Definition

Memory disorders are common after a head injury. Post-traumatic amnesia (PTA) is the inability to learn new information following a brain injury. People with PTA often appear confused, unable to recognize their surroundings (disoriented), and unable to remember events occurring after the head trauma. In this condition, individuals are usually conscious but may not recognize healthcare providers and close family members. Unlike retrograde amnesia, where a person cannot remember past events, PTA (anterograde amnesia) involves difficulty learning new information after the injury.

PTA is one of the complications of head injuries, alongside slowed thinking processes, impaired cognitive abilities, behavioral changes, and other issues.

Causes

Head trauma from accidents or sports can damage brain cells. The frontal lobes of the brain, which regulate behavior and cognitive functions, are most commonly affected in head injuries.

The causes of PTA include damage to various brain structures, such as the medial temporal lobes, medial and midline thalamus, basal frontal regions, and frontal connections.

Risk factor

The primary risk factor for PTA is head injury.

Populations more prone to head injuries include:

• Children, especially infants up to 4 years old
• Teenagers, between 15–24 years old
• Elderly individuals, over 60 years old
• Males

Symptoms

The most evident symptom of PTA is memory loss about current events. Individuals with PTA may still recognize friends or family but cannot accept that they are in the hospital or have suffered a head injury.

Other symptoms of PTA include:

• Confusion, agitation, anxiety
• Uncharacteristic behavior such as violence, swearing, yelling, and vulgar actions
• Inability to recognize previously known people
• Staring blankly
• Some may become quiet
• False memories

PTA lasting more than 24 hours indicates a higher likelihood of severe head injury and long-term complications, while PTA lasting an hour or less suggests a milder head injury.

• In mild head injuries, symptoms typically include dizziness, nausea, confusion, and an inability to understand information. Loss of consciousness is usually <15 minutes, and PTA lasts <1 hour. 
• In moderate head injuries, symptoms include fatigue, headaches, difficulty maintaining concentration, memory issues, and behavioral changes. Loss of consciousness lasts 15 minutes–6 hours, and PTA lasts 1–24 hours.
•  In severe head injuries, PTA lasts more than 24 hours, and loss of consciousness lasts >48 hours.

Diagnosis

PTA occurs following a head injury, which is an emergency condition. After addressing life-threatening conditions, your doctor will ask questions about the head injury mechanism, allergies, medications, last meal, existing illnesses, and other symptoms. Since individuals with PTA often have poor memory, caregivers or family members provide necessary information. 

Physical examination includes checking reflexes, sensory function, balance, and cognitive assessments. Doctors may ask general questions (location, time, and full name) and sometimes require writing or repeating previously mentioned words. Imaging tests like CT scans are crucial to examine brain damage, such as bleeding or masses. Blood tests and electroencephalogram (EEG) may be conducted as indicated.

Management

PTA can last from minutes to months. Some medications are used to improve amnesia, but their effectiveness varies, making them infrequently used. The duration of PTA is unpredictable.

Treatment focuses on helping individuals recall memories and learn new information, which can be challenging and often requires support from many parties, such as occupational therapy.

Living with someone with PTA is challenging. They may unintentionally harm family members, both physically and emotionally. Some steps to handle this condition include:

• Avoid forcing them to learn new information or correct their believed memories
• Encourage them to talk about what they remember (events before the head injury)
• Engage in stress-reducing activities like walking or playing games
• Stay calm in the face of their emotional changes
• Create a low-stimulation environment to aid recovery. Avoid high-stimulation activities like watching TV or using phones and tablets. Reduce noise and dim lights.
• Do not take their words to heart; they may say hurtful things due to poor emotional control.
• Join support groups for families dealing with PTA.

Complications

There are no additional complications from PTA, except that behavioral changes in individuals with PTA may endanger themselves and others. The duration of PTA and coma are indicators of extensive brain damage, which can lead to long-term complications.

Complications from head injuries include:

• Loss and disturbance of consciousness
• Seizures later on
• Hydrocephalus
• Infections
• Brain blood vessel damage
• Facial paralysis or loss of facial sensation
• Hearing impairment
• Intellectual/cognitive disorders (memory loss, learning ability, attention)
• Communication disorders (difficulty understanding speech)
• Behavioral changes (use of vulgar language, lack of self-control)
• Emotional changes (depression, anxiety, mood swings)
• Degenerative diseases

Prevention

PTA can be prevented by avoiding head injuries. Steps to reduce the risk of brain injury include:

• Use seat belts and airbags. Always wear a seat belt while driving. Children under 12 should sit in the back seat with an appropriate and safe car seat.
• Avoid alcohol and drugs. Do not drive under the influence of alcohol or drugs, including prescription medications that may cause drowsiness or impaired consciousness.
• Wear helmets. Use helmets when riding motorcycles, bicycles, skateboards, etc. Use head protection while playing baseball, skiing, skating, and horse riding.
• Be aware of your surroundings. Avoid driving or walking while using your phone or tablet to prevent falls.

Tips to reduce the risk of falls at home for adults include:

• Use non-slip mats in bathrooms
• Improve home lighting
• Use handrails when climbing stairs
• Have regular eye check-ups

Tips to reduce the risk of falls in children include:

• Use window guards to prevent falls
• Use non-slip mats in bathrooms
• Use safe, non-slip rugs
• Supervise children playing on balconies
• Use safety gates at the top of stairs to prevent falls

When to see a doctor?

Anyone who has a head injury followed by loss of consciousness, inability to communicate, memory loss, or confusion should be immediately taken to the nearest healthcare facility. A person with amnesia may be unable to identify their current location, so assisting them to a healthcare facility is crucial.

See a doctor within one to two days after a head injury if symptoms persist.

If your child experiences the following after a fall, seek immediate medical attention:

• Loss of consciousness, confusion, not recognizing their surroundings
• Severe headache
• Imbalance
• Vomiting
• Memory loss
• Behavioral and emotional changes

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