Central Mechanisms of Tremor

Abstract

Physiologic and pathologic tremors are mechanistically classified into two broad groups: (1) those produced by oscillation in sensorimotor loops, so-called mechanical-reflex tremors, and (2) those produced by the oscillatory properties of central neuronal networks. This review provides a contemporary perspective of tremor pathophysiology while acknowledging that no form of tremor is understood completely. Indeed, the origin of oscillation in most forms of tremor is undefined, and in many instances the underlying pathology is unknown.

Usefulness of intermuscular coherence and cumulant analysis in the diagnosis of postural tremor

“…As high coherence between different muscles at the tremor frequency indicates a common drive and generator mechanism (Elble 1996)we expected high coherence in PD, which we indeed found. ET is also considered to be of central origin (Raethjen et al 2000) and our results also support this.…”

“…EPT is regarded as a composite of 1) a peripheral mechanical reflex oscillation, which is dependent of the hand s resonant frequency and therefore changes with increased inertial loading, and 2) a centrally driven component in the 7-14 Hz range (Elble 1996). Under normal circumstances, coherence does not occur as a result of mechanical reflex oscillation; this only happens under high load conditions (Matthews and Muir 1980).…”

“…Coherence analysis is a method to detect a common input for the generation of two signals, and is therefore relevant for the study of relationships between the activities of tremulous muscles (Elble 1996). Coherence is a normalized measure, which takes on a value of 1 in case of absolute dependence, and 0 in case of complete independence between two signals.…”

A possible role of olivary gap-junctions in the generation of physiological and pathological tremors

“…The inferior olive (IO) has been implicated in several types of tremor. 1,2 In particular, electrical synapses have been shown to be essential for the generation of oscillatory activity in the IO, 3 which may manifest as tremor. In a recent paper, 4 we described how the electrical coupling of non-oscillating cells can generate oscillatory network behavior.…”

“…While the neurological literature regarding the diagnostic criteria of essential tremor is equivocal, it is considered to be the most common adult movement disorder and affects 0.4-4% of the population. 1 Of particular importance is the alcohol withdrawal tremor, from which many alcoholics suffer. The 6-10.5 Hz tremor of the hands starts 1-3 days after abstinence, and can last up to a week.…”