Correspondence Address: Sanjay Pandey Department of Neurology, Govind Ballabh Pant Postgraduate Institute of Medical Education and Research, New Delhi - 110 002 India
Source of Support: None, Conflict of Interest: None
Objective: To study the frequency, types, phenomenology, and effectiveness of sensory tricks in patients with primary blepharospasm and idiopathic cervical dystonia. Background: 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%. Materials and Methods: 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. Results: 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. Conclusions: 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.
Keywords: Dystonia, Geste antagoniste, sensorimotor integration Key Message:
Sensory tricks are commonly applied to relieve primary blepharospasm (including cold water application, separating lids apart with finger, and touching of eyelid) or idiopathic cervical dystonia (including applying pressure over the side/back of the neck and placing the hand over the chin/cheek). These sensory tricks were more common in patients with primary blepharospasm than in patients with idiopathic cervical dystonia and were usually effective in relieving the abnormal movement. The relief was, however, often only partial.
How to cite this article: Pandey S, Soni G, Sarma N. Sensory tricks in primary blepharospasm and idiopathic cervical dystonia. Neurol India 2017;65:532-6
Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. Dystonic movements are typically patterned, twisting, and may be tremulous. Sensory trick, also known as 'geste antagoniste' or 'alleviating manoeuvre', is used by patients with dystonia to transiently suppress their dystonic movement or dystonic posture. The patients attenuate dystonia in a manner that is otherwise not considered to antagonize the dystonic movement physiologically. This phenomenon was first described by Brissaud in 1894; however, the term 'Geste antagoniste' was used by Brissaud's two pupils, Henry Meige and Eugene Feindel, in 1902. Unfortunately, Brissaud and Meige misinterpreted the phenomenon of sensory trick and anchored the psychogenic origin of dystonia. Later, Herz in 1944 and Marsden in the 1970–1980s established the organic nature of dystonia and reinforced the significance of sensory tricks in clinical diagnosis. The presence of a sensory trick usually suggests an organic origin of dystonia and it is typically absent in patients with psychogenic dystonia. The presence of a sensory trick also helps in differentiating dystonic tremor from essential tremor. Cessation of tremors during the performance of the sensory trick is seen in dystonic tremor but not in essential tremor., In 2014, the term 'alleviating maneuver' was proposed to replace 'Geste antagoniste' or 'sensory trick.' Movement disorder society's classification of dystonia in 2013 considered sensory trick as a major sign and a part of the clinical phenomenology.,
Different variations of sensory tricks have been described, such as motor tricks, forcible tricks, imaginary tricks, and reverse sensory tricks. Motor tricks are those that involve voluntary movement as the evident clinical feature. Forcible tricks require the use of force and is always in the direction opposite to that of the dystonia. Hence, the use of force and the opposing direction in which it is applied distinguishes forcible tricks from sensory tricks. Forcible tricks have been found to be more effective than classical sensory tricks for severe dystonia. Sensory tricks involve the use of a stimulus that results in a change in the dystonic muscle contractions. They tend to be heterogeneous in nature, implying different patients may use different manoeuvres to negate the same type of dystonia., Imaginary tricks are sensory tricks with a mental imagery as the effective agent. Types of dystonia in which sensory tricks have been documented include cervical dystonia, blepharospasm, writer's cramp, Meige's syndrome, lower cranial dystonia, laryngeal dystonia, runner's dystonia, and camptocormia. Different sensory modalities used as sensory tricks include tactile, proprioceptive, auditory, visual, and thermal stimuli.
In this prospective study, we analyzed the frequency, types, phenomenology, and effectiveness of sensory tricks in patients suffering from primary blepharospasm or idiopathic cervical dystonia and evaluated their clinical correlates. We compared blepharospasm and cervical dystonia because both of them are the most common causes of focal dystonia; however, the types of sensory tricks used for both these disorders are different. The frequency and types of sensory tricks reported in these two types of focal dystonia are different in the reported studies from the West.,,,,, We aimed to study this variation in the Indian population.
