Effect of high, low, and asymmetric frequency stimulation of the subthalamic nucleus in Parkinson's disease

This study investigated the clinical efficacy of asymmetric frequency stimulation (AFS), which involved the unilateral low-frequency and contralateral high-frequency stimulation, in the treatment of PD.

In a randomized controlled design, we compared the efficacy of Bi-LFS and Bi-HFS (n = 33) and explored the efficacy of AFS (n = 20) in the acute setting in one cohort of postural instability gait difficulty (PIGD) motor subtype of patients with PD. Motor evaluations included MDS UPDRS-III, Berg balance scale (BBS), and gait kinematic analysis, and 6 to 12 months of telephone follow-up.

Bi-LFS was superior to Bi-HFS in improving axial (p = 0.044) and bradykinesia (p = 0.049) sub-score of the MDS UPDRS-III and BBS (p = 0.030). AFS significantly reduced the total score of the MDS-UPDRS-III compared to Bi-HFS (p = 0.015) and Bi-LFS (p = 0.010). AFS was comparable to Bi-LFS in axial, bradykinesia and balance symptoms but outperformed Bi-HFS (p = 0.022, 0.013, 0.040), while AFS was comparable to Bi-HFS but superior to Bi-LFS (p = 0.027) regarding the non-axial symptoms. Seventeen out of 20 participants (85.0%) who received AFS in the randomized phase favored AFS stimulation for the subsequently open-label phase, while half of those not tested with AFS switched back to Bi-HFS (46.2%).

AFS may offer benefits for both axial and appendicular symptoms of PD and could be an alternative programming strategy in the management of parkinsonian axial symptoms refractory to conventional high-frequency STN DBS.