What's on this Page
Pathophysiology of Essential Tremor
What pathophysiologic mechanisms underlie Essential Tremor?
The pathological findings in several series have suggested a heterogeneous pathology in Essential Tremor with the majority showing cerebellar Purkinje cell loss and gliosis.
The abnormal pathology appears to be supported by functional imaging studies. Only 14 patients with Essential Tremor have had a thorough pathologic examination, and no specific abnormality was found.
It has been suggested that the postural tremor of Essential Tremor arises from spontaneous firing of the inferior olivary nucleus, which drives the cerebellum and its outflow pathways via the thalamus to the cerebral cortex and then to the spinal cord.
Functional magnetic resonance imaging (fMRI) studies have demonstrated increased activation of the cerebellum and red nucleus in Essential Tremor.
Most positron emission tomography (PET) and fMRI evidence indicates that the inferior olive is not likely to be the tremor generator in Essential Tremor; instead, the generator is probably in the cerebellum.
This theory is supported by bilateral overactivity of cerebellar connections by PET in patients with primary writing and primary orthostatic tremor.
Clinical data also support a cerebellar role in the pathogenesis of Essential Tremor: over 50% of patients with Essential Tremor have difficulty in performing tandem gait, which is considered an indicator of cerebellar function, and hemispheric cerebellar stroke may abolish ipsilateral Essential Tremor.
Sources
- Deng H, Le W, Jankovic J: Genetics of essential tremor. Brain 130(Pt 6):1456-1464, 2007.
- Mostile G, Jankovic J: Alcohol in essential tremor and other movement disorders. Mov Disord 25:2274-2284, 2010.
- Thenganatt MA, Louis ED: Distinguishing essential tremor from Parkinson’s disease: bedside tests and laboratory evaluations. Expert Rev Neurother 12:687-696, 2012.
- Jankovic J: Essential tremor: clinical characteristics. Neurology 54(11 Suppl 4):S21-S23, 2000.
