BACKGROUND: Primary blepharospasm is a focal dystonia characterised by excessive 
involuntary closure of the eyelids. The pathophysiology of primary blepharospasm 
is unresolved.
AIM: 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.