INTELLECTUAL AND NEUROPSYCHOLOGICAL ASSESSMENT

Overview of Cognitive Testing in Clinical Psychology

Measuring cognitive performance has been a hallmark of clinical psychology since its inception (Wood, Garb, & Nezworski, 2007). Understanding a client's cognitive functioning, including strengths and deficits, aids clinical psychologists in diagnosing and treating various issues. Assessments targeting specific learning disorders, intellectual disabilities (previously known as mental retardation), or giftedness are specifically centered around cognitive issues. Other assessments focused on mood disorders or disruptive behavior utilize cognitive tests to provide context. This chapter examines three kinds of assessments related to cognitive functioning:

  1. Intelligence tests measure a client's intellectual abilities.
  2. Achievement tests assess what a client has achieved with their intellectual capabilities.
  3. Neuropsychological tests evaluate cognitive or brain dysfunction, considering the effects of brain injuries and illnesses.

Intelligence Testing

Classic Theories of Intelligence

Intelligence tests used by clinical psychologists are rooted in differing theories of intelligence. There has been no consensus on the definition of intelligence, with experts emphasizing various abilities:

  • Speed of mental processing
  • Sensory capacity
  • Abstract thinking
  • Imagination
  • Adaptability
  • Capacity to learn through experience
  • Memory
  • Reasoning
  • Inhibition of instinct
    (As summarized by Sternberg, 2000; Sternberg & Grigorenko, 2008; Wasserman & Tulsky, 2005).
Singular vs Plural Nature of Intelligence

A significant debate in intelligence theory focuses on whether intelligence is singular or plural (Wasserman, 2018).

  • Charles Spearman proposed that intelligence is a singular characteristic, termed “g”, referring to general intelligence, suggesting a singular factor underlying multiple specific abilities. He found a strong correlation among various capabilities indicating a single intelligence source. However, he acknowledged the existence of specific abilities (referred to as “s”), positing that they play a relatively minor role in intelligence.

  • Louis Thurstone countered Spearman’s view by arguing for multiple distinct intelligences—a concept he explored through multiple factor analysis. His analysis identified several independent abilities: verbal comprehension, numerical ability, spatial reasoning, and memory. He argued that knowing someone's skill in one area (e.g., mathematics) does not predict capability in another (e.g., verbal skills).

Through discussion, both Spearman and Thurstone acknowledged each other’s views and settled upon a hierarchical model whereby specific abilities exist but relate to a more general intelligence (g) (Willis, Dumont, & Kaufman, 2015a).

More Contemporary Theories of Intelligence

New theories emerged since Spearman and Thurstone.

  • James Cattell proposed two intelligences: fluid intelligence (reasoning in novel problem-solving) and crystallized intelligence (accumulated knowledge from life experiences).
  • John Carroll’s three-stratum theory of intelligence suggests a hierarchy: a single “g” at the top, eight broad factors below, and more than 60 specific abilities under those broad factors (Wasserman & Tulsky, 2005). This contemporary view aligns with most intelligence tests, which produce an overall score and separate scores for specific abilities.
Notable Intelligence Tests

Key intelligence tests widely used include:

  • Wechsler:
    • WAIS-IV (Wechsler Adult Intelligence Scale—Fourth Edition)
    • WISC-V (Wechsler Intelligence Scale for Children—Fifth Edition)
    • WPPSI-IV (Wechsler Preschool and Primary Scale of Intelligence—Fourth Edition)
  • Stanford-Binet Intelligence Scales—Fifth Edition (SB5).
    Other tests like the Woodcock-Johnson Tests and Kaufman Assessment Battery for Children-II further contribute to this field.
Wechsler Intelligence Tests

The Wechsler tests have become dominant among clinical psychologists since their inception in the early 1900s (Drozdick et al., 2018; G. Goldstein, 2008). Here are distinguishing features:

  • Test Types and Age Ranges:
    • WAIS-IV (2008): Ages 16 to 90.
    • WISC-V (2014): Ages 6 to 16.
    • WPPSI-IV (2012): Ages 2 years 6 months to 7 years 3 months.
    • SB5 (2003): Ages 2 to 85+.
  • Structure: Each test yields a full-scale IQ score, index scores, and multiple subtest scores, indicating a hierarchical model where the full-scale IQ reflects g while index and subtest scores reflect specific areas of ability.
Characteristics of Wechsler Tests
  • Administration: Administered one-on-one and face-to-face.
  • Subtest Structure: Brief (2–10 minutes) and progressively more challenging tasks.
  • Norms: Standardized on about 2,000 people representing U.S. demographics.
    • Full-scale and index IQ are calculated with a mean of 100 and a standard deviation of 15.
    • Each subtest has a score of 10 (average) with a standard deviation of 3.

