The significance of ophthalmological symptoms in idiopathic blepharospasm

Tear osmolarity, dry eye syndrome, blepharospasm and botulinum neurotoxin

PURPOSE

To assess the severity of dry eye disease in patients with blepharospasm (BEB) before (control) and after injection of botulinum neurotoxin A (BoNT/A).

DESIGN

Cross-sectional study.

METHODS

Patients with clinically diagnosed BEB and no known history of dry eye syndrome prior to the onset of the disease, before (controls) or after injection with one of the three available types of BoNT/A: onabotulinumtoxinA (Botox®; Allergan, Irvine, CA, USA), abobotulinumtoxinA (Dysport®; Beaufour Ipsen Pharma SAS, Paris, France) or incobotulinumtoxinA (Xeomin®; Merz Pharma GmbH, Frankfurt, Germany) every 3 months. Tear osmolarity and Schirmer's I-test were measured at the first visit for non-treated BEB patients as controls and 3 months after BoNT/A injection.

RESULTS

The study consisted of 101 BEB patients (86 females, 15 males) with a mean age of 67 years (range 30-86 years). Seventeen patients were untreated, 26 treated with onabotulinumtoxinA, 23 treated with abobotulinumtoxinA and 35 treated with incobotulinumtoxinA. Post-injection mean tear osmolarity was not significantly higher among patients treated with onabotulinumtoxinA, abobotulinumtoxinA, or incobotulinumtoxinA (P=0.65, P=0.92, and P=0.15, respectively), compared to controls, remaining less than 308 mosm/mL. Mean Schirmer's I-test results remained under 5mm and did not vary between the four groups.

CONCLUSIONS

The results clearly demonstrate that reduced tear secretion appears to be present in BEB patients even prior to treatment. This decreased lacrimal secretion was not correlated with hyperosmolarity. Clinicians should proactively treat dry eye syndrome in conjunction with management of the blepharospasm.

Second hit hypothesis in dystonia: Dysfunctional cross talk between neuroplasticity and environment?

One of the great mysteries in dystonia pathophysiology is the role of environmental factors in disease onset and development. Progress has been made in defining the genetic components of dystonic syndromes, still the mechanisms behind the discrepant relationship between dystonic genotype and phenotype remain largely unclear. Within this review, the preclinical and clinical evidence for environmental stressors as disease modifiers in dystonia pathogenesis are summarized and critically evaluated. The potential role of extragenetic factors is discussed in monogenic as well as adult-onset isolated dystonia. The available clinical evidence for a "second hit" is analyzed in light of the reduced penetrance of monogenic dystonic syndromes and put into context with evidence from animal and cellular models. The contradictory studies on adult-onset dystonia are discussed in detail and backed up by evidence from animal models. Taken together, there is clear evidence of a gene-environment interaction in dystonia, which should be considered in the continued quest to unravel dystonia pathophysiology.

Botulinum toxin type A therapy for blepharospasm

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Blepharospasm is the second most common form of focal dystonia. It is a disabling disorder, characterised by chronic, intermittent or persistent, involuntary eyelid closure, due to spasmodic contractions of the orbicularis oculi muscles. Currently, botulinum toxin type A (BtA) is considered the first line of therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with blepharospasm.

SEARCH METHODS

We searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of included articles, and conference proceedings. We ran all elements of the search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with blepharospasm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We performed meta-analyses using a random-effects model, for the comparison of BtA versus placebo, to estimate pooled effects and corresponding 95% confidence intervals (95% CI). We did not carry out any prespecified subgroup analyses. The primary efficacy outcome was improvement on any validated symptomatic rating scale. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included three RCTs, assessed at low to moderate overall risk of bias, which randomised 313 participants with blepharospasm. Two studies excluded participants with poorer prior responses to BtA treatment, therefore, they included an enriched population with a higher probability of benefiting from this therapy. All trials were industry-funded. All RCTs evaluated the effect of a single BtA treatment session. BtA resulted in a moderate to large improvement in blepharospasm-specific severity, with a reduction of 0.93 points on the Jankovic Rating Scale (JRS) severity subscale at four to six weeks after injection (95% confidence interval (CI) 0.61 to 1.25; I² = 9%) compared to placebo. BtA was also resulted in a moderate to large improvement in blepharospasm-specific disability and blepharospasm-specific involuntary movements at four to six weeks after injection (disability: 0.69 JRS disability subscale points, 95% CI 0.18 to 1.19; I² = 74%; blepharospasm-specific involuntary movements: standardised mean difference (SMD) 0.79, 0.31 to 1.27; I² = 58%) compared to placebo. BtA did not show a risk of adverse events (risk ratio (RR) 1.18, 95% CI 0.87 to 1.60; I² = 0%). However, BtA increased the risk of vision complaints and eyelid ptosis (vision complaints: RR 5.73, 95% CI 1.79 to 18.36; I² = 51%; eyelid ptosis: RR 4.02, 95% CI 1.61 to 10.00; I² = 39%). There was no distinction between BtA and placebo in the number of participants who dropped out of the trial. A single trial estimated the duration of effects to be 10.6 weeks (range 6.1 to 19.1). We found no evidence supporting the existence of a clear dose-response relationship with BtA. We found no data reporting the impact of BtA on health-related quality of life, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We are moderately certain that a single BtA treatment resulted in a clinically relevant reduction of blepharospasm-specific severity and disability, and have low certainty that it is well tolerated, when compared with placebo. There is low-certainty evidence that people treated with BtA are not at an increased risk of developing adverse events, though BtA treatment likely increases the risk of visual complaints and eyelid ptosis. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, or the impact on quality of life.

