The Importance of Early Neurocognitive Assessment in Children Recovering from Brain Injury

By: Gillian A. Hotz, PhD, Co-Director Pediatric Brain & SCI Program, Associate Research Professor, Department of Neurosurgery & The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine

With the advancements in neuroimaging that reports structural, physical and metabolic changes of the brain, neuropsychological testing is still essential in order to assess neurocognitive functioning.  Neurocognitive assessment during the course of recovery from a traumatic (TBI) or acquired brain injury (ABI) is essential also when developing rehabilitation goals. A clinical need exists for a standardized neurocognitive and language functioning test that is specifically designed for children and adolescents with brain injuries. Such a test is required in order to: 1) assess current skill levels 2) obtain objective data for tracking recovery (Adelson, et al., 2003) and 3) the information produced by such a test may also be used in order to fulfill the justification for continued inpatient and outpatient services and to make recommendations to return to the classroom. The Pediatric Test of Brain Injury (PTBI) was created to specifically address these issues so that effective recommendations may be made for treatment during recovery and for school reintegration.

Problems with the current methodology for neurocognitive assessment

1. Lack of Developmental Perspective

Currently, in order to assess a child’s neurocognitive–linguistic abilities at various key points during recovery from brain injury (e.g., at baseline, 1 month, 3 months, 6 months, 12 months, and beyond), clinicians must adapt tools that were designed for other purposes, or may need to sample a wide range of domains by administering a lengthy neuropsychological test battery which is not appropriate or would be valid during the acute phases of recovery. What is commonly found in the medical records is an initial Glasgow Coma Scale (Teasdale & Jennett, 1974), which rates basic functions and levels of consciousness in the earliest stages following injury. It is used frequently with children and adolescents, although it was not intended for pediatric populations and importantly, it does not allow for developmental considerations.

TBI involves a cascade of interrelated processes that occur following the initial insult to the central nervous system (Gennarelli & Graham, 1998). The main difference between recovery from brain injury in adults versus children is that the brain of the child is faced with the maturational challenge of moving from one developmental level to the next, whereas in the mature brain of the adult, most skills are already fully developed (Dennis, 2000). An added challenge in pediatric TBI is that the functions that have not yet developed are particularly vulnerable to significant residual cognitive impairment (Anderson, Catroppa, Morse, Haritou, & Rosenfeld, 2005). The tests currently being used on children do not account for the fact that age-based functional neural plasticity involves not only recovery of old skills, but also monitoring the acquisition of new skills. This is problematic because in order to measure new skill acquisition and to accurately assess age-appropriate competency, careful consideration of many developmental indices is critical.

Considering the complexity of the biological recovery process and the uncertainties of the processes of functional neural maturation, the accurate assessment and prediction of prognosis following pediatric brain injury has been questionable with the current testing methods.

2. Lack of Longitudinal Considerations

It has been empirically shown that neurocognitive deficits that are not detectable in the acute phase following TBI may emerge over development as more complex skills become necessary (for review, see: (Gil, 2003)). For this reason, any neurocognitive evaluations that are designed to be performed solely during the time period immediately following injury may not be valid over time if such factors are not accounted for in the testing measure. Currently, the Children’s Orientation Amnesia Test (Ewing-Cobbs, Levin, Fletcher, Miner, & Eisenberg, 1990), which was developed to assess cognition in children, screens only orientation levels and post-traumatic amnesia. This test does not account for any deficits that are present and remain undetectable during the acute phase and as the child recovers.

Additionally, in children (and adults) with ABI, such as brain tumors, long-term outcomes are difficult to predict due to the lack of  neurocognitive endpoints (Meyers & Brown, 2006) which enable the establishment of a pre-treatment baseline. Further complicating the unique challenge of serially assessing children with ABI is the fact that the tests may change over time due to the need to make the tests developmentally appropriate, and thereby making longitudinal comparisons quite difficult.

3. Subjective Rating Systems

A newer instrument, the Cognitive and Linguistic Scale (Slomine, Eikenberg, Salorio, Suskauer, Trovato, & Christensen, 2006), is designed to assess cognitive–linguistic abilities following brain injury in children, but it uses a relatively subjective rating system. Also, it was not designed to be of specific relevance to the curricular expectations of schools, which is a major factor to be considered when assessing a child’s prognosis following brain injury. Since insurance companies and other third party payers make it difficult to provide authorization and press for reduced length of stay for acute and rehabilitation care of children following brain injury, it is even more important to have an objective, standardized measure that can identify and properly assess neurocognitive recovery throughout recovery. Furthermore, in instances where children with brain injury are prematurely discharged from acute care facilities due to limited economic resources, valid concerns have been raised (Glang, Tyler, Pearson, Todis, & Morvant, 2004) that some type of universal documentation regarding the student’s status and level of recovery is available to support the child’s transitions across settings.

