Postural laterality in torticollis and torsion dystonia

The effect of cognitive task on postural stability in cervical dystonia

BACKGROUND

Cervical dystonia (CD) is the most common form of focal dystonia. It is not known exactly whether abnormal head postures in cervical dystonia cause balance problems. Dual-tasking is a common every-day life situation.

OBJECTIVE

We aimed to evaluate postural stability (PS) in patients with CD and the effect of cognitive task on PS. As a secondary aim, we evaluated the effect of onabotulinum toxin A (BoNT) injection on PS.

METHODS

A total of 24 patients with CD who were on BoNT treatment for at least one year and 23 healthy controls were included. Posturographic analyses were carried out in all the subjects on static posturography platform under four different conditions: eyes open, eyes closed, tandem stance and cognitive task. In patients, posturographic analysis was carried out just before the BoNT injections and was repeated four weeks later.

RESULTS

Before treatment, the anterior-posterior sway was significantly higher in CD patients with the eyes open condition compared to the controls (p=0.03). Cognitive task significantly affected several sway velocities. Tandem stance significantly affected many sway parameters, whereas the eyes closed condition did not. After treatment, only two parameters in tandem stance and one in cognitive task improved within the patient group, in a pairwise comparison.

CONCLUSIONS

Postural control is impaired in CD patients probably due to the impaired proprioceptive and sensorimotor integration. In reference to dual task theories possibly due to divided attention and task prioritization, cognitive dual-task and harder postural task disturbes the PS in these patients.

The Dystonias

Dystonia is a difficult problem for both the clinician and the scientist. It is sufficiently common to be seen by almost all physicians, yet uncommon enough to prevent any physician from gaining broad experience in its diagnosis and treatment. Each case represents a difficult challenge even to the specialist. The basic scientist is faced with investigating a disorder that is without relevant animal models and which is so rare that obtaining suitable tissue for study is a major obstacle. Dystonia may be idiopathic, or associated with lesions from many sources, including a variety of rare diseases. If idiopathic, it may be genetically transmitted or sporadic. If genetically transmitted, it may be generalized or focal, with symptoms varying in different members of the same family. It may be refractory to treatment, or it may respond to any one of a number of individual drugs that have very different mechanisms of action. For idiopathic dystonias, no clear method of genetic transmission has been established and no consistent pathology identified.

Hypnosis and spasmodic torticollis--report of four cases: a brief communication

Dystonia and particularly spasmodic torticollis are neuromuscular disorders that are extremely resistant to most therapies (physical, medical, or surgical). Torticollis is a unilateral spasm of the neck muscles, particularly of the sternocleidomastoid, that produces violent, tonic turning of the head to one side. The etiology remains uncertain, although the role of psychogenic factors has been emphasized. This article reviews the literature and reports four cases of spasmodic torticollis treated successfully with hypnosis. In all four cases, psychogenic causes were involved. Postural hypnosis (i.e., hypnosis in the standing position) was employed to counteract and minimize muscle spasms due to postural reflexes. A hypnobehavioral approach was adopted along with hypnotic strategies that included hierarchical desensitization, sensory-imaging conditioning, ego-boosting suggestions, and hypnosis-facilitated differential muscle retraining. In two cases, a combined hypnosis and electromyographic-biofeedback approach was used to equilibrate and retrain affected neck muscles. Although the hypnotherapeutic process took several months to induce and stabilize significant changes, outcome results were good to excellent in all cases, with marked reduction of the torticollis and the hypertrophy of the neck muscles as well as a reduced interference of symptoms in daily living.

Click-evoked vestibulocollic reflexes in torticollis

A total of 26 patients with torticollis were studied using a recently developed technique for recording vestibulocollic reflexes from the sternocleidomastoid muscles in addition to conventional caloric tests of vestibular function. Previous reports of abnormalities of vestibulo-ocular reflexes in these patients were confirmed with just fewer than half having significant canal pareses or directional preponderances (nine of 20 tested). In addition, there was a high incidence of abnormal click-evoked vestibulocollic reflexes (17 of 26 tested), which were not simply the result of prior treatment with botulinum toxin, nor due to unequal levels of muscle activation. In patients never previously treated with botulinum toxin (14 patients), the effect almost always consisted of suppressed responses in the sternocleidomastoid muscle ipsilateral to the direction of head turning. Because responses were not abnormal in all patients tested, and more commonly so in those with a history of torticollis of > or = 5 years (eight of nine patients) than in de novo patients, we suggest that the changes are more likely to be compensatory than causal.

The relationship between eye dominance and head tilt in humans

Previous data suggest that vertical imbalances between the eyes produced by lateral head tilt are linked to ocular dominance, but no studies have heretofore objectively measured head tilt in addressing this relationship. Photographic measurements of the head tilt of 70 subjects were made, along with measures of sighting dominance and vertical misalignment during sighting. The analyses revealed that photographically measured head tilt is significantly associated with vertical imbalances during sighting and with sighting dominance. These data support the theory that motoric dominance in humans is partly related to mechanisms underlying postural asymmetry.

Spasmodic torticollis--review of 220 patients

220 patients with isolated and idiopathic spasmodic torticollis were followed and treated over a 14 year period. Each patient was given a short questionnaire leading to the present retrospective data analysis. In most areas, including female preponderance and frequency of postural tremor, the findings confirmed previous studies and highlighted particular points: importance of psychopathological antecedents and association with stressful life-events. The discussion deals with some of the conflicting debates surrounding this unusual disorder. What is the role of psychopathological factors? What is the therapeutic prognosis? The best therapeutic results were obtained by combining anticholinergic drugs, local injections and rehabilitation.