Blepharospasm: Update on Epidemiology, Clinical Aspects, and Pathophysiology

This review will consider the knowledge that neuroimaging studies have provided to the understanding of the anatomy of dystonia. Major advances have occurred in the use of neuroimaging for dystonia in the past 2 decades. At present, the most developed imaging approaches include whole-brain or region-specific studies of structural or diffusion changes, functional imaging using fMRI or positron emission tomography (PET), and metabolic imaging using fluorodeoxyglucose PET. These techniques have provided evidence that regions other than the basal ganglia are involved in dystonia. In particular, there is increasing evidence that primary dystonia can be viewed as a circuit disorder, involving the basal ganglia-thalamo-cortical and cerebello-thalamo-cortical pathways. This suggests that a better understanding of the dysfunction in each region in the network and their interactions are important topics to address. Current views of interpretation of imaging data as cause or consequence of dystonia, and the postmortem correlates of imaging data are presented. The application of imaging as a tool to monitor therapy and its use as an outcome measure will be discussed. © 2013 Movement Disorder Society. Copyright © 2013 Movement Disorder Society. Show more

Idiopathic cervical dystonia (CD) and benign essential blepharospasm (BEB) are the most common forms of focal dystonia. Previous autopsy and imaging studies suggested that these disorders are not accompanied by structural brain abnormalities. However, recent brain voxel-based morphometry (VBM) studies of these conditions suggest that there actually may be changes in gray matter. The objective of this stdy was to detect possible gray matter abnormalities in patients with CD and BEB using VBM and to compare the results between the two conditions and with age- and gender-matched controls. High-resolution MRI was employed to evaluate healthy controls and individuals with BEB and CD. Eleven BEB, 9 CD, and 14 healthy control subjects were imaged. VBM revealed alterations of gray matter structures involved in sensorimotor processing in the individuals with focal dystonia. In CD subjects there was increased gray matter in the thalamus, caudate head bilaterally, superior temporal lobe, and left cerebellum, while gray matter was decreased in the putamen bilaterally. BEB subjects had increased gray matter in the caudate head and cerebellum bilaterally as well as decrease in the putamen and thalamus bilaterally. These findings strongly underline the recent notion that idiopathic focal dystonias might have a detectable structural correlate. They also demonstrate structural similarities of the investigated focal dystonias, possibly reflecting a shared common pathophysiological origin. Show more