Visualizing the next steps in Parkinson’s disease
Bodis-Wollner I.(2002) Visualizing the next steps in Parkinson’s disease , Aug;59(8):1233-4
This article is an editorial written collaboratively to the Diederich article also reviewed in the current science reviews. This author added that visual complaints are common in patients with PD. He noted that the difficulties are often attributed to aging, macular (central portion of the retina) changes, or other eye conditions that are not related to PD. Through his research he has found that vision deficits can be found in patients with PD that do not have age or disease related optical or retinal changes, that levodopa has shown improved performances on visual tests, and that dopamine blockers have been shown to cause impairments in visual processing. This author has also found that vision can fluctuate concurrently with ON/OFF states. He hypothesizes, similarly to Diederich, that visual impairment is related to reductions in dopamine related to PD. He also cited studies that have show the visual deficits are not due to poor acuity that instead it is due to contrast sensitivity causing spatial problems. He noted that spatial difficulties also tend to be worse in environments with low lighting as there is less contrast between objects, steps, words, etc. This author also noted the importance of the Diederich article in discussing that visual impairments correlate with "motor severity, progresses along with the motor symptoms, and fluctuates in parallel with motor fluctuations." The author discussed various hypotheses regarding the cite of injury in the brain/eye that would cause visual disturbances but at this time it is unclear whether retinal changes causes changes in the processing areas of the brain or vice versa. The author also questioned what type of damage to the visual system is responsible for walking/balance/gait disturbances that are seen in patients with PD. The author correctly discussed that a single lesion may not be identifiable to explain visual deficits as well as there are likely multiple processes (specific lesions, changes between areas in the brain that communicate and work cooperatively, etc.) to explain these deficits. He suggested that additional pathophysiological work needs to be done to explore PD in general but to also explore visual deficits.