Sue, it may make you feel better to know that you dad still IS very intelligent, it is just not being able to be properly communicated. It's like talking on a bad telephone line, the people at both ends are making sense, but the static is scrambling and muffling the sounds. Just like when a PWP is trying to move a limb and the brain is sending the signal, but the timing of the signal is wrong and the confirmation from the limb to the brain is not being received properly. If you notice, when a PWP is properly medicated, what they say makes perfect sense, even if they do not always choose the appropriate word, it is related to the one they should have used. (This is based mostly what I have learned from this list, and personal observations.) I have hopes for your father, and mine, and all the other folks with PD, that they will get a cure, and unlock their knowledge and talents for themselves and the world to benefit by again. Ken