Accelerometry to distinguish psychogenic from essential or parkinsonian tremor (original) (raw)
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A cross-over clinical and electromyographic assessment of treatment for parkinsonian tremor
Parkinsonism & Related Disorders, 2001
Background: Whether dopaminergic and anticholinergic drugs exert in¯uence on parkinsonian rest and postural tremor is a subject of debate. Different types of tremor may be in¯uenced differently by the drugs. The aim of this study was to reevaluate the differential effects of levodopa and anticholinergic drugs on parkinsonian tremor in different limb positions and on different types of postural tremor. Methods: Thirty-eight patients with parkinsonian resting tremor and postural tremor were included in this study. Patients were divided into two groups according to the electromyographic pattern of the postural tremor. We found fast synchronous postural tremor (.7 Hz) in 16 patients, and slow alternating postural tremor in 22 patients. The tremor was scored clinically in each limb position using the Webster Tremor Scale. Surface electromyographic recordings from the most involved limb in all positions were also performed. The patients were randomly assigned to levodopa (one 250/50-mg tablet), or to biperiden (one 3-mg tablet). Tremor was assessed by clinical and electromyographic examinations at base line 1 h following ingestion of the drug. The subjective tremor improvement was also assessed. Results: We found that levodopa had a good effect on the amplitude of the resting tremor, while the effect of biperiden was weaker. Both levodopa and biperiden has less effect on postural tremor. However, levodopa's effect was better than that of biperiden. Levodopa and biperiden had better effect on slow alternating postural tremor than on fast synchronous postural tremor. They had no effect on kinetic and intention tremors. Conclusions: Levodopa and anticholinergic drugs have differing effects on both resting and postural tremor Also, the different categories of postural tremor respond differently to treatment. The mechanisms underlying resting parkinsonian tremor may be different from those underlying postural, kinetic and intention tremor. Moreover, the mechanisms underlying different types of postural tremor may be different.
Journal of Clinical Neurophysiology, 2004
The objective of the current study was to investigate the diagnostic potential of the routine tremor neurophysiologic analysis for the diagnosis of essential tremor (ET) in patients with postural tremor syndrome. Three hundred consecutive outpatients attending for postural tremor were included. Accelerometry and surface electromyography was performed between 1 and 4 weeks after the first clinical visit. A final clinical diagnosis (mean follow-up period, 53 months) of the postural tremor syndrome was made by two neurologists blind to the neurophysiologic results. Six neurophysiologic criteria for the diagnosis of ET were applied to define the neurophysiologic examination as compatible or not compatible with ET (all criteria must be present): (1) rhythmic burst of postural tremor on EMG; (2) tremor frequency greater than or equal to 4 Hz; (3) absence of rest tremor or, if present, frequency 1.5 Hz lower than the postural tremor; (4) absence of tremor latency from rest to postural position; (5) changes of the dominant frequency peak less or equal to 1 Hz after the weight load test; and (6) no changes in tremor amplitude after mental concentration. The neurophysiologic criteria for ET showed a sensitivity of 97.7%, a specificity of 82.3%, a positive predictive value of 95.1%, a negative predictive value of 91.1%, and positive probability ratio of 5.5. The odds ratio was 198.43 (95% CI, 66.03 to 596.35). For the diagnosis of ET in patients with postural tremor, routine neurophysiologic tests have high diagnostic and predictive value that justifies its practice in movement disorders clinics.
Diagnosis and Treatment of Common Forms of Tremor
Seminars in Neurology, 2011
Tremor is the most common movement disorder presenting to an outpatient neurology practice and is defined as a rhythmical, involuntary oscillatory movement of a body part. The authors review the clinical examination, classification, and diagnosis of tremor. The pathophysiology of the more common forms of tremor is outlined, and treatment options are discussed. Essential tremor is characterized primarily by postural and action tremors, may be a neurodegenerative disorder with pathologic changes in the cerebellum, and can be treated with a wide range of pharmacologic and nonpharmacologic methods. Tremor at rest is typical for Parkinson's disease, but may arise independently of a dopaminergic deficit. Enhanced physiologic tremor, intention tremor, and dystonic tremor are discussed. Further differential diagnoses described in this review include drug-or toxin-induced tremor, neuropathic tremor, psychogenic tremor, orthostatic tremor, palatal tremor, tremor in Wilson's disease, and tremor secondary to cerebral lesions, such as Holmes' tremor (midbrain tremor). An individualized approach to treatment of tremor patients is important, taking into account the degree of disability, including social embarrassment, which the tremor causes in the patient's life.
