Various patterns of gestes antagonistes in cervical dystonia

Sensory tricks modulate corticocortical and corticomuscular connectivity in cervical dystonia

OBJECTIVE

To examine interactions between cortical areas and between cortical areas and muscles during sensory tricks in cervical dystonia (CD).

METHODS

Thirteen CD patients and thirteen age-matched healthy controls performed forewarned reaction time tasks, sensory tricks, and two tasks replicating aspects of the tricks (moving necks/arms). Control subjects mimicked sensory tricks. Corticocortical and corticomuscular coherence values were calculated from surface electrodes placed over motor, premotor, and sensory cortical areas and dystonic muscles.

RESULTS

During initial preparation (after the warning stimulus), the only between-task difference was found in the γ-band corticocortical coherence (higher during tricks than during voluntary neck movements). With movements (before/after the imperative stimulus), the γ-band coherence of CD patients significantly increased during tricks but decreased during voluntary movements, while opposite trends were observed in healthy subjects. Additionally, the α- and β-band coherence decreased in healthy subjects during movements. Between the two patient subgroups (typical vs. forcible tricks), only those with typical tricks showed significant decrease in corticomuscular coherence during tricks.

CONCLUSIONS

Observed changes in the corticocortical coherence suggest that sensory tricks improve cortical function, which reduces corticomuscular connectivity and the dystonia.

SIGNIFICANCE

We demonstrated that sensory tricks fundamentally affect sensorimotor integration in CD, both in movement preparation and execution.

Sensory trick effect in craniofacial dystonia as one of the possible impacts of wearing face masks during the COVID-19 pandemic

BACKGROUND

The report of a patient with blepharospasm during the COVID-19 pandemic suggested a potential ameliorating effect of wearing a face mask.

OBJECTIVE

We prospectively evaluated a possible symptom change through wearing a face mask in all consecutive patients with craniofacial hyperkinesias in our botulinum toxin outpatient treatment cohort.

METHODS

Patients with craniofacial hyperkinesia were asked to rate changes of symptoms between - 2 (markedly worsened), - 1 (slightly worsened), 0 (no change), + 1 (slightly improved) and + 2 (markedly improved).

RESULTS

Of 101 patients (19 with blepharospasm [BSP], 54 with cervical dystonia [CD], 6 with oromandibular dystonia [OMD], and 22 with hemifacial spasm [HFS]) 81 (80%) rated no symptom change, 11 (11%) symptom improvement, and 9 (9%) symptom worsening. Improvements in 9 of the 82 dystonia patients (BSP, CD, OMD) consisted of a perceived decrease in dystonic activity. 33% of dystonia patients had previously noticed or used a sensory trick. Its presence turned out to be a significant predictor of improvement during mask wearing. Deteriorations were attributed from all patients to disturbing effects of the mask interacting with facial muscle overactivity. Improvements in HSF patients were attributed to the symptom-hiding nature of the mask and not to an effect on the spasm activity itself.

CONCLUSIONS

Wearing a face mask did not affect self-perceived symptoms in 80% of patients with craniofacial hyperkinesis. 11% of patients reported an improvement, which occurred as sensory trick in dystonia patients and as a concealment of a stigmatizing facial expression in patients with HSF.

Neurobiological mechanisms associated with antipsychotic drug-induced dystonia

Dystonia is by far the most intrusive and invalidating extrapyramidal side effect of potent classical antipsychotic drugs. Antipsychotic drug-induced dystonia is classified in both acute and tardive forms. The incidence of drug-induced dystonia is associated with the affinity to inhibitory dopamine D2 receptors. Particularly acute dystonia can be treated with anticholinergic drugs, but the tardive form may also respond to such antimuscarinic treatment, which contrasts their effects in tardive dyskinesia. Combining knowledge of the pathophysiology of primary focal dystonia with the anatomical and pharmacological organization of the extrapyramidal system may shed some light on the mechanism of antipsychotic drug-induced dystonia. A suitable hypothesis is derived from the understanding that focal dystonia may be due to a faulty processing of somatosensory input, so leading to inappropriate execution of well-trained motor programmes. Neuroplastic alterations of the sensitivity of extrapyramidal medium-sized spiny projection neurons to stimulation, which are induced by the training of specific complex movements, lead to the sophisticated execution of these motor plans. The sudden and non-selective disinhibition of indirect pathway medium-sized spiny projection neurons by blocking dopamine D2 receptors may distort this process. Shutting down the widespread influence of tonically active giant cholinergic interneurons on all medium-sized spiny projection neurons by blocking muscarinic receptors may result in a reduction of the influence of extrapyramidal cortical-striatal-thalamic-cortical regulation. Furthermore, striatal cholinergic interneurons have an important role to play in integrating cerebellar input with the output of cerebral cortex, and are also targeted by dopaminergic nigrostriatal fibres affecting dopamine D2 receptors.

