From Dianne Craft's website on lecithin:
There is another important fatty acid, lecithin, that helps the body digest and utilize the fats and oils that are so important to efficient brain and nerve function. Perhaps the greatest recent discovery is the use of lecithin to activate a sluggish mind, and improve memory. It accomplishes this by providing the body with the ingredients necessary to produce the vital neurotransmitter, acetylcholine. This is the neurotransmitter that is responsible for memory storage and retrieval, and the effectiveness of nerve signals in many areas of the brain.She also has some information about lecithin and how it relates to hyperactivity. You can read the whole article here.
One of the most exciting areas in which I have seen lecithin make noticeable differences is in the improvement of auditory processing function in children. I have received many reports from speech pathologists and parents telling of greatly improved auditory processing (hearing and remembering) in children who take this natural soybean product. My experience is that when lecithin is taken alone, it is very helpful, but when taken along with the essential fatty acids (fish oil, flaxseed oil, evening primrose oil) and Vitamin E, it produces marked results. Because of its fat emulsifying properties it helps the child's body digest the extra oils, thereby making use of them properly. Many children who have suffered with numerous ear infections benefit from the regular use of lecithin. The "cilia of the ear," (the tiny hair-like parts of the ear) are frequently damaged when many ear infections have occurred. It is known that the highest concentration of Vitamin A in the whole body is in the "cilia" of the ear. Lecithin increases the body's absorption of this vital Vitamin A dramatically. Thus it is very healing to the areas in the ear structure and brain that affect efficient auditory processing function. In the MIT study referred to earlier, in testing adult subjects in learning and memory tasks, it was found that the subjects taking lecithin daily showed "improvement of thinking and intelligence." Since we know that the left hemisphere of the brain is responsible for auditory storage, and we often refer to it as the "thinking hemisphere," we can see how any substance that improves auditory processing would also affect the thinking ability of the brain. The MIT study also referred to substantial improvement in the area of speech. Again, this is mainly a left-brain function. This is a very exciting application of research, since auditory processing problems are historically difficult and lengthy to treat. Dr. Levinson, a neurologist from New York, in his book Total Concentration, states that he frequently uses lecithin to help both attention and learning in his young patients.