Dyslexia is a learning difficulty that primarily impacts reading abilities. Individuals with dyslexia often encounter challenges with reading quickly, spelling words, and comprehending what they read. These difficulties can manifest in varying degrees. While often identified in school-aged children, reading challenges can also emerge later in life.
Acquired Dyslexia: A Distinct Form
Acquired dyslexia, also referred to as alexia, is a form of reading difficulty that emerges later in life. Unlike developmental dyslexia, which is typically identified during a child’s early learning years and can have genetic influences, acquired dyslexia develops after an individual has already established normal reading skills.
Acquired dyslexia occurs when previously intact brain functions related to reading are disrupted. The condition is directly linked to specific neurological events that impact the brain’s processing capabilities for reading.
Common Causes of Acquired Dyslexia
Acquired dyslexia results from damage to brain regions that are essential for reading. A common cause is a stroke, especially when it affects areas of the brain crucial for language processing, such as the left hemisphere. Traumatic brain injuries (TBI) can also lead to acquired dyslexia by damaging neural networks involved in processing language and reading. The extent and specific manifestation of the reading difficulty can depend on the location and severity of the brain injury.
Neurodegenerative diseases, such as Alzheimer’s disease, can progressively impair brain function, including reading ability, leading to acquired dyslexia. Brain tumors, which are abnormal growths, can also disrupt reading networks if they are located in or press upon relevant brain areas. Furthermore, brain infections like encephalitis can cause widespread or localized damage, resulting in the sudden onset of reading difficulties. These medical events directly interfere with the brain’s capacity to process written language, leading to a loss of previously mastered reading skills.
Recognizing and Diagnosing Acquired Dyslexia
Recognizing acquired dyslexia involves observing specific changes in an individual’s reading abilities. Individuals may struggle to read words they previously knew, misread familiar words, or experience a loss of reading fluency. Despite these reading difficulties, they might still be able to understand spoken language or comprehend the overall meaning of a text even if they cannot read individual words accurately. Spelling difficulties often accompany these reading challenges. The specific symptoms can vary depending on the exact brain areas affected.
Diagnosis of acquired dyslexia involves a comprehensive evaluation by medical professionals. This process often begins with a neurological examination to assess overall brain function and identify any underlying medical conditions. Neuropsychological testing plays an important role, including specialized assessments of reading, language, and other cognitive skills to pinpoint the impairment and differentiate it from other conditions. Brain imaging techniques, such as MRI or CT scans, are also frequently used to visualize the brain and identify the location and extent of any damage. Diagnosis also confirms the individual had normal reading abilities before onset, distinguishing it from developmental forms.