Improvement of action tremor by chronic cortical stimulation.

The authors present a patient who had long-term improvement of a severe upper limb action tremor after chronic cortical stimulation. A 40-year-old woman complained of facial pain and tremor of the left arm after removal of an acoustic neurinoma. A motor cortex stimulation was performed to treat the deafferentation facial pain in 1993. Chronic cortical stimulation induced complete relief of both pain and tremor and allowed the patient to recover functional capacity of the limb. These effects persisted throughout a 32-month follow up. Differential effects on pain and tremor were observed when parameters of stimulation were varied, suggesting different mechanisms for the relief of pain and tremor. Attention was focused on control of the tremor. This effect could be the result of the inhibition of subcortical structures which are involved in tremor. Chronic cortical stimulation appears to be an effective treatment for controlling severe action tremors.