Involuntary closure of eyelids in parkinsonism. Electrophysiological evidence for prolonged inhibition of the levator palpebrae muscles

Pretarsal blepharospasm: Clinical and electromyographic characteristics

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.

Progressive Supranuclear Palsy, Corticobasal Degeneration, and Multiple System Atrophy

PURPOSE OF REVIEW

Patients who have parkinsonian features, especially without tremor, that are not responsive to levodopa, usually have one of these three major neurodegenerative disorders rather than Parkinson disease: progressive supranuclear palsy (PSP), multiple system atrophy (MSA), or corticobasal degeneration (CBD). Each of these disorders eventually develops signs and symptoms that distinguish it from idiopathic Parkinson disease, but these may not be present at disease onset. Although these conditions are not generally treatable, it is still important to correctly diagnose the condition as soon as possible.

RECENT FINDINGS

In recent years, it has been increasingly recognized that the symptoms of these diseases do not accurately predict the pathology, and the pathology does not accurately predict the clinical syndrome. Despite this, interest has grown in treating these diseases by targeting misfolded tau (in the case of PSP and CBD) and misfolded α-synuclein (in the case of MSA).

SUMMARY

Knowledge of the characteristic signs and symptoms of PSP, MSA, and CBD are essential in diagnosing and managing patients who have atypical parkinsonian syndromes.

How to spot ocular abnormalities in progressive supranuclear palsy? A practical review

Background

For parkinsonian disorders, progressive supranuclear palsy (PSP) continues to be significant for differential diagnosis. PSP presents a range of ocular abnormalities that have been suggested as optional tools for its early detection, apart from the principal characteristic of postural unsteadiness. Nonetheless, such symptoms may be difficult to identify, particularly during the early onset stage of the disorder. It may also be problematic to recognize these symptoms for general practitioners who lack the required experience or physicians who are not specifically educated and proficient in ophthalmology or neurology.

Main body

Thus, here, a methodical evaluation was carried out to identify seven oculomotor abnormalities occurring in PSP, comprising square wave jerks, the speed and range of saccades (slow saccades and vertical supranuclear gaze palsy), ‘round the houses’ sign, decreased blink rate, blepharospasm, and apraxia of eyelid opening. Inspections were conducted using direct visual observation. An approach to distinguish these signs during a bedside examination was also established. When presenting in a patient with parkinsonism or dementia, the existence of such ocular abnormalities could increase the risk of PSP. For the distinction between PSP and other parkinsonian disorders, these signs hold significant value for physicians.

Conclusion

The authors urge all concerned physicians to check for such abnormalities with the naked eye in patients with parkinsonism. This method has advantages, including ease of application, reduced time-consumption, and requirement of minimal resources. It will also help physicians to conduct efficient diagnoses since many patients with PSP could intially present with ocular symptoms in busy outpatient clinics.

Electronic supplementary material

The online version of this article (10.1186/s40035-019-0160-1) contains supplementary material, which is available to authorized users.

Bilateral ptosis: Lesion in the oculomotor nuclei or supranuclear lesion?

BACKGROUND

Bilateral ptosis is a very interesting clinical challenge for doctors because of the multiple possible localizations of a lesion which can lead to this neurological sign.

OBJECTIVES

Through this case report, we aim to determine the difference between an apraxia of lid opening (ALO) with difficulty in initiating the act of lid elevation, in spite of adequate understanding, motor control and cranial nerve pathways, and a bilateral ptosis with a lesion in the oculomotor nucleus or blepharospasm.

METHODS

The case report of a 50-year-old patient presenting bilateral ptosis and multiple ischemic lesions in the brainstem and bilateral frontal lobe lesions after the emergency removal of a large frontal tumor.

RESULTS

Our patient had an ALO according to the neurological follow-up and showed the ability, after a few weeks, of initiating the act of opening her eyes with her hand. The ophthalmic evaluation confirmed that in her case the ALO was associated with a nuclear lesion of the oculomotor nerve secondary to a midbrain lesion.

CONCLUSION

Our case report confirms multiple differential diagnoses in bilateral ptosis and the importance of clinical examination in spite of good neurological imaging.

