There is no specific medication for improving the memory, though pills called Memory Plus and so on are sold in the market. I would not advise giving any medication to a child for lack of concentration. I would advise attention to her diet and sleep and rest periods. Do not overfeed the child with fat-rich foods. Make sure she eats with the family. If she attends a Nursery school, consult her teacher also for activities. If she is loaded with academic exercises, she may be unable and unwilling to give them any attention. Her lessons should be right for her age.