NAB®

Technical information

• All NAB tests were standardized on the same sample of more than 1,400 healthy adults.
• Interrater reliability studies conducted on those NAB tests that require more subjective scoring indicated excellent agreement. A 6-month test-retest study (n = 95) resulted in very good temporal stability and provides important practice effect information. The reliability estimates for the NAB Index scores are excellent (e.g., Total NAB Index score r = .96).
• Extensive validation evidence has been established through both exploratory and confirmatory factor analyses, criterion validity investigations, and several clinical validation studies. Additional validity studies included a comparison of the NAB with measures of functional independence in an inpatient rehabilitation hospital and an investigation involving a group of simulated malingerers who received the NAB, along with several existing measures of symptom validity.

Test structure

The NAB consists of five domain-specific modules: Attention, Language, Memory, Spatial, and Executive Functions. A sixth module, Screening, allows the clinician to determine which of the other five domain-specific modules are appropriate to administer to an individual patient. Each of the six NAB modules is self-contained and may be administered independently of the other modules.

• The Attention Module provides a marker of an individual’s attentional capacity, working memory, psychomotor speed, selective attention, divided attention, and information processing speed.
• The Language Module provides a marker of the severity of aphasia and related disorders of language production, comprehension, and word-finding.
• The Spatial Module provides a marker of the examinee’s visuoperceptual skills, attention to visual detail, visuoconstruction, right-left orientation, topographical orientation, and visual scanning.
• The Memory Module provides a marker of an individual’s verbal explicit learning, visual explicit learning, verbal delayed free recall, visual delayed recognition memory, and verbal explicit learning and recognition of information likely to be encountered in day-to-day living. A stand-alone Memory Module Professional Manual and special combination kits are available.
• The Executive Functions Module provides a marker of planning, engaging with others effectively, problem solving, successfully interacting with the environment to get one’s needs met, judgment, conceptualization, cognitive response set, mental flexibility, verbal fluency, and generativity.
• The Screening Module streamlines the assessment process by providing scores that quickly let you know whether further assessment should be conducted. It also helps to generate initial hypotheses regarding differential diagnosis and treatment recommendations and provides an estimate of the examinee’s functioning in a particular domain when more in-depth examination is either not warranted or not possible.

The NAB Embedded Validity Indicators (EVIs) are a set of performance validity indicators consisting of both individual and composite validity indicators for the NAB Main Modules Score Report.

The EVIs enable clinicians to determine whether a client’s performance on the NAB is credible. Because the EVIs are embedded, clinicians will not have to administer as many additional stand-alone validity tests to determine credibility. This allows validity testing to be less detectable to clients and saves valuable administration time.

Though EVIs are typically less sensitive to detecting underperformance than stand-alone performance validity tests, the NAB provides several EVI composites, which combine multiple individual validity indicators to enhance overall sensitivity.