Exams can be one of the most stressful situations that we find ourselves in. Stress and memory are not good bedfellows. We are more likely to remember what we want when we are stress free and relaxed.
One of the causes of exam stress is the fear that we will forget everything before we have the chance to commit it to paper. This is one situation in which mind maps are ideal. Their use of key words, key ideas and the logical connection of related concepts makes them a perfect aide memoire for exam situations.
They can be used for revision: when revising make an initial mind map of all the information you want to learn and then revise by putting that mind map to one side and attempting to reconstruct it. When you have done this, compare your new mind map to the original to see the areas where you are strong and those areas that require further attention.
In the exam itself, spend the first few minutes doing quick-fire mind maps of the question you intend to answer. This should be a kind of memory dump. This will mean that you have all the information you need to recall on the page in front of you and so your mind will be freed up to concentrate on the questions themselves without the added stress of trying to remember.