Problems and Pitfalls in the Assessment of Posttraumatic Amnesia

Interaction of discourse processing impairments, communicative participation, and verbal executive functions in people with chronic traumatic brain injury

Introduction

Especially in the chronic phase, individuals with traumatic brain injury (TBI) (IwTBI) may still have impairments at the discourse level, even if these remain undetected by conventional aphasia tests. As a consequence, IwTBI may be impaired in conversational behavior and disadvantaged in their socio-communicative participation. Even though handling discourse is thought to be a basic requirement for participation and quality of life, only a handful of test procedures assessing discourse disorders have been developed so far. The MAKRO Screening is a recently developed screening tool designed to assess discourse impairments. The test construction is based on psycholinguistic frameworks and the concept of macro-rules, which refer to cognitive functions responsible for organizing and reducing complex information (e.g., propositional content) in discourse.

Aim

The aim of our study was to investigate discourse processing in IwTBI in different tasks and to assess problems in communicative participation in the post-acute and chronic phase. In this context, we also aimed to analyze the influence of the severity of the initial impairment and the verbal executive abilities on the discourse performance. Additionally, the impact of macrolinguistic discourse impairments and verbal fluency on perceived communicative participation was targeted in our analysis.

Methods

Data from 23 IwTBI (moderate to severe) and 23 healthy control subjects have been analyzed. They completed two subtests of the MAKRO screening: Text production and Inferences. Discourse performance was examined in relation to measures of semantic fluency and verbal task-switching. Socio-communicative problems were evaluated with the German version of the La Trobe Communication Questionnaire (LCQ).

Results

IwTBI showed lower test results than the control group in the two subtests of the MAKRO-Screening. Difficulties in picture-based narrative text production also indicated greater perceived difficulties in communicative participation (LCQ). We also found that the subject's performance on the MAKRO-Screening subtests can partly be explained by underlying dysexecutive symptoms (in terms of verbal fluency and verbal task switching) and the severity of their injury. The preliminary results of our study show that cognitive-linguistic symptoms in IwTBI are also evident in the chronic phase. These can be detected with procedures referring to the discourse level, such as the MAKRO-Screening. The assessment of discourse performance should be an integral part in the rehabilitation of IwTBI in order to detect cognitive-linguistic communication disorders and to evaluate their impact on socio-communicative participation.

Aspects of Cognitive Impairment Associated with Agitated Behaviour during Post-traumatic Amnesia

OBJECTIVES

Post-traumatic amnesia (PTA) is a transient period of recovery following traumatic brain injury (TBI) characterised by disorientation, amnesia, and cognitive disturbance. Agitation is common during PTA and presents as a barrier to patient outcome. A relationship between cognitive impairment and agitation has been observed. This prospective study aimed to examine the different aspects of cognition associated with agitation.

METHODS

The sample comprised 82 participants (75.61% male) admitted to an inpatient rehabilitation hospital in PTA. All patients had sustained moderate to extremely severe brain injury as assessed using the Westmead Post-Traumatic Amnesia Scale (WPTAS) (mean duration = 42.30 days, SD = 35.10). Participants were assessed daily using the Agitated Behaviour Scale and WPTAS as part of routine clinical practice during PTA. The Confusion Assessment Protocol was administered two to three times per week until passed criterion was achieved (mean number assessments = 3.13, SD = 3.76). Multilevel mixed modelling was used to investigate the association between aspects of cognition and agitation using performance on items of mental control, orientation, memory free recall, memory recognition, vigilance, and auditory comprehension.

RESULTS

Findings showed that improvement in orientation was significantly associated with lower agitation levels. A nonsignificant trend was observed between improved recognition memory and lower agitation.

CONCLUSIONS

Current findings suggest that the presence of disorientation in PTA may interfere with a patient's ability to understand and engage with the environment, which in turn results in agitated behaviours. Interventions aimed at maximizing orientation may serve to minimize agitation during PTA.

More than amnesia: prospective cohort study of an integrated novel assessment of the cognitive and behavioural features of PTA

Background and Objective:

Post-traumatic amnesia (PTA) is an early significant stage of recovery from traumatic brain injury (TBI). Current prospective PTA scales do not assess the full range of PTA symptomatology. This study conducted a novel integrated assessment of cognition and behaviour during PTA.

