Post-traumatic amnesia ( PTA ) is a state of confusion that occurs immediately after a traumatic brain injury (TBI) in which an injured person is disorienting and can not recall events that occurred after an injury. The person may not be able to say his name, where he is, and what time it is. As the memory continues again, the PTA is deemed to have been resolved. When PTA is in progress, new events can not be stored in memory. About a third of patients with mild head injury are reported to have a "memory island", in which patients can remember only a few events. During PTA, patient awareness is "overcast". Because PTA involves confusion in addition to the loss of typical amnesia memories, the term " post-traumatic confusion " has been proposed as an alternative.
There are two types of amnesia: retrograde amnesia (loss of memory formed just before the injury) and anterograde amnesia (problems with creating new memories after injury). Retrograde and anterograde forms can be referred to as PTA, or this term may be used to refer only to anterograde amnesia.
A common example in sports concussion is a quarterback capable of performing complex mental tasks to lead a soccer team after a concussion, but not having memories the next day from a part of the game that occurs after an injury. Retrograde amnesia sufferers may recover some memory later, but the memory does not come back with anterograde amnesia because they are not coded correctly.
The term "post-traumatic amnesia" was first used in 1940 in a paper by Symonds to refer to the period between injury and the return of a continuous memory, including at any time during an unconscious patient.
Video Post-traumatic amnesia
Measure the severity of traumatic brain injury
PTA has been proposed to be the best measure of head trauma severity, but this may not be a reliable outcome indicator. However, the duration of PTA can be attributed to the possibility that psychiatric and behavioral problems will occur as a consequence of TBI.
The classification system for determining the severity of TBI may use PTA duration alone or with other factors such as the Glasgow Coma Scale (GCS) score and the long-lost awareness (LOC) to divide TBI into mild, moderate, and severe categories. One common system uses all three factors and one using PTA alone is shown in the table on the right. PTA duration is usually correlated well with GCS and usually lasts about four times longer than unknowingly.
PTA is considered a sign of concussion, and is used as a measure to predict its severity, for example in the scale of concussion assessment. It may be more reliable to determine the severity of a concussion than GCS because the latter may not be sensitive enough; Patients with concussions often quickly regain GCS score 15.
A longer period of amnesia or loss of consciousness immediately after an injury may indicate a longer recovery time from residual symptoms of a concussion. Increased duration of PTA is associated with a high risk for TBI complications such as post-traumatic epilepsy.
Maps Post-traumatic amnesia
Assessment
PTA duration may be difficult to measure accurately; may be excessive (for example, if the patient is asleep or under the influence of drugs or alcohol for some time) or underestimated (eg, if some recall returns before continuous memory returns). The Galveston Orientation and Amnesia Test (GOAT) exists to determine how patient-oriented and how much material they can remember. GOAT is the most widely used standard scale for prospective assessment of PTA in the United States and Canada. This test consists of 10 items that assess the orientation and recollection of events before and after the injury. This can be used to assess PTA duration; this particular KAMU assessment has been found to predict functional outcomes measured by the Glasgow Results Scale, back to productivity, psychosocial function and distress.
An alternative to GOAT is the Postme Traumatic Westmead (WPTAS) Ammunition Scale (WPTAS) that checks not only orientation to people, places and times, but also the most important ability to consistently remember new information from one day to the next. It consists of twelve questions (seven orientation questions, and five memory items) and is given once daily, daily, until the patient gets a 12/12 perfect score on three consecutive days . Suitable for patients with moderate to severe traumatic brain injury. WPTAS is the most common post-traumatic amnesic scale used in Australia and New Zealand. A shortened version has been developed to assess patients with mild traumatic brain injury, PTA Scale Abbreviated Westmead (AWPTAS).
