Increased Visual Dependence in Parkinson's Disease

Abstract

The present study tested the hypothesis that there is increased visual dependence perceptually in patients with Parkinson's disease. We also evaluated whether the visual control of posture and locomotion was related to perceptual visual field dependence. 21 patients with idiopathic Parkinson's disease and 22 age-matched normal subjects were compared on judgment of the visual vertical using the Rod-and-Frame test with visual perturbations in the frontal plane with a tilted frame. Patients had significantly larger errors than controls in the estimation of the subjective vertical. In the same experiment, we performed a posture and a gait analysis in both groups. Posturographic evaluation did not indicate significant differences in unsteadiness between patients and controls. Gait analysis indicated a typical pattern of reduced velocity, shortened stride length, and normal step width. A significant correlation of .89 was found only in the Parkinsonian group between their errors in estimating subjective visual vertical and the Romberg quotient evaluating visual contribution to postural control. No specific locomotor pattern was correlated with visual dependence. Considering our results and previous reports on the visual control of posture, we conclude that patients with Parkinson's disease showed a significantly increased dependence upon visual information both perceptually and motorically, with an increased perceptual visual dependence in the patients being predictive of an equivalent visual dependence or visual control of posture and equilibrium.

Subjective visual vertical perception and sense of smell in Parkinson disease

“…This suggests that patients of mild to moderate PD severity (with normal cognitive function) do not have any increased impairment in perception of SVV. These findings are different from a similar study by Azulay et al [8], who reported that patients with PD made significantly more errors on the RFT than nondisabled controls. These contrasting results between us and Azulay et al might be caused by a number of factors, including:…”

“…All participants had an MMSE score greater than 26, and their vision was normal or corrected to normal. It was not clear whether the cognitive function of patients with PD in Azulay et al was tested or not [8]. However, it could be argued that the MMSE score has limited value in detecting subtle cognitive impairment in patients with PD [26].…”

“…Our sample size was double that used in Azulay et al, which might, in part, be responsible for these differences in results [8].…”

“…Patients with PD were reported to have reduced visual acuity [5], color vision [6], and contrast sensitivity [7]. It has also been reported that there is an increased visual dependence perceptually in patients with PD [8]. Interest in visual dysfunction is enhanced by the possible relationships between gait disorders and visual perception [9].…”

Possibilities of non-drug treatment for Parkinson’s disease

“…Роль постуральной неустойчивости особенно значи-тельна на поздней стадии заболевания, когда смещение центра тяжести больного не вызывает компенсаторных движений туловища и конечностей, что ведет к падениям [3,6,7].…”