Abstract Details

Title Basal Ganglia and Cerebellar Circuits Have Distinct Roles in Blepharospasm

Topic Movement Disorders

Presentation(s) P4 - Poster Session 4 (5:30 PM-6:30 PM)

Poster/Presentation
Number 10-010

Objective To identify areas of brain activity associated with involuntary muscle contractions in patients with blepharospasm (BSP) using functional MRI (fMRI).

Background Previously considered a purely motor disorder of the basal ganglia, dystonia is now viewed as a network disorder with widespread dysfunction. Understanding the distinct brain regions linked to symptoms in focal dystonias such as BSP could help elucidate underlying pathology and lead to more effective treatments.

Design/Methods fMRI data were collected on 15 patients with BSP during 8-minute resting state scans with spontaneous orbicularis oculi muscle contractions simultaneously recorded using MRI-compatible surface electromyography (EMG). Spasm severity and onset/offset were modeled using the amplitude of the signal (EMG-Amp) and its first temporal derivative (EMG-Onset), respectively, and included in a multiple regression fMRI analysis using SPM12. Primary outcome was within-BSP-group blood-oxygen-level dependent activations that co-varied with EMG-Amp and EMG-Onset. Results were corrected for multiple comparisons using the autocorrelation function approach incorporated into the 3dClustSim function in Analysis of Functional NeuroImages for an overall corrected p<0.05.

Results fMRI data were excluded for 1 subject due to excessive movement. EMG-Amp co-activated with left postcentral/precentral gyri, left cerebellum (lobule VI), and right lingual gyrus (Brodmann area 18). EMG-Onset co-activated with left lenticular nucleus.

Conclusions These findings suggest that cerebello-cortical circuits in BSP drive the intensity of eyelid spasms while basal ganglia circuits are associated with the onset of spasms. This supports the network model for dystonia and identifies specific areas of involvement consistent with know brain regions responsible for control of movement. Interestingly, the two-circuit model for eyelid spasms in BSP suggested by these findings is analgous to the network model recently proposed to explain parkinsonian rest tremors.

Authors/Disclosures
Amanda Glickman PRESENTER	Ms. Glickman has nothing to disclose.
Erika Shelton	No disclosure on file
Brian Berman, MD, MS, FAAN (Virginia Commonwealth University)	The institution of Dr. Berman has received research support from Dystonia Medical Research Foundation. The institution of Dr. Berman has received research support from National Institutes of Health. The institution of Dr. Berman has received research support from Neurocrine Biosciences. The institution of Dr. Berman has received research support from Benign Essential Blepharospasm Research Foundation. The institution of Dr. Berman has received research support from National Institutes of Health.

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