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Dear Martha Rohrer, You said: "My husband can be walking fairly well until he moves from a well lit area into darkness. At that point he freezes instantly and cannot move until there is light provided. I have to make sure in the evening that bedroom and bathrooms are well lighted ahead of the time of need. In spite of the bright night lights placed everywhere he might possibly need to go during the night, They do not help. He cannot move until a room light is turned on. He can no longer go outside to enjoy the garden on our pleasant summer evenings, even at dusk when others can see quite well." It is difficult to respond to your husband's situation without seeing him but I would suggest the following as a possibility. First of all let me clarify that I am not advocating closing one's eyes as a kind of therapeutic approach to walking problems in PD. Rather it is a maneuver which can work for a step or two and is intended to merely illustrate a point that the complete absence of processing of visual data (i.e. eyes closed) is superior in maintaining walking than flawed processing of visual data. I believe that this flawed visual processing occurs in one's peripheral vision where normally we track the apparent motion associated with walking. This means that objects on our sides appear to move as we walk - like the apparent motion of fence posts as we pass by them. Things like fence posts support walking quite well because they are a reliable source of visual feedback in the periphery. However, in the real world objects in the periphery come and go and wide open places (a garden?) can be particularly troublesome. Similarly in a low lighting situations, environments which are ok in bright light may cause problems. If you like try the following. If there is a hallway wall passing along an environment that gives your husband trouble try "decorating" the wall with a series of regularly spaced objects in a contrasting color (say black on white which can easily be seen in low lighting. (You might try a long sheet of buthcher paper that you 've drawn dark, regularly spaced vertical lines on - like fence posts.) This should help him avoid freezing and would also support my cotention regarding the importance of periheral visual data. Hope I haven't confused you too much. regards, Tom