Uniform qualitative electrophysiological changes in postoperative rest tremor

Area of Science:

• Neurosurgery
• Movement Disorders
• Electrophysiology

Background:

• Pharmacologically uncontrollable tremor, often seen in Parkinson's disease (PD) and essential tremor (ET), significantly impacts quality of life.
• Neurosurgical interventions like ablation and deep brain stimulation (DBS) are established treatments for severe, medication-resistant tremor.

Purpose of the Study:

• To compare the postoperative electrophysiological changes in resting hand tremor following ablative procedures and DBS in patients with PD and ET.
• To identify potential electrophysiological indicators of successful tremor suppression after neurosurgery.

Main Methods:

• A cohort of 32 patients undergoing ablation and 12 patients receiving DBS for tremor-dominant PD or ET were studied.
• Preoperative and postoperative accelerometric data were collected to analyze tremor characteristics, including frequency and approximate entropy (ApEn).

Main Results:

• Effective ablative and DBS treatments resulted in significant resting tremor reduction, increased tremor frequency, and increased ApEn in PD patients.
• DBS demonstrated superior long-term tremor reduction compared to ablation.
• Post-thalamotomy, essential tremor patients showed a greater increase in frequency and ApEn than PD patients, suggesting etiological influence.
• Lack of change in frequency and ApEn on the second postoperative day predicted later tremor recurrence.

Conclusions:

• Postoperative increases in tremor frequency and ApEn, alongside tremor reduction, may serve as immediate indicators of successful neurosurgical intervention for tremor.
• The findings suggest that these electrophysiological changes are linked to the attenuation of pathological oscillators driving the tremor.
• DBS offers a more durable tremor suppression compared to ablative techniques in the long term.