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A holistic perspective on Post-traumatic amnesia 

Specialists at St Andrew’s Healthcare explain how clients are supported through PTA

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Post-traumatic amnesia (PTA) can be defined as the period following traumatic brain injury (TBI) during which continuous memories are unable to be established.

This is the time after a period of unconsciousness when the injured person is conscious and awake, but is behaving or talking in a bizarre or uncharacteristic manner.

The terminology of PTA is misleading as the name alludes to a single primary deficit in memory. While the inability to consolidate new memories or anterograde amnesia is the hallmark of PTA, further characteristics include impairment in orientation, attention and executive functioning along with retrograde amnesia and disinhibition

This article is based on a narrative review supported by the clinical experience of delivering interventions following traumatic brain injuries in patients on the brain injury assessment ward, at St Andrew’s Healthcare. The review included the definition of PTA, presentation, assessments and management. 

Pathophysiology

PTA can occur when the force of an injury results in breakage, bruising and/or swelling of the axons with the consequence that message pathways are interrupted and/or broken. This is commonly described as Diffuse Axonal Injury (DAI). Diffuse axonal injury has been shown to be the main determinant of the relationship between PTA and severity of injury.

The amnesia resulting from trauma may be retrograde amnesia, particularly where there is damage to the frontal or anterior temporal regions. However, in some cases, anterograde amnesia develops several hours after the injury. 

PTA may be either short term or longer-lasting, in some cases over a month, but is rarely permanent. When continuous memory returns, the person can usually function normally.

Retrograde amnesia sufferers may partially regain memory later, but memories are never regained with anterograde amnesia because they were not encoded properly. Memories from just before the trauma are often completely lost, partly due to the psychological repression of unpleasant memories (psychogenic amnesia), and partly because memories may be incompletely encoded if the event interrupts the normal process of transfer from short-term to long-term memory.

There is also some evidence that traumatic stress events can actually lead to a long-term physical reduction of the volume of the brain’s hippocampus, an organ integrally involved in the making and processing of memories.

Why is PTA important?

PTA has long been considered one of the strongest predictors of global outcome in severe TBI, and it is used as an instrument for determining the required level of patient supervision, as well as the timing and planning of discharge.

In addition, PTA has been demonstrated to have more precise predictability of outcome, in terms of functional independence level, disability severity, and determining the level of required supervision than either the Glasgow Coma Scale and the presence of loss of consciousness and cognitive impairment in TBI. 

Clinical presentation and MDT assessment – the need to undertake a comprehensive multidisciplinary assessment

Patients with PTA may present with confusion, agitation, distress and anxiety. Other features seen are uncharacteristic behaviours such as violence, aggression, swearing, shouting, disinhibition, inability to recognise familiar people, and a tendency to wander. However, in other cases, individuals may be uncharacteristically quiet, docile, loving and friendly. Other features may include headaches, nausea, vomiting, dizziness, unsteady gait and intolerance to bright light or loud noise*

In all patients, it is essential to undertake a comprehensive multidisciplinary assessment of their health, impairments, as well as care and support needs.  This enables staff to provide appropriate levels of support and intervention and should include neurological impairment, cognitive and communication abilities, eating and drinking  abilities, nutrition and hydration status and psychological and behavioural difficulties. 

The assessment should include the gathering of a comprehensive medical, psychological, psychiatric, occupational, educational, forensic and social history including any history of substance misuse. This will involve obtaining information from a variety of sources including interviews with family and friends and a detailed review of all multisource case records. The assessment should continue after the period of PTA has ended as the person progresses to the rehabilitation phase.

There should also be consideration of the use of the appropriate legal framework, such as detention under the Mental Health Act or provisions of the Mental Capacity Act during treatment and hospital stay.

The importance of family and friend engagement

It is important to work with the family and friends of the patient to help increase their awareness and understanding of the presentation and the likely prognosis. It can also sometimes be beneficial to the patient if visits are short and to acknowledge that too many visitors at once may be overwhelming and difficult for the patient to manage. All this will help the family understand the patient’s need for rest and quiet without excessive stimulation.

At times it may be better just to sit quietly with the person rather than engage in too much conversation which the person may find overwhelming and may struggle to follow.

