Clinical and electromyographic features of levator palpebrae superioris muscle dysfunction in involuntary eyelid closure

Neural control of blinking

Blinking is a motor act characterized by the sequential closing and opening of the eyelids, which is achieved through the reciprocal activation of the orbicularis oculi and levator palpebrae superioris muscles. This stereotyped movement can be triggered reflexively, occur spontaneously, or voluntarily initiated. During each type of blinking, the neural control of the antagonistic interaction between the orbicularis oculi and levator palpebrae superioris muscles is governed by partially overlapping circuits distributed across cortical, subcortical, and brainstem structures. This paper provides a comprehensive overview of the anatomical and physiological foundations underlying the neural control of blinking. We describe the infra-nuclear apparatus, as well as the supra-nuclear control mechanisms, i.e., how cortical, subcortical, and brainstem structures regulate and coordinate the different types of blinking.

Debunking the Puzzle of Eyelid Apraxia: The Muscle of Riolan Hypothesis

PURPOSE

Apraxia of eyelid opening (AEO) has been defined by the presence of an intermittent nonparalytic bilateral loss of the volitional ability to open the eyes or to maintain the eyelids in a sustained elevated position. It is not known whether the condition represents an apraxia, a dystonia, or a freezing phenomenon, and several different nomenclatorial terms have been suggested for this condition including the so-called AEO (scAEO), blepahrocolysis, focal eyelid dystonia, and so on. The primary goal of this review is to attempt to clarify the pathogenetic mechanisms underlying scAEO as a clinical phenomenon. This review also addresses the issue of whether scAEO is part of the spectrum of blepharospasm (BSP) which includes BSP, dystonic blinks and other dystonic eyelid conditions, or whether it is a separate phenomenologically heterogeneous disease with clinical features that merely overlap with BSP.

METHODS

A literature review was conducted in PubMed, MEDLINE, PubMed Central (PMC), NCBI Bookshelf, and Embase for several related keywords including the terms "apraxia of eyelid opening," "pretarsal blepharospasm," "blepharocolysis," "eyelid freezing," "eyelid akinesia," "levator inhibition," "blepharospasm-plus," as well as "blepharospasm." The clinical findings in patients with scAEO who fulfilled the classic diagnostic criteria of the disease that were originally set by Lepore and Duvoisin were included, while patients with isolated blepharospasm or dystonic blinks (DB) were excluded. In addition, electromyographic (EMG) studies in patients with scAEO were reviewed in detail with special emphasis on studies that performed synchronous EMG recordings both from the levator muscle (LPS) and the pretarsal orbicularis oculi muscle (OO).

RESULTS

The apraxia designation is clearly a misnomer. Although scAEO behaves clinically as a hypotonic freezing phenomenon, it also shares several cardinal features with focal dystonias. The authors broadly categorized the EMG data into 3 different patterns. The first pattern (n = 26/94 [27.6%]) was predominantly associated with involuntary discharges in the OO muscle and has been termed pretarsal blepharospasm (ptBSP). The commonest pattern was pattern no. 2 (n = 53/94 [56.38%]), which was characterized by involuntary discharges in the OO muscle, together with a disturbed reciprocal innervation of the antagonist levator muscle and is dubbed disturbed reciprocal innervation (DRI). This EMG pattern is difficult to discern from the first pattern. Pattern no. 3 (n = 15/94 [15.9%]) is characterized by an isolated levator palpebrae inhibition (ILPI). This levator silence was observed alone without EMG evidence of contractions in the pretarsal orbicularis or a disturbed reciprocal relation of both muscles.

CONCLUSION

EMG evidence shows that the great majority (84%) of patients show a dystonic pattern, whereas ILPI (16%) does not fit the dystonic spectrum. The authors propose that a spasmodic contraction of the muscle of Riolan may be the etiological basis for levator inhibition in patients with ILPI. If this is true, all the 3 EMG patterns observed in scAEO patients (ptBSP, DRI, and ILPI) would represent an atypical form of BSP. The authors suggest coining the terms Riolan muscle BSP ( rmBSP ) for ILPI, and the term atypical focal eyelid dystonia ( AFED ) instead of the term scAEO, as both terms holistically encompass both the clinical and EMG data and concur with the authors' theorem.

