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Query: UMLS:C0013421 (dystonia)
 8,418 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tardive dyskinesia (TD) is a consequence of chronic neuroleptic therapy. It is an irregular stereotyped movement disorder that is usually choreic in appearance, and is subject to temporary volitional control. Dystonia, akathisia, and tics are uncommon variants of the classic tardive syndrome. Characteristic clinical features including amelioration by action, augementation by distraction, partial volitional suppressibility, and lack of subjective distress help differentiate TD from other movement disorders such as resting tremor, Huntington's disease, spontaneous dyskinesias, and abnormal movements accompanying psychiatric illnesses.
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PMID:Recognition and differential diagnosis of tardive dyskinesia. 257 70

Movement disorders have rarely been the result of psychiatric disturbances. Psychogenic dystonia is caracterized by inconsistent findings, a known precipitant factor, onset in legs, pain, multiple somatizations and incongruent association with other movement disorders. We report two patients with clinically established psychogenic dystonia. Patient 1: a female that presented sudden loss of strength in her four limbs; she developed feet dystonia, alternant laterocollis, generalized and irregular tremor, and limb hypertonia that disappeared with distraction; psychological examination showed severe depression, hypochondria and obsessive disorder. Patient 2: a female that presented with irregular limb tremors that disappeared with distraction and left foot dystonia nine years ago; she gradually lost her walk capacity; she complained pain in lumbar area and in her left limb, psychological examination showed infantile behaviour, low frustration tolerance, impulsivity and self-aggression. Their complementary exams showed no alterations and they had no response to specific pharmacological treatment. Dystonia is rarely psychogenic, but this etiology is suggested when clinical characteristics are inconsistent and incongrous with a classical disorder. It should be part of differential diagnosis when appears in association with other somatization or psychiatric disorders.
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PMID:[Psychogenic dystonia: report of 2 cases]. 1092 Apr 17

The link between basic physiology and its modulation by cognitive states, such as attention, is poorly understood. A significant association becomes apparent when patients with movement disorders describe experiences with changing their attention focus and the fundamental effect that this has on their motor symptoms. Moreover, frequently used mental strategies for treating such patients, e.g. with task-specific dystonia, widely lack laboratory-based knowledge about physiological mechanisms. In this largely unexplored field, we looked at how the locus of attention, when it changed between internal (locus hand) and external (visual target), influenced excitability in the primary motor cortex (M1) in healthy humans. Intriguingly, both internal and external attention had the capacity to change M1 excitability. Both led to a reduced stimulation-induced GABA-related inhibition and a change in motor evoked potential size, i.e. an overall increased M1 excitability. These previously unreported findings indicated: (i) that cognitive state differentially interacted with M1 physiology, (ii) that our view of distraction (attention locus shifted towards external or distant location), which is used as a prevention or management strategy for use-dependent motor disorders, is too simple and currently unsupported for clinical application, and (iii) the physiological state reached through attention modulation represents an alternative explanation for frequently reported electrophysiology findings in neuropsychiatric disorders, such as an aberrant inhibition.
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PMID:An unavoidable modulation? Sensory attention and human primary motor cortex excitability. 2494 68

Functional or psychogenic movement disorders are common and disabling, and sometime difficult to diagnose. The history and physical exam can give positive features that will support the diagnosis, which should not be based solely on exclusion. Some clues in the history are sudden onset, intermittent time course, variability of manifestation over time, childhood trauma, history of other somatic symptom and secondary gain. Anxiety and depression are common, but not necessarily more than the general population. On examination, distraction and suggestibility may be present. There are specific signs that should be looked for with different types of movements. For example, with tremor, change in frequency over time and entrainment are common features. With myoclonus, the movements might be complex in type with long latencies to stimulus induced jerks. Gait disorders show good balance despite claims to the contrary. Functional dystonia still remains a challenging diagnosis in many circumstances, although fixed dystonia is one sign more likely to be functional.
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PMID:Functional (psychogenic) movement disorders - Clinical presentations. 2636 78

Objectives Although primary dystonia is typically characterized as a movement disorder, it is also associated with cognitive alterations in the domain of executive functioning which may arise from changes in cortico-basal ganglia circuits. Specifically, in comparison to healthy controls, patients with dystonia show deficits in neuropsychological tests of cognitive flexibility. However, it is unclear whether cognitive inflexibility is caused by the pathomechanisms underlying primary dystonia or by confounding factors such as depression or symptom-related distraction.Methods The present study aimed to eliminate these confounds by examining cognitive flexibility in dystonia patients and in patients with similar motor symptoms but without a comparable central pathophysiology. Eighteen patients with primary blepharospasm, a common form of dystonia affecting the muscles around the eyes, and 19 patients with hemifacial spasm, a facial nerve disorder causing similar eyelid spasms, completed a computerized version of the Wisconsin Card Sorting Test (cWCST). The two groups were further compared on tests of global cognitive functioning, psychiatric symptoms, health status, and impulsiveness. Results Blepharospasm patients committed significantly more errors on the cWCST than patients with hemifacial spasm. Group differences were most pronounced with regard to integration errors, a measure of rule-inference processes on the cWCST. Integration errors were also associated with impulsiveness in patients with blepharospasm. Conclusions Primary blepharospasm is related to deficits in cognitive flexibility, even when blepharospasm patients are compared with patients who suffer from motor symptoms of non-dystonic origin. Our results support the possibility that cognitive inflexibility results from the specific pathophysiological processes underlying primary dystonia. (JINS, 2016, 22, 662-670).
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PMID:Cognitive Flexibility in Primary Dystonia. 2733 37

