Neuropsychological Evaluation

Originally, the neuropsychological assessment was directed at diagnosing the presence, nature, and site of brain dysfunction. The focus has shifted from diag­nosis to assessment of a child's function to identify and implement effective management, rehabilitation, or remediation services.

Neuropsychological Batteries

As mentioned earlier, neuropsychological batteries have been developed to provide a comprehensive eval­uation of cognitive abilities. The two most common in practice today are the downward extensions of the Halstead Reitan Neuropsychological Battery and the NEPSY-II, developed specifically for children.

The Halstead Reitan Battery has been refined and redefined over the years since Ward Halstead's original conceptualization in the 1940s to a larger series of tests to diagnose so-called brain damage for ages 14 and above (25), and subsequently the downward extension for ages 9-14, called the Halstead Neuropsychological Test Battery (HRNB) for Older Children. It takes approximately four to six hours to administer and uses subtests from the adult Halstead Reitan Battery, with some modifications. The battery for children ages 5-8 is called the Reitan Neuropsychological Test Battery and requires a similar time interval for administration. These batteries, in wide usage earlier, are criticized for a number of pivotal problems. The first is on concep­tual grounds, in that the battery was not developed for children, but for adults, and is perhaps reflected in the minimal assessment of memory, academics, and lan­guage, with no direct measure of attention. The psycho­metric properties are widely acknowledged to be quite poor, such that reliance on those alone for interpreta­tion is inappropriate. Considerable clinical acumen is required to interpret findings. Dean concludes a review of the batteries saying, “The HRNB cannot be recom­mended for general clinical use without considerable training and familiarity with research on the battery (26).” Considering norms published in the interim, Lezak et al.

The only neuropsychological battery ever developed specifically for children is the NEPSY-Developmental Neuropsychological Assessment (27), with the new­est version, the NEPSY-II (28), published in 2007. Both batteries are based on the diagnostic principles of the Russian neuropsychologist Alexandr Luria. The origi­nal NEPSY had two forms and covered ages 3-4 and 5-12, with a core battery of 11 to 14 subtests repre­sented to tap five functional domains: attention and executive functions, sensorimotor functions, language, visuospatial processing, and memory and learning functions. This original version was criticized for its content and psychometric properties (29). It is well standardized, and though some instability is noted in some subtests, this may indeed reflect the reality of the developmental status of the brain.

The most recent version has not been tested enough to generate a literature on its strong points or weaknesses. It does expand the age range to 16 years, extending one ostensible benefit of a battery that cov­ers the childhood range, allowing for the ideal serial assessment. The content has also changed, with tar­geted groupings of subtests for various diagnoses, nonverbal elements, and new measures of executive functioning, memory and learning, which reportedly solves some of its statistical problems. A functional domain in social perception has been added as well.

Attention, Concentration, and Information Processing

The processes of attention, concentration, and infor­mation processing are often central concerns for any patient with a medical condition involving the brain (30). In many ways, they form the basis on which the other component processes occur. Overall cognitive productivity suffers from losses or failures to develop these skills.

Attention has been conceptualized in a number of ways, generally relating to an organism’s recep­tivity to incoming stimuli.

The multitude of processes subsumed in the concept of attention are necessary because of the overall effect. Most notable is the developmental nature of attention in childhood and adolescence. Increasing demands in school participation are seen in the shifting requirements throughout the academic process. In the early grades, a child is more directly engaged by the teacher, but as the years progress, the capacity for independent (ie, volun- tary/deliberate) processes grows. Attentional processes are a central aspect of the changing capacity of normal development. Attention’s vulnerability to normal varia­tion, as with fatigue or anxiety, is a part of typical func­tioning. Attentional processes require a certain “tone” to the brain’s functioning, attention and its concomitants are often affected in brain disorders. Furthermore, with acquired deficits in the disordered brain, the demands are higher, as an individual struggles with recognizing the need to attend along with implementing a specific compensatory task.

Lezak and colleagues (23) note that underlying many attention problems is slowed processing. This can be misinterpreted as a memory disorder (32), as competing stimuli in normal activity interrupt the processing of the immediately preceding stimuli and something is “forgotten,” in common parlance. The discernment of this specific problem is important, as strategies alleviating the effects of slowed processing would be different from those for memory per se.

All of these aspects warrant examination, notably in those with a brain disorder, due to the overall effect on functioning and the demand for acquisition of aca­demic and adaptive behaviors throughout childhood. The effects of anxiety about an illness process, its treat­ment, and demands for coping can all affect attention, and in a competent diagnosis are differentiated from primary brain disruption.

Because of the issue of time in competent atten­tion processes, computerized testing has real utility to control for calibration of presentation and response. Absent a fully computerized administration, the use of taped auditory stimulus in attention testing allows for standardized presentation increments. Typically, the computerized tasks involve visual stimulus and the taped presentations involve auditory ones. This differ­entiation between verbal and nonverbal, or auditory versus visual, is necessary to capture these two cen­tral aspects of stimulus processing.