» Materials and Methods
This study was performed at a tertiary care teaching hospital and was approved by the institute's ethical committee. Patients were recruited after signing the informed consent. Patients of primary blepharospasm and idiopathic cervical dystonia were recruited from the movement disorder clinic if they fulfilled the following inclusion criteria; age at onset of first the symptom of dystonia >18 years; a lapse of >3 months after the last botulinum toxin injection; and, the presence of dystonia during the interview conducted at the time of clinical examination. Patients were excluded if they had any neurological deficit other than dystonia (except tremor); any features suggestive of secondary or psychogenic dystonia; and, any history of exposure to antipsychotic medications or other dopamine receptor blocking drugs before the onset of dystonia.
A detailed history and clinical examination was conducted in all the patients by a neurologist, including the elicitation of the demographic and clinical data. The Burk-Fahn-Marsden dystonia rating scale (BFMDRS) was used to assess the severity of symptoms using individual items of eyes and neck for patients with blepharospasm and cervical dystonia, respectively.
A questionnaire regarding the sensory trick was administered to all the patients by another neurologist [Table 1]. There were four questions related to different characteristics of sensory tricks. The first question was related to whether or not the patient was using the sensory trick, and the second question was related to what type of sensory trick was being used by the patient. Questions 3 and 4 were related to the efficacy of the sensory trick. During the interview, a 2–3 min video was recorded where the patients were also asked to demonstrate their sensory trick [Video 1] and [Video 2].
Table 1: Questionnaire used to interview patients with blepharospasm and cervical dystonia regarding sensory tricks
All data were entered on an excel spreadsheet, and statistical analyses were done using Epi info version 7.0 software package (Centre for disease control and prevention, 1600 Clifton Road Atlanta, GA 30329-4027 USA). Chi-square test was used for nominal data, when appropriate. Student t-test was used to compare the means. Categorical data was summarized as frequencies and percentages, and continuous data was summarized as mean (minimum, maximum). The level of significance was set at P< 0.05.
The mean age of the patients with blepharospasm in our study was 51.7 ± 13.8 years (age range, 25–78 years), which was significantly higher than the cervical dystonia group, in which the patients had a mean age of 42.2 ± 11.8 years (age range, 21–60 years) [Table 2] and [Table 3]. The sex ratio was equal in blepharospasm patients (male:female = 10:10); however, female patients were more affected (11:09) in the cervical dystonia group. The mean duration of illness (± standard deviation) was longer (4.23 ± 5.64 years) in patients with blepharospasm than in those with cervical dystonia (3.27 ± 2.9 years); however, it was statistically not significant (P = 0.84). The duration of illness ranged from 2 months to 25 years in patients with blepharospasm, whereas it was 20 days to 10 years in patients with cervical dystonia. Ten out of 20 patients with blepharospasm had equal severity of dystonia in both eyes, 9 had more severe manifestations in the left eye, whereas1 patient had more severity in the right eye. Nine patients with cervical dystonia had an associated head tremor. The severity of dystonia, as assessed by the Burke Fahn Marsden severity score in the patients with blepharospasm (mean ± SD; 3.05 ± 0.65) and cervical dystonia (mean ± SD; 2.9 ± 0.64) respectively, was almost similar (P = 0.46). A significantly higher number of patients with blepharospasm (18/20; 90%) used sensory tricks to relieve their dystonia than those with cervical dystonia (7/20; 35%; P= 0.0003). Forcible sensory trick was more common than the classic sensory trick in both groups of patients with blepharospasm (10 versus 8) and cervical dystonia (5 versus 2). Sensory tricks were always effective (100% of the times) in the majority of the patients in both the groups (13 in the blepharospasm and 6 in the cervical dystonia group); however, most of the patients had partial (<50%) benefit (11 in the blepharospasm and 3 in the cervical dystonia group) only. The most common sensory tricks used by patients with blepharospasm were cold water application, separating lids apart with finger, and touching of eyelid (4 each);whereas, the most common sensory tricks used by patients with cervical dystonia were pressure over the side/back of the neck and placing their hand over their chin/cheek (2 each).
