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Objective: To describe the clinical and electromyographic characteristics of blepharospasm caused by selective involvement of the pars pretarsalis of the orbicularis oculi muscle., Methods: Clinical assessment and simultaneous electromyographic recordings from levator palpebrae superioris and pars orbitaria and pretarsalis of orbicularis oculi muscles were performed in patients with blepharospasm and primary failure to botulinum toxin injections. Patients with selective abnormal electromyographic activity of the pars pretarsalis of the orbicularis oculi muscle were identified and treated with selective pretarsal injections of botulinum toxin., Results: We found 24 patients with pretarsal blepharospasm confirmed by the electromyographic assessment. All of them were functionally blind. Three clinical-electromyographic patterns were identified: (a) Impairment of eyelid opening; (b) Increased blinking; (c) Spasms of eye closure combined with varying degrees of excessive blinking and impairment of eye-opening. Pretarsal injections of botulinum toxin induced a significant improvement in all patients and 50 % regained normal or near-normal vision. The clinical improvement was sustained after repeated pretarsal injections., Conclusions: Pretarsal blepharospasm can be suspected on clinical grounds and it can be confirmed by electromyographic recordings., Significance: Recognition of this type of blepharospasm is important because of its excellent response to botulinum toxin injections applied into the pretarsal part of the orbicularis oculi muscle., Competing Interests: Declaration of Competing Interest F. Grandas received honoraria for lecturing from Allergan S.A. The other authors: none., (Copyright © 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

We report on a patient who presented a transient eyelid motor disorder characterized by bilateral reflex blepharospasm as the main clinical manifestation of a right-sided striatal infarction. This case emphasizes the role of the nondominant striatum in the pathophysiology of eyelid motor abnormalities.

To determine whether Botulinum Toxin Type A (BTXA) has an effect on the Central Nervous System, the authors studied the excitability of the blink reflex recovery cycle in 12 patients with blepharospasm before and 3 weeks after unilateral BTXA injections. To avoid recording from severely denervated muscles, the R2 response of the blink reflex was obtained from the untreated orbicularis oculi with both ipsilateral and contralateral supraorbital nerve stimulation. Baseline recovery curves were compared with a control group (n = 11) and showed an enhanced recovery of the R2 component. There were no significant differences between the recovery curves of the R2 component of the blink reflex taken before BTXA treatment and those taken after treatment. This finding confirms that BTXA does not modify the excitability of brainstem interneurons that mediate the bilateral R2 response of the blink reflex in patients with blepharospasm.

A case that combines cerebral eyelid ptosis and blepharospasm secondary to cerebral hemisphere infarction is shown. EMG recording from the facial and eyelid muscles revealed lack of the levator palpebrae superioris, orbicularis oculi and corrugator muscles activity. Any voluntary opening attempt lead to a simultaneous contraction of the three muscles. Blink reflex responses were normal although showed facilitation features on the right side and mild inhibition characteristics from the left side. Median nerve SEP revealed a loss of precentral components (P22-N30) as well as a delay and amplitude decrease of N20. Transcranial magnetic stimulation disclosed a complete lesion of corticospinal pathway for right upper limb. In this case, a right hemisphere lesion caused an unusual eyelid motor abnormality: cerebral eyelid ptosis and blepharospasm induced by the voluntary eyelid opening.

Blepharospasm is a cranial dystonia characterized by forceful spasms of the orbicularis oculi muscle which may lead to functional blindness in approximately two-thirds of patients. Botulinum toxin injection is a simple procedure, very effective and with little morbidity. It is considered as the treatment of choice for patients with disabling blepharospasm.

The response to different therapeutic methods was evaluated in a series of 264 patients with blepharospasm. The most effective drug therapy were anticholinergic agents, which resulted in the initial improvement of symptoms in 20% of treated patients. There was improvement in isolated cases treated with levodopa, dopaminergic agonists, neuroleptics, benzodiazepines and tricyclic antidepressants. Bilateral avulsion of the facial nerve was carried out in 29 patients; 27 of these (93%) improved. Spasms relapsed in 22 cases, after a mean period of 12 months. Myectomy of the orbicular muscle was performed in 8 patients. In only 2 cases some improvement was obtained. One hundred and fifty-one patients were treated with infiltrations of botulinum toxin A in the orbicular muscle. 78% of cases improved. The mean duration of the benefit of each injection was 9.2 weeks. The most common secondary effects were local (ptosis, diplopia) and transient.

Two hundred and seventy-two patients with idiopathic blepharospasm were reviewed to establish the role of local eye disease in their illness. The majority of patients (57%) had symptoms at the onset of their illness such as dryness of the eyes, grittiness, irritation or photophobia suggesting eye lid or ocular surface disease. Detailed ophthalmological examination at the time of presentation had been carried out in 170 of the 272 cases; 64% of these patients had ocular symptoms, and 40% had demonstrable ocular surface or eye lid pathology. Such pathology was usually bilateral, chronic and resistant to local treatment. Blepharospasm developed in these patients after a long latent period, often of many years. Unilateral pathology was acute, normally responded well to local treatment, but was followed by the development of bilateral blepharospasm usually within six months. Amongst all 272 patients, those without ocular symptoms at presentation rarely developed them subsequently; if they did, there were no abnormal signs. The data suggest that ophthalmological disorders may trigger idiopathic blepharospasm in a substantial proportion of cases predisposed to develop this condition.

The natural history and response to different treatments have been evaluated in 264 patients with blepharospasm. The mean age of onset was 55.8 years and there was a female preponderance of 1.8 to 1. Dystonia elsewhere was found in 78% of patients, usually in the cranial-cervical region, and appeared to follow a somatotopic progression. A family history of blepharospasm or dystonia elsewhere was found in 9.5% of cases, which suggests a genetic predisposition. Ocular lesions preceded the onset of blepharospasm in 12.1% of cases. The response to drugs was inconsistent, although initial improvement was experienced by one fifth of patients treated with anticholinergics. Twenty-nine bilateral facial nerve avulsion operations were performed with benefit in 27 cases; but recurrences appeared in 22, on average one year after surgery. Botulinum toxin injections were performed in 151 patients. Significant improvement was achieved in 118 cases. Mean duration of benefit was 9.2 weeks. Transient ptosis and diplopia were the commonest side effects.