Simultaneous loss of bilateral voluntary eyelid opening and sustained winking response following bilateral posterior cerebral artery infarction

Spontaneous opening and closing of both eyes usually occurs in the normal awake state, unless a deliberate and voluntary attempt is made to open only one eye. We present a rare case of a male patient who was unable to open both eyes simultaneously after bilateral posterior cerebral artery infarction. He was able to close both eyes voluntarily. However, he was unable to keep both eyes open simultaneously and either the right or left eye remained closed. Upon a verbal command to open both eyes, the opened eye closed and the contralateral eye opened. When the closed eye was forced open, the opened eye closed. We thus presented a case of right-left dissociation of voluntary eyelid opening following bilateral posterior cerebral artery infarction, which was treated with botulinum toxin type A injection. Differential diagnosis to other movement disorders of the eyelids was discussed.

Animal models for investigating benign essential blepharospasm

The focal dystonia benign essential blepharospasm (BEB) affects as many as 40,000 individuals in the United States. This dystonia is characterized by trigeminal hyperexcitability, photophobia, and most disabling of the symptoms, involuntary spasms of lid closure that can produce functional blindness. Like many focal dystonias, BEB appears to develop from the interaction between a predisposing condition and an environmental trigger. The primary treatment for blepharospasm is to weaken the eyelid-closing orbicularis oculi muscle to reduce lid spasms. There are several animal models of blepharospasm that recreate the spasms of lid closure in order to investigate pharmacological treatments to prevent spasms of lid closure. One animal model attempts to mimic the predisposing condition and environmental trigger that give rise to BEB. This model indicates that abnormal interactions among trigeminal blink circuits, basal ganglia, and the cerebellum are the neural basis for BEB.

Effects of varying subthalamic nucleus stimulation on apraxia of lid opening in Parkinson's disease

Apraxia of lid opening (ALO) is a non-paralytic inability to open the eyes or sustain lid elevation at will. The exact pathophysiological mechanisms underlying the syndrome are still unknown. ALO has been reported in patients with Parkinson's disease (PD) after subthalamic nucleus (STN) deep brain stimulation (DBS), suggesting a possible involvement of the basal ganglia. We aimed to assess the effects of varying STN stimulation voltage on ALO in PD patients. Seven out of 14 PD patients with bilateral STN stimulation consecutively seen in our centre presented with ALO. We progressively increased voltage on each STN, using either 130 Hz (high-frequency stimulation, HFS) or 2 or 3 Hz (low-frequency stimulation, LFS). In five patients, HFS induced ALO time-locked to stimulation in 7 out of 10 STNs at a voltage higher than that used for chronic stimulation. LFS induced myoclonus in the pretarsal orbicularis oculi muscle (pOOm) with a rhythm synchronous to the frequency. In the other two patients with ALO already present at the time of the study, HFS improved ALO in 3 out of 4 STNs. ALO recurred within minutes of stimulation arrest. Our findings show that STN-DBS can have opposite effects on ALO. On the one hand, ALO is thought to be a corticobulbar side effect due to lateral current spreading from the STN, in which case it is necessary to use voltages below the ALO-inducing threshold. On the other hand, ALO may be considered a form of off-phase focal dystonia possibly improved by increasing the stimulation voltages.

Animal models of focal dystonia

Animal models indicate that the abnormal movements of focal dystonia result from disordered sensorimotor integration. Sensorimotor integration involves a comparison of sensory information resulting from a movement with the sensory information expected from the movement. Unanticipated sensory signals identified by sensorimotor processing serve as signals to modify the ongoing movement or the planning for subsequent movements. Normally, this process is an effective mechanism to modify neural commands for ongoing movement or for movement planning. Animal models of the focal dystonias spasmodic torticollis, writer's cramp, and benign essential blepharospasm reveal different dysfunctions of sensorimotor integration through which dystonia can arise. Animal models of spasmodic torticollis demonstrate that modifications in a variety of regions are capable of creating abnormal head postures. These data indicate that disruption of neural signals in one structure may mutate the activity pattern of other elements of the neural circuits for movement. The animal model of writer's cramp demonstrates the importance of abnormal sensory processing in generating dystonic movements. Animal models of blepharospasm illustrate how disrupting motor adaptation can produce dystonia. Together, these models show mechanisms by which disruptions in sensorimotor integration can create dystonic movements.

