What is the WAIS-IV Intellectual Assessment?
The Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV), was originally developed in English and has been adapted to several languages, including German. It is a comprehensive assessment tool that evaluates intellectual functioning and general cognitive ability in individuals aged 16 to 90. While it does not diagnose clinical conditions, it can provide valuable information that may contribute to the assessment of various conditions. These include ADHD, learning difficulties, cognitive decline, autism spectrum disorder, and other forms of cognitive impairment when used as part of a broader clinical evaluation.
Research shows that general intelligence predicts job performance and overall psychological well-being.
Wechsler believed that cognitive processes of thinking, reasoning or remembering only made up a part of intelligence. He described intelligence as the competence of a person to act purposefully, to think reasonably and to handle their environment effectively.
The WAIS-IV is the gold standard of intellectual assessment, measuring intelligence through actual performance. Understanding intelligence as performance highlights that raw intellectual ability does not determine the capacity to adapt to life’s challenges. What determines that is how a person applies their intellectual resources to real situations.
What are the Domains of Intelligence, and how does WAIS-IV assess them?
The WAIS-IV test measures overall cognitive ability through the Full-Scale Intelligence Quotient (FSIQ). It includes ten core and five optional subtests that assess four equally important domains of intelligence:
• Perceptual reasoning
• Verbal comprehension
• Processing speed
• Working memory
The Verbal Comprehension Index (VCI) assesses the ability to listen, acquire knowledge, reason through an answer and express thoughts verbally. It can reveal preferences for spoken information and difficulties with novel situations or deciding on the spot.
The Perceptual Reasoning Index (PRI) tests the ability to evaluate a problem, employ visual skills, arrange thoughts, generate solutions and then examine them. It can also display preferences for certain visual materials, discomfort with new situations or an inclination to learn by doing.
The Working Memory Index (WMI) assesses the ability to remember new information, keep it in short-term memory, focus on and operate it to generate results. It is significant in achievement, learning and higher-order thinking. The WMI can expose sequencing proficiency, cognitive flexibility, attentiveness, and planning skills, but is sensitive to anxiety. It is an important element of learning and achievement.
The Processing Speed Index (PSI) evaluates the ability to concentrate attention and quickly scan, discriminate between and sequentially order visual materials. It requires persistence and planning capacity, but working under time pressure, insufficient motivation and deficient motor coordination can obstruct it.
WAIS-IV Assessment: Supporting ADHD Evaluation and Measuring Cognitive Resourcefulness
Although Wechsler understood intelligence as a comprehensive construct, he held intelligence to include multiple, specific elements that could be separately evaluated.
Moreover, he emphasised that what we measure is not what the test measures, e.g. not reasoning ability, not spatial perception and not information. These are only a means to an end.
The intellectual assessment measures something much more significant: the person’s capacity to understand the world and the resourcefulness to deal with life challenges.
In addition to supporting ADHD evaluation and assessing general intellectual functioning, the WAIS-IV may help on specific occasions. These include testing intellectual giftedness or intellectual disability and learning disorders.
The Challenge of Twice-Exceptionality (2e)
Twice-exceptional individuals are those who are intellectually gifted but also have a co-occurring disability or neurodivergence, such as ADHD, Autism, or a Specific Learning Disorder (e.g., dyslexia).
For 2e individuals, the composite Full Scale IQ (FSIQ) is often highly misleading. Because their high scores and low scores average each other out, the final number often looks “average,” completely missing both their high potential and their struggle. As a result, a gifted individual with ADHD might end up with an FSIQ of 110 instead of the 130+ required to identify giftedness. Thus, clinicians also evaluate the General Ability Index (GAI), an alternative composite score in the WAIS-IV. It is calculated using only the subtests from two specific areas: the Verbal Comprehension Index (VCI) and Perceptual Reasoning Index (PRI).
WAIS-IV Assessment Stages
The assessment process typically consists of three stages:
- Intake (typically one or two sessions)
- Assessment (typically a double session)
- Feedback and Recommendations session, followed by a written feedback/report.
WAIS-IV Administration in Austria
In Austria, the WAIS-IV is a protected clinical instrument. According to the Austrian Psychologists Act (Psychologengesetz 2013), only clinical psychologists (Klinische Psycholog:innen) can carry out psychological diagnostics and administer the tool. All practising clinical psychologists must be registered with the Austrian Federal Ministry BMSGPK.
The WAIS-IV is not a clinical diagnostic tool, but it can complement the diagnosis of ADHD. The test can reveal a deficiency in processing speed and working memory, which are impaired in people with ADHD.