Method:

Twenty-four moderate-to-severe TBI participants in PTA and 23 TBI controls emerged from PTA were matched for age, gender, and years of education. All completed PTA measures (Galveston Orientation and Amnesia Test: GOAT, Westmead Post-traumatic Amnesia Scale: WPTAS), a cognitive battery; and behaviour ratings scored by 2 independent raters (informant and staff).

Results:

Significantly poorer performance was found during PTA for attention, processing speed, delayed verbal free recall and recognition, and visual learning. A large effect size was found for category fluency only. Behaviour ratings were significantly higher during PTA. Five behaviours were rated as high frequency (>50%) by both raters: Inattention, Impulsivity, Sleep Disturbance, Daytime Arousal, and Self-Monitoring. Prospective PTA measures produced significantly different duration estimates from 2 days (GOAT vs. WPTAS 1st day) to 9 days (WPTAS 1st day vs. 3-day). The WPTAS correlated most highly with processing speed and language tasks; whilst the GOAT correlated most highly with language and executive control of verbal memory.

Conclusion:

New prospective measures are needed that integrate core cognitive and behavioural features are brief, easy to administer, and capable of measuring emergence. The term PTA is a misnomer that requires revision to better accommodate the clinical syndrome.

Comparing the Westmead Posttraumatic Amnesia Scale, Galveston Orientation and Amnesia Test, and Confusion Assessment Protocol as Measures of Acute Recovery Following Traumatic Brain Injury

BACKGROUND

The duration of the acute period of recovery following traumatic brain injury (TBI) remains a widely used criterion for injury severity and clinical management. Consensus regarding its most appropriate definition and assessment method has yet to be established.

OBJECTIVE

The present study compared the trajectory of recovery using 3 measures: the Westmead Post-Traumatic Amnesia Scale (WPTAS), the Galveston Orientation and Amnesia Test (GOAT), and the Confusion Assessment Protocol (CAP). Patterns of symptom recovery using the CAP were explored.

PARTICIPANTS

Eighty-two participants with moderate to severe TBI in posttraumatic amnesia (PTA) on admission to an inpatient rehabilitation hospital.

DESIGN

Prospective longitudinal study.

OUTCOME MEASURES

Length of PTA (days), agreement between measures (%, κ coefficient), and pattern of symptom recovery.

RESULTS

Participants emerged from PTA earliest on the CAP followed the GOAT, and last on the WPTAS. There was good agreement between the CAP and the GOAT as to PTA status, but both tests had poor agreement with the WPTAS. Of patients considered out of PTA on the CAP, the majority exhibited signs of amnesia on the WPTAS and one-third had clinical levels of agitation.

CONCLUSION

The WPTAS identifies a later stage of PTA recovery that requires specialized management due to ongoing amnesia and agitation. The CAP and the GOAT are less sensitive to this extended period of PTA.

Opiate analgesics and testing of post traumatic amnesia in school-aged children

OBJECTIVE

To assess the validity of the Westmead PTA scale in school-aged children treated with opiate analgesics.

METHOD

Twenty-eight hospitalized children without brain injury, aged between 8 and 16 years treated with opiate analgesics for pain relief following surgery were tested on the Westmead PTA scale. Pain and stress levels were also self-reported each day.

RESULTS

Only 29% (n = 7) of children assessed over four days obtained a maximum score of 12/12 on three consecutive days, thus 71% would have been deemed to have been in PTA when they were not. The percentage of children who obtained a maximum score significantly decreased over consecutive days of assessment, due to an increase in error rate on picture memory items. Self-reported pain and stress ratings were not correlated with PTA scores.

CONCLUSIONS

Opiate analgesia can disrupt performance on the Westmead PTA scale in school-aged children resulting in a high false-positive error rate. It is therefore important to record pain medication schedules and interpret results cautiously when opiate analgesia is used following a TBI. Alteration of the method of administration of the memory items should be researched as this may increase the validity of the scale for children with TBI treated with opiate analgesics.

Traumatic brain injury and post-traumatic amnesia: a retrospective review of discharge outcomes

PRIMARY OBJECTIVE

To investigate if patients with traumatic brain injury, who are discharged to the community before emergence from post-traumatic amnesia (PTA), experience more adverse outcomes than those discharged after emergence from PTA.

RESEARCH DESIGN

A retrospective review of previously collected data and medical records.

METHODS AND PROCEDURES

Occurrences of adverse events including hospital readmissions, disengagement from follow-up services, non-compliance with discharge precautions, support system breakdown or undue carer strain at the post-discharge clinic review were recorded. The Glasgow Outcome Scale - Extended (GOS-E) and Supervision Rating Scale (SRS) were completed, retrospectively. Twenty-seven patients discharged to the community, prior to emergence from PTA, were compared to 20 patients discharged within seven days of emergence from PTA.