Sensory Tricks in Pantothenate Kinase-Associated Neurodegeneration: Video-Analysis of 43 Patients

Background

Sensory tricks are a classic hallmark of primary dystonia and result in specific maneuvers that temporarily improve dystonic posture or movement. Pantothenate kinase-associated neurodegeneration (PKAN) is a progressive neurological disorder that courses with prominent dystonia. Although previously described, sensory tricks are considered to be rare in PKAN.

Cases

We reviewed videotaped motor examinations of 43 genetically confirmed patients with PKAN in order to identify and classify sensory tricks. All patients presented some feature of dystonia. Eighteen (42%) had one or more well-structured sensory tricks. Twelve different sensory tricks were identified, eight typical and four atypical (forcible motor): four in cervical dystonia, four in limb dystonia, three in oromandibular dystonia, and one in blepharospasm. A characteristic forcible motor maneuver for oromandibular dystonia (previously described as the "mantis sign") was present in 8 patients.

Conclusions

Sensory tricks are common in PKAN, particularly for oromandibular dystonia. The mantis sign may be a useful clue for the diagnosis.

The clinical phenomenology and associations of trick maneuvers in cervical dystonia

Sensory trick is an unusual clinical feature in cervical dystonia that attenuates disease symptoms by slight touch to a specific area of the face or head. Using a semi-quantitative questionnaire-based study of 197 patients with idiopathic cervical dystonia, we sought to determine probable pathophysiologic correlates, with the wider aim of examining its eventual clinical significance. The typical sensory trick, i.e., light touch, not necessitating the use of force leading to simple overpowering of dystonic activity, was present in 83 (42.1 %) patients. The vast majority of the patients required a specific sequence of sensorimotor inputs, including touch sensation on the face or different areas of the head, and also sensory and motor input of the hand itself. Deviations often led to a significant decrease in effectiveness and lack of expected benefit. Moreover, patients able to perform the maneuver reported compellingly higher subjective effect of botulinum toxin treatment (median 7 vs. 5 on a scale of 0-10; p < 0.0001) and lower depression score (median 10 vs. 14 on the Montgomery Åsberg Depression Rating scale; p < 0.001). Overall, the results point to marked disruption of sensorimotor networks in cervical dystonia. The mechanism of the sensory trick action may be associated with balancing the abnormal activation patterns by specific sensorimotor inputs. Its presence may be considered a positive predictive factor for responsiveness to botulinum toxin treatment.

Early Illustrations of Geste Antagoniste in Cervical and Generalized Dystonia

Background

Geste antagoniste, or sensory trick, is a voluntary maneuver that temporarily reduces the severity of dystonic postures or movements. We present a historical review of early reports and illustrations of geste antagoniste.

Results

In 1894, Brissaud described this phenomenon in Paris in patients with torticollis. He noted that a violent muscular contraction could be reversed by a minor voluntary action. He considered the improvement obtained by what he called “simple mannerisms, childish behaviour or fake pathological movements” was proof of the psychogenic origin of what he named mental torticollis. This concept was supported by photographical illustrations of the patients. The term geste antagoniste was used by Brissaud’s pupils, Meige and Feindel, in their 1902 monograph on movement disorders. Other reports and illustrations of this sign were published in Europe between 1894 and 1906. Although not mentioned explicitly, geste antagoniste was also illustrated in a case report of generalized dystonia in Oppenheim’s 1911 seminal description of dystonia musculorum deformans in Berlin.

Discussion

Brissaud-Meige’s misinterpretation of the geste antagoniste unfortunately anchored the psychogenic origin of dystonia for decades. In New York, Herz brought dystonia back into the realm of organic neurology in 1944. Thereafter, it was given prominence by other authors, notably Fahn and Marsden in the 1970–1980s. Nowadays, neurologists routinely investigate for geste antagoniste when a dystonic syndrome is suspected, because it provides a further argument in favor of dystonia. The term alleviating maneuver was proposed in 2014 to replace sensory trick or geste antagoniste. This major sign is now part of the motor phenomenology of the 2013 Movement Disorder Society’s classification of dystonia.

