Background Within the category of visual impairments, there are a multitude of changes due to Huntington’s disease (HD): decreased visual acuity, particularly low-contrast acuity or contrast sensitivity; slowed saccadic eye movements and small amplitude pursuits; impaired visual fixation with difficulty suppressing eye movements; visual perceptual slowing; visual object and visuospatial errors. Problems with visual perception in HD, including visuospatial dysfunction and poor contrast sensitivity, are likely to have a direct relationship to the impaired motor learning and control in these individuals. Healthy individuals are quite good at describing action based on a relatively small number of moving points. The ability to perceive biological motion using moving points has since been well-established.
Aims The purpose of this pilot study was to determine if individuals with HD have deficits in the ability to accurately perceive biological motion compared to healthy peers.
Methods Three point of light images generated from digitally recorded human motion were randomly displayed on a laptop at subject selected intervals. Participants with HD were compared to participants with Parkinson’s disease and healthy peers in the ability to accurately define the image motion.
Results Perception is affected by both age and disease state with older individuals and those with basal ganglia dysfunction showing a decreased ability to accurately perceive biological motion.
Conclusion Many of the neural substrates underlying motor action and motion perception are the same. Activation patterns of mirror neurons in the parietal and premotor cortex suggest a strong link between perception and action. In addition, there is increasing evidence that internal representations used for each may overlap. Impairments demonstrated in perception of biological motion may suggest an inability for individuals with HD to accurately use visual perception to drive motion.
- motor control