MAIN OUTCOMES AND RESULTS

Patients discharged prior to emergence from PTA did not experience an increase in adverse outcomes and showed a higher level of engagement in follow-up services (p = 0.015). There was no difference between groups in the improvements from discharge to clinic review on the GOS-E (p = 0.113) and SRS (p = 0.165).

CONCLUSIONS

Patients can be discharged prior to emergence from PTA, if all other discharge criteria have been met, without an increase in adverse outcomes.

Recovery of components of memory in post-traumatic amnesia

PRIMARY OBJECTIVE

Post-traumatic amnesia by definition indicates significant impairment of new learning ability, however very few studies have, examined the natural history and resolution of memory and new learning during PTA. Those studies which have, tended to examine orientation separately from the memory processes required to achieve orientation. Analysis of the order of recovery of the items of the Westmead PTA scale was used to examine recovery of memory and new learning capacity.

METHODS

The results of daily assessment of 34 patients with traumatic brain injury (TBI) on the Westmead PTA scale were analysed for order of recovery.

RESULTS

The pattern of rank order of item recovery indicated that Date of Birth recovered consistently first. There was variability in the remaining items, however items reflecting long-term memory tended to recover second and items reflecting simple new learning followed. Recall of all three pictures reflecting complex new learning recovered last.

CONCLUSION

The pattern of recovery of memory and new learning during PTA reflects a number of complex, inter-related variables including; the familiarity with the information, amount of rehearsal both before and since the accident and the number of cues available in the environment.

Sequence of recovery during the course of emergence from the minimally conscious state

OBJECTIVE

To document and examine recovery profiles of persons during the course of emergence from a minimally conscious state (MCS) after traumatic brain injury (TBI).

DESIGN

Case series.

SETTING

Participants in an inpatient brain injury rehabilitation program.

PARTICIPANTS

Nine people with TBI who emerged from MCS.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The Western Neuro Sensory Stimulation Profile.

RESULTS

In all cases, stereotyped (nonreflexive) movement was the first behavior to resolve, yet by itself it was never sufficient to indicate emergence from the MCS. Two of the 9 patients showed consistent object manipulation before all 3 elements of functional communication. Conversely, in 2 patients, all 3 components of functional communication emerged before object manipulation. In the remaining 5 patients, object manipulation occurred along with components of functional communication.

CONCLUSIONS

During the course of data collection, issues were raised about differentiation between the MCS and posttraumatic amnesia. The data are also discussed within the context of the work of Giacino et al and the development of their scale to measure duration of the MCS. These data support the theory that functional communication and object manipulation are the 2 key indicators of emergence from MCS.

Predicting duration of posttraumatic amnesia (PTA) from early PTA measurements

OBJECTIVES

To determine a set of variables that would reliably predict duration of posttraumatic amnesia (PTA) in patients with traumatic brain injury and to test the efficacy of the model.

DESIGN

Simultaneous standard multiple regression analyses.

PARTICIPANTS

Two independent samples of patients with traumatic brain injury who were in the early stages of PTA: a test sample (n = 61) and a cross-validation sample (n = 25).

MAIN OUTCOME MEASURE

The Modified Oxford PTA Scale (MOPTAS) is a 12-item test measuring orientation (8 items) and anterograde memory (4 items). The Galveston Orientation and Amnesia Test (GOAT) was also used on a subset of the test sample.

PROCEDURE

Patients were examined daily until they emerged from PTA.

RESULTS

A statistically significant model, using three predictor variables, was derived that reliably predicted duration of PTA, accounting for 89% of the variance. A second model, using two predictor variables readily available to the clinician (day posttrauma on which PTA testing began and aggregate PTA scores over the first 5 days of testing) had comparable predictive accuracy. A third model, using GOAT data, was also statistically significant and successfully accounted for 72% of the variance. The MOPTAS model showed excellent application to an independent (validation) sample, with an intraclass correlation coefficient between observed and predicted durations of PTA of 0.95. Regression equations for all three models are provided to enable calculation of the predicted duration of PTA.

CONCLUSIONS

These models can be readily applied in clinical practice and will provide clinically useful estimates of the duration of PTA within the first week of testing after admission to rehabilitation. This information will be important in terms of family counseling and planning of rehabilitation programs.