Ocular surface status in patients with hemifacial spasm under long-lasting treatment with botulinum A toxin: A comparative fellow eye study

Purpose:

The purpose of this study was to assess the effect of long-lasting botulinum A toxin injections on ocular surface parameters and to further investigate the relationship between these parameters and the duration of the treatment.

Methods:

In this retrospective study, patients with unilateral hemifacial spasm who were receiving botulinum A toxin injections for at least 1 year were analyzed. Healthy contralateral eyes acted as controls. The ocular surface examination included Ocular Surface Disease Index questionnaire, Schirmer test type I, tear film break-up time (TFBUT), tear osmolarity, corneal sensitivity, and corneal fluorescein staining.

Results:

Twenty-six patients (6 males and 20 females; mean age 76.4 ± 8.9 years) were included in the study. The mean duration of the treatment was 7.2 ± 5.4 years, and the mean frequency of injections was of one every 3.3 ± 0.4 months. TFBUT, Schirmer test, and corneal sensitivity were significantly lower in the eye homolateral to hemifacial spasm compared with the contralateral one (5.9 ± 3.2 vs 7.5 ± 4.2 s, P = 0.001; 6.2 ± 3.4 vs 9.2 ± 6.6 mm, P = 0.031; 50.8 ± 3.7 mm vs 52.3 ± 2.9 mm, P = 0.048, respectively). One month after the last injection, TFBUT further decreased from 5.9 ± 3.2 to 2.3 ± 1.2 s (P = 0.028). A significant positive correlation was found between the duration of treatment and tear osmolarity (ρ = 0.542, P = 0.025).

Conclusion:

Patients with hemifacial spasm under long-lasting treatment with serial botulinum A toxin injections showed a reduction in tear film production and stability, as well as corneal sensitivity in the treated eye compared with the contralateral one. Tear film stability further decreased 1 month after the last injection.

Sex, blinking, and dry eye

Blinking sustains the corneal tear film generated by sexually dimorphic lacrimal and meibomian glands. Our study examines whether trigeminal control of blinking is also sexually dimorphic by investigating trigeminal reflex blinking, associative blink modification, and spontaneous blinking in male and female rats before and after unilateral dry eye caused by exorbital gland removal. Before gland removal, female rats exhibited a lower threshold for evoking trigeminal reflex blinks, a weaker effect of associative blink modification, and longer-duration spontaneous blinks than males. Spontaneous blink rate, reflex blink excitability, and occurrence of blink oscillations did not differ between the sexes. Reanalysis of previous data showed that humans showed the same blink sexual dimorphisms as rats. During the first 2 wk of dry eye, trigeminal blink circuit excitability and blink oscillations steadily rose in male rats, whereas excitability and blink oscillations did not change in females. Following dry eye, spontaneous blink duration increased for both males and females, whereas spontaneous blink rate remained constant for males but decreased for females. The associative modification treatment to depress trigeminal blink amplitude initially produced blink depression in males that converted to blink potentiation as trigeminal excitability rose, whereas females exhibited progressively more blink depression. These data indicated that dry eye increased excitability in male trigeminal reflex blink circuits at the expense of circuit modifiability, whereas trigeminal modifiability increased in females. This increased modifiability of female trigeminal blink circuits with dry eye may contribute to the preponderance of females developing the focal dystonia, benign essential blepharospasm.NEW & NOTEWORTHY All the elements controlling the corneal tear film are sexually dimorphic. Blinking, which smooths and maintains the tear film, also exhibits sex differences. Dry eye increases the sexual dimorphisms of blinking, including increased exaggeration of excitability in males and enhanced modifiability of the female trigeminal complex. This increased modifiability may explain female predominance in the development of the focal dystonia, benign essential blepharospasm.

Effect of Botulinum Toxin A Treatment on Eyelid Pressure in Eyes with Blepharospasm

OBJECTIVE

To determine the effect of botulinum toxin A (BTX-A) on the eyelid pressure in patients with benign essential blepharospasm (BEB).

METHODS

Twenty normal volunteers (10 men, 10 women; average age 59.7 ± 11.3 years) and 33 patients (12 men, 21 women; average age 61.1 ± 14.7 years) with BEB were studied. The upper and lower eyelid pressures were measured with a blepharo-tensiometer in the normal subjects (N group). The eyelid pressures and intraocular pressures (IOP) were measured before and after the BTX-A injections in the BEB patients (B group).

RESULTS

The mean eyelid pressure in the N group was 31.0 ± 6.8 mmHg for the upper eyelid and 29.9 ± 6.5 mmHg for the lower eyelid (P > 0.05). The mean eyelid pressure in the B group before treatment was 35.3 ± 7.0 mmHg for the upper eyelid and 37.8 ± 6.6 mmHg for the lower eyelid. The eyelid pressure in the B group was significantly higher than in the N group for the upper and lower eyelids (both P < 0.001). The eyelid pressure was significantly decreased after BTX-A treatment for the upper (29.9 ± 7.5 mmHg) and the lower (32.8 ± 7.0 mmHg) eyelids (both P < 0.001). The mean IOP was 15.1 ± 2.9 mmHg before, and it significantly decreased to 14.5 ± 2.8 mmHg (P = 0.020) after the BTX-A injections. The IOP was significantly correlated with the lower eyelid pressure (P = 0.0435), but not with the upper eyelid pressure (P = 0.175).

