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AAN 2014: Differential Patterns Of White Matter Degradation In Relation To Cognitive And Motor Deficits In Parkinson's Disease

Zhang, Y; Schuff, N; the Parkinson\'s Progression Markers Initiative
AAN: Philadelphia, PA
Download Presentation: AAN2014 Differential-Patterns ZhangSchuff.pdf
OBJECTIVE: To investigate whether MRI diffusion tensor imaging (DTI) provides differential patterns of white matter degradation for cognitive and motor deficits in patients with non-demented de-novo Parkinson?s disease (PD).

BACKGROUND: Patients with PD often suffer also from cognitive deficits. However, the identification of a biological marker which can track cognitive and motor deficits differentially remains elusive.

DESIGN/METHODS: DTI data from 149 patients (mean age: 61 ± 9.2 years) with de novo PD from the Parkinson?s Progression Markers Initiative (PPMI) were analyzed. Motor impairment was measured using part III of the Movement Disorder Society-modified Unified Parkinson Disease Rating Scale (MDS-UPDRS-III). Cognitive impairment was measured using MDS assessments of memory, executive, visuospatial and attention domains. All patients had DTI scans using 3 Tesla MRI. A diffeometric anatomical registration algorithm through exponential Lie algebra (DARTEL) was used to align the individual DTI data to a brain atlas of white matter tracks, providing 74 white matter parcellations. Multiple regression was used to assess the association between white matter integrity and clinical measures.

RESULTS: Decreased executive function was associated with reduced fractional anisotropy (FA) in the cingulum (p=0.03) and the fornix (p=0.01); Decreased visuospatial function was associated with reduced FA primarily in the frontooccipital connections (p=0.01); No significant associations were found for FA and memory or attention functions. In contrast to cognition, increased motor deficits were associated with decreased FA in lower brain stem regions (p<0.001).

CONCLUSIONS: The results are consistent with the view that cognitive impairment is associated with white matter degradation of limbic regions, whereas motor deficits in PD are associated with white matter alterations in lower brain stem. These patterns of white matter degradation potentially provide a marker of clinically relevant cognitive impairment in early PD.

Study Supported by: Parkinson?s Progression Markers Initiative (PPMI).