1 The scientific rigour of the Wechsler scales
Developed by David Wechsler and continually updated, with WISC-V for children aged 6 to 16 and WAIS-IV for adults aged 16 to 79, these scales are among contemporary psychology's most reliable and rigorously standardised psychometric instruments. They allow a Full Scale Intelligence Quotient (FSIQ) to be calculated and five distinct cognitive indices to be mapped.
2 The five cognitive dimensions assessed
The test systematically assesses the Verbal Comprehension Index, covering conceptual reasoning and lexical knowledge; the Visual Spatial Index, covering shape analysis and coordination of visual details; the Fluid Reasoning Index, covering abstract logic and novel problem-solving; the Working Memory Index, covering the mental retention and manipulation of information; and the Processing Speed Index, covering graphomotor speed and selective attention.
3 Clinical uses and diagnostic screening
Administration of the Wechsler tests is essential to confirm high intellectual potential, characterise intellectual impairment, screen for attention-deficit/hyperactivity disorder, identify specific learning disorders such as dyslexia, or measure the consequences of neurological injury.
4 The place of this approach within care
Within care, this approach can never be reduced to a bare number: an IQ score does not define a person's worth. The clinician interprets discrepancies between indices, observes problem-solving strategies and stress management, and makes practical recommendations for recognised educational or workplace adjustments.
5 Ethical reporting and support for the family
The findings of an intellectual assessment are discussed in a warm, reassuring feedback session that puts them into perspective. The psychologist provides a comprehensive written report that illuminates the person's life trajectory, offers reassurance about their potential and makes practical educational recommendations recognised by schools.