1,720,978 research outputs found
The environmental epidemiology of primary dystonia
Full text linkBackground: Dystonia is a movement disorder characterized by involuntary muscle contractions that cause twisting movements and abnormal postures. Primary dystonia is the most common form and is thought to be a multifactorial condition in which one or more genes combine with environmental factors to reach disease.
Methods: We reviewed controlled studies on possible environmental risk factors for primary early‐ and late‐onset dystonia.
Results: Environmental factors associated with primary early‐onset dystonia are poorly understood. Early childhood illnesses have been reported to be more frequent in patients with DYT1 dystonia than in subjects carrying the DYT1 mutation that did not manifest dystonia, thus raising the possibility that such exposures precipitate dystonia among DYT1 carriers. Conversely, several environmental factors have been associated with primary adult‐onset focal dystonias compared to control subjects. Namely, eye diseases, sore throat, idiopathic scoliosis, and repetitive upper limb motor action seem to be associated with blepharospasm (BSP), laryngeal dystonia (LD), cervical dystonia (CD), and upper limb dystonia, respectively. In addition, an inverse association between coffee drinking and BSP has been observed in both case‐unrelated control and family‐based case‐control studies. Additional evidence supporting a causal link with different forms of primary late‐onset dystonia is only available for diseases of the anterior segment of the eye, writing activity, and coffee intake.
Conclusion: There is reasonable epidemiological evidence that some environmental factors are risk‐modifying factors for specific forms of primary adult‐onset focal dystonia
Rest tremor in idiopathic adult-onset dystonia
No full textBackground: Tremor in dystonia has been described as a postural or kinetic abnormality. In recent series, however, patients with idiopathic adult-onset dystonia also displayed rest tremor. Methods: The frequency and distribution of rest tremor were studied in a cohort of 173 consecutive Italian patients affected by various forms of idiopathic adult-onset dystonia attending our movement disorder clinic over 8 months. Results: Examination revealed tremor in 59/173 patients (34%): 12 patients had head tremor, 34 patients had arm tremor, whilst 13 patients presented tremor in both sites. Head tremor was postural in all patients, whereas arm tremor was postural/kinetic in 28 patients, only at rest in one and both postural/kinetic and at rest in 18 patients. Patients with tremor were more likely to have segmental/multifocal dystonia. Patients who had rest tremor (either alone or associated with action tremor) had a higher age at dystonia onset and a greater frequency of dystonic arm involvement than patients with action tremor alone or without tremor. Conclusions: Both action and rest tremor are part of the tremor spectrum of adult-onset dystonia and are more frequently encountered in segmental/multifocal dystonia. The higher age at dystonia onset and the greater frequency of arm dystonia in patients with rest tremor may have pathophysiological implications and may account, at least in part, for the previous lack of identification of rest tremor as one possible type of tremor present in dystonia. Click here to view the accompanying paper in this issue
Recommended from our members
The environmental epidemiology of primary dystonia
Full text linkBackground:Dystonia is a movement disorder characterized by involuntary muscle contractions that cause twisting movements and abnormal postures. Primary dystonia is the most common form and is thought to be a multifactorial condition in which one or more genes combine with environmental factors to reach disease.Methods:We reviewed controlled studies on possible environmental risk factors for primary early‐ and late‐onset dystonia.ResultsEnvironmental factors associated with primary early‐onset dystonia are poorly understood. Early childhood illnesses have been reported to be more frequent in patients with DYT1 dystonia than in subjects carrying the DYT1 mutation that did not manifest dystonia, thus raising the possibility that such exposures precipitate dystonia among DYT1 carriers. Conversely, several environmental factors have been associated with primary adult‐onset focal dystonias compared to control subjects. Namely, eye diseases, sore throat, idiopathic scoliosis, and repetitive upper limb motor action seem to be associated with blepharospasm (BSP), laryngeal dystonia (LD), cervical dystonia (CD), and upper limb dystonia, respectively. In addition, an inverse association between coffee drinking and BSP has been observed in both case‐unrelated control and family‐based case‐control studies. Additional evidence supporting a causal link with different forms of primary late‐onset dystonia is only available for diseases of the anterior segment of the eye, writing activity, and coffee intake.ConclusionThere is reasonable epidemiological evidence that some environmental factors are risk‐modifying factors for specific forms of primary adult‐onset focal dystonia.</p
The anatomical basis of upper limb dystonia: lesson from secondary cases
No full textUpper limb dystonia is a focal dystonia that may affect muscles in the arm, forearm and hand. The neuroanatomical substrates involved in upper limb dystonia are not fully understood. Traditionally, dysfunction of the basal ganglia is presumed to be the main cause of dystonia but a growing body of evidence suggests that a network of additional cortical and subcortical structures may be involved. To identify the brain regions that are affected in secondary upper limb dystonia may help to better understand the neuroanatomical basis of the condition. We considered only patients with focal upper limb dystonia associated with a single localized brain lesion. To identify these patients, we conducted a systematic review of the published literature as well as the medical records of 350 patients with adult-onset dystonia seen over past 15 years at our movement disorder clinic. The literature review revealed 36 articles describing 72 cases of focal upper limb dystonia associated with focal lesions. Among patients at our clinic, four had focal lesions on imaging studies. Lesions were found in multiple regions including thalamus (n = 39), basal ganglia (n = 17), cortex (n = 4), brainstem (n = 4), cerebellum (n = 1), and cervical spine (n = 7). Dystonic tremor was not associated with any particular site of lesion, whereas there was a trend for an inverse association between task specificity and thalamic involvement. These data in combination with functional imaging studies of idiopathic upper limb dystonia support a model in which a network of different regions plays a role in pathogenesis
Smoking and age-at-onset of both motor and non-motor symptoms in Parkinson's disease
No full textIntroduction: Several evidence suggest that smoking may decrease the risk of Parkinson's disease and is associated with an older age-at-onset of motor signs. The relation between smoking and age-at-onset of non-motor symptoms has never been analyzed. Objective of the study is to evaluate whether smoking habit and pack-years of smoking are associated with a delay of age-at-onset of motor signs, and of some non-motor symptoms.
