diease

Dyslexia


OVERVIEW OF Dyslexia :

Dyslexia is a difficulty in learning to read. It might be due to hereditary factors or other factors that affect the brain development. Dyslexia occurs due to neurological development issues and it occurs from the childhood.


CAUSES :

Genes and Familial factors

A premature baby

Low birth weight baby

Exposure during pregnancy to nicotine, drugs, alcohol or infection that may alter brain development in the foetus

Individual differences in the parts of the brain that enable reading

 

Primary dyslexia:

This is most common type of dyslexia and is the dysfunction and damage to the left side of the brain that is called as cerebral cortex and does not changes with the age. The individuals continue to struggle significantly with reading, writing and spelling throughout their adult lives. Primary dyslexia is passed in family lines through genes or through new gentic mutations and it is found more often in boys than in girls.

Secondary or Developmental dyslexia:

This type of dyslexia arises caused by the problems with the brain development during the early stages of brain development. Developmental dyslexia diminishes as the child matures. This type is also more common among boys.

Trauma dyslexia:

This type of dyslexia usually occurs after some form of brain trauma or injury to the area of the brain that controls reading and writing. It is rare among the school age population.

Visual Dyslexia:

The term visual dyslexia  is sometimes used to refer to visual processing disorder, a condition in which the brain does not properly interpret visual signals.

Auditory dyslexia:

The term auditory dyslexia has been used to refer to auditory processing disorder. Similar to visual processing disorder, there are problems with the brain's processing of sounds and speech.

Dysgraphia:

It  refers to the child's difficulty holding and controlling a pencil so that the correct markings can be made on the paper.

 

 


PATHOPHYSIOLOGY :

Visual perceptual problems:

Some said at the beginning of the 20 th century that the dyslexia  was caused due to the defects in the visual processing system that reversed and transposed words and letters.

The visual system involves cortical function in the occipital and subsequently occipito-parietal and occipito-temporal lobes. The process for deciphering of visual images begins in the retina, is transmitted via the optic nerve, and is ultimately processed in the brain. The processes of visual sequencing, visual perception, and memory do not cause dyslexia.

Phonetic Processing:

Dyslexia involves deficient decoding of indivduals linguistic units called Phonemes which are small detectable sound in a spoken word. Phonemes are the building blocks of the linguistic system and critical to develop the spoken language. Phonological processing areas in the brain must break words into phonemic units before in individual can identify, understand, store or remember them. Any dysfuntion of this system might result in phonetic impairement.

Neurophysiology:

The variations in the right temporoparietal- occipital region among patients with dyslexia.

The specific asymmetrics have been located in the angular gyrus and corpus callosum. The angular gyrus is located in the parietal lobe, specifically broadmann’s area 39 and it is involved in language, cognition and in mathematics.

Genetics:

It shows autosomal dominant transmission. The familial also plays an vital role in transmitting the disease.


DIAGNOSTIC :

The physician might raise some questions about these areas and want to know about any conditions that run in the family including the dyslexia runs in a family or not.

The family problems might also affects the growing children. Hence the physician might also investigate regarding the family members and their role towards to the children.

The physician might also investigate the child, family members and also the teachers answer to written  questions and conclude the diagnosis.

Imaging tests: CT scan, MRI scan SPECTs and  PET scans help doctors to determine the abnormalities in the brain.

Neurological exam: During a neurological exam, your doctor will look for changes in your balance, coordination, mental status, hearing, vision and reflexes. These changes can point to the part of your brain that may be affected by a tumor.

Psychological testing:

The doctor may ask you and your child questions to better understand your child's mental health. This can help determine whether social problems, anxiety or depression may be limiting your child's abilities.

Testing reading and other academic skills:

The  child may take a set of educational tests and have the process and quality of reading skills analyzed by a reading expert.

 


TREATMENT AND PROGNOSIS :

Prevention:

The school plays a vital role in minimizing the dyslexia disorder.

Hear, listen and learn process should be implemented and the teachers should watch the students who shows difference in their activities.

Family also should help the children and support them to get rid from the disorder


PROGNOSIS :

The prognosis is mainly depends on the duration of the diagnosis and the encouragement by the surrounding members.