Objective: To determine whether patients with blepharospasm have abnormal s
ensorimotor processing similar to patients with writer's cramp. Background:
Blepharospasm is a focal dystonia manifest by involuntary, excessive blink
ing and squeezing of the eyes. Altered sensorimotor processing may contribu
te to the development of dystonic movements. Previously the authors demonst
rated decreased vibration-induced cortical blood flow responses in hand pri
mary sensorimotor area (PSA) in patients with hand dystonia. Methods: In th
is prospective, case-control study, seven patients with blepharospasm were
compared with seven normal subjects. PET measurements of regional blood flo
w were obtained using bolus administration of (H2O)-O-15 at rest or during
sequential vibration of either the left or the right hand or side of the mo
uth. Results: PSA activation decreased significantly in the patients with b
lepharospasm both ipsilateral (-68%; p = 0.0004) and contralateral to the s
ide of facial stimulation (-56%; p = 0.0009). Patients had a 31% lower mean
contralateral PSA response to hand vibration and a 51% smaller right suppl
ementary motor area response to left-hand vibration than normal subjects, b
ut these differences did not reach statistical significance. Conclusions: P
atients with blepharospasm have abnormal sensorimotor processing in respons
e to lower face vibration. They may also have abnormal brain responses to s
timulation of clinically uninvolved parts of the body, but this requires co
nfirmation.