Protecting a person’s right to privacy

Protecting the patient’s right to privacy and dignity is also an important consideration for the treating team. The family should be supported to think about who should be permitted to visit. The patient may behave in a manner which is out of character and perhaps embarrassing for them and it may be helpful to wait until the patient is more settled and potentially more able to communicate effectively and appropriately. 

Visitors may find it appropriate to visit on a rota, especially if they feel unable to leave the patient without familiar faces for any length of time. It is also useful to provide guidance on how best to support communication with the patient.

Testing 

The Westmead Post-Traumatic Amnesia Scale (WPTAS) is the most commonly used method for measuring PTA (Kosch et al, 2010). WPTAS is a standardised and validated instrument which is suitable for patients with moderate-to-severe traumatic brain injury. It is a prospective measure of PTA and has been shown to have a high level of interrater reliability.

The scale contains 12 questions related to orientation and memory. These include seven in relation to normal day-to-day orientation and five for testing the laying down of new information as well as autobiographical memory, such as age and date of birth. It can be conducted by any trained member of the multidisciplinary team in a variety of settings.

A care approach for people suffering with PTA

The care of a patient suffering from PTA requires a multidisciplinary approach that addresses the patient’s environment, their interactions within that environment and their cognition and behaviour

Patients with PTA require a consistent team approach to create and maintain a low-stimulus, quiet and supportive environment. These patients require a lot of rest with only short periods of stimulus. The following are recommended: 

  • To be nursed in a single room where possible, in a quiet and calm environment
  • Reduction or minimisation of external stimuli
  • Develop a consistent routine and structure. This will include clustering activities so patients are not overwhelmed, and allowing enough rest in between activities or tasks
  • Carefully managing visits
  • Create a familiar environment; using a few key personal objects and photos.
  • Clear communication within the multidisciplinary team, by using appropriate yet discreet signage on the patients’ room door to notify all staff that the patient has PTA 
  • Using a modified approach to ward rounds, assessment, meals and care. 
  • Keeping instructions simple during communication 
  • Appropriate Occupational Therapy and nursing interventions during PTA to include introducing the patient to simple tasks such as personal care. 
  • Family support by the multidisciplinary team to ensure a focus on education and the provision of support for family and friends
  • An understanding that management strategies for patients who present with aggression that involve negotiation and problem solving are unlikely to be successful
  • The use of sedation to manage behavioural problems to reduce the patient’s level of arousal can increase confusion and prolong agitation as indicated by inconclusive studies relating to this area.
  • Restraints should also be avoided as they can lead to greater agitation.

Our experience of PTA at St Andrew’s Healthcare

The Brain Injury Assessment unit, Tallis ward, at St Andrew’s Healthcare often receives referrals for patients with PTA who present with severe and challenging behaviour. The team has adopted a holistic, multidisciplinary approach based on the points described above. This includes ascertaining a robust and comprehensive history from family and other professionals alongside assessments undertaken in relation to physical health, functional ability, cognition, behaviour and communication. 

Physical health considerations include seizure management, mobility and falls assessments, dysphagia and nutritional assessments and ongoing maintenance of skin integrity. Each of these is modified and adapted to the individual patient and their presentation at the time. Environmental adaptations like the use of an extra care area on the ward associated with concerted efforts to reduce external stimuli are also employed. 

Assessments related to the use of appropriate and least restrictive legal frameworks is usually continuous and relate to timely and decision specific capacity assessments, including those related to consent to treatment and care.  

This wide range of comprehensive interventions enable the team to effectively implement risk manage and treatment strategies to safely support patients through an episode of Post Traumatic Amnesia to reach a point where they can embark on their rehabilitation journey. 

By: Dr Vishelle Kamath (consultant neuropsychiatrist – St Andrew’s Healthcare)

Dr Sanjith Kamath (executive medical director – St Andrew’s Healthcare)

Dr Awut Majak (speciality doctor – St Andrew’s Healthcare)

To find out more about St Andrew’s brain injury services visit Stah.org/brain-injury

* (Liersch et al, 2020: Liersch, K., Gumm, K., Hayes, E., Thompson, E. and Henderson, K. (2020). TRM 01.01 POST TRAUMATIC AMNESIA SCREENING AND MANAGEMENT GUIDELINE Trauma Service Guidelines Title: Post Traumatic Amnesia Screening and Management Developed by: K. Gumm, T, Taylor, K, Orbons, L, Carey, PTA Working Party Created: Version 1.0, April 2007.

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