Memory loss may range from mild forgetfulness to more sever and permanent dementias.

It is normal to be mildly forgetful with age. However, some worrying symptoms should alert the patient as well as the family and relatives as to the underlying causes of memory loss.

Questions asked to sufferers of amnesia

Some of the questions asked the sufferer to self or by family before deciding on consulting a physician include (1-2):

• Is the memory impairment disrupting daily living activities? For example, memory loss affecting driving capabilities, maintaining personal hygiene etc.
• Frequency of lapses in memory. Forgetting an appointment or event once in a while is normal but forgetting it repeatedly might mean a more severe memory lapse.
• Types of things that are being forgotten. For example, forgetting the name of a new acquaintance is normal but a long term acquaintance is not.
• If there is significant confusion. This may mean serious lapses in memory for example putting something in an inappropriate place. For example, a sufferer may place his shoes in the refrigerator.
• If the memory loss is progressively becoming worse. If the memory loss worries friends or family.
• Other features like repeating same phrases, questions, or stories in the same conversation or forgetting how to do routine tasks like combing hair, brushing teeth etc. There may be trouble making decisions or handling money and frequent episodes of getting lost in familiar places.

Specific symptoms of amnesia

Specific symptoms of memory loss and specifically amnesia include (3-5):

• Loss of explicit memory or recent memory - The typical amnesic patient is unable to recall recent information like what they ate for lunch or a newly heard telephone number etc.

  These are called explicit memory as they are memories for facts and events that are capable of being consciously remembered. Patient or sufferer of loss of explicit memory can often declare the loss as this is in his or her knowledge.

• Loss of implicit memory – Implicit memory refers to retention of the event or material information but incapability to recall it through conscious effort. In many cases the patient does not even have the knowledge that he or she has this information.
• Normal or near-normal ability to learn new skills in amnesia patients. Patients have good learning ability (e.g. making a circle using a compass) which implies good implicit memory but they do not remember ever having practised the skill which implies poor explicit memory.
• Anterograde amnesia – this means the patient forgets all events that have happened after a particular traumatic event. This is seen in acute or sudden onset amnesia like after a head injury, stroke or seizure.

  These patients do not tend to forget their childhood, events and skills prior to the accident. They however have trouble remembering day-to-day events.

• Retrograde amnesia refers to an inability to remember information that was acquired before the traumatic event or disease. Typically there is very poor recall of events that occurred in the near past of the brain damage.
• In Korsakoff’s psychosis memory loss is caused by alcohol abuse. The person's short-term memory may appear normal, however, if given a string of words or pictures or a simple story to remember, the patient falters.

  This is called “Confabulation” in which the sufferers make up stories to fill the gaps in their memory. There are other features like loss of feeling in the fingers and toes. This type of amnesia may remain even after five years of abstinence from alcohol

• Childhood amnesia – This means inability to recall events from early childhood.
• Transient global amnesia – This manifests as repetitive questioning, confusion about one’s own identity etc. It lasts for 4-12 hours with a full recovery.

  Loss of one’s own identity is termed fugue amnesia and is due to severe psychological trauma. Memory usually returns gradually.