Amnesia

Head trauma is a very broad range as it deals with any kind of injury or active action toward the brain which might cause amnesia. Retrograde and anterograde amnesia is more often seen from events like this, an exact example of a cause of the two would be , which would cause both briefly for the receiving patient.

electroconvulsive therapy

Traumatic events are more subjective. What is traumatic is dependent on what the person finds to be traumatic. Regardless, a traumatic event is an event where something so distressing occurs that the mind chooses to forget rather than deal with the stress. A common example of amnesia that is caused by traumatic events is , which occurs when the person forgets an event that has deeply disturbed them.^[21] An example would be a person forgetting a fatal and graphic car accident involving their loved ones.

dissociative amnesia

Physical deficiencies are different from head trauma because physical deficiencies lean more toward passive physical issues. Examples of physical deficiencies include , neurological paraneoplastic syndromes such as anti-NMDA receptor encephalitis, and vitamin B12 deficiency.

Alzheimer's disease

is the inability to create new memories due to brain damage, while long-term memories from before the event remain intact. The brain damage can be caused by the effects of long-term alcoholism, severe malnutrition, stroke, head trauma, encephalitis, surgery, Wernicke–Korsakoff syndrome, cerebrovascular events, anoxia or other trauma.^[25] The two brain regions related with this condition are medial temporal lobe and medial diencephalon.^[26] Anterograde amnesia cannot be treated with pharmacological methods due to neuronal loss.^[27] However, treatment exists in educating patients to define their daily routines and after several steps they begin to benefit from their procedural memory. Procedural memory can be intact even when other forms of memory is not, although not always the case.^[28] Likewise, social and emotional support is critical to improving quality of life for those with anterograde amnesia.^[27] Fentanyl use by opioid users has been identified as a potential cause in a cluster of cases that occurred in Boston, Massachusetts.^[29]

Anterograde amnesia

is inability to recall memories before onset of amnesia. One may be able to encode new memories after the incident. Retrograde is usually caused by head trauma or brain damage to parts of the brain besides the hippocampus. The hippocampus is responsible for encoding new memory. Episodic memory is more likely to be affected than semantic memory. The damage is usually caused by head trauma, cerebrovascular accident, stroke, tumor, hypoxia, encephalitis, or chronic alcoholism. People with retrograde amnesia are more likely to remember general knowledge rather than specifics. Recent memories are less likely to be recovered, but older memories will be easier to recall due to strengthening over time.^[30] Retrograde amnesia is usually temporary and can be treated by exposing them to memories from the loss.^[31] Another type of consolidation (process by which memories become stable in the brain) occurs over much longer periods of time/days, weeks, months and years and likely involves transfer of information from the hippocampus to more permanent storage site in the cortex. The operation of this longer-term consolidation process is seen in the retrograde amnesia of patients with hippocampal damage who can recall memories from childhood relatively normally, but are impaired when recalling experiences that occurred just a few years prior to the time they became amnesic.^[32] In the case of LSJ, her case shows that retrograde amnesia can affect many different parts of knowledge. LSJ was not able to remember things from her child or adult life. She was not able to remember things that most people pick up in everyday life such as logos or the names of common songs.^[14]

Retrograde amnesia

is generally due to a head injury. Traumatic amnesia is often transient, but may be permanent or either anterograde, retrograde, or mixed type. The extent of the period covered by the amnesia is related to the degree of injury and may give an indication of the prognosis for recovery of other functions. Mild trauma, such as a car accident that results in no more than mild whiplash, might cause the occupant of a car to have no memory of the moments just before the accident due to a brief interruption in the short/long-term memory transfer mechanism. The patient may also lose knowledge of who people are. Having longer periods of amnesia or consciousness after an injury may be an indication that recovery from remaining concussion symptoms will take much longer.^[33]

Post-traumatic amnesia

Dissociative amnesia

is the loss of memory about one specific event. It is a type of amnesia that leaves a lacuna (a gap) in the record of memory in the cortex region of the brain. The cause of this type of amnesia is the result of brain damage to the limbic system which control memories and emotions.

