A brain injury that affects language areas and their connections can cause aphasic disorders, which may be temporary or permanent. Aphasia can occur as a result of brain damage most commonly caused by:
• Traumatic brain injury
• Stroke and other cerebrovascular diseases
• Brain tumors
• Degenerative diseases (such as Alzheimer’s)
• Infectious processes affecting the brain and meninges (such as herpes encephalitis)
• Multiple sclerosis (though aphasia is an uncommon symptom of MS, occurring in less than 1% of cases)
• Other causes, such as epilepsy, migraines, and metabolic disorders
To function properly, the brain requires oxygen, glucose, and nutrients. Following neurological damage such as those listed above, brain areas that are no longer properly supplied with blood lose some of their nerve cells. Neural losses in the affected area inevitably result in functional impairments—primary or secondary functions, as well as neuromotor or cognitive functions for which the affected area was responsible, may suffer. While the brain does have some plasticity, and certain areas can eventually take over the functions of the damaged areas, this functional adaptability has its limits.
About Stroke
Although traumatic brain injuries can occur unexpectedly in anyone’s life, regardless of age, gender, or general health (e.g., following a car accident or a severe head injury), a stroke—though it also occurs spontaneously and evolves rapidly—is often preceded by predisposing factors and warning signs. The individual typically has both a genetic predisposition and a lifestyle that includes factors such as excessive stress, inadequate diet or sleep, substance abuse, a particular personality type (e.g., Type A personality), etc., all of which negatively influence health over an extended period.
According to statistics, stroke is the leading cause of aphasia. These same statistics reveal that 1 in 3 people who have suffered a stroke develop some form of aphasia.
A stroke occurs when a blood vessel (an artery) supplying oxygen and nutrients to the brain:
• Becomes blocked by a blood clot (ischemic stroke)—approximately 80% of all strokes
• Bursts (hemorrhagic stroke)
Within minutes, nerve cells in that area of the brain are affected and may die within hours. The functions coordinated by the affected brain area can no longer be performed properly. Just as in the case of a heart attack, the sooner emergency treatment begins after the onset of symptoms, the more the effects of the stroke can be reduced.