History
Initial documentation
C.P. Symonds
Although Franklin describes PTA, it was the British physician C. P. Symonds who first addressed specific symptom amnesios that often follow cerebral contusions, which are a special type of traumatic brain injury. Symonds observes that the patient remains "stuperose, restless and irritable" after restoring consciousness. He also identifies a day-to-day recovery period for this post-compulsive condition. Presumably, the shorter duration of PTA, which is now included in the definition, is not considered serious enough for documentation. Most importantly, it identifies the amnesia experienced by patients during this recovery period, and recommends the use of "formal tests for memory and retention" to assess recovery.
In the WWI army
Despite the lack of knowledge of the mechanism, the patient review seen during World War I showed symptoms of post-traumatic amnesia (PTA) in many soldiers. The term shell shock is used to refer to an acute psychological state accompanied by exposure to a shell explosion, and more generally, exposure to combat conditions. There are a number of documented cases of shock victims. These soldiers usually display dizziness, varying degrees of awareness, loss of personal information that is not traumatic, and a lack of normal self-awareness that lasts from hour to day. Many shock shell symptoms are very similar to PTA. The following excerpt from the case report illustrates the loss of personal information observed in one patient:
The researchers found that doctors have documented reports of combatants in which "[b] central and peripheral information about traumatic experiences is lost." Patients show gaps in memory memories for periods after trauma, sometimes up to the time of hospitalization, which could be several weeks later.
The initial assessment supports the role of concussion in causing these symptoms. Concussions can explain the anterograde amnesia and retrograde amnesia observed in the patient, as well as the period of fluctuating or delirium consciousness that is sometimes followed. However, many soldiers who show this amnesia effect do not suffer injuries that will cause a concussion. Consequently, there is controversy about the possible causes of PTA in this uncomplicated army, with the separation between supporters of Freudian repression and those who support the dissociative view of the condition. This dissociative view is ultimately supported, and noted for the fugue states seen in warriors considered to have been separated from normal consciousness.
Symptoms
The most prominent symptom of post-traumatic amnesia (PTA) is the loss of memory today. As a result, patients are often unaware of their condition and may behave as if they will live their ordinary lives. This can lead to complications if the patient is confined to the hospital and may cause agitation, distress and/or anxiety. Many patients report feeling as if they are "held back" and prevented from continuing their daily lives. Other symptoms include agitation, confusion, disorientation, and anxiety.
Patients also often display behavioral disorders. Patients may shout, swear and behave in an unavoidable manner. There are cases where patients who do not recognize anyone will ask family members or acquaintances they have not seen for years. Some patients exhibit childlike behavior. Other patients exhibit behavior that is not calm, friendly and affectionate. Although this behavior may seem less threatening because of its lack of aggressiveness, it may be equally alarming.
PTA patients are often unaware of their environment and will ask questions repeatedly. Patients may also have a tendency to wander, which can be of primary concern to those who have suffered additional injuries during trauma, such as injured limbs, as it may lead to deterioration of secondary injury.
Caution
Attention is the cognitive resource that contributes to many mental functions. The ability to attract attention requires a certain level of awareness, stimulation and concentration of consciousness, all mechanisms that are generally disturbed by traumatic brain injury. Attention involvement in a large number of cognitive processes has led to suggestions that attention deficits may act as underlying factors in the range of cognitive deficits observed in patients with post-traumatic amnesia (PTA).
Attention has been regarded as an important factor in healthy coding functions, verbal comprehension and new learning. Automatic attention processes (such as forward counting) are restored before simple memory capabilities (such as verbal material recognition tests) in individuals with mild to moderate brain injury. This means that the recovery of attention capability precedes the development of memory recovery after injury, helping to pave the way for regaining the ability to learn new. In the event of a more severe brain injury, the task of automatic attention tasks is restored before disorientation is completely lost.
One of the weaknesses of the method most commonly used in assessing PTA, Galveston Orientation and Amnesia Test (GOAT), is that it does not include an assessment of concern, which may help provide an indication of a better potential for recovery. By eliminating attention, this test eliminates some important aspects of a person's cognitive abilities.
