Aphasia can be caused by anything that disrupts or damages the part of the brain associated with language. Conditions that may cause aphasia include:

• Stroke. A life-threatening event in which part of the brain is deprived of adequate oxygen (hypoxia). Also known as a cerebrovascular accident (CVA) or a “brain attack,” a stroke occurs when a blood vessel in the brain bursts or becomes clogged by a blood clot or other mass. This prevents oxygen and nutrients from reaching nerve cells in the affected area of the brain. These nerve cells can die within minutes, and the area of the body that they control can cease to function. Stroke is the most common cause of aphasia.
  
  
• Transient ischemic attack (TIA). A mini-stroke caused by a brief and temporary loss of blood supply to the brain. Although TIAs may result in similar symptoms to a stroke, they last for a short period of time (usually between one and 24 hours) before resolving themselves. TIAs are rarely life-threatening. However, they may be an indication that a person is at risk for a stroke and should be treated as a medical emergency.
  
  
• Dementia. A collection of symptoms including memory loss, behavioral changes and language difficulties. Dementia syndromes that result from damage to the cerebral cortex (such as Alzheimer's disease and Creutzfeldt-Jakob disease) are more likely to cause aphasia.
  
  
• Head injury. Aphasia may occur if a traumatic head injury damages the part of the brain that is associated with language.
  
  
• Brain tumor or lesion. Tumors or brain lesions, which can cause pressure to build in the brain, can disrupt the function of neurons in the brain. This can lead to aphasia, which may occur suddenly or gradually.
  
  
• Schilder’s disease. A type of multiple sclerosis (MS) that develops during childhood. Schilder’s disease is a progressive disorder, although, like many forms of MS, it may go through periods of remission. This disease may cause aphasia in addition to symptoms such as personality changes, seizures and tremors.
  
  
• Primary progressive aphasia (PPA). A type of dementia that involves the slow degeneration of cells in the areas of the brain associated with language. It is not the same as Alzheimer's disease, which is more prevalent in people over 65 (although people with Alzheimer's disease sometimes also develop PPA). The symptoms of PPA usually start when a person is around 50 years old. Unlike sudden-onset aphasia, PPA may cause damage to other areas of the brain as the brain cells continue to degenerate.
  
  
• Landau-Kleffner syndrome. An extremely rare epileptic disorder in children, which may or may not involve seizures. It is also called acquired epileptic aphasia. Children with Landau-Kleffner syndrome may develop normal language skills and then suddenly lose them for no apparent reason. Although seizures (if they are present) often disappear by adulthood, children with Landau-Kleffner syndrome may have difficulty recovering their lost language skills.
  

  

• Infections. Infections that affect the brain, such as meningitis and encephalitis, may cause aphasia. Aphasia caused by infection may develop gradually, depending on the severity and location of the infection. In many cases, aphasia may go away following treatment of the infection. However, sometimes the damage to the brain (and any resulting aphasia) may be permanent.