CONCLUSION

The eyelid pressure was higher in the patients with BEB. The eyelid pressure and the IOP were significantly reduced after the BTX-A injections. In addition, the IOPs were significantly correlated with the eyelid pressure of the lower eyelid.

Protective Effect of Blepharospasm on the Anterior Segment of the Eye

The aim of the study was to determine the role of blepharospasm as a protective factor for the anterior segment of the eye by comparing the degree of blepharospasm and changes of the anterior segment structures. The study included sixty female patients older than forty years with the clinical diagnosis of blepharospasm. They were divided into two groups; the first group consisted of patients with stage I and II of blepharospasm with dominant dry eye symptoms, and the second group consisted of patients with stage III and IV of blepharospasm who required interventional therapy (all patients in this study were treated with botulinum toxin type A). Staining of ocular surface with vital dyes such as fluorescein was used to determine ocular surface defects. Fluorescein stains the corneal epithelial defects, which were statistically less pronounced in the interventional group. In conclusion, comparison of the results between the two groups of patients may implicate that advanced blepharospasm has a protective effect on ocular surface.

A Dynamic Circuit Hypothesis for the Pathogenesis of Blepharospasm

Blepharospasm (sometimes called “benign essential blepharospasm,” BEB) is one of the most common focal dystonias. It involves involuntary eyelid spasms, eye closure, and increased blinking. Despite the success of botulinum toxin injections and, in some cases, pharmacologic or surgical interventions, BEB treatments are not completely efficacious and only symptomatic. We could develop principled strategies for preventing and reversing the disease if we knew the pathogenesis of primary BEB. The objective of this study was to develop a conceptual framework and dynamic circuit hypothesis for the pathogenesis of BEB. The framework extends our overarching theory for the multifactorial pathogenesis of focal dystonias (Peterson et al., 2010) to incorporate a two-hit rodent model specifically of BEB (Schicatano et al., 1997). We incorporate in the framework three features critical to cranial motor control: (1) the joint influence of motor cortical regions and direct descending projections from one of the basal ganglia output nuclei, the substantia nigra pars reticulata, on brainstem motor nuclei, (2) nested loops composed of the trigeminal blink reflex arc and the long sensorimotor loop from trigeminal nucleus through thalamus to somatosensory cortex back through basal ganglia to the same brainstem nuclei modulating the reflex arc, and (3) abnormalities in the basal ganglia dopamine system that provide a sensorimotor learning substrate which, when combined with patterns of increased blinking, leads to abnormal sensorimotor mappings manifest as BEB. The framework explains experimental data on the trigeminal reflex blink excitability (TRBE) from Schicatano et al. and makes predictions that can be tested in new experimental animal models based on emerging genetics in dystonia, including the recently characterized striatal-specific D1R dopamine transduction alterations caused by the GNAL mutation. More broadly, the model will provide a guide for future efforts to mechanistically link multiple factors in the pathogenesis of BEB and facilitate simulations of how exogenous manipulations of the pathogenic factors could ultimately be used to prevent and reverse the disorder.

Blepharospasm 40 years later

Forty years ago, C.D. Marsden proposed that blepharospasm should be considered a form of adult-onset focal dystonia. In the present paper, we provide a comprehensive overview of the findings regarding blepharospasm reported in the past 40 years. Although prolonged spasms of the orbicularis oculi muscles remain the clinical hallmark of blepharospasm, patients with blepharospasm may be characterized by various types of involuntary activation of periocular muscles. In addition to motor features, blepharospasm patients may also have nonmotor manifestations, including psychiatric, mild cognitive, and sensory disturbances. The various motor and nonmotor symptoms are not present in all patients, suggesting that blepharospasm is phenomenologically a heterogeneous condition. This emphasizes the need for tools for severity assessment that take into account both motor and nonmotor manifestations. The cause of blepharospasm remains elusive, but several lines of evidence indicate that blepharospasm is a multifactorial condition in which one, or several, as yet unknown genes together with epigenetic and environmental factors combine to reach the threshold of the disease. Although blepharospasm was originally believed to be solely a basal ganglia disorder, neurophysiological and neuroimaging evidence point to anatomical and functional involvement of several brain regions. The contribution of multiple areas has led to the hypothesis that blepharospasm should be considered as a network disorder, and this might reflect the varying occurrence of motor and nonmotor manifestations in blepharospasm patients. Despite advances in the aetiology and pathophysiology, treatment remains symptomatic. © 2017 International Parkinson and Movement Disorder Society.

