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Apraxia of lid opening

Eye Department, Worthing Hospital, UK

Correspondence: Marta Ugarte
Email: mugarte{at}doctors.org.uk Worthing Hospital, Worthing BN11 2DH, UK Tel: +44-(0)1903 205111; Fax: +44-(0)1903 285045.

Date of acceptance: 6th April 2007

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Introduction

We describe eyelid movement abnormalities in a patient with apraxia of lid opening (ALO), a nonparalytic motor abnormality characterized by difficulty in initiating the act of lid elevation after lid closure.1 ALO may be caused by involuntary levator palpebrae inhibition (ILPI), pretarsal orbicularis oculi (OO) motor persistence, or both.2 The heterogeneity in the underlying mechanisms results in variable therapeutic responses. Botulinum toxin A treatment is expected to be beneficial when ALO is caused by pretarsal OO motor persistence but not when it results from ILPI. We examined and recorded the lid and eye movements in a man with this unusual syndrome and here we discuss the clinical features which may assist in its diagnosis.

Case Report

An 80-year-old Caucasian man presented with a 12-month history of insidious onset and slowly progressive inability to open his eyes voluntarily following lid closure. In his forties, following a serious head injury he underwent a cranioplasty and insertion of a frontal metal plate, which left him with a chronic lower motor neurone VII palsy on the left side. He was confined to a wheelchair due to general weakness in his lower limbs resulting from a combination of ischaemia centrally, spinal stenosis at the level of L5/S1 and sensory motor axonal neuropathy. Clinically, there was no evidence of extrapyramidal or frontal lobe disease.

On examination, there was inability to open his lids at will following closure. Attempted eye opening resulted in forceful contraction of the frontalis muscle on the right side, backward thrusting of the head and lengthened duration of lid closure. The inability to reopen the lids was not evident during spontaneous reflex blinking and he had no difficulty in keeping the lids open once they had been manually lifted up. There were no episodes of involuntary drooping of the eyelids or spasmodic contraction of the OO causing involuntary eyelid closure. However, on the command to open his lids following voluntary closure, occasional persistent pretarsal OO muscle contraction was clinically noticeable. There was no restriction of pursuit eye movements, the vestibulo-ocular reflex was preserved and both horizontal and vertical saccades were normal. Brain MRI was not possible, CT scanning was affected by artefact from his frontal metal plate and it could not be determined whether there was an identifiable lesion responsible for his ALO. Treatment with botulinum toxin injections at various points, including the pretarsal and preseptal portions of the OO, resulted in no improvement of his symptoms but he found some benefit using lid crutches.

Comment

The underlying mechanism of the eyelid opening disorder occurring in this patient is suggested to be the result of involuntary levator palpebrae inhibition and pretarsal OO contraction. Upon command to open his eyes following voluntary closure, motor persistence of the pretarsal OO muscle was often evident during which the eyelids remained closed. Interestingly, motor persistence of the OO did not occur during spontaneous blinking. Involuntary spasmodic contraction of the OO was not detected either when the eyes were open. There was no increased blinking or episodes of involuntary closure of the eyelids. There was normal activity of the OO and apparent normal levator palpebrae inhibition on the command to close his lids. Injection of botulinum toxin into the pretarsal and preseptal portions of the OO did not improve his inability to open the lids suggesting that the activity of the levator palpebrae was somehow inhibited.

The anatomical location of the lesion and the pathophysiology in ALO have not been clearly identified but there is evidence to believe that this condition is due to an abnormality in the supranuclear control of eyelid movement. Disordered function of the basal ganglia and/or frontal lobes has been linked to ILPI, either isolated or combined with blepharospasm (involuntary contractions of the OO resulting in frequent blinking and/or forceful closure of the lids). 2 The excitatory levator palpebrae response necessary to lift the lids up is likely to be in very close connection with the OO antagonistic inhibitory response. Disturbances of the pre-motor control of the levator palpebrae activity may parallel abnormalities in the regulation and control of the OO activity. Alterations in one or another pre-motor structure (including burst, tonic and/or pause neurons) may explain not only the patient’s inability to raise the lids due to inhibition of the levator palpebrae but also the motor persistence of the pretarsal OO.3 The human OO muscle consists of three functional groups of motor units: pretarsal, preseptal and the third group which extends from the preseptal to the orbital regions. The activity of the pretarsal portion seems to be the most susceptible to abnormalities in supranuclear signals. Patients with ALO may have a sensory trick, such as, touching of the temporal area or opening the mouth, that improve their eyelid opening. The physiology of these tricks is unknown.

The features of this case confirm that despite the clinically visible persistence of pretarsal OO activity on attempted eye opening, treatment with botulinum toxin may not reduce the disability in patients with ALO associated with levator palpebrae inhibition. The variable effect of botulinum toxin treatment reflects the heterogeneity of the underlying mechanisms of this condition. Those cases that are refractory to botulinum toxin may sometimes benefit from using lid crutches. Some success has been reported with levo-dopa, levator aponeurosis tightening or frontalis suspension. Therapy should be tailored to the patient’s needs.

References