Methods: The study population consisted of 262 consecutive parkinsonian patients. Information on relevant demographic/clinical data focused on motor signs, REM sleep behavior disorder, constipation, depression, and hyposmia. Patients were stratified according to smoking habit (ever-versus never smoker) and number of pack-years of smoking was computed. Repeatability of data on age-at-onset was checked 6 months after the initial interview in a randomly recruited subsample.
Results: Smoking habit and number of pack-years smoked were associated with an older in age-at-onset of motor signs, REM sleep behavior disorder and depression. By contrast, smoking did not affect age-at onset of hyposmia and constipation.
Conclusion: information from this study confirms that smoking may be associated with an older age-at onset of motor signs, and that a similar effect can be observed on some non-motor symptoms like REM sleep behavior and depressio
Chronic coffee consumption and striatal DAT-SPECT findings in Parkinson's disease
No full textCoffee may interfere with the dopaminergic transmission, and this action would possibly enhance motor activity and exert an antidyskinetic effect in Parkinson’s disease (PD). This study aimed to see whether coffee habit could be associated with change in striatal dopamine active transporter (DAT)-single photon emission computed tomography (SPECT) imaging in PD. A total of 83 PD patients (71 current coffee drinkers and 12 never drinkers) underwent a DAT-SPECT study, using [123I]FP-CIT as radionuclide. Socio-demographic and clinical information as well as smoking habit was collected at the time of imaging acquisition. The Unified Parkinson’s Disease Rating Scale part III was used to evaluate disease severity. On multivariable analysis, chronic coffee consumption was not associated with any significant change in striatal uptake of the radionuclide. However, the number of years patients drunk coffee was correlated with a significant increase in age at PD onset (p < 0.001). Confirming a previous report, current cigarette smoking was associated with a reduction of radionuclide uptake in putamen and caudate (p < 0.001)
Is tremor in dystonia a phenotypic feature of dystonia?
No full textTo understand better the features and mechanisms distinguishing tremor in dystonia, we reviewed the epidemiologic, clinical, and neurophysiologic data in patients with dystonia and tremor. Clinical studies suggest that tremor starts at or after dystonia onset in body parts
affected or unaffected by dystonia. Tremor in dystonia manifests during posture or voluntary movements even though some dystonic patients may have tremor at rest. Prevalence rates for tremor in dystonia are higher in patients with adult-onset dystonia and cervical dystonia than in
other dystonias and highest in patients in whom dystonia spreads. Neurophysiologic investigations in patients with dystonia and tremor show reduced reciprocal inhibition between agonist and antagonist upper limb muscles, a lack of brainstem interneuronal inhibition, and abnormal
sensory integration. The neurophysiologic abnormalities in patients with dystonia and tremor resemble those in dystonia but differ from those described in essential tremor. Tremor is a phenotypic motor feature in dystonia
Diagnostic delay in adult-onset dystonia: Data from an Italian movement disorder center
No full textAdult-onset dystonia (AOD) may manifest in focal forms (as blepharospasm, oromandibular dystonia, cervical dystonia, laryngeal dystonia, and hand dystonia) or in segmental forms. Time from onset of dystonia to diagnosis can be an indicator of the quality of care received during the diagnosis of AOD, likely reflecting factors associated with both the patient and their health system. Three previously reported single-center studies showed that diagnosis of AOD may be delayed for several years. Here, we examined the time lapse between onset and diagnosis in patients with different forms of AOD from an Italian movement disorder center. We found the time lapse between dystonia onset and diagnosis was very long for patients who developed AOD before 1980; and even in the most recent years reaching a correct diagnosis required more than year in almost half of cases. Our results suggest that the delay in diagnosis of adult-onset focal and segmental dystonia has improved over time, but remains unacceptable. The findings are a promising indicator of improvements in care of this uncommon disorder. However, education of patients and doctors is still needed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