In vivo confocal microscopy of meibomian glands in primary blepharospasm: A prospective case-control study in a Chinese population

The aim of the study was to evaluate the morphological changes of meibomian glands (MGs) in primary blepharospasm (PBS) by in vivo laser scanning confocal microscopy (LSCM) and to investigate the correlations between clinical data of PBS and LSCM parameters of MGs. This prospective and case-control study recruited 30 consecutive PBS patients and 30 age- and gender-matched healthy controls. After questionnaire assessments of ocular surface disease index (OSDI), Jankovic rating scale, and blepharospasm disability index, all subjects underwent blink rate evaluation, tear film break-up time (TBUT), corneal fluorescein staining (CFS), Schirmer test, MG expressibility, meibum quality, MG dropout, and LSCM examination of the MGs. The main LSCM outcomes included the mean MG acinar area and density, orifice diameter, meibum secretion reflectivity, acinar irregularity, and inhomogeneity of interstice and acinar wall. The PBS patients had significantly higher blink rate, higher OSDI and CFS scores, lower TBUT and Schirmer test value, and worse MG expressibility than the controls (All P < 0.05), whereas meibum quality showed no difference (P > 0.05). The PBS patients showed lower values of MG acinar area, orifice diameter and meibum secretion reflectivity, and higher scores of acinar irregularity and inhomogeneity of interstices than the controls (All P < 0.05). For the PBS patients, the severity of blepharospasm evaluated by JCR scale was strong correlated with MG acinar area (P < 0.001), orifice diameter (P = 0.002), meibum secretion reflectivity (P = 0.002), and MG acinar irregularity (P = 0.013). The MG expressibility was significantly correlated to MG acinar area (P = 0.039), orifice diameter (P < 0.001), and MG acinar irregularity (P = 0.014). The OSDI score was moderate correlated with MG acinar irregularity (P = 0.016), whereas the TBUT value was positively correlated with MG acinar area (P = 0.045) and negatively correlated to MG acinar irregularity (P = 0.016). The CFS score was negatively correlated to MG orifice diameter (P = 0.008). The LSCM provided a noninvasive tool for in vivo histopathologic studies of MGs in PBS patients. The excessive constriction of lid muscles closely related to MG morphological alterations of PBS, which offered a new research approach to interpret the interactional mechanism between dry eye and PBS.

Five-Year Retrospective Review of Cases with Benign Essential Blepharospasm and Hemifacial Spasm Presenting in a Tertiary Eye Care Center in North India

Retrospective analysis of epidemiological and clinical characteristics of patients diagnosed with benign essential blepharospasm and hemifacial spasm who reported to the oculoplasty clinic of a tertiary eye care center in north India between January 2010 and April 2015 was carried out. Dry eye, as well as all the local factors that can cause blepharospasm or hemifacial spasm, was ruled out. Systemic evaluation was done to rule out any neurological disorder. A detailed history was taken to rule out any associated psychiatric disorders as well as use of any medication which could be responsible for dystonic movements. In every patient of hemifacial spasm, magnetic resonance imaging (MRI) of the brain was done for any facial nerve compression or tumor involving posterior fossa. Botulinum type A injections were given after assessing their requirements on the basis of guidelines given by Jankovic et al.

Blink reflex studies in postparalytic facial syndrome and blepharospasm: trigeminal and extratrigeminal somatosensory stimulation

PURPOSE

The somatosensory-evoked blink reflex (SBR) is one of the release phenomena of blink reflex, possibly resulting from increased excitability of brainstem reticular formation.

METHODS

The authors investigated trigeminal blink responses and SBR in 26 patients with postparalytic facial syndrome (PFS) with synkinesia, 18 patients with essential blepharospasm, and 36 healthy volunteers (control participants).

RESULTS

Trigeminal blink reflex responses were elicited in all participants, whereas SBRs were elicited in 44.4% of control participants, 38.9% of patients with essential blepharospasm, and 65.4% of patients with PFS. The mean R2 amplitude and duration and the mean amplitude and duration of SBR were highest in patients with essential blepharospasm. The mean latency of SBR was shorter on the symptomatic side of patients with PFS when compared with the asymptomatic side. The mean R2 duration on the symptomatic side of the patients with PFS was longer than the control participants.

CONCLUSIONS

These results showed that somatosensory stimulation could be used as an alternative method to demonstrate increased excitability in facial motor neuron in patients with PFS and essential blepharospasm. Disease states relating to different peripheral and/or suprasegmental structures could also influence blink reflex and change its basal excitability and manner in which the reflex responds to modulatory factors.

Clinical Analysis of Patients with Primary Blepharospasm: A Report of 100 Cases in China

PURPOSE

This study explored the clinical characteristics, diagnosis and treatments of primary blepharospasm.

METHODS

In this retrospective analysis, 100 patients with blepharospasm were enrolled. Data were collected from medical records and face-to-face interviews with patients and their families.

RESULTS

The age of onset was 56.4 ± 2.7 (range, 32-76 years). The duration between onset and accurate diagnosis was 38.7 ± 36.0 months (range, 2-120 months). Dry eyes occurred in 54% of the patients. The initial diagnostic accuracy was 10%. Dry eye syndrome, conjunctivitis/keratitis and myasthenia gravis caused the most confusion in the differential diagnosis. Regular botulinum toxin type A injections improved both eyelid spasms and subjective ocular symptoms in all patients.

CONCLUSIONS

Regular botulinum toxin type A injections improved both eyelid spasms and subjective ocular symptoms in blepharospasm patients. The differentiation of primary blepharospasm differentiation from dry eye syndrome, conjunctivitis/keratitis and myasthenia gravis must be improved.

The influence of benign essential blepharospasm on dry eye disease and ocular inflammation

PURPOSE

To study the influence of blepharospasm on dry eye disease by analyzing the clinical features, tear cytokine, and treatment response of patients with dry eye disease accompanied by benign essential blepharospasm.

