ABSTRACT
I. Introduction 28
II. Physiological Characteristics of Peripheral Tremor 28
A. Tremor Analysis 29
B. Correlation between Tremor in Different Limbs 31
III. Other Neurophysiologic Tests in Essential Tremor 32
A. Resetting the Tremor Rhythm by Peripheral and
Central Stimuli 32
B. Evoked Potentials and Reflex Studies 33
IV. Interaction of Essential Tremor with Voluntary Movements 34
A. The Muscle Activation Pattern 35
B. Goal-Directed Movements 36
C. Gait 36
D. Oculomotor Function 38
E. Cerebellar Involvement 38
V. Representation of Essential Tremor Rhythm in the Central
Nervous System 40
A. Tremor Related Activity in the Thalamus 40
B. Tremor Related Activity in the Cortex 42
VI. General Conclusions 43
References 44
I. INTRODUCTION
The understanding of the physiology of essential tremor is dependent on the
methodological tools which are available at a given time. Early attempts to under-
stand tremor go back to researchers such as Pelnar, Altenholz, and Jung (1-4).
These were mainly based on recordings of muscle volume and dealt with the
analysis of tremor rhythms in different muscles. New tools to study the positive
and negative symptoms of tremor have led to a better understanding of the
mechanisms of these rhythmic involuntary movements.
