ISSN:0885-3185    

DOI:10.1002/mds.870131302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThis is a proposal of the Movement Disorder Society for a clinical classification of tremors. The classification is based on the distinction between rest, postural, simple kinetic, and intention tremor (tremor during target‐directed movements). Additional data from a medical history and the results of a neurologic examination can be combined into one of the following clinical syndromes defined in this statement: enhanced physiologic tremor, classical essential tremor (ET), primary orthostatic tremor, task‐ and position‐specific tremors, dystonic tremor, tremor in Parkinson's disease (PD), cerebellar tremor, Holmes' tremor, palatal tremor, drug‐induced and toxic tremor, tremor in peripheral neuropathies, or psychogenic tremor. Conditions such as asterixis, epilepsia partialis continua, clonus, and rhythmic myoclonus can be misinterpreted as tremor. The features distinguishing these conditions from tremor are described. Controversial issues are outlined in a comment section for each item and thus reflect the open questions that at present cannot be answered on a scientific basis. We hope that this statement provides a basis for better communication among clinicians working in the field and stimulates tremor r

ISSN:0885-3185    

DOI:10.1002/mds.870131303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractPathologic tremors occur when the normal, continuous pattern of muscle activation is replaced by relatively synchronous bursting. This article discusses the possible roles of stretch reflex and central oscillators in producing tremor. The gain and conduction delay in some reflex arcs places the stretch reflex close to oscillation in some muscles during normal operation. Within the brain, cells in the thalamic relay nuclei and inferior olive contain a set of ionic conductancies in the cell membrane that can interact to produce oscillations in membrane potential. This tendency is exaggerated by hyperpolarizing or depolarizing the cell away from the normal resting potential. The activity of neighboring cells can be coupled (by electrotonic gap junctions in the olive and by recurrent axonal projections from the reticular nucleus in the thalamus), thus a large population of cells can oscillate together and exert a powerful rhythmic influence on motor output

ISSN:0885-3185    

DOI:10.1002/mds.870131304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractRhesus and vervet monkeys respond differently to treatment with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine hydrochloride neurotoxin (MPTP). Both species develop akinesia. rigidity, and severe postural instability. However, rhesus monkeys only develop infrequent, short episodes of high‐frequency tremor, whereas vervet monkeys have many prolonged episodes of low‐frequency tremor. After MPTP treatment, the spiking activity of many pallidal neurons became oscillatory and highly correlated. Oscillatory autocorrelation functions were dominated by lower frequencies, cross‐correlograms by higher frequencies. The phase shift distribution of the oscillatory cross‐correlograms of pallidal cells in MPTP‐treated vervet monkey were clustered around 0 phase shift, unlike the oscillatory correlograms in the MPTP‐treated rhesus monkey, which were widely distributed between 0° and 180°. Analysis of the instantaneous phase differences between tremors of two limbs in the MPTP monkeys and human parkinsonian patients showed short periods of tremor synchronization. We thus concluded that the rhesus and the vervet models of MPTP‐induced parkinsonism may represent the tremulous and nontremulous variants of human parkinsonism. We suggest that the tremor phenomena of Parkinson's disease (PD) are related to the emergence of synchronous neuronal oscillations in the basal ganglia. Finally, the oscillating neuronal assemblies in the pallidum of tremulous parkinsonian primates are more stable (in time and in space) than those of parkinsonian prim

ISSN:0885-3185    

DOI:10.1002/mds.870131305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThis article is devoted to animal models of tremors that emerge from lesions in the Guillain‐Mollaret triangle. Cerebellar intention tremor is caused by lesions in the brachium conjunctivum or in the interpositus nucleus, possibly in combination with damage to the dentate nucleus. Impaired feedforward motor control delays the braking of rapid movements, resulting in target overshoot and subsequent oscillation. Transcortical and transcerebellar sensorimotor loops undergo oscillation at a frequency that depends on the mechanical properties of the limb and the length of the sensorimotor loop (mechanical reflex oscillation). The crescendo quality of intention tremor may be a result of amplification of tremor in reverberating brain stem‐cerebellar or thalamocortical loops. So‐called rubral or midbrain tremor is caused by a combination of damage to the brachium conjunctivum and nigrostriatal pathways in the vicinity of the red nucleus. Secondary compensatory changes in the motor system are probably involved because midbrain tremor in people usually begins weeks or months after a midbrain stroke or trauma. Harmaline causes enhanced neuronal synchrony and rhythmicity in the inferior olive; this animal model, although as yet unproven, is the most popular one for essential tremor (ET). Additional studies in laboratory animals are needed to define the seemingly universal involvement of the cerebellum and ventrolateral thalamus (ventralis intermedius [Vim]) in virtually all human tremor diso