DESIGN

Prospective case series study.

METHODS

Forty adults with a diagnosis of benign essential blepharospasm (BEB) and dry eye disease (DED) were consecutively recruited. Forty subjects with dry eye disease only and 40 healthy adults were recruited as eligible controls. A tear specimen was collected from all participants for cytokine analysis. The patients with benign essential blepharospasm were treated with botulinum neurotoxin type A. The main outcome measures were the following: (1) Ocular Surface Disease Index (OSDI) questionnaire; (2) clinical features, including tear break-up time (BUT), Schirmer І test, and fluorescein staining; (3) conjunctival impression cytology; and (4) multiplex cytokine immunobead assay.

RESULTS

The symptoms of DED + BEB patients were significantly different from those of DED controls and healthy controls. Cytokine analysis in tear fluid also showed that tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-2, IL-17, and vascular endothelial growth factor levels were significantly increased in DED + BEB patients. In treatment, botulinum neurotoxin type A injection effectively relieved blepharospasm in all of the DED + BEB patients. Moreover, in this group of patients, OSDI decreased significantly after the botulinum neurotoxin type A injection, and BUT was increased as well.

CONCLUSION

BEB may participate in the progress of inflammation in DED + BEB patients. Botulinum neurotoxin type A injections could effectively relieve the symptoms of DED + BEB patients and improve their ocular surface condition.

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.

Blink reflex in patients with postparalytic facial syndrome and blepharospasm: trigeminal and auditory stimulation

OBJECTIVE

The enhancement of blink reflex (BR) excitability was shown in patients with postparalytic facial syndrome (PFS) and essential blepharospasm (EB). We prospectively investigated patients with PFS and EB whether BR alterations demonstrated by trigeminal stimulation will similarly be observed upon auditory stimulation.

METHODS

Fifteen patients with PFS, 15 patients with EB, and 30 healthy volunteers were involved. Electrically stimulated trigeminal BR and auditory BR were studied bilaterally.

RESULTS

The mean R2 amplitude and duration values were highest in EB patients, being significantly higher than PFS patients (p < 0.05) and control group (p < 0.01). The mean R2 duration in PFS patients were also significantly longer in compared to control group (p = 0.025). EB patients showed a higher mean R (auditory) amplitude and duration than PFS patients (p < 0.05) and controls (p < 0.04). The mean R (auditory) duration was longer on symptomatic side of PFS patients in compared to controls (p = 0.05).

CONCLUSIONS

We observed that there is an enhanced excitability of BR circuit in postparalytic facial syndrome and essential blepharospasm, which could be evoked by auditory stimulation in addition to trigeminal stimulation.

SIGNIFICANCE

The enhanced excitability in patients with EB and PFS probably originates from the final common pathway of BR circuit, namely facial motor or premotor neurons.

Review and update of involuntary facial movement disorders presenting in the ophthalmological setting

We review the existing literature on the involuntary facial movement disorders-benign essential blepharospasm, apraxia of eyelid opening, hemifacial spasm, and aberrant facial nerve regeneration. The etiology of idiopathic blepharospasm, a disorder of the central nervous system, and hemifacial spasm, a condition involving the facial nerve of the peripheral nervous system, is markedly different. We discuss established methods of managing patients and highlight new approaches.

Photophobia in essential blepharospasm--a positron emission tomographic study

To localize regional alterations in cerebral glucose metabolism in essential blepharospasm (EB) patients with photophobia. We have studied 22 EB patients by performing positron emission tomography and [(18)F]-fluorodeoxyglucose analysis. The patients were classified into two subgroups, namely, EB with photophobia (P group) and EB without photophobia (NP group), and compared with a healthy control group (n = 44). There were no significant differences between the two patient groups with respect to the severity of motor symptoms or the duration for which the condition persisted. The FDG-PET images were analyzed using the statistical parametric mapping software. As compared to the control group, the P group exhibited significant hypermetabolism in the thalamus (P = 0.002), while the NP group exhibited significant hypometabolism in the dorsal midbrain, especially, in the superior colliculus (P = 0.005). The P group exhibited significant hypermetabolism in the thalamus and the dorsal midbrain as compared to the NP group (P < 0.001). These findings suggest that photophobia in EB patients may be associated with abnormal hyperactivity in the thalamus. Either hyperactivity of the thalamus or hypoactivity of the superior colliculus, or both may be associated with excessive blinking in these patients.

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.

Benign Essential Blepharospasm: Risk Factors with Reference to Hemifacial Spasm

BACKGROUND

To identify risk factors associated with benign essential blepharospasm (BEB) with reference to hemifacial spasm (HFS). Persons with BEB and HFS experience similar physical symptoms, yet the two disorders have different etiologies.

METHODS

Patients with BEB (n = 159) or HFS (n = 91) were identified from two large neuro-ophthalmology clinics. Demographic, medical, behavioral, and psychological characteristics were obtained from chart review and a telephonic survey questionnaire.

RESULTS

The average age of BEB and HFS was 66 years. Most patients in both groups were retired, white, and female. BEB patients were more than two times as likely to meet the diagnostic criteria for generalized anxiety disorder than HFS patients (odds ratio, 2.13; 95% confidence interval, 1.22-3.72). There was no difference between the two groups regarding demographics, smoking, a family history of dystonia, Parkinson disease, Bell palsy, Tourette disorder, obsessive compulsive symptoms, history of head trauma, alcohol use, or caffeine consumption.