Botulinum toxin therapy of dystonia

Botulinum toxin (BT) is used to treat a large number of muscle hyperactivity syndromes. Its use in dystonia, however, is still one of the most important indications for BT therapy. When BT is injected into dystonic muscles, it produces a peripheral paresis which is localised, well controllable and follows a distinct and predictable time course of around 3 months. Adverse effects are always transient and usually mild, long-term application is safe. With this profile BT can be used to treat cranial dystonia, cervical dystonia and limb dystonia including writer's and musician's cramps. The recent introduction of BT high dose therapy also allows to treat more wide-spread dystonia including segmental and generalised dystonia. BT can easily be combined with other anti-dystonic treatments such as deep brain stimulation and intrathecal baclofen application. Best treatment results are obtained when BT therapy is integrated in the multimodal and long-term 'multilayer concept of treatment of dystonia'. The biggest challenge for the future will be to deliver state of the art BT therapy to all dystonia patients in need, regardless of whether they live in developed countries or beyond.

Treatment of blepharospasm and Meige's syndrome with abo- and onabotulinumtoxinA: long-term safety and efficacy in daily clinical practice

INTRODUCTION

Thirty years after their approval, botulinum toxin injections still are the first-line therapy for blepharospasm. The aim of our study was to analyze long-term data concerning safety and efficacy in a large cohort over decades.

METHODS

Treatment data of all patients with blepharospasm and Meige´s syndrome in our outpatient clinic having undergone at least three subsequent treatment sessions with current onabotulinumtoxinA or abobotulinumtoxin A were analyzed with respect to the course of dose, effect duration, side effects, patients´ satisfaction and occurrence/reasons for treatment discontinuation.

RESULTS

The observation period was up to 18 years for onabotulinumtoxinA and 29 years for abobotulinumtoxinA with a total of 1778 and 9319 treatment sessions in 69 patients with onabotulinumtoxinA, 281 with abobotulinumtoxin A and 2 of these having used both products. The dose increased in the first years followed by a stable dose in the following years. The mean dose was 39.1/198.7 mouse units (onabotulinumtoxinA/abobotulinumtoxinA). In over 25% of all sessions, inhibition of the eyelid opening was effectively treated with pretarsal injections. The most common adverse events included ptosis (4%/5%), epiphora/sicca (4%/5%), double vision (1%/1%) and facial asymmetry (1%/1%). Reasons for therapy discontinuation were change to a nearby doctor, age, other diseases, spontaneous improvement, side effects or possible treatment failure. Only one patient was tested positive for neutralizing antibodies against botulinum toxin A.

CONCLUSION

The treatment of blepharospasm and Meige's syndrome with onabotulinumtoxinA and abobotulinumtoxinA is safe and effective, also over a long observation period of up to 29 years.

How Many Dystonias? Clinical Evidence

Literary reports on dystonia date back to post-Medieval times. Medical reports are instead more recent. We review here the early descriptions and the historical establishment of a consensus on the clinical phenomenology and the diagnostic features of dystonia syndromes. Lumping and splitting exercises have characterized this area of knowledge, and it remains largely unclear how many dystonia types we are to count. This review describes the history leading to recognize that focal dystonia syndromes are a coherent clinical set encompassing cranial dystonia (including blepharospasm), oromandibular dystonia, spasmodic torticollis, truncal dystonia, writer's cramp, and other occupational dystonias. Papers describing features of dystonia and diagnostic criteria are critically analyzed and put into historical perspective. Issues and inconsistencies in this lumping effort are discussed, and the currently unmet needs are critically reviewed.

Double eye brow: a rare case report

Eye brows are essential for esthetic and functional purposes. Various kinds of eye brows are found in human species. Protective function is one of the important functions of eye brows. Double eye brow is a very rare condition found in human. This case report describes one of the rare cases of double eye brow.

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.