In addition, assessing attention during the PTA period can help determine whether the patient is still in a PTA state or if they are suffering from a more permanent form of memory deficit. In patients with mild TBI, the damage consists primarily of diffuse axonal injury (extensive damage to white matter) without focal damage (damage to specific areas). Sometimes, brainstem injuries are also observed. In this case, there is the possibility of a deficit of attention without the correct state of amnesiac. In more severely damaged individuals, damage to the temporal lobes and frontal lobe serves as a good indication that amnesia will occur. Patients suffering from more chronic forms of memory impairment exhibit poor performance when tested on a PTA scale, making the distinction between two types of memory impairment extremely difficult. PTA patients exhibit poor simple reaction times, reduced information processing speed and reduced verbal fluency, all of which are attention deficits that can be used to distinguish these patients from those with more severe and permanent memory problems.
Communication skills
The effects of PTA on communication skills were studied using the Edinburgh Revised Functional Communication Profile (REFCP), which measures both linguistic elements (related to speech) and pragmatic elements (related to body language and other non-verbal communication skills). PTA has an effect on memory, perception and attention, all of which are important for communication. Patients exhibit mild deficits in verbal communication skills, and moderate to severe deficits in nonverbal communication skills such as maintaining eye contact, initiating greetings, and responding appropriately. Also, a negative correlation was found between the duration of episodes of PTA patients and their REFCP scores; the longer the PTA episode, the more severe the deficit in non-linguistic pragmatic skills. However, the small sample size of the study (only 10 males) means that the results should be interpreted with caution, as they may not generalize to larger samples or to the general population.
Test
Prior to the development of the current test for post-traumatic amnesia assessment (PTA), a retrospective method was used to determine the patient's condition, consisting of one or more interviews with the patient after the PTA episode was assessed to be over. The retrospective method, however, fails to explain the apparent clarity of patients who are still subjected to substantial disorientation, or the finding that recovery from post-traumatic amnesia is often characterized by a "memory island" (brief period of clarity). Failure to consider these facts may have a retrospective method that is biased to underestimate the length and severity of PTA episodes. Also, retrospective methods depend on retrospective memory, one's memory for past events, which is not very reliable in healthy individuals, and even less so in patients who have recently had traumatic brain injury (TBI). Patients may also unconsciously or consciously bias their answers because they want to appear healthier or sicker than they really are, or because of poor insight. Retrospective methods are also defective because there is no standard measurement procedure. Although retrospective methods may provide useful subjective data, it is not a useful tool for measurement or categorization.
GOAL
The Galveston Orientation and Amnesia Test (GOAT) is the most commonly used test for assessing PTAs in the United States and Canada. This test consists of 10 items that involve recalling events that occur just before and after the injury, as well as questions about disorientation. A score of 75 or more on this scale (out of a total score of maybe 100) corresponds to the termination of the PTA episode. GOALS usually classify orientations into three categories: orientation to person, orientation to place, and orientation to time. The idea behind these questions is that each of these classifications places great demand on patient memory and learning ability.
WPTAS and AWPTAS
The Westmead Post-Traumatic Amnesia Scale (WPTAS) is commonly used in Australia and New Zealand. It questions twelve questions that check the orientation to people, place and time, in addition to the ability to consistently remember new information from one day to the next. The scale is given once daily, until the patient scores 12/12 on three consecutive days. WPTAS is suitable for patients with moderate to severe traumatic brain injury. Shortened version of WPTAS, PTA Scale Abbreviated Westmead (AWPTAS) assessed patients with mild traumatic brain injury.
Weakness
Although GOAT has been shown to be beneficial in acute care, recent research has drawn attention to some of its drawbacks. GOAT orientation assessment may put too much focus on memory as the main mechanism behind the orientation. The range of cognitive and behavioral symptoms associated with PTA seems to indicate that patient disorientation is more than a memory deficit. As a result, it may be useful to incorporate other cognitive function tests, such as attention, that are related to memory and orientation.