CONCLUSIONS

As compared to HFS, BEB was significantly more often associated with generalized anxiety disorder. Given the similarity of other clinical features of these two disorders, it is reasonable to conclude that anxiety is a cause not a consequence of BEB. Contrary to previous studies, BEB was not associated with obsessive-compulsive symptoms, head trauma, Parkinson disease, Bell palsy, Tourette disorder, or lack of smoking.

Modulation of sensory photophobia in essential blepharospasm with chromatic lenses

PURPOSE

To determine the effect of photochromatic modulation with tinted lenses on the sensory symptoms of photophobia in blepharospasm patients.

DESIGN

Nonrandomized case-control study.

PARTICIPANTS

Thirty-four subjects (24 benign essential blepharospasm patients and 10 normal controls).

METHODS

Subjects were seated in front of a calibrated light source. Beginning at 0%, the intensity of the light source was increased gradually until the patient reported symptomatic photophobia. The intensity of the light source was then measured with a light meter. This procedure was performed first with no chromatic lens and then with 7 different chromatic lenses, each blocking specific wavelengths of the visible spectrum. The subject was then asked which lens provided the greatest symptomatic improvement of photophobia. Statistical significance was calculated with analysis of variance and t test analysis.

MAIN OUTCOME MEASURES

Objective measurement of light intensity tolerated and subjective assessment of photophobia were obtained for each chromatic lens tested.

RESULTS

The light intensity tolerated by the normal subjects compared with the blepharospasm group was not statistically significant with no lens, but grew to 3.5 times that tolerated by the blepharospasm group as more of the higher wavelengths of the visible spectrum were blocked (P = 0.048). Lenses 4, 5, 6, and 7 allowed blepharospasm patients to tolerate a significantly higher intensity of light when compared with no lens (P = 0.04, P = 0.007, P = 0.03, and P = 0.01, respectively). Although the highest intensity of light tolerated was measured with lens 6, 71% of blepharospasm patients reported the greatest relief of photophobia with lens 7.

CONCLUSIONS

Blepharospasm patients tolerate a lower intensity of light when compared with normal subjects; this differential in light tolerance becomes significantly more pronounced as the higher wavelengths of the visible spectrum are blocked. The symptoms of photophobia in blepharospasm patients can be reduced significantly with photochromatic modulation. Despite lens 6 allowing the patients to tolerate a higher intensity of light, the majority of patients preferred lens 7 for symptomatic relief of photophobia. These findings suggest that sensory photophobia may be related more to the wavelength than to the intensity of the light exposure.

Relationship between eye symptoms and blepharospasm: A multicenter case–control study

Although patients with primary blepharospasm (BSP) commonly report experiencing ocular symptoms before the onset of orbicular spasms, the precise frequency and pathogenic role of this subjective ocular discomfort are poorly understood. We conducted a multicenter case-control study to investigate symptoms related to disorders of the anterior segment of the eye, administering a questionnaire to 165 patients with BSP and 180 age- and gender-matched control patients with hemifacial spasm. On a validation sample, our questionnaire yielded high accuracy in detecting eye diseases (predominantly, dry eye syndrome) using detailed ophthalmological examination as the criterion. Logistic regression analysis indicated a significant association between ocular symptoms at disease onset and BSP. Ocular symptoms starting in the year preceding disease onset (short-latency symptoms) showed a stronger association with BSP than ocular symptoms occurring earlier in time (long-latency symptoms). The association was stronger when short-latency symptoms developed from 40 to 59 years of age, whereas this was not observed for long-latency symptoms. Our findings support the view that eye symptoms associated with BSP result from eye diseases and may be involved in the pathogenesis of BSP. The differential risk of developing BSP, based on age at onset of ocular symptoms, suggests that age and eye diseases may interact in giving rise to BSP.

Botulinum toxin type A therapy for blepharospasm

BACKGROUND

Blepharospasm is a focal dystonia characterized by chronic intermittent or persistent involuntary eyelid closure due to spasmodic contractions of the orbicularis oculi muscles. Other facial and neck muscles are also frequently involved. Most cases are idiopathic and blepharospasm is generally a life-long disorder. Its severity can range from repeated frequent blinking to persistent forceful closure of the eyelids with functional blindness. Botulinum toxin type A (BtA) is the current first line therapy.

OBJECTIVES

To determine whether botulinum toxin (BtA) is an effective and safe treatment for blepharospasm.

SEARCH STRATEGY

We identified studies for inclusion in the review using the Cochrane Movement Disorders Group trials register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, handsearches of the Movement Disorders Journal and abstracts of international congresses on movement disorders and botulinum toxin, communication with other researchers in the field, reference lists of papers found using above search strategies, and contact with authors and drug manufacturers.

SELECTION CRITERIA

Studies were eligible for inclusion in the review if they evaluated the efficacy of BtA for the treatment of blepharospasm. They must have been randomised and placebo-controlled.

DATA COLLECTION AND ANALYSIS

We used a paper pro-forma to collect data from the included studies using double extraction by two independent reviewers. The two reviewers separately assessed each trial for internal validity and they settled differences between them by discussion. The outcome measures used included adverse events, improvement in symptomatic rating scales, subjective evaluation by patients and clinicians, and changes in quality of life assessments.

