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Dear Tim Hodgens, Your post has a lot to respond to ... in the interest of brevity allow me= to pick and choose a little. Regarding the visual component of gait,I mean this in the physiological sense not the psychological sense. That is to say vision can impact on ga= it the way gasoline can impact on the ability of a car to move. For example= , imagine you are stopped at a traffic light in your car and then the parke= d car next to you begins to move. Your reaction is to slam on the brakes. = This is because we are programmed to interpret motion seen in our peripheral vision as being apparent (not real) motion and thus evidence o= f our own movement. Whenever our perceived motor activity is inconsistent with our sensory feedback the result is akinesia until the conflict is resolved. In the absence of a rationale to explain the aberrant sensory information (for eg. realizing that it is a parked car that's starting to= move) one next turns to a pathology as an explanation. This pathology in= PD is either one of perception (we see it wrong) or processing (the information comes into the brain ok but then is erroneously "digested". = But also note that there is an autonomic nervous system component which c= an produce all of the gait pathology independently of vision. Indeed one could make an arguement that the only difference between a normal person and a PD person's response to an ANS adrenalin surge is the duration of recovery. Note how freezing can be overcome by closing one's eyes. Akinesia and dyskinesia are generally considered to be pathology. Howeve= r, I would suggest that they are not inherently pathologic but rather are normal components of motor function. An example is the primate frozen in fear phenomenon. It is abnormalities in degree, duration and timing of these signs, which are pathologic, reflecting an imbalance in the levels = or actions of neurotransmitters in PD. Crutches work because they reduce weightbearing in the legs not because they allow one to redirect one's attention. For the same reason an akinetic PD'er can walk in waste deep= water. This is getting too long and may not be of interest to the listmebers. S= o let me refer you to a site where my paper has been posted:http://www.psicologia.net./ regards, Tom =