Another recent study compared the success of GOAT and Orientation Log (O-Log) in predicting rehabilitation results, and found that, while O-Log and GOAT did the same as the size of PTA severity and duration, O-Log provides a more accurate picture of rehabilitation.
While KAMBING is a useful tool, these results suggest that using alternative methods to assess PTA can increase the amount of information available to physicians and can help predict the success of rehabilitation. The international cognitive panel (INCOG) panel has recommended the use of validated PTA scales such as CAMBRIDGE or WPTAS to assess PTA duration in patients with moderate to severe traumatic brain injury on a daily basis.
Severity
The severity of post-traumatic amnesia (PTA) is directly related to its duration, although longer duration does not always show more severe symptoms. The duration of PTA in patients with brain injury is a useful predictor of the expected long-term effects of injury, along with the duration of loss of consciousness (LOC), and scores on the Glasgow Coma Scale (GCS), which measures the degree of consciousness, with higher scores indicating the level higher functionality. A score of 3 shows total unconsciousness, and a score of 15 indicates a normal function.
In patients with PTA for duration:
Up to 1 hour - Very mild injury in severity and full recovery is expected. The patient may experience some minor post-concussive symptoms (eg headache, dizziness).
1 - 24 hours - Injuries are in severity and full recovery is expected. The patient may experience some minor post-concussive symptoms (eg headache, dizziness).
1 - 7 days - Severe injuries, and recovery may take weeks for months. The patient may be able to return to work, but may be less able than before the injury.
1-2 weeks - Injuries are severe, and recovery is likely to take months. Patients tend to experience long-term cognitive effects such as decreased verbal and non-verbal intelligence as well as decreased performance on visual tests. However, the patient should still be able to return to work.
2 - 12 weeks - Injuries are very severe, and recovery is likely to take a year or more. Patients tend to show a permanent deficit in memory and cognitive function, and patients may not be able to return to work.
12 weeks - very severe injuries and accompanied by significant disabilities that will require long-term rehabilitation and management. Patients are unlikely to return to work.
Note: returning work is meant to show back to a reasonable level of functionality, both in the professional and personal arena.
The long-term prognosis of PTA is generally positive. Many patients recover many cognitive functions, although they may not return to the state before the injury.
Pathophysiology
Pathophysiology is the study of changes in the physical, biological, and/or mental function of a person as a result of illness, injury, or other damage. At present, the pathophysiological mechanisms that produce post-traumatic amnesia are not fully known. The most common research strategy to clarify this mechanism is the examination of the functional abilities capability of people with post-traumatic amnesia (PTA) after traumatic brain injury.
Neurological Mechanism
Research on the effects of emotional trauma on memory retention and amnesia symptoms has shown that exposure to prolonged levels of extreme stress has a direct effect on the hippocampus. Increased stress levels can lead to increased production of enkephalin and corticosteroids, which can produce abnormal neural activity and disrupt long-term potentiation (neuronal mechanisms associated with learning) in the hippocampus. Individuals who have experienced recurrent sexual abuse during childhood or who have experienced combat show a significant decrease and atrophy from the hippocampal region of the brain. The amygdala, the area of ​​the brain involved in emotional regulation, may be involved in generating memory for some aspects of trauma. Although memory traces for trauma may be missing from the hippocampus, it may remain partially encoded in the form of emotional memory in the amygdala where it can then be recalled in flashback or partially recovered memory.
Diaschisis
Diaschisis refers to the sudden dysfunction of the part of the brain due to lesions in distant but connected neurons. Diaschisis is involved as playing an important role in PTA, more specifically in declarative memory disorders observed in patients who experience PTA episodes. The loss of function observed after traumatic brain injury, as well as the loss of consciousness occurring, is thought to be mediated by 'neural shock' associated with diaschisis.