MAIN RESULTS

We found few controlled trials. They were of short duration and enrolled small numbers of patients. Because of their poor internal validity, the characteristics of the populations studied, and the types of interventions and outcomes, none of the trials fitted our criteria for inclusion. However, all these trials found BtA to be superior to placebo as did large case-control and cohort studies, which reported that around 90% of patients benefited.

AUTHORS' CONCLUSIONS

There are no high quality, randomised, controlled efficacy data to support the use of Bt for blepharospasm. Despite this, other studies suggest that BtA is highly effective and safe for treating blepharospasm and support its use. The effect size (90% of patients benefit) seen in open studies makes it very difficult and probably unethical to perform new placebo-controlled trials of efficacy of BtA for blepharospasm. Future trials should explore technical factors such as the optimum treatment intervals, different injection techniques, doses, Bt types and formulations. Other issues include service delivery, quality of life, long-term efficacy, safety, and immunogenicity.

Primary Blepharospasm

Primary blepharospasm is an adult-onset focal dystonia characterised by involuntary contractions of the orbicularis oculi muscles. Patients may have various types of movements arising from the different parts of the orbicularis oculi muscle. These include typical blepharospasm associated with Charcot's sign, pretarsal blepharospasm and flickering of the eyelids. Primary blepharospasm may be associated with so-called apraxia of eyelid opening as well as dystonia in the lower face, jaw or cervical muscles. Unless there are clinical clues to a symptomatic cause, adults presenting with blepharospasm do not require extensive aetiological investigation because the condition is rarely due to an identifiable condition. As the aetiology of primary blepharospasm is largely unknown, therapeutic approaches are symptomatic, with type A botulinum toxin being the treatment of choice.

Orbicularis oculi muscle graft augmentation after protractor myectomy in blepharospasm

PURPOSE

To evaluate the effectiveness of free orbicularis oculi muscle grafts in correcting volume deficit deformities after protractor myectomy in patients with essential blepharospasm.

METHODS

Prospective case series. During the 13-month period from October 2000 through November 2001, all patients with essential blepharospasm undergoing primary eyelid protractor myectomy received an orbicularis oculi muscle graft to replace the volume deficit deformity created by the myectomy. Only patients who had at least 6 months of postoperative follow-up were included in the analysis.

RESULTS

Forty-six patients underwent primary eyelid protractor myectomy and had a free orbicularis oculi muscle graft for volume replacement. All patients had significant functional improvement of their eyelid spasms after the myectomy. Of the 38 patients who underwent upper eyelid myectomy, 3 patients were overcorrected and no patients were undercorrected with the orbicularis muscle graft. Two of the overcorrected patients underwent surgical debulking of their muscle grafts. Of the 8 patients who underwent lower eyelid myectomy, no patients were overcorrected and 1 patient was undercorrected. None of the patients were observed to have any spasms, contractions, or other signs of muscular activity or aberrant innervation of the muscle graft.

CONCLUSIONS

The orbicularis oculi muscle graft is a useful adjunct to protractor myectomy in improving the aesthetic outcomes for blepharospasm patients. Our study demonstrates the viability of the orbicularis oculi muscle graft and may lead to future applications of the graft in facial aesthetics.

Epidemiology of primary blepharospasm

We review epidemiological data on primary blepharospasm (BSP). There is a large variation in the stated prevalence of BSP, with crude estimates ranging from 16 to 133 per million in different studies. A large proportion of this variability may be the result of differences in physician education on BSP. Age and female gender may increase the risk of developing BSP. The few case-control studies focusing on adult dystonias including BSP showed an increased risk in association with family history of dystonia and/or postural tremor, prior head and face trauma, and prior eye disease (e.g., blepharitis and keratoconjunctivitis), and a decreased risk associated with cigarette smoking. No association was found with age-related medical conditions such as hypertension and diabetes, family history of parkinsonism, and a history of anxiety or depression. Broocks et al. [Am J Psychiatry, 1998;155:555-557] found a significantly higher frequency of obsessive-compulsive symptoms in BSP than hemifacial spasm despite the clinical similarity. Among putative risk factors for BSP, age at onset, female gender, and prior head or face trauma may affect spread of dystonia to adjacent body regions. While limited, the body of epidemiological data support the idea that environmental and familial, possibly genetic, factors may both be important in the etiology of BSP.

Monocular involuntary eyelid closure

OBJECTIVES

Monocular blepharospasm (MBLS) is precipitated by ipsilateral ocular pathology and becomes bilateral over time. Two patients are reported with monocular visual disturbance exhibiting monocular involuntary eyelid closure (MIEC), resembling MBLS.

MATERIAL AND METHODS

A 31-year-old female with hyperthyroidism developed monocular polyopia with left eye vision on binocular fixation followed by ipsilateral visual extinction. Monocular vision was otherwise normal. A 57-year-old male with renal failure developed monocular blindness secondary to retinal hemorrhage.

RESULTS

The first patient had anisocoria and proptosis. Brain magnetic resonance (MR) was normal. The second patient had involuntary movements of the left eye. Head computerized tomography (CT) was normal. Both patients exhibited MIEC of the eye with visual impairment that could be overcome voluntarily, but reappeared upon distraction. Neither of the two developed BLS in long-term follow-up.

