Motor and psychiatric features in idiopathic blepharospasm: A data-driven cluster analysis

Longitudinal assessment of blepharospasm severity in patients with long disease duration

INTRODUCTION

Blepharospasm (BSP) represents one of the most common idiopathic adult-onset dystonia. A few longitudinal observations indicated progression and worsening of BSP severity within 16 years of onset. Information is lacking about the trend of BSP severity in the later stages of the disease.

METHODS

The study comprised 15 women and 3 men that underwent a standardized video protocol at two time points: 14 ± 9 years after BSP onset and 11 ± 2 years later. BSP severity was rated by the Blepharospasm Severity Rating Scale (BSRS). Two independent observers reviewed 36 videos in a pseudo-randomized order, yielding satisfactory agreement.

RESULTS

Mean total severity score was 7.6 ± 3.9 years at baseline, 6.4 ± 2.5 at the last examination (p = 0.14). The last video examination showed a stable BSRS score in 14/18 patients, while the score of 4 patients decreased by two points or more, due to disappearance (n.3) or reduction (n.1) of prolonged spasms with complete rim closure. Over the long term, the BoNT dosage increased in those who improved, but remained stable in the other patients. On follow-up examination, dystonia spread to the lower face or neck in two new patients. No significant correlations emerged between disease duration and BSP severity. The presence of sensory trick significantly correlated with disease duration but not with BSP severity.

DISCUSSION

This study provides novel information on the long-term prognosis in patients with idiopathic BSP, showing that severity of BSP may not worsen in the later stages of the disease.

Five decades of the use of botulinum toxin in ophthalmology

Botulinum toxin (BoNT) has been known for over 50 years. It has conquered many areas of medicine and has become indispensable in contemporary medicine. Now, BoNT is used to treat at least 26 conditions in six medical specialties. Although the use of BoNT began in strabology, it became the gold standard for many ophthalmologic pathologies. The present review of the literature focuses on the use of BoNT in ophthalmology and treatment of the following conditions: blepharospasm, facial hemispasm, facial palsy, spastic entropion, strabismus, endocrine orbitopathy, convergence spasm, and facial trauma. We conclude that nearly half a century of experience in utilizing BoNT in ophthalmology ensured a satisfactory level of effectiveness and safety for patients with many pathologies. Areas of future research include the application of BoNT in new selected indications, the development of the route of application without injections, and the development of long-acting BoNT forms for patients who require repeated long-term treatment.

Are Cognitive Symptoms Part of the Phenotypic Spectrum of Idiopathic Adult-Onset Dystonia? Summary of Evidence from Controlled Studies

BACKGROUND

Cognitive dysfunction has been reported in idiopathic adult-onset dystonia (IAOD), but whether this is a primary or secondary component of the disorder remains uncertain.

OBJECTIVE

Here, we aimed to analyze the key domains of abnormal cognitive performance in IAOD and whether this is associated with motor or mood changes.

METHODS

Article selection for our critical review was guided by PRISMA guidelines (mesh terms "dystonia" and "cognitive," publication period: 2000-2022). Only peer-reviewed, English-language original case-control studies involving patients with IAOD who were not exposed to dopamine- or acetylcholine-modulating agents and validated cognitive assessments were included.

RESULTS

Abstract screening ultimately yielded 22 articles for full-text review and data extraction. A greater proportion of studies (17 of 22, 82%) reported abnormal cognitive performance in IAOD. Most of these studies focused on blepharospasm (BSP) and cervical dystonia (10 and 14, respectively). Most studies reporting cognitive impairment (11 of 17) identified multidomain impairment in cognition. Executive functions were the domain most frequently explored (14 of 22 studies), 79% of which detected worse performance in people with dystonia. Results related to other domains were inconclusive. Cognitive abnormalities were independent of motor symptoms in most studies (7 of 12) that explored this relationship and independent of mood status in all 8 that investigated this.

CONCLUSIONS

Within IAOD, cognitive dysfunction (in particular, executive dysfunction) has been documented mainly in BSP and cervical dystonia. More comprehensive testing is warranted to assess abnormalities in other domains and in other forms of IAOD, as well as to evaluate longitudinal progression of cognitive disturbances in this condition.

Abnormal supplementary motor areas are associated with idiopathic and acquired blepharospasm

Blepharospasm is a common form of focal dystonia characterized by excessive and involuntary spasms of the orbicularis oculi. In addition to idiopathic blepharospasm, lesions in various brain regions can also cause acquired blepharospasm. Whether these two types of blepharospasm share a common brain network remains largely unknown. Herein, we performed lesion coactivation network mapping, based on meta-analytic connectivity modeling, to test whether lesions causing blepharospasm could be mapped to a common coactivation brain network. We then tested the abnormality of the network in patients with idiopathic blepharospasm (n = 42) compared with healthy controls (n = 44). We identified 21 cases of lesion-induced blepharospasms through a systematic literature search. Although these lesions were heterogeneous, they were part of a co-activated brain network that mainly included the bilateral supplementary motor areas. Coactivation of these regions defines a single brain network that encompasses or is adjacent to most heterogeneous lesions causing blepharospasm. Moreover, the bilateral supplementary motor area is primarily associated with action execution, visual motion, and imagination, and participates in finger tapping and saccades. They also reported decreased functional connectivity with the left posterior cingulate cortex in patients with idiopathic blepharospasm. These results demonstrate a common convergent abnormality of the supplementary motor area across idiopathic and acquired blepharospasms, providing additional evidence that the supplementary motor area is an important brain region that is pathologically impaired in patients with blepharospasm.

What can epidemiological studies teach on the pathophysiology of adult-onset isolated dystonia?

Several demographic and environmental factors may play an important role in determining the risk of developing adult-onset isolated dystonia (AOID) and/or modifying its course. However, epidemiologic studies have provided to date only partial insight on the disease mechanisms that are actively influenced by these factors. The age-related increase in female predominance in both patients diagnosed with AOID and subjects carrying its putative mediational phenotype suggests sexual dimorphism that has been demonstrated for mechanisms related to blepharospasm and cervical dystonia. The opposite relationship that spread and spontaneous remission of AOID have with age suggests age-related decline of compensatory mechanisms that protect from the progression of AOID. Epidemiological studies focusing on environmental risk factors yielded associations only with specific forms of AOID, even for those factors that are not likely to predispose exclusively to specific focal forms (for example, only writing dystonia was found associated with head trauma, and only blepharospasm with coffee intake). Other factors show biological plausibility of their mechanistic role for specific forms, e.g., dry eye syndrome or sunlight exposure for blepharospasm, scoliosis for cervical dystonia, repetitive writing for writing dystonia. Overall, the relationship between environment and AOID remains complex and incompletely defined. Both hypothesis-driven preclinical studies and well-designed cross-sectional or prospective clinical studies are still necessary to decipher this intricate relationship.