Diaschisis was originally believed to be the result of disturbances in neural networks, but more recent evidence implies an increase in the activity rate of choline acetyltransferase, the enzyme responsible for the production of acetylcholine, as the primary cause. Based on these findings, diaschisis can be helped through the use of drugs that will reduce cholinergic activity (acetylcholine), and reduce the level of acetylcholine in the brain. This idea is supported by the fact that there is an increase in acetylcholine concentration in the brain after head injury. Animal studies have shown that bloating wounds in rats cause changes in the central nervous system's cholinergic system. This increase in acetylcholine levels has also been linked to behavioral suppression and unconsciousness, both of the PTA symptoms. In long-term recovery, acetylcholine levels associated with diaschisis may continue to play a role in maintaining memory deficits.
Brain imaging studies
Brain imaging techniques are useful for examining changes in the brain that occur as a result of damage. Metting et al. (2001) used a CT scan to examine the pathophysiologic damage in patients currently experiencing PTA episodes, patients with completed PTA, and non-PTA-controlled groups. Blood flow to the occipital lobe, the caudate nucleus, and gray matter from the frontal lobe were significantly reduced in patients who were scanned during the PTA episode. There was no visible difference between patients with completed PTA and control groups. This encouraging finding suggests a positive long-term prognosis of PTA; most patients return to normal levels of functioning. The frontal lobe is associated with explicit memory retrieval, and deficits in explicit memory tasks are often found in patients with PTA.
A working memory deficit is a common symptom in patients with PTA. The duration of the PTA episodes correlates with reduced blood flow to the right hemisphere, a finding that is consistent with a functional MRI study linking working memory with right frontal activity. The prefrontal cortex, which plays an important role in explicit memory retrieval, was also found to decrease nerve activation in patients who were scanned during the PTA episode. The researchers noted that the damage was associated with vascularization and nervous function, but not for structural injury, suggesting that PTA resolution depends on functional changes.
New memory and learning involve the cerebral cortex, subcortical projection, hippocampus, diencephalon and thalamus, areas often damaged as a result of TBI . Frontal lobe lesions may also play a role in PTA, as damage to these areas is associated with behavioral changes, including irritability, aggressiveness, disinhibition, and loss of judgment. Damage to this area may explain the unusual behavior that is often shown in PTA patients.
Accelerated forgetting
The researchers also found that individuals who experienced PTA showed accelerated forgetfulness. This contrasts with the normal forget observed by patients with normal amnesia associated with brain damage. The temporal lobes are often most susceptible to diffuse (widespread) and focal (more specific) effects of TBI and possibly temporal lobe lesions can explain the accelerated slowing observed in patients with PTA. This prediction is supported by findings that most patients who demonstrate fast forget also have lesions into the temporal lobes. Bilateral damage to the temporal lobe also causes severe anterograde amnesia, so the possibility of lesions in this area will be involved in PTA. Patients show a temporal gradient with memory loss, which means that old memories are preserved at the expense of newer memories. Temporal lobe damage has been associated with this kind of temporal gradient, since the old memory is less dependent on the hippocampus and thus less affected by the damage.
There is a significant relationship between individuals currently suffering from PTA and their performance on the Wechsler Adult Intelligence Scale (WAIS). Scores of those currently experiencing PTA episodes compared with individuals who previously suffered a traumatic brain injury that resulted in PTA. Those still suffering from PTA were significantly worse on WAIS verbal performance and subscale. Also, people in the early stages of PTA have a substantial disruption to the anterograde memory function. For example, in case reports of patients referred to as "JL", Demery et al. noted that his memory disorder was so severe after an injury that he forgot that he had attended the Major League Baseball game less than 30 minutes after returning to the center where he was treated.
The majority of available neuropsychological studies show that the medial temporal lobe is the most important system in the pathophysiology of PTA. However, there is little research done on this topic, and as new research is done, more information should be made about functionality in areas in PTA patients. One MRI study showed that long duration of PTA correlates with damage in the hemispheric and central regions, regardless of whether the duration of coma is relatively short. In patients with longer coma duration, deeper lesions in the central region are observed without extensive damage to the hemisphere region.