CONCLUSION

MIEC represents a complication of ipsilateral ocular pathology in the absence of other involuntary movements, apraxia of eyelid opening, or blepharospasm (BLS). MIEC needs to be distinguished from MBLS, since not all MBLS becomes bilateral.

The mechanism of action of botulinum toxin type A in focal dystonia is most probably through its dual effect on efferent (motor) and afferent pathways at the injected site

OBJECTIVE

To highlight some clinical and physiological features related to treatment with botulinum toxin type A (BTX-A) injections for focal dystonia that may suggest an effect through efferent (alpha motoneuron) and afferent pathways.

DATA SOURCES

This review is based on published clinical and physiological studies as well as personal experience regarding the effect of BTX-A in focal dystonia.

DATA SYNTHESIS

Long or short lag period between BTX-A injections and clinical improvement, remote effect, an effect on the basic physiological characteristics of dystonia, poor correlation between the local weakness and the clinical improvement and alleviation of pain are clinical observations which are difficult to explain on the basis of the known effect of BTX-A on the neuromuscular junction of the alpha motoneuron. These observations as well as recent scientific reports are used to discuss a hypothesis that in addition to its effect as local muscle relaxant, BTX-A acts at the level of the central nervous system (CNS) for 'reorganization'. Such an effect on CNS activity can be mediated through afferent pathways coming from the injected site--possibly originated in muscle spindles. Its effect through afferent pathways on the CNS may be considered as a long-term 'sensory trick'.

Animal model explains the origins of the cranial dystonia benign essential blepharospasm

The current study demonstrates that combining two mild alterations to the rat trigeminal reflex blink system reproduces the symptoms of benign essential blepharospasm, a cranial dystonia characterized by uncontrollable spasms of blinking. The first modification, a small striatal dopamine depletion, reduces the tonic inhibition of trigeminal reflex blink circuits. The second alteration, a slight weakening of the lid-closing orbicularis oculi muscle, begins an adaptive increase in the drive on trigeminal sensory-motor blink circuits that initiates blepharospasm. By themselves, neither of these modifications causes spasms of lid closure, but combined, they induce bilateral forceful blinking and spasms of lid closure. A two-factor model based on these rodent experiments may explain the development of benign essential blepharospasm in humans. The first factor, a subclinical loss of striatal dopamine, creates a permissive environment within the trigeminal blink circuits. The second factor, an external ophthalmic insult, precipitates benign essential blepharospasm. This two-factor model may also be applicable to the genesis of other cranial dystonias.

Blink reflex recovery curves in blepharospasm, torticollis spasmodica, and hemifacial spasm

R1 and R2 blink reflex responses to single and paired stimuli were investigated in 23 control subjects, 21 patients with blepharospasm (BSP), 20 patients with torticollis spasmodica (TS), and 23 with hemifacial spasm (HFS). For paired stimuli, we compared measurements of area and peak responses at two and three times R2 threshold. R1 and R2 indices were calculated as the average of the recovery values at 0.5-, 0.3-, and 0.21-s interstimulus intervals to test individual patients. Peak amplitude measurements at three times R2 threshold were optimal. The R2 index was abnormal in 67% of BSP patients, 37% of TS patients, and 50% of HFS patients on the affected side and 20% on the unaffected side. A normal R2 index in one third of patients with BSP may indicate that different pathophysiological mechanisms are involved in this type of focal dystonia.

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.

Sensory symptoms in cranial dystonia: a potential role in the etiology?

Cranial dystonia is normally considered as a pure movement disorder. Sensory symptoms have not received much attention, but we found ill-defined pain, discomfort, distortion of sensory modalities, 'phantom' kinetic or postural sensations in the orofacial areas subsequently involved by the dyskinesia in all of 11 consecutive patients, preceding by weeks or months the motor syndrome. Physicians were often mislead, initially making diagnoses such as trigeminal neuralgia, dental problems, sicca syndrome, chronic conjunctivitis, glossitis or stomatitis. The patients reported that the orofacial movements were at first willingly performed in order to decrease the discomfort which was felt in these facial areas before the movements finally escaped voluntary control and became socially disturbing. We suspect that the sensory symptoms, for which no objective substrate could be found, and which were always reported before and in the exact location of the subsequent dyskinesia, could be the earliest manifestation of an evolving process in cranial and perhaps other focal dystonias.

A new variant of blepharospasm

Ten patients who were unable to initiate or sustain eye opening in the absence of overt spasm of the orbicularis oculi, were investigated. In five, the problem was isolated. Three had Parkinson's disease and two progressive supra-nuclear palsy for between one to six years before the eye opening difficulty developed. The clinical features and electrophysiological investigation suggested that the disorder is a variant of blepharospasm due to abnormal contraction in the pre-tarsal orbicularis oculi.

The management of blepharospasm and hemifacial spasm

The aetiology of blepharospasm and hemifacial spasm is different, but both produce involuntary eye closure and facial movements which do not respond to systemic drug treatment. The introduction of therapeutic focal muscle weakening with botulinum toxin injections in the early 1980s appeared to offer great promise in the management of these conditions. In this paper the results of botulinum toxin treatment of 234 patients with blepharospasm and 73 patients with hemifacial spasm over a 7-year period have been analysed. Most patients receive sustained benefit from repeated injections whilst side-effects become less frequent. A clinically recognisable subgroup of patients with blepharospasm respond poorly and may be better treated surgically.