Table 2: Different types of sensory tricks used by patients with blepharospasm and cervical dystonia*
To our knowledge, this is the first study from India, where the characteristics of sensory tricks were systematically evaluated in patients with focal dystonia through clinical evaluations and videos. In this study, a significantly higher number of patients with primary blepharospasm used a sensory trick when compared to patients with idiopathic cervical dystonia. There is a wide variability in the reported frequency of sensory tricks in patients with blepharospasm (17–87%), and cervical dystonia (23.7–89.6%)., On comparing our findings with the previous published studies, the frequency of sensory tricks in cervical dystonia was found to be significantly lower when compared to the other series, whereas the frequency of sensory tricks in blepharospasm was comparable with other studies. In a study published from Italy, Martino et al., reported the presence of sensory tricks in 71.2% (out of 59) of patients with blepharospasm and in 84.4% (out of 32) patients with cervical dystonia. In another study from Brazil, Loyola et al., reported sensory tricks in 55% (out of 20) patients with blepharospasm and in 81% (out of 21) patients with cervical dystonia. One possible explanation may be that our patients with cervical dystonia were younger than those with blepharospasm. A similar observation was reported by Koukouni et al., where only 23.7% patients with young-onset cervical dystonia had the presence of sensory tricks. This difference in the frequency of sensory tricks can be due to age related changes in cortical plasticity as well as in the intracortical inhibitory circuits that have effects on the phenomenology of dystonia.,,,,, Another possible hypothesis of a lower frequency of sensory tricks seen among patients with cervical dystonia can be the presence of bulkier muscles and more complex movements in the production of dystonia in the cervical region than in the eye muscles involved in patients with blepharospasm. Sensory tricks have been implicated to occur as a result of proprioceptive/tactile modulation of sensorimotor integration and motor output., It might be possible that movements that are more complex and involve bulkier muscles require more modulation compared to lesser ones. However, the difference in age among the patients with cervical dystonia or blepharospasm, respectively, in our study may be a manifestation of the type of clinical sample we acquired at the teritiary care hospital in which we work, which may not be a perfect representation of the general population.
In our study, cold water application, separating of lids with fingers, and touching of eyelids were the most common sensory tricks reported in blepharospasm. The most common sensory tricks reported in the literature in blepharospasm patients include using the forefinger and/or thumb to touch the upper eyelid, stretching or rubbing of eyebrows, eyelids, or forehead, and touching the forehead or chin.,, The most common sensory tricks observed in our patients with cervical dystonia were pressure over the side/back of the neck and placing a hand over the chin/cheek. The most common sensory trick reported in patients with cervical dystonia reported in literature was touching their face or neck by Koukouni et al., placing their head on the hands, holding the chin, and leading it toward the midline by Loyola et al; and touching the cheek, chin, mastoid or skull, pushing the cheek, back of head, mastoid, chin, or forehead by Martino et al. Our findings corroborate with the previous studies in this aspect. These different types of sensory tricks employed by patients portray the heterogeneity in the expression of dystonia.
In our study, sensory tricks were effective in the majority of the patients in both the groups (13 in the blepharospasm and 6 in the cervical dystonia group). Martino et al., in their study found sensory tricks to be always effective in 47.2% patients with blepharospasm and in 51.9% patients with cervical dystonia. However, in our study, the benefit of the sensory trick was only partial (<50%) in most of the patients with blepharospasm (11 out of 18) and cervical dystonia (3 out of 7). This indicates that modulation of sensorimotor integration is an important method for the control of dystonic movements; however, there are also other pathways that are independent of sensory modulation that result in the production of dystonia.,, The loss of efficacy over time may be due to the deterioration of sensory trick mechanism or due to the progression of dystonia.,
Sensory tricks were more common in patients with primary blepharospasm than those with idiopathic cervical dystonia. The age of the patients with cervical dystonia was significantly less than those with blepharospasm. Our study did not find any correlation between sensory tricks with respect to gender distribution, duration of dystonia, and the severity scales. The most common types of sensory tricks in patients with blepharospasm were cold water application, separating the lids apart with finger, and touching of eyelid, whereas, the most common type of sensory tricks in patients with cervical dystonia were applying pressure over the side/back of the neck and placing the hand over chin/cheek. Majority of the patients had benefit with sensory tricks every time they used it; however, the relief was only partial.
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