Dyslexia overview and Definition

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.


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.


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.


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

Differential Diagnosis

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.



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