Tremor-Some Controversial Aspects

Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, United Kingdom.
Movement Disorders (Impact Factor: 5.68). 01/2011; 26(1):18-23. DOI: 10.1002/mds.23289
Source: PubMed


The commonest cause of pathological tremor is essential tremor (ET). However, it has proved difficult to identify genetic mutations causing ET, particularly because other causes of tremor continue to be misdiagnosed as ET. Whether subjects with dystonia or Parkinson's disease (PD) carry an increased genetic risk of developing ET, or vice versa, is controversial. In addition, the notion of a separate disorder of benign tremulous parkinsonism (BTP) has been debated. This article gives a selective viewpoint on some areas of uncertainty and controversy in tremor.

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    • "In clinical practice, tremor is mostly diagnosed by using clinical examination only. However, by using only clinical examination, ET is accurately diagnosed in 50–63% of cases, whereas the PT in 76% of the pathologically confirmed cases [2]. The occasional overlap between different types of tremor makes diagnosing even more difficult. "
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    ABSTRACT: The most frequently seen types of tremor are essential (ET) and parkinsonian tremor (PT) and in some patients clinical characteristics of these tremor types overlap. It is vital to distinguish between these two types of tremor in order to reach the right diagnosis and select the appropriate treatment. One of the widely used methods for tremor detection and discrimination, appropriate for a quick ambulatory assessment of the patient's tremor, is spirography. With spirography, the tremor can be observed through several parameters, for example, tremor spectrum and spiral image, which give useful information for its identification. Standard spirography parameters of ET and PT can overlap; therefore, these parameters are often not enough for identification of the observed tremor. To increase the specificity and sensitivity of spirography for PT, ET and normal, tremor free controls, we used the wavelet analysis with Morlet wavelet transform. To facilitate analysis, comparison, storage, and retrieval of spirography tremor records we also developed an integrated computer assisted spirography system that increases the convenience of outpatient tremor identification and follow-up. We conclude that wavelet analysis of spirography records increases the sensitivity and specificity of the method, thus, facilitating the distinction between ET and PT.
    BioMed Research International 08/2014; 2014:934746. DOI:10.1155/2014/934746 · 3.17 Impact Factor
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    • "The mean age at onset in DYT6 is 24.4 years (range, 2-62 years),4 and the most common site of onset is the upper limb (47%) followed by cranial dystonia (25%), cervical dystonia (23%), and rarely leg dystonia (17%).4,5 In more than half of DYT6 patients, dystonia spreads to become generalized or multifocal, which contrasts our DYT24 patients.2,4–8 Recently, mutations in GNAL have also been identified to cause craniocervical dystonia.9 "
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    ABSTRACT: Genes causing primary dystonia are rare. Recently, pathogenic mutations in the anoctamin 3 gene (ANO3) have been identified to cause autosomal dominant craniocervical dystonia and have been assigned to the dystonia locus dystonia-24 (DYT24). Here, we expand on the phenotypic spectrum of DYT24 and provide demonstrative videos. Moreover, tremor recordings were performed, and back-averaged electroencephalography, sensory evoked potentials, and C-reflex studies were carried out in two individuals who carried two different mutations in ANO3. Ten patients from three families are described. The age at onset ranged from early childhood to the forties. Cervical dystonia was the most common site of onset followed by laryngeal dystonia. The characteristic feature in all affected individuals was the presence of tremor, which contrasts DYT24 from the typical DYT6 phenotype. Tremor was the sole initial manifestation in some individuals with ANO3 mutations, leading to misdiagnosis as essential tremor. Electrophysiology in two patients with two different mutations showed co-contraction of antagonist muscles, confirming dystonia, and a 6-Hz arm tremor at rest, which increased in amplitude during action. In one of the studied patients, clinically superimposed myoclonus was observed. The duration of the myoclonus was in the range of 250 msec at about 3 Hz, which is more consistent with subcortical myoclonus. In summary, ANO3 causes a varied phenotype of young-onset or adult-onset craniocervical dystonia with tremor and/or myoclonic jerks. Patients with familial cervical dystonia who also have myoclonus-dystonia as well as patients with prominent tremor and mild dystonia should be tested for ANO3 mutations. © 2014 International Parkinson and Movement Disorder Society.
    Movement Disorders 06/2014; 29(7). DOI:10.1002/mds.25802 · 5.68 Impact Factor
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    • "While the ET clinically manifests as action tremor, the pathogenesis of this clinical feature is likely heterogenous.55 Some experts contend that there are abnormal central oscillations in the olivo-cerebello-thalamo-cortical loop that trigger as yet, unknown biochemical changes.3,38,56 "
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    ABSTRACT: Essential tremor (ET) is the most common pathological tremor characterized by upper limb action-postural tremor (PT)/kinetic tremor (KT). There are no specific neuropathological or biochemical abnormalities in ET. The disability is consequent to amplitude of KT, which may remain mild without handicap or may become disabling. The most effective drugs for sustained tremor control are propranolol and primidone. Symptomatic drug treatment must be individualized depending on the circumstances that provoke the tremor-related disability. Broad guidelines for treatment are discussed in this review. Patients may be treated intermittently only on stressful occasions with propranolol, clonazepam, or primidone monotherapy, or an alcoholic drink. Those with persistently disabling tremor need continued treatment.
    04/2014; 6:29-39. DOI:10.4137/JCNSD.S13570
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