Eyelid movements in health and disease. The supranuclear impairment of the palpebral motility

The eyelid movements are mediated mainly by the orbicularis oculi (OO) and the levator palpebrae superioris (LPS) muscles. Dissociated upper lid functions exhibit different counterbalanced action of these muscles, and in blinking they show a strictly reciprocal innervation. The disturbance of this close LPS-OO relationship likely leads to many of the central lid movement disorders. Three groups of supranuclear motor impairment of lid movements are considered: the disorders of the lid-eye movements' coordination, the disturbances of blinking and lid "postural" maintenance, and the alteration of voluntary lid movements. Nuclei of the posterior commissure control the inhibitory modulation of LPS motor-neuronal activity and they are involved in the lid-eye coordination disorders such as lid retraction, which is observed in the Parinaud's syndrome and also in parkinsonism and progressive supranuclear palsy. Spontaneous (SB) and reflex blinking consist of two components: the inhibition of the basal tonic LPS activity, which keeps the eyes open, and the concurrent activation of the OO muscles. LPS inhibition precedes and outlasts the OO activation. This normal configuration is impaired in parkinsonism and blepharospasm (BSP). SB shows a highly interindividual rate variation (among 10-20 per minute in adults) and abnormal blink rates occur in neurological diseases related to dopaminergic transmission impairments. Lid postural abnormalities include involuntary eyelid closure, which is usually associated with inability to open the eyes. Two major disorders share these two aspects: BSP and blepharocolysis (BCO). BSP consists of an involuntary overactivity of the OO, with LPS co-contraction activity, and is expressed as frequent and prolonged blinks, clonic bursts, prolonged tonic contraction or a blend of all of them. BCO (commonly named "so-called lid opening apraxia") is an overinhibition of the LPS with no evidence of ongoing OO activity. BSP and BCO occur in many instances of idiopathic dystonias and basal ganglia diseases and, less frequently, in rostral brainstem lesions. Both may coincide in the same patient. Voluntary lid movement disorders comprise the impairment of Bell's phenomenon, the voluntary eyelid closure palsy and the so-called cerebral ptosis, all related to lesions of frontal cortical areas and/or the corticospinal system.

Botulinum toxin in motor disorders: practical considerations with emphasis on interventional neurophysiology

After a brief review of the pharmacological properties of the botulinum toxin (BT), its mechanism of action on the nerve endings of the neuromuscular junctions, and the general therapeutic principles and adverse side effects, we discuss the advantages of interventional neurophysiology for the treatment of focal motor disorders by means of botulinum toxin A (BTA) muscle infiltration. Electromyography (EMG) provides a valuable objective information in the diagnosis of many motor disturbances and enables the precise identification of the muscles that contribute to the abnormal movement or posture. The use of EMG guidance for BTA injection seems advisable in every muscle but it become indispensable in those difficult to access, deeply located or partially atrophied by previous toxin infiltrations. The EMG study also serves to localise the areas with the highest abnormal activity and the motor point of the muscle, where the injection of toxin exerts its maximal effect. Consequently, lower doses of BTA can be employed without decreasing the efficacy of treatment but reducing the potential risk of side effects, antibody production and the cost of treatment. Electrophysiological diagnosis and BTA treatment may be performed during the same exploration. Considerations on the particular aspects and lines of action are given referring to the main focal muscular hyperactivity motor disorders such as cervical, oromandibular and laryngeal dystonias, blepharospasm, writer's cramp, hemifacial and hemimasticatory spasms, infantile and adult forms of spasticity and some other focal disturbances such as strabismus, detrusor-sphincter dyssynergia and anismus.

Guidelines for the therapeutic use of botulinum toxin in movement disorders. Italian Study Group for Movement Disorders, Italian Society of Neurology

Since its introduction in the early '80s the use of botulinum toxin has improved the quality of life of the patients affected by movement disorders. Toxin's neuromuscular blocking action allows a symptomatic treatment of those clinical conditions characterised by excessive muscular activity. Although the dosages used are safe and the side-effects are reversible, a correct use of botulinum toxin depends on the knowledge of its clinical pharmacology and of the anatomy of the body segments to be injected. In addition, the treatment of more complex conditions, i.e. laringeal dystonia, imposes an inter-disciplinary approach and specialised injection techniques. In this review, the Italian Study Group on Movement Disorders presents the consensus guidelines for the therapeutic use of botulinum toxin in movement disorders. The main toxin types, their use and administration modalities, and the training guidelines will be presented.

"Apraxia of lid opening," a focal eyelid dystonia: clinical study of 32 patients

We have seen 32 patients with "apraxia of lid opening" (ALO) in the following clinical settings: as an isolated condition (3 patients), idiopathic blepharospasm (BSP, 20 patients, including 4 familial cases), progressive supranuclear palsy (PSP, 7 patients), and dystonic parkinsonian syndrome (2 patients). Twenty-nine patients treated with botulinum toxin into the orbicularis oculi muscle were rated before and after treatment and 83% of the patients improved on a clinical scale. Best results were obtained with injections directed toward the junction of the preseptal and pretarsal parts of the palpebral orbicularis oculi. Several patients also improved on anticholinergic drugs. Besides medical treatment, lid crutches, in conjunction with botulinum toxin injections, were useful in some patients. ALO is not a true apraxia; it constitutes an eyelid dystonia as shown by its clinical and electrophysiological features as well as pharmacological reactions and is encountered in a clinical spectrum ranging from an isolated form to predominant BSP. It was an important cause of treatment failures in botulinum toxin-treated BSP but by modifying our injection strategy and by adding anticholinergic drugs and also lid crutches, we obtained a good functional benefit.

Eyelid motor abnormalities in progressive supranuclear palsy

Eyelid motor abnormalities found in progressive supranuclear palsy are reviewed. Electrophysiological correlates of blepharospasm, levator inhibition (blepharokolysis) and supranuclear paralysis of lid closure are presented. Disorders of eyelid motility are not uncommon in progressive supranuclear palsy (PSP). They may be found in about one third of patients with this syndrome (Jackson et al., 1983; Golbe et al., 1989). This is not surprising since ocular and eyelid movements are highly coordinated, mainly in the vertical plane (Gordon, 1951; Kennard and Smith, 1963; Kennard and Glaser, 1964), and a supranuclear ophthalmoplegia with down gaze impairment is a cardinal feature of PSP (Steele et al., 1964). The spectrum of eyelid motor disorders described in PSP includes blinking abnormalities, lid retraction, blepharospasm, levator inhibition and supranuclear palsy of eye closure.

Botulinum A toxin treatment for eyelid spasm, spasmodic torticollis and apraxia of eyelid opening

Botulinum-A toxin (botAtox) was used in the treatment of blepharospasm (BS), idiopathic hemifacial spasm (HFS), idiopathic spasmodic torticollis (ST) and apraxia of eyelid opening (AEO). The injection of 7.5-30 U botAtox per eye spread over 3 or 4 sites in the palpebral part of orbicularis palpebrae (OP) reduced palpebral spasm in 12/13 cases of BS and in 7/8 cases of HFS. The effect lasted for 14.5 weeks on average (range 4-30 weeks). Palpebral ptosis (lasting 1-3 weeks) was the most frequent side effect (16/107 eyes treated) but was not related to dose of botAtox or number of inoculation sites. Injection of 60-160 U botAtox into the sternocleidomastoid, trapezius and splenius capitis muscles reduced ST objectively in 1/4 patients for about 4 weeks. In the other patients the reduction or abolition of the hypertrophy of the previous hyperactive muscles was accompanied by persistence or rearrangement of the dystonia pattern, suggesting a change in the pattern of activity of the neck muscles after botAtox. 5 U botAtox per eye spread over 4 sites in the OP significantly reduced the frequency of the episodes of involuntary eyelid closure in 2 patients with AEO but not BS. The therapeutic effect lasted for 7 months after the first treatment and for 8 months after the second in a 46 year old woman with a 6 month history while the second patient (72 year old parkinsonian) has now completed her 3rd month of treatment.

Chronic progressive spinobulbar spasticity with disturbance of voluntary eyelid closure. Report of a case with special reference to MRI and electrophysiological findings

We describe a 56-year-old man who had a progressive pseudobulbar palsy, spastic tetraparesis, forced laughing and disturbance of voluntary eyelid closure, and was clinically compatible with chronic progressive spinobulbar spasticity. Magnetic resonance images (MRI) revealed atrophy of the bilateral motor cortices and single photon emission tomography after intravenous injection of N-isopropyl-p-iodoamphetamine iodine-123 (IMP-SPECT) showed hyporadioactivity in the same regions. Electrophysiological studies on supranuclear paralysis of eyelid closure demonstrated that so-called apraxia and motor impersistence coexisted and that in attempts to keep the eyelid closed the inhibition of basal activity of the levator palpebrae superioris muscle and activation of the orbicularis oculi muscle were insufficient, indicating the impaired reciprocity of these ocular muscles. The corresponding lesion of these eyelid symptoms was considered to be the bilateral motor cortices.