Recent development of a battery of attention tasks for children, the Test of Everyday Attention-Children will be described next. It attempts to cover a number of aspects of attention processes and for the compar­ison of subtest scores to allow for relative differentia­tion of components.

Inattention, slowness, and poor concentration have a wide-ranging effect on competent cognitive and adaptive functioning. Other processes may be quite competent, but attention and its aspects can be a pri­mary “rate limiting” factor. These should be addressed in even a screening of functioning, whether at bed­side or in the clinic, both as an overall indicator of current cognitive activity, but also as a harbinger for developmental problems to come, signaling the need for more stringent monitoring. Commonly used tests are described in Table 3.1.

Problem-Solving and Executive Functioning Tests

As with attention processes, deficits in these realms can have a devastating effect on overall functioning. Cognitive process can be intact, but with executive functioning impairments, the output can be substan­tially derailed.

3.1

Tests of Attention and Speed of Processing

The competent measurement of these skills requires a multidimensional approach and is quite complex (40).

Lezak (23) differentiates these brain skills as

“Questions about executive functions [are generally phrased \as how or whether a person goes about doing something (eg, Will you do it and, if so, how and when?); questions about cognitive functions are generally phrased in terms of what or how much (eg, How much do you know? What can you do?).”

There are many models, as in attention, as to what comprises these skills and how to measure the com­ponents, since it is far from a unitary concept. Again, as in attention, the developmental progress of these skills is a central aspect of childhood and adolescence. In the teenage patient, assessment of these skills is vital, as adult-like capabilities for work, driving, and independence can be severely affected and, in the par­ticular case of driving, have disastrous results. The enactment of graduated driver license requirements for teen driving in some states implies the central­ity of these skills and their necessity for that activity. Stepwise exposure and supervision of driving for teens allows for a graduated experience before full driving privileges are granted. Specialized assessment through rehabilitation-based driving evaluations using com­puter simulation should be considered by a rehabilita­tion team in any teen with a history of brain disorder.

Definitions of executive skills include the capac­ity for planning and flexible use of strategies, and the ability to generate, maintain, and shift cognitive sets; to use organized search strategies; and to use self­monitoring and self-correction, as well as the capacity to utilize working memory. It is distinct from general intelligence, though it does correlate at lower levels of intelligence. Again, as in attention skills, these skills are vulnerable and easily disrupted in many circumstances, as they are largely acquired through­out childhood as an essential central process of com­petent development. Therefore, deficits acquired can be “silent” until they are called on for future devel­opment. The range of tasks is wide, from inhibiting behavior in the absence of visible authority to plan­ning how to accomplish several assignments due at the same time.

Though the cognitive aspects are difficult to quan­tify, the literature on these is substantial. However, the emotional and behavioral aspects of executive skills is less studied (41). Executive skills act to regulate behav­ior (42), inhibit and manage emotions, tolerate frustra­tion, and provide persistence. Notable is the result of limited empathy (ie, taking the position of the other). They are observed collaterally in any sound testing process, but are captured better, to the extent possible, in the questionnaire approach discussed previously. The effect of impairment in these skills can be wide­spread and debilitating, especially as expectations for empathy and self-awareness increase in adolescence.

One of the questionnaires does differentiate these two factors. In the BRIEF (131), questions about such skills yield feedback for the behavioral regulation composite, as differentiated from another composite reflecting the cognitive aspect, metacognition. A list of tests that cover this wide-reaching domain is listed in Table 3.2.

Nonverbal/Visual-Perceptual Function Tests

This type of cognitive task is seen as one of the two major classes of cognitive input/output. At its base is the perceptual capacity of vision. From earliest infancy, humans already have sufficient visual perception to mimic another's facial expression (29). Related to the developmental aspects of childhood, by age 9, visual processes are integrated with tactile and proprioceptive functions. Tests of visuoperceptual, visuospatial, and visuomotor function are all within this domain and include the ability to discriminate between objects, distinguish between left and right, judge spatial ori­entation and the relationship among objects in space, copy a model, understand symbolic representations of maps and routes, and solve nonverbal problems. Direct functional outputs include being able to navi­gate the environment and depth perception. Testing of these functions can illuminate visual field cuts, visual neglect, and apraxia.

3.2

Tests of Problem Solving and Executive Function

However, these tasks often involve other aspects of cognition, such as attention, memory, speed of think­ing, and motor impairment. At the base is the requisite of normal visual acuity, screened for in the pediatric clinic setting or in school admission testing. However, after a brain injury or illness, the intactness of the basic perceptual components of nonverbal function­ing should not be assumed. Issues like cortical visual defects or loss of binocular vision require examination by vision specialists; in more severe TBIs, such injuries are not uncommon. Consideration of the myriad factors involved in this domain's assessment requires examin­ing other test performances to discern patterns, as well as factors that may affect visual function output but not be a deficit in these processes per se. The importance of these functions as a basic component of input and output of cognitive function is seen in their presence in all intelligence and neuropsychological batteries. Table 3.3 provides a representative listing of these tests.