4. Ecological, Contextualized Observations

Ecological, contextualized observations are invaluable to the assessment process; however, it is difficult to make such observations when the child is hospitalized or in a rehabilitation setting (Ylvisaker, Turkstra, & Coelhpo, 2005). Further complicating factors in this type of setting are the array of emotional issues; anxiety, depression, irritability, and impulsivity, behavioral issues and  impairments in memory, attention, communication skills, and executive functioning skills, (Franzen, 2000) and social consequences observed in  poor school performance and difficulty in performing daily activities (Yeates, et al., 2004).

Time For A New Kind of Test

The Pediatric Test of Brain Injury (PTBI) is designed to assess, in approximately 30 minutes, the neurocognitive, language, and literacy abilities that are relevant to the school curriculum of children and adolescents aged 6-16 years who are recovering from brain injury. The test is best administered by speech language pathologists, psychologists or other specialists trained to assess children and adolescents with cognitive and language impairments. More specifically, it is intended to help clinicians: 1) establish baseline levels of cognitive-linguistic abilities in the acute stages of recovery, 2) identify strengths and weaknesses for informing intervention, 3) monitor functional changes and track recovery patterns, and 4) guide decision-making related to school reintegration and educational performance. (Hotz, Helm-Estabrooks, Nelson, Plante, 2010).

The PTBI is a different kind of test because it is a criterion-referenced test that measures a range of developmentally appropriate abilities. It is criterion-referenced in that it provides cut-off scores for each subtest. This objective measurement can be useful in describing age-related ability ratings and severity classifications. The PTBI is able to evaluate abilities that are of particular concern for children with brain injury.  

Most literature reviewing pediatric brain injury discusses typical areas of impairment which include a wide range of deficits involving arousal, attention, perception, concentration, speed of processing, memory (immediate and delayed), language, learning, thinking, reasoning, problem solving and executive functioning (Ylvisaker, Hanks, Johnson-Greene, 2003).  Not only are the multi areas of impairment evident but age at the time of injury and the development of cognitive and language skills also must be taken into consideration. The evidence-based model showing the conceptual framework for the development of the ten subtests that comprise the PTBI involves both “constrained” and “unconstrained” developmental abilities (Paris, 2005).  

Constrained abilities are defined as those abilities that reach the top of the developmental curve fairly early and once attained, very little variance is observed, (for e.g., demographics, orientation, command following, naming, etc.). In contrast, unconstrained abilities are defined as those abilities that develop across a wider age range of time. These abilities require a level of organization and integration that cross cognitive and linguistic domains and involve executive functioning, (for e.g., story re-telling, word fluency, identifying “same” objects, etc.). An outline of which constrained and unconstrained developmental abilities (broken down by factor) are assessed in each of the ten subtests of the PTBI is shown in Table 1.

Table 1. Evidence-Based Model: Conceptual Framework for PTBI Subtests

Basic Skills
(constrained developmental skills)

Skills that Develop across the School-Age Years
(unconstrained developmental skills)

 

Factor 1
Developmental language abilities for meeting curricular cognitive-linguistic demands

  • narration
  • discourse comprehension and inference

Factor 2
Complex cognitive-linguistic processes likely to be affected by brain injury

  • recall and organization of semantically related information
  • flexible thinking about relationships

Factor 3
Attention and Immediate Memory

  • Orientation
  • Following Commands

6.   Naming (anomia)

  • Story Retelling-Immediate
  • Story Retelling-Delayed
  • Yes/No/Maybe
  • Picture Recall
  • What Goes Together

5.  Digit Span

 

Skills that Reflect Complex Abilities
(Related to factors 1-3)

  • Word Fluency
  • What Goes Together (loads heavier on Factor 2, but also on Factors 1 and 3)

 *from Pediatric Test of Brain Injury Examiners Manual (2010) 14

1. Test Development

The old adage that “children are not little adults” when discussing brain injury is important also when it comes to developing assessment measures. Helm-Estabrooks & Hotz (1991) had previous experience from developing a neurocognitive test for adults called the Brief Test of Head Injury and had always planned to develop a test for children.  The theoretical basis and design of the PTBI, as well as empirical evidence supporting the psychometric properties of the test, have been delineated in great detail in another publication (Hotz, Helm-Estabrooks, & Nelson, 2009).