ISSN:0885-3185    

DOI:10.1002/mds.870131306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe mechanism of parkinsonian tremor may involve a central oscillator, peripheral feedback to the central nervous system (CNS), or both. The thalamus or the globus pallidus is the most likely site for a central oscillator and would be predicted to generate thalamic tremor‐related activity characterized, respectively, by calcium spike‐associated bursts and by maximal tremor‐related activity in the pallidal relay nucleus of thalamus. Thalamic spike trains demonstrate neither of these characteristics. However, cross‐correlation, latency, and transfer function analysis indicate that sensory feedback is a critical element in the relationship between thalamic activity and parkinsonian tremor. Therefore, thalamic spike train activity is most consistent with parkinsonian tremor being mediated by peripheral inputs involved in either an unstable reflex loop or sensory modulation of a central osc

ISSN:0885-3185    

DOI:10.1002/mds.870131307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe physiology differs in the many forms of human tremor. Tremors may derive from mechanical oscillations, mechanical reflex oscillations, normal central oscillators, and pathologic central oscillators. Methods of studying tremor include accelerometry and electromyography (EMG). An excellent method consists of accelerometry and EMG combined with spectral analysis and weighting of the body part, which allows separation of tremors coming from mechanical reflex and central oscillators. Physiologic tremor is a mechanical tremor with a possible contribution of the normal 8–12 Hz central oscillator; exaggerated physiologic tremor is a mechanical reflex tremor. Essential tremor (ET) comes from a central oscillator that can be easily influenced with sensory input. The classic rest tremor of Parkinson's disease (PD) comes from a central oscillator that seems less easily influenced with sensory input but can be affected by transcranial magnetic stimulation. Other tremors with central oscillators are palatal tremor and orthostatic tremor. Other tremors whose physiology involves central loops includes cerebellar tremor and cortical tremor. Neuropathic tremors may be a result of delays in peripheral loops, but central oscillators play a role in som

ISSN:0885-3185    

DOI:10.1002/mds.870131308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractSymptomatic tremors are labeled in the literature under different names including rubral tremor, midbrain tremor, thalamic tremor, myorhythmia, Holmes' tremor, cerebellar tremor, and goal‐directed tremor. The most common tremor is a delayed‐onset postural and action tremor with a low frequency of 3 Hz and a proximal distribution. Resting irregular tremor is sometimes present. Mild cerebellar dysmetria is often detected. The lesions are mainly located in the thalamus, the brain stem, and the cerebellum, with secondary interruption and degeneration of various pathways and olivary hypertrophy. The more consistent lesions are found in the cerebello‐thalamocortical and dentato‐rubro‐olivary pathways. The role of superimposed dysfunction of the nigrostriatal system may account for the rest component. The role of the basal ganglia in the emergence and control of tremor is poorly u

ISSN:0885-3185    

DOI:10.1002/mds.870131309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractEssential tremor (ET) is one of the most common movement disorders. However, the etiology and pathogenesis are as yet unknown. Continued research will give us clues to understanding the impact on society, identifying genetic and environmental contributors to the disease, understanding the significance of a sporadic case, the phenotypic spectrum and timing of presentation, and the relationship with other neurologic disorders. Because the condition is both clinically and genetically heterogeneous and there is overlap with these other disorders, such as dystonia, parkinsonism, peripheral neuropathy. and migraine, the definition of phenotype plagues research in this area. Advances in understanding the genetic and molecular underpinnings of tremor should provide additional tools to unravel the clinical phenotype (including physiology), genotype‐phenotype relationships, and the epidemiology of tremo

ISSN:0885-3185    

DOI:10.1002/mds.870131310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractWe review the insight that has been obtained from positron emission tomography (PET) and magnetic resonance imaging (MRI) activation studies on the functional anatomy underlying different forms of tremor. The effects of treatment, both pharmacologic and interventional approaches, on the dysfunctional cerebral systems involved in tremor, also are considered. Finally, we speculate on the neuropharmacology basis of different types of tremor based on available in vivo PET evidence.

ISSN:0885-3185    

DOI:10.1002/mds.870131311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY