form
  • Delayed spoken language
  • Problems with reading comprehension
  • Confusion about directions in space or time (right & left, up & down, early & late, yesterday & tomorrow, months & days)
  • Confusion about right or left handedness
  • Difficulty with handwriting

These are but a few common areas that accompany areas in ADHD and Dyslexia, there are seven common areas of Dyslexia, hence an Educational Assessment is vital, for the child, so that the areas in learning can be identified and dealt with early with in the mainstream schools.