Funding agencies: This work was supported by the National Institutes of Health/National Institute for Neurological Disorders and Stroke Human Motor Control Section and the Max Kade Foundation (New York, New York, USA; to G.K.).
Long-term depression-like plasticity of the blink reflex for the treatment of blepharospasm
Article first published online: 11 FEB 2013
Copyright © 2013 Movement Disorder Society
Volume 28, Issue 4, pages 498–503, April 2013
How to Cite
Kranz, G., Shamim, E. A., Lin, P. T., Kranz, G. S. and Hallett, M. (2013), Long-term depression-like plasticity of the blink reflex for the treatment of blepharospasm. Mov. Disord., 28: 498–503. doi: 10.1002/mds.25329
Relevant conflicts of interest/financial disclosures: Nothing to report.
Full financial disclosures and author roles may be found in the online version of this article.
- Issue published online: 8 APR 2013
- Article first published online: 11 FEB 2013
- Manuscript Accepted: 26 NOV 2012
- Manuscript Revised: 12 NOV 2012
- Manuscript Received: 26 APR 2012
- clinical trials randomized controlled;
- blink reflex
Our previous work showed a beneficial therapeutic effect on blepharospasm using slow repetitive transcranial magnetic stimulation, which produces a long-term depression (LTD)-like effect. High-frequency supraorbital electrical stimulation, asynchronous with the R2 component of the blink reflex, can also induce LTD-like effects on the blink reflex circuit in healthy subjects. Patients with blepharospasm have reduced inhibition of their blink recovery curves; therefore, a LTD-like intervention might normalize the blink reflex recovery (BRR) and have a favorable therapeutic effect. This is a randomized, sham-controlled, observer-blinded prospective study. In 14 blepharospasm patients, we evaluated the effects of high-frequency supraorbital stimulation on three separate treatment days. We applied 28 trains of nine stimuli, 400 Hz, either before or after the R2 or used sham stimulation. The primary outcome was the blink rate, number of spasms rated by a blinded physician and patient rating before, immediately after and 1 hour after stimulation while resting, reading, and talking; secondary outcome was the BRR. Stimulation “before” and “after” the R2 both showed a similar improvement as sham stimulation in physician rating, but patients felt significantly better with the before condition. Improvement in recovery of the blink reflex was noted only in the before condition. Clinical symptoms differed in the three baseline conditions (resting, reading, and talking). Stimulation before R2 increased inhibition in trigeminal blink reflex circuits in blepharospasm toward normal values and produced subjective, but not objective, improvement. Inhibition of the blink reflex pathway by itself appeared to be insufficient for a useful therapeutic effect. © 2013 Movement Disorder Society