"Closing the loop" in cervical dystonia: a new clinical phenomenon

BACKGROUND

The sensory trick or geste antagoniste is a cardinal feature of cervical dystonia. Patients are often aware of their tricks, using them to their advantage to temporarily improve dystonic symptoms. The typical sensory trick must be internally generated by the patient in order to be effective, and external mechanical pressure alone may not be sufficient.

METHODS

We present a case description. We present and demonstrate a new clinical phenomenon in patients with cervical dystonia, which we call "closing the loop".

DISCUSSION

We discuss the possible mechanisms underlying this finding.

Tricks in dystonia: ordering the complexity

Sensory tricks are various manoeuvres that can ameliorate dystonia. Common characteristics are well known, but their variety is wide, sensory stimulation is not necessarily the critical feature, and their physiology is unknown. To enumerate the various forms of sensory tricks and describe their nature, research findings and theories that may elucidate their neurophysiologic mechanism, we reviewed the literature pertaining to sensory tricks, including variants like motor tricks, imaginary tricks, forcible tricks and reverse sensory tricks. On the basis of this information, we propose a new classification of sensory tricks to include its variants. We highlight neurophysiologic evidence suggesting that sensory tricks work by decreasing abnormal facilitation. We tie this with established dystonia pathogenesis and postulate that sensory tricks decrease abnormally increased facilitation to inhibition ratios in the dystonic brain. It appears worthwhile for patients to search for possible sensory tricks.

Alleviating manoeuvres (sensory tricks) in cervical dystonia

BACKGROUND

There is limited information on the phenomenology, clinical characteristics and pathophysiology of alleviating manoeuvres (AM), also called 'sensory tricks' in cervical dystonia (CD).

METHODS

Individual data, collected from 10 sites participating in the Dystonia Coalition (http://clinicaltrials.gov/show/NCT01373424), included description of localisation and phenomenology of AM collected by systematic review of standardised video examinations. Analyses correlated demographic, neurologic, and psychiatric features of CD patients with or without effective AM.

RESULTS

Of 154 people studied, 138 (89.6%) used AM, of which 60 (43.4%) reported partial improvement, 55 (39.8%) marked improvement, and 4 (0.03%) no effect on dystonic posture. Light touch, usually to the lower face or neck, was used by >90%. The presence or location of AM did not correlate with the severity of the dystonia.

CONCLUSIONS

In this large and comprehensive study of CD, we found no clinical predictors of effective AM. Further studies of sensorimotor integration in dystonia are needed to better understand the pathophysiology of AM.

Characteristic "Forcible" Geste Antagoniste in Oromandibular Dystonia Resulting From Pantothenate Kinase-Associated Neurodegeneration

Geste antagonistes are usually considered typical of primary dystonia, although rarely they have been described in secondary/heredodegenerative dystonias. We have recently come across a particular geste antagoniste in 5 of 10 patients with pantothenate kinase-associated neurodegeneration (PKAN) who had prominent oromandibular involvement with severe jaw-opening dystonia. It consists of touching the chin with both hands characteristically clenched into a fist with flexion at the elbows. Because of the resemblance of this geste antagoniste with the praying-like posture of Mantis religiosa, we coined the term "mantis sign." Reviewing videos of PKAN cases in literature, including what is considered the first cinematic depiction of a case of this disorder, 3 additional cases with akin maneuvers were identified. In contrast, examining 205 videos of non-PKAN dystonic patients from our database for the presence of a similar maneuver was unrevealing. Thus, we consider the mantis sign to be quite typical of PKAN and propose it to be added as a clinical hint toward diagnosis.

The definition of dystonia: current concepts and controversies

The definition of dystonia has been a subject of much debate and controversy for the last century. In this paper, a practical definition of dystonia for the movement disorders expert is presented, based on a new algorithm. © 2013 Movement Disorder Society.

