Sensory tricks in primary blepharospasm and idiopathic cervical dystonia

To study the frequency, types, phenomenology, and effectiveness of sensory tricks in patients with primary blepharospasm and idiopathic cervical dystonia.

Sensory tricks are maneuvers seen in patients with dystonia, which are used to temporarily reduce the severity of dystonic postures. In different types of dystonia, the frequency of sensory tricks have been described to range from 17-89%.

In this cross-sectional observational study, we analyzed the frequency, types, phenomenology, and effectiveness of sensory tricks in 20 patients with primary blepharospasm and 20 patients with idiopathic cervical dystonia, respectively. Patients underwent a clinical examination, and the severity of dystonia was measured using the Burke Fahn Marsden dystonia rating scale (eyes and neck components).A questionnaire regarding the sensory tricks was administered to all the patients.

Eighteen patients with blepharospasm and 7 patients with cervical dystonia used sensory tricks to alleviate their dystonic movements (P < 0.05). The age group of the patients with cervical dystonia presenting with sensory tricks was significantly lower than that of those having blepharospasm (P < 0.05). Sensory tricks, when used, were effective every time in 72.2% of patients with blepharospasm and in 85.8% of patients with cervical dystonia. However, majority of the patients with blepharospasm (61.1%) and cervical dystonia (42.9%) had only partial benefit (<50%) with these maneuvers.

In this study, sensory tricks were more common in patients with primary blepharospasm than in patients with idiopathic cervical dystonia.Age of the patients with cervical dystonia was significantly lesser than those suffering from blepharospasm.We did not find any correlation between the presence of sensory tricks, the severity of dystonia and the duration of the disease.Majority of the patients derived benefit with sensory tricks every time; however, the benefit was only partial.