Many forms of brain damage can damage memory and alter new learning:
> An accident or physical trauma to the brain,
> Diseases affecting the brain, such as stroke, brain tumor, brain infection, Alzheimer 's disease, syphilis with neurological involvement, other dementias, epilepsy, etc.
> A neurosurgical operation with removal of a part of the brain.
> Toxic causes: acute alcohol intoxication, cannabis intoxication or other neurotoxic substances, Korsakoff syndrome, carbon monoxide poisoning ...
Depending on the damaged brain area, the type of memory reached will be different. For example, any damage to the hippocampus region may result in semantic and / or procedural amnesia. This is the case in Alzheimer's disease, where the hippocampus gradually decreases in volume, and gradually loses more and more neurons, until spreading to other areas of the brain. This is why the first symptoms of Alzheimer's disease relate to memory.
The causes of amnesia can also be psychic. There are several types: hysterical conversion, somatization, dissociative amnesia. The latter is a kind of "black hole" that occurs after a psychological shock or trauma.
As for simple memory lapses, which happen to everyone, without being pathological, the causes can be very varied: fatigue, lack of interest, lack of concentration, stress, lack of self-confidence, lack of sleep, etc.