The Wechsler tests are widely respected for their psychometric data, showing strong reliability and validity (Canivez & Watkins, 2010). They are used for various clinical applications, including assessments for intellectual disabilities and educational planning.

Stanford-Binet Intelligence Scales—Fifth Edition

The Stanford-Binet scale, widely respected in clinical psychology, also utilizes a hierarchical model, measuring fluid reasoning, knowledge, quantitative reasoning, visual-spatial processing, and working memory. The SB5, administrated face-to-face, encompasses a single test for ages 2 to 85+ and features strong reliability and validity metrics.

Addressing Cultural Fairness in Intelligence Testing

Recent critiques of traditional IQ tests have highlighted cultural bias, particularly against individuals from minority cultures (Ortiz et al., 2018). In response, tests such as the Universal Nonverbal Intelligence Test-2 (UNIT-2) emerged. This entirely language-free test requires no linguistic shared understanding, using hand gestures for instructions and responses through pointing or manipulation of objects. Normed on 1,800 participants, the UNIT-2 assesses memory and reasoning abilities through diverse subtests while boasting generally acceptable reliability and validity (Bracken & McCallum, 2015).

Achievement Testing

Achievement vs Intelligence

Intelligence tests measure cognitive potential, while achievement tests assess what has been accomplished, primarily in academic subjects like reading and math. This distinction is essential in psychological evaluations, especially for identifying specific learning disorders.

Wechsler Individual Achievement Test—Third Edition (WIAT-III)

The WIAT-III is a comprehensive achievement test for individuals aged 4 to 50. It assesses four broad areas: reading, math, written language, and oral language, providing standard scores and age/grade equivalents. Strong reliability and validity data support this test's use in clinical settings.

Neuropsychological Testing

Purpose of Neuropsychological Testing

Neuropsychological testing is specialized within clinical psychology to assess cognitive functioning or brain impairment. Such tests help to localize issues resulting from brain injuries, substance abuse, or degenerative diseases and can guide treatment and rehabilitation.

Full Neuropsychological Batteries
  1. Halstead-Reitan Neuropsychological Battery (HRB): It encompasses 8 standardized tests suitable for ages 15+ and focuses on identifying brain damage and cognitive deficits. It’s comprehensive but has limitations in its length and flexibility, given its fixed structure.
  2. Luria-Nebraska Neuropsychological Battery (LNNB): It comprises 12 scales with a qualitative approach observing the testing process.
  3. NEPSY-II: Designed for children aged 3–16, assessing various cognitive domains with flexibility in test selection.
Brief Neuropsychological Measures
  1. Bender-Gestalt Test: A common screen for neuropsychological assessment, evaluating visuoconstructive abilities through a copying task.
  2. Rey-Osterrieth Complex Figure Test: Assesses visual memory and complex copying abilities.
  3. Repeatable Battery for the Assessment of Neuropsychological Status (RBANS): A broader test encompassing memory, attention, and language skills.
Cultural Competence Considerations

Practitioners must maintain cultural awareness when selecting and interpreting neuropsychological tests due to potential biases ingrained in traditional assessment tools standardized mainly on European American populations.

Chapter Summary

Clinical psychologists utilize intelligence tests, achievement tests, and neuropsychological assessments to gain an understanding of their clients' cognitive capabilities. The most acknowledged intelligence tests typically adopt a hierarchical intelligence model, yielding both general and specific scores. The Wechsler and Stanford-Binet intelligence tests remain dominant, while recent advancements in culturally fair testing methods aim to address past biases. Achievement tests differentiate from intelligence tests by measuring achievements in core academic subjects, while neuropsychological tests focus on cognitive functions and assessing potential brain dysfunction.