Development and validation of a clinical guideline for diagnosing blepharospasm

Abstract

Objective: To design and validate a clinical diagnostic guideline for aiding physicians in confirming or refuting suspected blepharospasm. Methods:The guideline was developed and validated in a 3-step procedure: 1) identification of clinical items related to the phenomenology of blepharospasm, 2) assessment of the relevance of each item to the diagnosis of blepharospasm, and 3) evaluation of the reliability and diagnostic sensitivity/specificity of the selected clinical items.Results: Of 19 clinical items initially identified, 7 were admitted by content validity analysis to further assessment. Both neurologists and ophthalmologists achieved satisfactory interobserver agreement for all 7 items, including "involuntary eyelid narrowing/closure due to orbicularis oculi spasms," "bilateral spasms," "synchronous spasms," "stereotyped spasm pattern," "sensory trick," "inability to voluntarily suppress the spasms," and "blink count at rest." Each selected item yielded unsatisfactory accuracy in discriminating patients with blepharospasm from healthy subjects and patients with other eyelid disturbances. Combining the selected items, however, improved diagnostic sensitivity/specificity. The best combination, yielding 93% sensitivity and 90% specificity, was an algorithm starting with the item "stereotyped, bilateral, and synchronous orbicularis oculi spasms inducing eyelid narrowing/closure" and followed by recognition of "sensory trick" or, alternatively, "increased blinking." Conclusion:This study provides an accurate and valid clinical guideline for diagnosing blepharospasm. Use of this guideline would make it easier for providers to recognize dystonia in clinical and research settings. Blepharospasm (BSP) is characterized by involuntary orbicularis oculi (OO) muscle spasms that are usually bilateral, synchronous, and symmetrical.1 Other signs and symptoms possibly accompanying BSP include sensory symptoms in the eyes often indicating ocular diseases (e.g., dry eye syndrome), 2 an increased spontaneous blink rate (BR), 3 and sensory tricks that can transiently improve eyelid spasms. 4 Diagnosing BSP and assessing the impact of treatments on the condition are major needs in clinical practice and research. Although a new scale specifically developed for rating the severity of BSP has been validated, 5 the diagnosis of BSP is presently based on clinical grounds and is open to bias. The lack of validated diagnostic criteria sometimes makes it difficult to distinguish BSP from other conditions of involuntary eyelid closure such as eyelid tics, hemifacial spasms, facial chorea, apraxia of eyelid opening, frequent blinking, and lid ptosis due to myasthenia or other causes. 6 BSP may be diagnosed several years after the first symptoms manifest, and in the interim, many patients visit numerous physicians, delaying access to treatment. 7 Family studies indicate that up to half of people with dystonia may be undiagnosed or misdiagnosed. 8,9 The lack of a diagnostic biomarker makes it essential to demarcate accurate diagno...

Diagnostic delay in adult-onset dystonia: Data from an Italian movement disorder center

“…Diagnostic guidelines on dystonia [5] are needed to enable primary care physicians and neurologists to give AOD patients the appropriate diagnosis and initiate therapy more rapidly.…”

Sensory aspects of movement disorders

“…The presence of these and other alleviating manoeuvres initially led to the misconception that cervical and other dystonias were of psychological origin; however, their presence is now a key diagnostic feature. 85 Patients with generalised dystonia also use a variety of alleviating manoeuvres, such as placing their hands in their pockets, behind their neck or back, or on their hip; dancing or walking backwards; and placing objects on their head (figure 1B). Whereas many patients report that doing a particular task, such as playing a musical instrument 86 or a particular sport, such a golf, 87 triggers their dystonia (eg, task-specific dystonia), some experience paradoxical improvement of dystonia—eg, while playing a piano—which previously has been interpreted as a form of sensory trick.…”

Botulinum toxin and blink rate in patients with blepharospasm and increased blinking

“…We enrolled 37 consecutive patients with primary BSP (18 patients had clonic OO spasms and 19 patients had tonic OO spasms) diagnosed according to published criteria1 4 and 8 patients with IB. We also enrolled 19 patients with idiopathic HFS.…”

“…All the BSP and IB patients were clinically evaluated before and 1 month after BoNT injection by means of the Blepharospasm Disability Index (BSDI), which measures the level of impairment in specific activities of daily living caused by spasms 20. All BSP, IB and HFS patients underwent a published standardised video protocol before and 1 month after the BoNT injection 4. Healthy subjects underwent the same standardised video protocol in a single session.…”