To develop the PTBI, there were two major phases of test development. In 2005, Phase I, data was collected from 44 subjects at 4 test sites and in 2009,Phase II, a standardized version was administered to a total of 257 subjects at 15 field sites throughout the United States and Canada were analyzed using item response theory(IRT). IRT permits each individual item on a test to be assigned a number that reflects how difficult that item is relative to the other items on the test. The items were scaled so that the easiest item on the test is rated at 0.5 and all other items are rated based on how much more difficult they are relative to the easiest item. IRT was used to determine ability scores per item and t tests were used to statistically validate the ability scores. For example, Table 2 outlines the IRT ability scoring for Subtest 2, which assesses the ability to follow commands.

Table 2.   Subtest 2: Following Commands

Item Command

Response Score

1. Where is your knee?                                                                         

0.5

2. Make a fist.                                                                                       

1.5

3. Stick out your tongue and then point to the door.                   

1.5

4. Before you point to the floor, point to your foot.                           

1.5

5. After you look at the ceiling, touch your heart.                              

1.5

6. With your thumb, touch your stomach.                                         

2.5

7. Look to the left and then to the right                                             

3.0

8. Point to the light after you shake your head.                                

3.0

TOTAL Following Commands ABILITY SCORE: 

_____ / 15.0

*from Pediatric Test of Brain Injury Test Form (2010)

In Phase II, data was collected on three groups of children: those who had suffered from TBI (134 subjects), those who had suffered from ABI (46 subjects: 10 stroke, 6 anoxic, 5 intracerebral hemorrhage, 3 encephalitis, 7 brain tumor, 3 arteriovenous malformation, 3 seizures, 7 other) and those who were typical in development (77 subjects).

2. Scoring

Typical tests are administered in order to measure current ability levels on specific measures. Most tests estimate the construct of ability level based on the number of items passed, i.e., the more items a child passes indicates that the child presumably has more ability regarding that specific measure. This approach ignores the fact that the difficulty of a test item may not be evenly incremental. For example, when describing the following-3 item test: item 1 is easy, item 2 is slightly less easy, and item 3 is difficult. A child can receive an overall score of 2 by passing item 1 and 2 but a child can also receive an overall score of 2 by passing a combination of any two of the three items.

The problem lies in the fact that unless the difficulty level of the items is known, it is impossible to know the true ability level of the child. A “1 point vs. no points” estimate of ability can mask the true amount of change experienced by children as they recover from brain injury. Thus, simply assigning a point for each item passed is an ineffective and inaccurate system for assessing the needs of children with brain injuries (Hotz, Helm-Estabrooks, Nelson, Plante, 2010).

In the PTBI, this concern is accounted for and mitigated by the use of criterion scoring. As previously mentioned, criterion scores are used to compare an individual’s performance to a standard in order to judge the adequacy of skill performance. The PTBI permits the calculation of an ability score to describe the current skill level for each subtest. It provides four performance categories (very low, low, moderate, and high performance) that describe a range of ability scores for each subtest. This design allows for a standard error of the mean to be generated for the computing of a statistical confidence interval. For each child, a performance profile pattern across each of the 10 subtests will emerge. By collecting this data, the clinician will be able to determine whether or not later changes in subtest scores represent true changes in ability when the test is re-administered over time. 

CONCLUSION

Neurocognitive assessment during the course of recovery in children from TBI or ABI is essential when developing rehabilitation objectives and goals. The PTBI is a new kind of criterion-referenced standardized test that is valid and reliable for the assessment of neurocognitive linguistic abilities in children and adolescents recovering from a brain injury. The PTBI can be administered during the acute and rehabilitation phases of recovery. The scores from the test can be useful for monitoring functional changes, tracking recovery patterns, and guiding decisions regarding a child’s strengths and weaknesses in order to implement effective rehabilitation interventions.

ACKNOWLEDGEMENTS

The development and publication of the Pediatric Test of Brain Injury would not have been possible without the team of co-authors; Nancy Helm-Estabrooks, ScD, Nickola Wolf Nelson, PhD, and Elena Plante, PhD. I would also like to thank Michelina Witte, PhD for her revisions of this manuscript.

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