BACKGROUND In genetic research on essential tremor (ET), certain individuals may be particularly challenging to categorize diagnostically. METHODS In the Family Study of Essential Tremor (>200 enrollees), 28 participants with borderline clinical findings who did not meet strict criteria for ET were assigned final diagnoses of ET. We scrutinized the clinical features of these cases and the sen...

Conflicting results on the existence of tremor-related cortical activity in essential tremor (ET) have raised questions on the role of the cortex in tremor generation. Here we attempt to address these issues. We recorded 64 channel surface EEGs and EMGs from forearm muscles in 15 patients with definite ET. EEG and EMG power spectra, relative power of the rhythmic EMG activity, relative EEG powe...

Essential tremor (ET) is a common movement disorder with a poorly understood etiology. The TRM/Kyo mutant rat, showing spontaneous tremor, is an animal model of ET. Recently, we demonstrated that tremors in these rats emerge when two mutant loci, a missense mutation in the hyperpolarization-activated cyclic nucleotide-gated potassium channel 1 (Hcn1) and the tremor (tm) deletion, are present si...

Although involvement of the cerebello-thalamo-cortical network has often been suggested in essential tremor, the source of oscillatory activity remains largely unknown. To elucidate mechanisms of tremor generation, it is of crucial importance to study the dynamics within the cerebello-thalamo-cortical network. Using a combination of electromyography and functional magnetic resonance imaging, it...

INTRODUCTION Physiological tremor is an involuntary, approximately rhythmic and roughly sinusoidal movement [1]. It is inherent in all humans. The characteristics of physiological tremor are highly dependent on the body parts [2]. For instance, the frequency of tremor in the elbow ranges from 3 to 5 Hz while it ranges from 8 to 12 Hz in the wrist. Physiological tremor is benign for everyday tas...

[1] Slow earthquakes, characterized by slow slip and associated seismic radiation called non-volcanic tremor, have been observed in major subduction zones worldwide. They constitute an important mode of stress release for the fault’s transition zone, which lies directly downdip of the locked segment, the nucleation zone of large damaging earthquakes. However, the depth of tremor in Cascadia, an...

OBJECTIVE Current pharmacological agents used to treat Parkinson disease (PD) tremor and essential tremor (ET) provide suboptimal benefit and are commonly associated with significant adverse effects. Botulinum toxin type A (BoNT-A) has been shown to be effective for wrist tremor though functionally bothersome muscle weakness frequently occurs. This is the longest study to date demonstrating tha...

The inferior olivary nuclei clearly play a role in creating oculopalatal tremor, but the exact mechanism is unknown. Oculopalatal tremor develops some time after a lesion in the brain that interrupts inhibition of the inferior olive by the deep cerebellar nuclei. Over time the inferior olive gradually becomes hypertrophic and its neurons enlarge developing abnormal soma-somatic gap junctions. H...

BACKGROUND Mild tremor may occur in relatives of patients with essential tremor (ET). However, this phenomenon has not been studied quantitatively or with a comparison group. Such a study may provide information on the penetrance of ET. OBJECTIVE To obtain data on the magnitude of tremor in case and control relatives who did not meet diagnostic criteria for ET. METHODS Cases with ET and con...

Tremor rating scales (TRSs) are used commonly in the clinical assessment of tremor, but the relationship of a TRS to actual tremor amplitude has never been quantified. Consequently, the resolution of these scales is unknown, and the clinical significance of a 1-point change in TRS is uncertain. We therefore sought to determine the change in tremor amplitude that corresponds to a 1-point change ...