When a person has short-term memory loss, he has problems remembering recent events, according to the National Institutes of Health (NIH). Some forgetfulness can occur with age, as more brain cells die as a person ages. But serious short-term memory loss, which impairs the person's life, can be a sign of a more serious condition in which the brain is injured.
Alzheimer's Disease
A degenerative neurological condition, Alzheimer's disease is caused by tangles (protein buildups) and plaques (dead cell clusters). The NIH notes that short-term memory problems actually begin in the stage before Alzheimer's disease, called mild cognitive impairment. For example, a patient with mild cognitive impairment can forget recent conversations. In the early stage of Alzheimer's disease, the patient misplaces items and forgets events. Memory loss gets progressively worse.
Electroconvulsive Therapy
A treatment for depression, electroconvulsive therapy (ECT) reduces symptoms by triggering a seizure. While ECT quickly treats the symptoms of depression, it can cause some short-term memory loss, such as trouble remembering events that occurred during the treatment. The Mayo Clinic notes, however, that permanent memory loss is rare.
Brain Injury
When the brain is injured as a result of head trauma, important brain functions can be lost. Damage to the temporal lobe, which contains the hippocampus---the brain structure that consolidates short-term memories---can cause memory loss.
Wernicke-Korsakoff Syndrome
A neurological disorder linked to alcoholism, Wernicke-Korsakoff syndrome affects both short-term memory and long-term memory. The cause of Wernicke-Korsakoff syndrome is a deficit of thiamine, or vitamin B1, which is not properly absorbed when a person abuses alcohol. The disorder has two parts: Wernicke's encephalopathy and Korsakoff syndrome. The memory loss occurs in the second half, the Korsakoff syndrome, when the damage to the brain has become more severe. Even if the patient stops drinking alcohol, the short-term memory loss is permanent.