Botulinum toxin for treatment of dystonia

Botulinum toxin (BT) is used in various medical specialties. However, dystonia is still one of the most important indications for BT therapy. BT drugs consist of botulinum neurotoxin, complexing proteins and excipients. Botox, Dysport and Xeomin are BT type A drugs and produce similar therapeutic and adverse effects (AE). Neurobloc/MyoBloc is based upon BT type B. Its use is limited by substantial systemic anticholinergic AE. The potency of BT drugs may be compared as follows: Botox:Xeomin:Dysport:Neuobloc/MyoBloc = 1:1:3:40. BT selectively blocks the cholinergic innervation of striate and smooth muscles and exocrine glands. It can produce obligate, local and systemic AE. However, its overall AE profile including long-term safety is excellent. BT can be blocked by antibodies. Risk factors include single doses, interinjection intervals and the immunological quality of the BT drug applied. Planning of BT therapy is based upon target muscle identification and estimation of their dystonic involvement. For planning of BT therapy and BT placement, electromyography and imaging techniques may be used additionally. So far, total Xeomin and Botox doses of up to 840 MU have been used without clinically detectable systemic AE. BT can be used to treat focal dystonias including cranial, pharyngolaryngeal, cervical and limb dystonias. In segmental and generalized dystonias, BT therapy has to be focussed on the most relevant target muscles. Combinations with all other treatment options including deep brain stimulation are possible. Recent safety data and availability of immunologically improved BT drugs are now allowing higher BT doses thus expanding the use of BT into more widespread dystonias.

Botulinum toxin in blepharospasm and oromandibular dystonia: comparing different botulinum toxin preparations

Amongst all regions of the body, the craniocervical region is the one most frequently affected by dystonia. Whilst blepharospasm--involuntary bilateral eye closure--is produced by spasmodic contractions of the orbicularis oculi muscles, oromandibular dystonia may cause jaw closure with trismus and bruxism, or involuntary jaw opening or deviation, interfering with speaking and chewing. Both forms of dystonia can be effectively treated with botulinum toxin injection. This article summarizes injection techniques in both forms of dystonia and compares doses, potency and efficacy of different commercially available toxins, including Botox, Dysport, Xeomin and Myobloc/NeuroBloc.

Apraxia in movement disorders

The definition of apraxia specifies that the disturbance of performed skilled movements cannot be explained by the more elemental motor disorders typical of patients with movement disorders. Generally this does not present a significant diagnostic problem when dealing with 'higher-level' praxic disturbances (e.g. ideational apraxia), but it can be a major confound in establishing the presence of limb-kinetic apraxia. Most motor disturbances characteristic of extrapyramidal disorders, particularly bradykinesia and dystonia, will compromise the ability to establish the presence of loss of dexterity and deftness that constitutes this subtype. The term 'apraxia' has also been applied to other motor disturbances, such as 'gait apraxia' and 'apraxia of eyelid opening', that perhaps are misnomers, demonstrating the lack of a coherent nomenclature in this field. Apraxia is a hallmark of corticobasal degeneration (CBD) and historically this has received the most attention among the movement disorders. Corticobasal degeneration is characterized by various forms of apraxia affecting limb function, particularly ideomotor apraxia and limb-kinetic apraxia, although buccofacial and oculomotor apraxia can be present as well. The syndrome of parkinsonism and prominent apraxia, designated the 'corticobasal syndrome' (CBS), may be caused by a variety of other central nervous system pathologies including progressive supranuclear palsy (PSP), Alzheimer's disease, dementia with Lewy bodies and frontotemporal dementias. Distinct from the CBS, PSP and Parkinson's disease can demonstrate varying degrees of apraxia on selected tests, especially in those patients with more severe cognitive dysfunction. Diseases that cause the combination of apraxia and a primary movement disorder most often involve a variety of cerebral cortical sites as well as basal ganglia structures. Clinical-pathological correlates and functional imaging studies are compromised by both this diffuse involvement and the confusion experienced in the clinical evaluation of apraxia in the face of the additional elemental movement disorders. Finally, although apraxia results in clear disability in patients with the CBS, it is not clear how milder ideomotor apraxia found on specific testing contributes to patients' overall day-to-day motor disability.

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 toxins in neurological disease

Botulinum toxins are among the most potent neurotoxins known to humans. In the past 25 years, botulinum toxin has emerged as both a potential weapon of bioterrorism and as a powerful therapeutic agent, with growing applications in neurological and non-neurological disease. Botulinum toxin is unique in its ability to target peripheral cholinergic neurons, preventing the release of acetylcholine through the enzymatic cleavage of proteins involved in membrane fusion, without prominent central nervous system effects. There are seven serotypes of the toxin, each with a specific activity at the molecular level. Currently, serotypes A (in two preparations) and B are available for clinical use, and have been shown to be safe and effective for the treatment of dystonia, spasticity, and other disorders in which muscle overactivity gives rise to symptoms. This review focuses on the pharmacology, electrophysiology, immunology, and application of botulinum toxin in selected neurological disorders.

