Bilateral grey-matter increase in the putamen in primary blepharospasm.
BACKGROUND
Primary blepharospasm is a focal dystonia characterised by excessive involuntary closure of the eyelids. The pathophysiology of primary blepharospasm is unresolved.


OBJECTIVE
To pinpoint grey-matter changes that are associated with primary blepharospasm.


METHODS
16 right-handed patients with primary blepharospasm (mean age 67.4 (SD 4.3) years; 12 women) were compared with 16 healthy volunteers matched for sex and age. High-resolution T1-weighted magnetic resonance imaging of each participant was obtained and analysed by voxel-based morphometry, a method to detect regionally specific differences in grey matter between patients and control group. To evaluate whether the identified grey-matter changes were correlated with the duration of primary blepharospasm or botulinum neurotoxin treatment (BoNT), separate regression analyses were carried out.


RESULTS
In patients with primary blepharospasm, grey-matter increase in the putamina was observed, whereas regression analyses did not indicate a correlation between grey-matter increases and the duration of primary blepharospasm or BoNT. Grey-matter decrease was detected in the left inferior parietal lobule; here regression analyses of grey-matter decrease showed a significant (p = 0.013) correlation of grey-matter decrease with the duration of BoNT.


CONCLUSIONS
The data suggest structural changes in primary blepharospasm and point to a crucial role of the putamen for the pathophysiology of this focal dystonia.
Etgen
T
T
Department of Neurology, Technische Universität München, München, Germany. thorleif.etgen@klinikum-traunstein.de
Mühlau
M
M
Gaser
C
C
Sander
D
D
D000368:Aged; D001764:Blepharospasm / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011699:Putamen / Q000473:pathology*; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18