Functional brain networks in movement disorders: recent advances.

PURPOSE OF REVIEW: Different neuroimaging techniques have been used to identify disease-specific functional brain networks in Parkinson's disease, atypical parkinsonian syndromes, and other movement disorders. This review highlights recent advances in network imaging and its clinical applications in movement disorders. RECENT FINDINGS: Positron emission tomography and functional MRI studies have revealed distinct, abnormal metabolic brain networks and altered interregional connectivity in Parkinson's disease and related movement disorders. Network-level functional changes have been found to correlate with disease severity and progression. Moreover, network-based categorization algorithms are proving useful in enhancing the accuracy of clinical diagnosis in patients with early symptoms and in providing objective evidence of treatment response. SUMMARY: Although in most movement disorders the predominant histopathology involves the basal ganglia, including the substantia nigra, functional changes in relevant neural circuits are not limited to these structures. The current advances in functional brain imaging have contributed to a better pathophysiological understanding of movement disorders as complex alterations of widespread functional brain networks. The promising findings from recent studies may help to establish new and reliable biomarkers to monitor disease progression and treatment effects in future clinical trials.