One of the most popular non-verbal methods of measuring intelligence. It is designed to assess the cognitive abilities of people who have difficulty with verbal expression or comprehension. This test is entirely instrumental and relies on motor and visual responses rather than language, making it suitable for young children, people with hearing or language impairments, and people from different cultures. The test measures a number of higher cognitive functions, such as attention, working memory, deductive reasoning, problem solving, visuospatial organization, and processing speed. The test is administered through a series of tasks that involve arranging images, matching shapes, classifying objects, or navigating mazes, all of which do not require verbal responses. The Leiter test is an important diagnostic tool because it reduces the influence of cultural and linguistic factors on intelligence assessment results, allowing for a more effective assessment of a person’s abilities. It is also used to diagnose neurodevelopmental disorders (such as autism spectrum disorders, communication disorders, and learning difficulties) and to assess the cognitive abilities of children with hearing impairment or language developmental delays. The test has been revised several times to develop criteria and provide statistical validity, making it a reliable benchmark for neuropsychological measurements.