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.

Dystonia in progressive supranuclear palsy

OBJECTIVES

To document the nature, distribution, and frequency of dystonic symptoms in progressive supranuclear palsy (PSP).

METHODS

Charts and videotapes of all clinically diagnosed patients with PSP seen between 1983 and 1993 were reviewed and the occurrence, nature, and distribution of all dystonic symptoms were recorded.

RESULTS

Of 83 identified cases 38 had some dystonic features. Twenty (24%) had blepharospasm (one was induced by levodopa), 22 (27%) had limb dystonia (one was induced by electroconvulsive therapy and another by levodopa), 14 (17%) had axial dystonia in extension, one had oromandibular dystonia induced by levodopa, and two had other cranial dystonias. Six patients had limb dystonia as an early or presenting feature, sometimes leading to misdiagnosis of cortical-basal ganglionic degeneration. All three patients who had postmortem confirmation of the diagnosis had other concurrent disease. One patient with bilateral limb dystonia and blepharospasm had evidence of previous hydrocephalus and severe arteriosclerotic changes. One with arm dystonia also had cerebrovascular disease and one with hemidystonia also had rare swollen chromatolytic neurons in the frontotemporal cortex.

CONCLUSIONS

Dystonia is a common manifestation of PSP. Limb dystonia is particularly common and may indicate the presence of concurrent disease. When dystonia occurs in PSP, dopaminergic medication should be cautiously reduced or discontinued to rule out the possibility of treatment induced symptoms.

Pretarsal application of botulinum toxin for treatment of blepharospasm

The response to botulinum toxin type A was compared after two injection techniques in 45 patients with blepharospasm. Initially, patients were treated according to a triple injection technique; two injections into the upper eyelid and one injection into the lower eyelid. Subsequently, without altering the dose, the same patient group received two further injections into the pretarsal portion of the orbicularis oculi muscle of the upper lid. Triple injections were given in 227 treatments, of which 81% were successful. Mean duration of benefit was 8.5 weeks. Additional pretarsal injections were given in 183 treatment sessions. The number of successful treatments significantly increased, to 95% (P < 0.001), and the mean duration of benefit increased to 12.5 weeks (P < 0.001). Ptosis occurred significantly less often after pretarsal injections (P < 0.01). Patients with combined blepharospasm and involuntary levator palpebrae inhibition responded better to the pretarsal injection technique.

Electromyography and recovery of the blink reflex in involuntary eyelid closure: a comparative study

Electromyographic (EMG) activity of orbicularis oculi and levator palpebrae muscles was recorded to study the origin of involuntary eyelid closure in 33 patients. The evoked blink reflex in all patients and in 23 controls was also studied. To examine the excitability of facial motoneurons and bulbar interneurons in individual patients and to compare the results with EMG findings, R1 and R2 recovery indices were calculated in all subjects, as the average of recovery values at 0.5, 0.3, and 0.21 second interstimulus intervals. Based on EMG patterns, the patients were divided into three subclasses: EMG subclass 1, 10 patients with involuntary discharges solely in orbicularis oculi muscle; EMG subclass 2, 20 patients with involuntary discharges in orbicularis oculi and either involuntary levator palpebrae inhibition or a disturbed reciprocal innervation between orbicularis oculi and levator palpebrae; EMG subclass 3, three patients who did not have blepharospasm, but had involuntary levator palpebrae inhibition in association with a basal ganglia disease. The total patient group showed an enhanced recovery of both R1 and R2 components compared with controls. Although 30 out of 33 patients had blepharospasm (EMG subclasses 1 and 2), R1 recovery index was normal in 64% and R2 recovery index was normal in 54%. Patients with an abnormal R2 recovery index had an abnormal R1 recovery index significantly more often. All patients from EMG subclass 1 had an abnormal R2 recovery index, whereas all patients from EMG subclass 3 had normal recovery indices for both R1 and R2 responses. Seventy five per cent of the patients from EMG subclass 2 had normal recovery indices. The results provide further evidence that physiologically blepharospasm is not a homogeneous disease entity, and indicate that different pathophysiological mechanisms at the suprasegmental, or segmental level, or both are involved.