Aptitude Tests and Personality Profiling are used more and more by employers to support an interview process, especially at a senior level.
Aptitude tests aim to assess your logical reasoning and are designed to measure a specific ability (e.g. numerical, data interpretation). The tests are administered under exam conditions and to a strict time period. There is very little preparation you can do, however you can search on-line for sample tests and practice word games and numerical tests to a specific time limit.
Personality Profiling aims to assess your personal qualities by your responses to questions or statements. Typical personality traits assess your ability to deal with your own / other's emotions, your motivations, work-style and how you relate to others. Unlike Aptitude Tests there is no preparation required and there are no right or wrong answers. When sitting the questionnaire, it is best to be yourself and don't try to guess what you think the answer should be.