Primary orthostatic tremor: further observations in six cases

Britton, Thomas C.; Thompson, Philip D.; Kamp, Wim van der; Rothwell, John C.; Day, B. L.; Findley, L J; Marsden, C. D.

doi:10.1007/bf00839142

Cited by 105 publications

(101 citation statements)

References 19 publications

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“…39 Tremor in the upper limbs has been described in OT, 7,32,40 and on clinical examination this was also present in 7 of our 11 patients. Upper limb tremor in OT may have a lower frequency than 13 to 18Hz 41 and therefore has been attributed often to associated essential tremor.…”

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confidence: 75%

[¹²³I]‐FP‐CIT‐SPECT demonstrates dopaminergic deficit in orthostatic tremor

Katzenschlager

Costa

Gerschlager

et al. 2003

Annals of Neurology

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There is increasing evidence of a potential role of the dopaminergic system in orthostatic tremor (OT): Association with parkinsonism and treatment effects of L-dopa and dopamine agonists have been reported. Eleven patients with isolated OT had single-photon emission computed tomography (SPECT) using (123)I-FP-CIT ([(123)I]-2 beta-carbomethoxy-3beta-(-4-iodophenyl)-N-(3-fluoropropyl)-nortropane) as dopamine transporter tracer. Results were compared with 12 age-matched normal controls and 12 patients with Parkinson's disease (PD). A marked reduction in striatal tracer binding was found in OT compared to normal controls (p < 0.001). Tracer uptake was significantly higher and more symmetrical than in PD, and caudate and putamen were equally affected. L-dopa challenges, performed in seven patients, showed a small but non-significant improvement on EMG and a small but significant improvement in clinical parameters on blinded video rating. Two-month open-label L-dopa treatment (600 mg/day) led to a small improvement in two of five patients but no significant overall change. Olfactory function on University of Pennsylvania Smell Identification Test was normal. Our finding of a marked tracer uptake reduction on dopamine transporter SPECT supports a role of the dopaminergic system in OT. Lack of evidence of a clinically relevant therapeutic response to L-dopa suggests that other mechanisms must also be involved in the pathogenesis.

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confidence: 75%

[¹²³I]‐FP‐CIT‐SPECT demonstrates dopaminergic deficit in orthostatic tremor

Katzenschlager

Costa

Gerschlager

et al. 2003

Annals of Neurology

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“…5 Another six were described previously by Britton and colleagues (1992) and one by Thompson and coworkers (1986). 17,18 We thought it reasonable to include these patients in the present report, because these earlier studies dealt essentially with a particular aspect of OT, for example, treatment response to levodopa 5 or electrophysiology, 17 and we wished to present the collective data of the entire group of OT patients, who have been seen and followed up at our institution in the past 16 years.…”

Section: Methodsmentioning

confidence: 99%

Natural history and syndromic associations of orthostatic tremor: A review of 41 patients

et al. 2004

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Orthostatic tremor (OT) is a rare condition characterized by unsteadiness when standing still that is relieved when sitting or walking and is thought to arise from a central generator in the cerebellum or brainstem. OT is considered to be a distinct, discrete condition, and little is known about its demographic characteristics, natural history, associated features, and treatment response. We have reviewed these aspects in 41 OT patients fulfilling current diagnostic criteria, seen at our institution between 1986 and 2001. We classified 31 (75%) as having idiopathic "primary OT" either with (n = 24) or without an associated postural arm tremor. We found that 10 of 41 (25%) cases had additional neurological features, and we defined this group as having "OT plus" syndrome. Of these 10, 6 had parkinsonism; 4 of these had typical Parkinson's disease (PD), 1 had vascular and 1 had drug-induced parkinsonism. Among the remaining 4 patients, 2 had restless legs syndrome (RLS), 1 had tardive dyskinesia, and 1 orofacial dyskinesias of uncertain etiology. One patient with PD and the patient with vascular parkinsonism also had RLS. Age at onset was significantly earlier in the "primary OT" (mean +/- SD, 50.4 +/- 15.1) than in the "OT plus" (61.8 +/- 6.4; z = 2.7; P =.006) group. In 7 of the 10 "OT plus" patients, OT leg symptoms preceded the onset of additional neurological features. OT appeared to be underdiagnosed, and on average, it took 5.7 years from the initial complaints until a diagnosis was made. In general, treatment response to a variety of drugs such as clonazepam, primidone, and levodopa was poor. In most cases, OT symptoms remain relatively unchanged over the years, but in 6 of 41 cases (15%), the condition gradually worsened over the years, and in some of these cases, symptoms spread proximally to involve the trunk and arms. OT may not be a discrete disorder as commonly believed and associated features like parkinsonism present in nearly 25% of cases. Dopaminergic dysfunction may have a role in the pathophysiology of this disorder.

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“…It has a characteristic high frequency in the range of 13-16 Hz. 14 Tracings on surface electromyography done with the patient in the standing position show this characteristic frequency. The patient may not be aware of the tremulousness, and the problem of stance and gait may be the only symptom.…”

Section: Diagnosismentioning

confidence: 95%