Coordination Deficits in Parkinson’s Disease: Effects of Attention and Medicine

Abstract

Parkinson’s disease is a progressive neurodegenerative disease that begins unilaterally in the dopaminergic neurons of the basal ganglia. This neurodegeneration results in various cognitive and motor deficits, including movement asymmetry, attentional deficits, and impairments in timing and rhythm, all of which contribute to or reflect the development of deficits in coordination. Dopaminergic medication is effective in treating some symptoms, but not all symptoms are responsive to dopamine. The purpose of this thesis was to better understand the nature and extents of coordination deficits in people with Parkinson’s disease. In particular, the three objectives of this thesis were to: 1) Test measurement validity of existing (a)symmetry metrics in the literature, 2) Measure the effects of a dual task on interlimb coordination in people with Parkinson’s disease while walking, and 3) Determine the effects of dopaminergic medication and auditory cueing on coordination of the upper and lower limbs in people with Parkinson’s disease. Article 1 showed that several existing symmetry metrics were equally valid and sensitive to producing findings of asymmetry, but one metric and one common transformation were found to cause or have significantly decreased sensitivity. Article 2 found that multiple aspects of interlimb coordination in people with Parkinson’s disease were not affected by a dual task, which suggests that interlimb coordination remains automatic, and not requiring attention, in Parkinson’s disease. Article 3 found that dopaminergic medication did not generally affect timing in people with Parkinson’s disease, but the presence of timing deficits in comparison to healthy controls were confirmed. These findings suggest that timing deficits in people with Parkinson’s disease are not directly the result of dopaminergic neurodegeneration, and alternate solutions (e.g. non-dopaminergic or non pharmaceutical therapies) should be sought.