Functional movement disorders (FMDs) affecting the eyelids, tongue, and other facial muscles are often underrecognized because their phenomenology has not been fully characterized. Nevertheless, these disorders are more common than previously thought. In this chapter we will discuss the phenomenology as well as the clinical and instrumental diagnosis of facial FMDs. Facial FMDs should be considered when a patient exhibits any combination of the following features: (1) fixed unilateral facial contractions, especially with lower lip, with or without ipsilateral jaw involvement, of maximal severity at onset; (2) inconsistent features such as changes in side and pattern during or between examination; (3) associated somatoform or nonphysiologic sensory or motor findings; (4) reduction or abolition of facial spasm with distraction; (5) response to suggestion or psychotherapy; (6) rapid onset and/or spontaneous remissions; and (7) normal neurologic examination. Supportive features are young age, female gender, and associated medical conditions such as depression, headaches, facial pain, fibromyalgia, or irritable-bowel syndrome. Finally, the differential diagnosis with the organic counterparts will be also addressed, particularly with respect to blepharospasm, oromandibular dystonia, and hemifacial spasm.
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PMID:Functional facial and tongue movement disorders. 2771 55

An important brain function is to predict upcoming events on the basis of extracted regularities of previous inputs. These predictive coding processes can disturb performance in concurrent perceptual decision-making and are known to depend on fronto-striatal circuits. However, it is unknown whether, and if so, to what extent striatal microstructural properties modulate these processes. We addressed this question in a human disease model of striosomal dysfunction, i.e. X-linked dystonia-parkinsonism (XDP), using high-density EEG recordings and source localization. The results show faster and more accurate perceptual decision-making performance during distraction in XDP patients compared to healthy controls. The electrophysiological data show that sensory memory and predictive coding processes reflected by the mismatch negativity related to lateral prefrontal brain regions were weakened in XDP patients and thus induced less cognitive conflict than in controls as reflected by the N2 event-related potential (ERP). Consequently, attentional shifting (P3a ERP) and reorientation processes (RON ERP) were less pronounced in the XDP group. Taken together, these results suggests that striosomal dysfunction is related to predictive coding deficits leading to a better performance in concomitant perceptual decision-making, probably because predictive coding does not interfere with perceptual decision-making processes. These effects may reflect striatal imbalances between the striosomes and the matrix compartment.
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PMID:Dysfunctions in striatal microstructure can enhance perceptual decision making through deficits in predictive coding. 2846 59

Functional movement disorders (FMDs), known over time as "hysteria", "dissociative", "conversion", "somatoform", "non-organic" and "psychogenic" disorders, are characterized by having a voluntary quality, being modifiable by attention and distraction but perceived by the patient as involuntary. Although a high prevalence of depression and anxiety is observed in these patients, a definitive role of psychiatric disorders in FMDs has not been proven, and many patients do not endorse such manifestations. Stressful events, social influences and minor trauma may precede the onset of FMDs, but their pathogenic mechanisms are unclear. Patients with FMDs have several abnormalities in their neurobiology including strengthened connectivity between the limbic and motor networks. Additionally, there is altered top-down regulation of motor activities and increased activation of areas implicated in self-awareness, self-monitoring, and active motor inhibition such as the cingulate and insular cortex. Decreased activation of the supplementary motor area (SMA) and pre-SMA, implicated in motor control and preparation, is another finding. The sense of agency defined as the feeling of controlling external events through one's own action also seems to be impaired in individuals with FMDs. Correlating with this is a loss of intentional binding, a subjective time compression between intentional action and its sensory consequences. Organic and functional dystonia may be difficult to differentiate since they share diverse neurophysiological features including decreased cortical inhibition, and similar local field potentials in the globus pallidus and thalamus; although increased cortical plasticity is observed only in patients with organic dystonia. Advances in the pathogenesis and pathophysiology of FMDs may be helpful to understand the nature of these disorders and plan further treatment strategies.
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PMID:Pathogenesis and pathophysiology of functional (psychogenic) movement disorders. 3079 5