Sensory tricks in primary cervical dystonia depend on visuotactile temporal discrimination

A characteristic feature of primary cervical dystonia is the presence of “sensory tricks” as well as the impairment of temporal and spatial sensory discrimination on formal testing. The aim of the present study was to test whether the amount of improvement of abnormal head deviation due to a sensory trick is associated with different performance of temporal sensory discrimination in patients with cervical dystonia. We recruited 32 patients with cervical dystonia. Dystonia severity was assessed using the Toronto Western Spasmodic Torticollis Rating Scale. Patients were rated according to clinical improvement to a sensory trick and assigned to 1 of the following groups: (1) no improvement (n = 6), (2) partial improvement (n = 17), (3) complete improvement (n = 9). Temporal discrimination thresholds were assessed for visual, tactile, and visuotactile modalities. Disease duration was shorter (P = .026) and dystonia severity lower (P = .033) in the group with complete improvement to sensory tricks compared with the group with partial improvement to sensory tricks. A significant effect for group and modality and a significant interaction between group × modality were found, with lower visuotactile discrimination thresholds in the group with complete improvement to sensory tricks compared with the other groups. In primary cervical dystonia, a complete resolution of dystonia during a sensory trick is associated with better visuotactile discrimination and shorter disease duration compared with patients with less effective sensory tricks, which may reflect progressive loss of adaptive mechanisms to basal ganglia dysfunction. © 2013 Movement Disorder Society

Spasmodic torticollis: the dental connection

Spasmodic torticollis or cervical dystonia (CD) is the most common form of focal dystonia and is characterized by sustained abnormal muscle contractions in the head and neck area resulting in abnormal positioning or posturing of the head. The dystonic muscle spasms associated with spasmodic torticollis may affect any combination of neck muscles. Three cases are reported of spasmodic torticollis that were treated by a dental appliance with individual varying occlusal heights to open the maxillomandibular vertical dimension. Upon increasing the vertical dimension of occlusion, there was a slowing and/or discontinuance of the symptoms of cervical dystonia. The proposed hypothesis for this reversal is that there may be neuritis of the auriculotemporal branch of the trigeminal nerve, which has direct input into the reticular formation (RF), and it may activate the cells of the pontine region of the RF known for the control and deviation of head posture. There is growing clinical evidence that temporomandibular joint (TMJ) dysfunction may be a factor in this neurological and painful disorder when it coexists.

The phenomenology of the geste antagoniste in primary blepharospasm and cervical dystonia

The geste antagoniste (GA), a relatively common feature of adult-onset primary dystonia, has been systematically evaluated only in cervical dystonia, but it is still unclear whether its frequency and phenomenology differ among the various forms of focal dystonia. We analysed the frequency, phenomenology, effectiveness, and relationship of the GA with demographic/clinical features of dystonia in a representative clinical series of patients with the two most common forms of adult-onset primary dystonia, blepharospasm (BSP) and cervical dystonia (CD). Clinical data were gathered using a standardized questionnaire, which showed substantial test-retest reliability (kappa = 0.79, P < 0.00001). The frequency of GA was similar among patients with BSP (42/59, 71.2%) and patients with CD (27/32, 84.4%), and in both groups GA showed similar effectiveness in reducing dystonia. The repertoire of GA was heterogenous in both BSP and CD patients, in whom seven BSP-related and five CD-related types of GA were recorded, and a "forcible" type of GA was present in 69% of BSP patients and in 48.1% of CD patients. In our whole patient population, age at dystonia onset was significantly lower among patients reporting a GA compared to those without GA (P = 0.01). GA features shared by BSP and CD predominate over differences, suggesting common mechanisms underlying this phenomenon in the two forms of primary adult-onset dystonia.

Transient tardive dystonia: overview and case presentation

Dystonia is a syndrome of involuntary, repetitive (or sustained) muscle contractions of opposing muscles, which may result in torsions and abnormal postures. Tardive dystonia is a form of the disorder that starts after longer term use of dopamine antagonists. It occurs in approximately 3% of patients receiving ongoing antipsychotic treatment and is often difficult to reverse. Dystonia can also be induced by compounds other than antipsychotics, such as antidepressants, levodopa, carbamazepine, dextroamphetamine, and diphenylhydantoin. In these cases, it is transient, generally disappearing after the dose is reduced or the causative drug is stopped. Dystonia induced by injury can also be transient. We report a case of transient oromandibular dystonia following a dental filling in a woman receiving quetiapine, a second-generation antipsychotic. The timing, localization, and transience of the dystonia suggested that the dental procedure may have played a triggering role. The dystonia symptoms responded within 8 weeks to benztropine and a dose reduction of quetiapine, and they did not return when benztropine was discontinued. This case benefited from prompt attention and has led to practical recommendations for psychiatric clinicians.