Lacunar amnesia

(also known as infantile amnesia) is the common inability to remember events from one's own childhood. Sigmund Freud notoriously attributed this to sexual repression, while modern scientific approaches generally attribute it to aspects of brain development or developmental psychology, including language development, which may be why people do not easily remember pre-language events. Some research states that most adults cannot remember memories as early as two or three years old. Research suggests there are cultural influences that affect memories that are recalled.^[40] Researchers have found that implicit memories cannot be recalled or described. Remembering how to play the piano is a common example of implicit memory, as are walking, speaking, and other everyday activities that would be difficult to focus on if they had to be relearned every time one got up in the morning. Explicit memories, on the other hand, can be recalled and described in words. Remembering the first time meeting a teacher is an example of an explicit memory.^[41]

Childhood amnesia

is a well-described medical and clinical phenomenon. This form of amnesia is distinct in that abnormalities in the hippocampus can sometimes be visualized using a special form of magnetic resonance imaging of the brain known as diffusion-weighted imaging (DWI). Symptoms typically last for less than a day and there is often no clear precipitating factor or any other neurological deficits. The cause of this syndrome is not clear. The hypothesis of the syndrome includes transient reduced blood flow, possible seizure or an atypical type of a migraine. Patients are typically amnestic of events more than a few minutes in the past, though immediate recall is usually preserved.

Transient global amnesia

is the inability to remember where, when or how previously learned information has been acquired, while retaining the factual knowledge.^[42] When individuals are unable to remember, false memories can occur and cause great confusion.^[43]

Source amnesia

can result from long-term alcoholism or malnutrition. It is caused by brain damage due to a vitamin B₁ deficiency and will be progressive if alcohol intake and nutrition pattern are not modified. Other neurological problems are likely to be present in combination with this type of amnesia, such as problems with the medial temporal lobe and frontal lobe dysfunction.^[44] Korsakoff's syndrome is also known to be connected with confabulation. The person's short-term memory may appear to be normal, but the person may have a difficult time attempting to recall a past story, or with unrelated words, as well as complicated patterns.^[45] Korsakoff's syndrome is unique because it involves both anterograde and retrograde amnesia.^[44]

Korsakoff's syndrome

is intentionally caused by injection of an amnestic drug to help a patient forget surgery or medical procedures, particularly those not performed under full anesthesia, or likely to be particularly traumatic. Such drugs are also referred to as "premedicants". Most commonly, a 2-halogenated benzodiazepine such as midazolam or flunitrazepam is the drug of choice, although other strongly amnesic drugs such as propofol or scopolamine may also be used for this application. Memories of the short time-frame in which the procedure was performed are permanently lost or at least substantially reduced, but once the drug wears off, memory is no longer affected.

Drug-induced amnesia

can arise in a variety of circumstances (for example, committing an offence, child sexual abuse) resulting in PTSD. It has been claimed that it involves a narrowing of consciousness with attention focused on central perceptual details and/or that the emotional or traumatic events are processed differently from ordinary memories.

Situation-specific amnesia

is a rare and unrecognized form of temporal lobe epilepsy, which is typically an episodic isolated memory loss. It has been recognized as a treatment-responsive syndrome congenial to anti-epileptic drugs.^[46]

Transient epileptic amnesia

affects semantic memory and primarily expresses itself in the form of problems with language use and acquisition.^[47] Semantic amnesia can lead to dementia.^[48]

Semantic amnesia

(otherwise known as depression-related cognitive dysfunction) is a condition where mental cognition can be temporarily decreased. The term pseudodementia is applied to the range of functional psychiatric conditions such as depression and schizophrenia, that may mimic organic dementia, but are essentially reversible on treatment. Pseudodementia typically involves three cognitive components: memory issues, deficits in executive functioning, and deficits in speech and language. Specific cognitive symptoms might include trouble recalling words or remembering things in general, decreased attention, control and concentration, difficulty completing tasks or making decisions, decreased speed and fluency of speech, and impaired processing speed. People with pseudodementia are typically very distressed about the cognitive impairment they experience. With in this condition, there are two specific treatments that have been found to be effective for the treatment of depression, and these treatments may also be beneficial in the treatment of pseudodementia. Cognitive behavioral therapy (CBT) involves exploring and changing thought patterns and behaviors in order to improve one's mood. Interpersonal therapy focuses on the exploration of an individual's relationships and identifying any ways in which they may be contributing to feelings of depression.

Pseudodementia