Darío H Scocco1, Judith N Wagner2, Juan Racosta3, Anabel Chade3, Oscar S Gershanik3. 1. Institute of Neuroscience, Favaloro University, Buenos Aires, Argentina; Institute of Cognitive Neurology (INECO), Buenos Aires, Argentina. Electronic address: dscocco@ffavaloro.org. 2. Department of Neurology, Ludwig-Maximilians University, Klinikum Grosshadern, Munich, Germany. 3. Institute of Neuroscience, Favaloro University, Buenos Aires, Argentina; Institute of Cognitive Neurology (INECO), Buenos Aires, Argentina.
Abstract
BACKGROUND: Parkinson's Disease (PD) alters perception and somatosensory information integration, including visual dependency and judgment of body position in space. PD may be associated with Pisa syndrome (PS), a lateral deviation of the longitudinal body axis (LBA) of unknown origin. We tested whether this inclination is associated with an altered perception of the subjective visual vertical (SVV) and if these alterations are secondary effects of the LBA deviation or of a primary perceptual dysfunction. Furthermore, we investigated the contribution of different sensory modalities and dopaminergic medication. METHODS: Seventeen PD patients (8 with PS, 9 without PS) and 18 healthy controls were tested. The SVV was assessed in a seated, in a lateral horizontal and - in PS patients - in a seated manually rectified position. Frame and moving-stimulus-patterns were used to test visual dependency. In PD and PS patients all trials were conducted in dopaminergic "on" and "off". RESULTS: When seated, SVV values on PD in "on" and PS in "on" and "off" differed significantly from controls. This difference remained in PS patients after manual rectification in "off". The SVV in a lateral horizontal position was not significantly different between the three groups. When inclined, visual dependency was higher in PD "off" than in controls. DISCUSSION: Both PS and PD patients showed SVV deviations compared to healthy controls. These cannot be explained by their intrinsic lateral deviation in PS patients. They must be secondary to either a primary perceptual dysfunction or alterations of internal models of verticality due to re-weighting of perceptual afferences.
BACKGROUND:Parkinson's Disease (PD) alters perception and somatosensory information integration, including visual dependency and judgment of body position in space. PD may be associated with Pisa syndrome (PS), a lateral deviation of the longitudinal body axis (LBA) of unknown origin. We tested whether this inclination is associated with an altered perception of the subjective visual vertical (SVV) and if these alterations are secondary effects of the LBA deviation or of a primary perceptual dysfunction. Furthermore, we investigated the contribution of different sensory modalities and dopaminergic medication. METHODS: Seventeen PDpatients (8 with PS, 9 without PS) and 18 healthy controls were tested. The SVV was assessed in a seated, in a lateral horizontal and - in PSpatients - in a seated manually rectified position. Frame and moving-stimulus-patterns were used to test visual dependency. In PD and PSpatients all trials were conducted in dopaminergic "on" and "off". RESULTS: When seated, SVV values on PD in "on" and PS in "on" and "off" differed significantly from controls. This difference remained in PSpatients after manual rectification in "off". The SVV in a lateral horizontal position was not significantly different between the three groups. When inclined, visual dependency was higher in PD "off" than in controls. DISCUSSION: Both PS and PDpatients showed SVV deviations compared to healthy controls. These cannot be explained by their intrinsic lateral deviation in PSpatients. They must be secondary to either a primary perceptual dysfunction or alterations of internal models of verticality due to re-weighting of perceptual afferences.
Authors: Diderik Jan A Eikema; Jung Hung Chien; Nicholas Stergiou; Sara A Myers; Melissa M Scott-Pandorf; Jacob J Bloomberg; Mukul Mukherjee Journal: Exp Brain Res Date: 2015-11-02 Impact factor: 1.972