Advanced Essential Tremor Research Articles

Tremor and Quality of Life in Patients With Advanced Essential Tremor Before and After Replacing Their Standard Deep Brain Stimulation With a Directional System

ObjectivesPatients with essential tremor treated with thalamic deep brain stimulation may experience increased tremor with the progression of their disease. Initially, this can be counteracted with increased stimulation. Eventually, this may cause unwanted side-effects as the circumferential stimulation from a standard ring contact spreads into adjacent regions. Directional leads may offer a solution to this clinical problem. We aimed to compare the ability of a standard and a directional system to reduce tremor without side-effects and to improve the quality of life for patients with advanced essential tremor. Materials and MethodsSix advanced essential tremor patients with bilateral thalamic deep brain stimulation had their standard system replaced with a directional system. Tremor rating scale scores were prospectively evaluated before and after the replacement surgery. Secondary analyses of quality of life related to tremor, voice, and general health were assessed. ResultsThere was a significantly greater reduction in tremor without side-effects (p = 0.017) when using the directional system. There were improvements in tremor (p = 0.031) and voice (p = 0.037) related quality of life but not in general health for patients using optimized stimulation settings with the directional system compared to the standard system. ConclusionsIn this cohort of advanced essential tremor patients who no longer had ideal tremor reduction with a standard system, replacing their deep brain stimulation with a directional system significantly improved their tremor and quality of life. Up-front implantation of directional deep brain stimulation leads may provide better tremor control in those patients who progress at a later time point.

A new diagnostic test to distinguish tremulous Parkinson's disease from advanced essential tremor

Clinical distinction between advanced essential tremor and tremulous Parkinson's disease can be difficult. In selected power spectra of accelerometric postural tremor recordings on the more affected side of 41 patients with essential tremor and 39 patients with tremulous Parkinson's disease being indistinguishable by tremor frequency, peak power or number of harmonic peaks, waveform asymmetry (autocorrelation decay), and mean peak power of all harmonic peaks were computed. Cutoff for essential tremor-Parkinson's disease distinction was determined by receiver operating characteristics. Diagnostic yield was tested in 12 clinically unclear patients with monosymptomatic tremor, subsequently definitively diagnosed with essential tremor (n = 2) or Parkinson's disease (n = 10) by 123-I FP-CIT-single-photon emission computed tomography, fluorodopa-positron emission tomography, or clinical course. By autocorrelation decay 64%, by mean harmonic peak power 94% (Parkinson's disease > essential tremor) of patients with a definite clinical diagnosis, and 11 of 12 clinically unclear patients were classified correctly. Mean harmonic power is a useful measure to separate clinically difficult cases of advanced essential tremor from tremulous Parkinson's disease.

Rest tremor in advanced essential tremor: a post-mortem study of nine cases

BackgroundRest tremor may occur in as many as 30% of essential tremor (ET) patients. It is not clear whether this tremor is a sentinel marker for brainstem Lewy body pathology....

Influence of thalamic DBS on gait in patients with advanced essential tremor

Influence of thalamic DBS on gait in patients with advanced essential tremor

Essential tremor and cerebellar dysfunction: abnormal ballistic movements

Background: Clinical characteristics reminiscent of cerebellar tremor occur in patients with advanced essential tremor. Ballistic movements are known to be abnormal in cerebellar disease. The hypothesis was proposed that ballistic...

Phase resetting and frequency entrainment of essential tremor

Step and sinusoidal forcings were delivered to the wrists of 10 patients with advanced essential tremor using a computer-controlled torque motor. Consistent (type 0) phase resetting was produced in only 5 patients, whereas all 10 patients exhibited harmonic and 2: 1 subharmonic entrainment of essential tremor. These results indicate that the oscillator of essential tremor is coupled to the stretch-reflex arc. Irregularity in the tremor rhythm and postperturbation mechanical-reflex oscillations obscured the phase of essential tremor, thereby impeding the computation of phase resetting curves. Sinusoidal forcings circumvented these problems, but frequency entrainment was produced only by forcings at frequencies within ±1 Hz of the tremor frequency and its second harmonic. Resonance accompanied frequency entrainment and probably plays a role in the clinical expression of tremor.