The differential diagnosis and treatment of tremor
Deutsches Ärzteblatt international, 2014
Essential tremor is the most common type of tremor, with a prevalence of 0.4% in the overall population and 4-7% in persons over age 65. In general, tremor is so common that patients with tremor are frequently treated not only by neurologists, but also by physicians from other specialties. This review is based on publications retrieved by a selective PubMed search and on guidelines from Germany and abroad. Particular tremor syndromes are usually diagnosed on the basis of their typical clinical presentation and whatever accompanying manifestations may be present. Ancillary tests are usually unnecessary. Unilateral rest tremor accompanied by rigidity and bradykinesia is typical of Parkinson's disease. Essential tremor is a bilateral postural tremor. The most common cause of intention tremor is multiple sclerosis. Mild tremor syndromes can often be treated satisfactorily with drugs. In case of severe tremor, which is rarer, a stereotactic operation can be considered. The usual outc...
A patient with tremor, part 2: from diagnosis to treatment
Canadian Medical Association Journal, 2011
• An etiologically focused diagnostic method is helpful in determining the diagnosis in a patient presenting with tremor. • Asymmetric resting tremor is the hallmark of Parkinson disease, but those affected may also have associated postural tremor. • Essential tremor is usually monosymptomatic and is characterized by symmetric postural tremor.
Electrophysiologic characteristics of tremor in Parkinson's disease and essential tremor
Arquivos de neuro-psiquiatria, 2014
Tremor in essential tremor (ET) and Parkinson's disease (PD) usually present specific electrophysiologic profiles, however amplitude and frequency may have wide variations. To present the electrophysiologic findings in PD and ET. Patients were assessed at rest, with posture and action. Seventeen patients with ET and 62 with PD were included. PD cases were clustered into three groups: predominant rest tremor; tremor with similar intensity at rest, posture and during kinetic task; and predominant kinetic tremor. Patients with PD presented tremors with average frequency of 5.29±1.18 Hz at rest, 5.79±1.39 Hz with posture and 6.48±1.34 Hz with the kinetic task. Tremor in ET presented with an average frequency of 5.97±1.1 Hz at rest, 6.18±1 Hz with posture and 6.53±1.2 Hz with kinetic task. Seven (41.2%) also showed rest tremor. The tremor analysis alone using the methodology described here, is not sufficient to differentiate tremor in ET and PD.
Journal of Clinical Neuroscience, 2002
This study statistically evaluated a set of commonly measured tremor parameters to determine their individual and combined ability to discriminate between essential tremor (ET) and Parkinsonian tremor (PT). Accelerometer and surface electromyographic (EMG) records of moderate to severe upper limb tremor in 20 patients with ET and 22 patients with PT were used to quantitatively compare tremor amplitude, frequency and pattern of muscle bursting in two resting and three non resting postures. The group statistics showed significant differences between ET and PT with respect to tremor frequency in all five postures, tremor amplitude at rest and muscle bursting patterns. Discriminant function analysis showed that no single parameter or combination of parameters was able to correctly classify all patients. Frequency was much more discriminating than amplitude or muscle bursting patterns in all limb postures. The best amplitude discrimination was obtained when the hand and forearm were both fully supported. Muscle bursting patterns were poorly discriminating and did not assist in correct classification of single patients. Group statistics confirmed a highly significant biological difference between the two tremor types. Optimal classification of single PT (86% correct) and ET (95% correct) patients was obtained using frequency and two selected amplitude parameters from the resting limb. Limb posture was an important variable in optimising the discriminative ability of tremor studies. The implications for routine tremor studies are summarised. &
Diagnostic and pathophysiological aspects of psychogenic tremors
Movement Disorders, 1998
Twenty-five patients from our movement disorder clinic with the clinical diagnosis of psychogenic tremor were included. According to a modified version of Fahn's criteria for psychogenic dystonia,I3 the diagnosis of psychogenic tremor was accepted if