Amnesia is a type of memory loss that can affect a person's ability to recall past events or experiences or to store new information. There are two main types of amnesia: retrograde and anterograde.

Retrograde amnesia is when a person loses the ability to recall events or experiences that occurred before the onset of amnesia. This type of amnesia is often seen in individuals who have suffered a traumatic brain injury or a stroke.

Anterograde amnesia is when a person has difficulty forming new memories or retaining new information. This type of amnesia is often seen in individuals who have suffered a brain injury, have a degenerative brain condition, or have taken certain medications that affect memory.

In some cases, amnesia can be temporary and may resolve on its own with time. In other cases, amnesia may be permanent and may require treatment and support to manage the symptoms and improve the overall quality of life.

Treatment for amnesia may include medications, rehabilitation therapy, and other support services to help individuals manage their symptoms and improve their ability to function in daily life.

If you or a loved one is experiencing symptoms of amnesia, it's important to see a doctor for an evaluation. They can help determine the underlying cause and develop a treatment plan to help manage the symptoms and improve overall health and well-being.

Normal memory function involves many parts of the brain. Any disease or injury that affects the brain can interfere with memory.

Amnesia can result from damage to brain structures that form the limbic system, which controls your emotions and memories. These structures include the thalamus, which lies deep within the center of your brain, and the hippocampal formations, which are situated within the temporal lobes of your brain.

Amnesia caused by brain injury or damage is known as neurological amnesia. Possible causes of neurological amnesia include:

• Stroke
• Brain inflammation (encephalitis) as a result of an infection with a virus such as herpes simplex virus, as an autoimmune reaction to cancer somewhere else in the body (paraneoplastic limbic encephalitis), or as an autoimmune reaction in the absence of cancer
• Lack of adequate oxygen in the brain, for example, from a heart attack, respiratory distress or carbon monoxide poisoning
• Long-term alcohol abuse leading to thiamin (vitamin B-1) deficiency (Wernicke-Korsakoff syndrome)
• Tumors in areas of the brain that control memory
• Degenerative brain diseases, such as Alzheimer's disease and other forms of dementia
• Seizures
• Certain medications, such as benzodiazepines or other medications that act as sedatives

Head injuries that cause a concussion, whether from a car accident or sports, can lead to confusion and problems remembering new information. This is especially common in the early stages of recovery. Mild head injuries typically do not cause lasting amnesia, but more-severe head injuries may cause permanent amnesia.

Another rare type of amnesia, called dissociative (psychogenic) amnesia, stems from emotional shock or trauma, such as being the victim of a violent crime. In this disorder, a person may lose personal memories and autobiographical information, but usually only briefly.

Because damage to the brain can be a root cause of amnesia, it's important to take steps to minimize your chance of a brain injury. For example:

• Avoid excessive alcohol use.
• Wear a helmet when bicycling and a seat belt when driving.
• Treat any infection quickly so that it doesn't have a chance to spread to the brain.
• Seek immediate medical treatment if you have any symptoms that suggest a stroke or brain aneurysm, such as a severe headache or one-sided numbness or paralysis.

Treatment for amnesia focuses on techniques and strategies to help make up for the memory problem, and addressing any underlying diseases causing the amnesia.

Occupational therapy

A person with amnesia may work with an occupational therapist to learn new information to replace what was lost, or to use intact memories as a basis for taking in new information.

Memory training may also include different strategies for organizing information so that it's easier to remember and for improving understanding of extended conversation.

Technological assistance

Many people with amnesia find it helpful to use smart technology, such as a smartphone or a hand-held tablet device. With some training and practice, even people with severe amnesia can use these electronic organizers to help with day-to-day tasks. For example, smartphones can be programmed to remind them about important events or to take medications.

Low-tech memory aids include notebooks, wall calendars, pill minders, and photographs of people and places.

Medications or supplements

No medications are currently available for treating most types of amnesia.

Amnesia caused by Wernicke-Korsakoff syndrome involves a lack of thiamin. Treatment includes replacing this vitamin and providing proper nutrition. Although treatment, which also needs to include alcohol abstinence, can help prevent further damage, most people won't recover all of their lost memory.

Research may one day lead to new treatments for memory disorders. But the complexity of the brain processes involved makes it unlikely that a single medication will be able to resolve memory problems.