Rehabilitation
North Star Project
The North Star project was developed by researchers at McGill University. Researchers develop a "reality orientation", which involves discussing common facts (eg dates, times, names of family members, etc.) with amnesia patients twice daily in an effort to reduce their confusion during their early stages of recovery. Younger patients often have shorter amnesic episodes than older patients, especially those in the North Star group. Although more improvements were recorded in the North Star group than in the control group, the investigators found no statistically significant effect of their intervention.
Findings
A comprehensive literature analysis based on the early rehabilitative effects of traumatic brain injury concluded that there was no strong evidence linking any of the specific post-injury care practices to the reduced severity of the symptoms. However, even in the absence of a concrete correlation between specific rehabilitation programs and better outcomes, available evidence and research can provide many good suggestions for how to proceed with treatment. All rehabilitation strategies reviewed have a positive effect on recovery, but no more than others.
The most accurate measure to determine the length of amnesia is still a measure of behavior, the duration of post-traumatic amnesia episodes, rather than neuroimaging techniques or electrophysiological or biochemical techniques. The length of amnesia is also one of the most accurate predictors for determining cognitive problems later in life, even more than the duration of either a coma or a period of loss of consciousness. The duration of amnesia after TBI, therefore, can be very useful in planning the length and intensity of the rehabilitation program for people suffering from PTA.
Treatment
Vasopressin
Animal research
Initial studies have demonstrated vasopressin as a potential treatment for improving memory of patients living with post-traumatic amnesia (PTA). Lysine vasopressin, a modified form of vasopressin molecule, has a positive effect on memory when administered by injection to patients with amnesia from traumatic brain injury and Korsakoff syndrome. Subsequent animal studies with rats found similar results, especially in reluctance and avoiding learning tasks. Mice lacking adequate vasopressin, either due to genetic defects or hypophysectomy, show significant improvements in memory and learning functions when exogenous vasopressin is given. What is particularly encouraging is the finding that short treatment periods produce long-term improvements, both in humans and in rats. However, the PTA animal model is very limited, since the dimensions of self-awareness and orientation are almost impossible for an adequate model. PTA in animals, especially mice, is often observed post-trauma (usually post-surgery), but is often measured only in terms of learning disorders or unusual behavior.
Human studies
One subsequent human study found no vasopressin effect on memory. The insignificant results were associated with many potential weaknesses of the study, particularly small sample size, vasopressin inability penetrating the cerebral blood barrier when administered as nasal spray, inadequate dosage and the difference in severity of head injury between samples. However, Eames et al. (1999) found statistically significant improvement in some memory tests with vasopressin nasal spray use, with no adverse effects reported. Although the rate of improvement is mild, and can be attributed to various other factors of the rehabilitation program, the lack of adverse effects suggests that vasopressin is, at least, a possible increase for treatment regimens.
Norepinephrine agonist
Diaschisis, as mentioned earlier, has been linked to the PTA mechanism. The noradrenergic system can play a role in diaschisis. Norepinephrine, also known as noradrenaline, is a catecholamine neurotransmitter. Administering the norepinephrine receptor agonist (the substance that initiates cell response when binding to the receptor) in the patient promotes memory recovery and many other cognitive functions after traumatic brain injury. In contrast, norpinephrine antagonist administration slows the recovery, and may cause a deficit recovery when administered after recovery. Noradrenergic antagonists are not prescribed for the purpose of slowing memory recovery. Instead, these findings are based on the effects of other commonly prescribed drugs that occur to block noradrenergic receptors. The alpha-1 adrenergic receptors are particularly involved. Although not yet thoroughly investigated, there is potential for stimulants, which promote catecholamine release, to be an effective treatment in the early stages of recovery from brain trauma, and this positive effect can reduce PTA symptoms.
Other psychological disorders
Researchers have investigated the relationship between posttraumatic amnesia (PTA) resulting from traumatic brain injury (TBI) and the development of symptoms of post-traumatic stress disorder (PTSD) and acute stress disorder (ASD). 282 outpatients, who averaged 53 days post-TBI in their recovery, were divided into 4 groups: PTA episodes lasting less than 1 hour; PTA episodes lasted between 1 hour and 24 hours; The PTA episode lasts between 24 hours and one week; and the PTA episode lasts more than a week. The patient's personal details are used as a classified variable for age, sex, marital status, elapsed time between injury and assessment, and type of injury (motor vehicle accidents, pedestrians, assaults and others). Patients were given two self-report inventories: Impact of Event Scale (IES) and General Health Questionnaire (GHQ). IES measures the symptoms of PTSD and contains questions about intrusive traumatic events (eg nightmares) and avoidance behaviors associated with traumatic events (eg avoidance of specific locations). GHQ is used as an indicator of overall psychological health. The majority of subjects were in Group 1 (PTA episodes lasting less than 1 hour), injured in motor vehicle accidents, and men.
No statistical differences were found with regard to age, sex, marital status and type of injury. Increased severity of all brain damage indicators for the longest PTA period; in particular, the GCS score for this group decreased and the number of patients with abnormal CT scans increased. There was a significant difference in IES scores when comparing groups with the most serious PTA episodes, lasting less than one hour, for all other groups, with a duration of PTA episodes lasting more than one hour. Groups with PTA episodes lasting less than an hour have higher IES scores and more intrusive and avoidance symptoms. The fact that GHQ scores are constant across all groups, although there are differences in IES scores, suggests that both scores measure different phenomena.
Aging
Gray and white matter are both found in many areas of the brain, as well as throughout the central nervous system. Gray matter is more involved in nerve function, and white matter is more involved in the maintenance of nerves, as well as the arrangement of unconscious functions. However, both are important for memory and learning. The volume of gray and white matter in the aging individual's brain has been correlated with memory work and retention of cognitive function. The researchers hypothesized that lesions of gray and white matter would be greater in older individuals and in those with more severe traumatic brain injury, and longer PTA episodes, and gray and white matter volumes would be smaller on those who were injured at older ages. age. A group of 98 participants, mainly men, were examined using fMRI. The results support this hypothesis, leading researchers to show that the impact of traumatic brain injury becomes more severe with age.
Although gray and white matter volumes are reduced throughout the brain, the researchers note that the gray matter from the brain region of the neocortex is severely affected. This is consistent with the fact that older people who have experienced PTA exhibit greater cognitive impairment than the control group of individuals of the same age who have not experienced PTA. The duration of the PTA episode relates to the size of the gray matter lesion; longer PTA episodes correlate with larger gray matter lesions. Old age is also correlated with reduced glial activity. With less gray matter, patients are less able to retrieve memories effectively, because neuron function is impaired.
Controversy
On the topic of trauma and memory, Richard McNally (2005) writes that memory is not a videotape of our experience, which means that it is not an irreversible recording. The mechanism that takes memory involves activation of several areas of the brain. Similarly, the mechanisms that encode memory require the use of different parts of the brain. Any errors in the coding system will degrade memory, and there are many potential errors, such as distortion by emotion, or focus on peripheral details at the expense of central details. The latter example is a well-known phenomenon in which a person is robbed at gunpoint so annoyed by a gun that they have no time to encode the robber's face.
The wrong fetch failure as traumatic amnesia is not the same phenomenon as post-traumatic amnesia, which describes the amnesia for the traumatic pass time, not the amnesia for the trauma of the past. Usually, "depressed memory" is the term used to describe such traumatic amnesia; the experience was so horrible that adults could not process what had happened years before. The controversial topic of repressed controversy in psychology; many doctors argue for its sake, while researchers remain skeptical of its existence. A more worthy explanation for this is the childhood amnesia, a phenomenon that illustrates the fact that most children do not remember events in their lives before the age of three, partly because of the lack of development of cognitive elements such as language.
References
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