Objective: To assess the effects of electrical stimulation of the Intrinsic Auricular Muscle Zone (IAMZ) on motor symptoms in patients with moderate-to-severe Parkinson’s disease (PD).

Background: Levodopa is the gold standard treatment for PD. However, chronic levodopa use can lead to motor complications, including OFF periods and dyskinesia. IAMZ stimulation has been shown to alleviate PD motor symptoms, with improvements extending beyond the stimulation period (1,2). Active IAMZ stimulation for 10-60 minutes has resulted in clinically significant reduction (minimum clinically important difference [MCID] of 3.25) in motor symptoms (3,4) including gait (1), during OFF Periods.

Method: In this single-center, randomized clinical study, patients with moderate-to-severe PD (MDS-UPDRS III score of ≥33) received IAMZ stimulation, either with a tonic signal (130 Hz/ 100 µsec; Group A) or a tonic signal with intermittent burst signals (520 Hz bursts of 100 µsec; Group B). Treatment order was randomized, and all treatment sessions were 40 minutes. Motor outcomes were assessed using MDS-UPDRS III at 40 and 90 minutes.

Results: A total of 15 patients (8 male, mean age 62.3, and mean PD duration of 10.1 years) completed all assessments. The mean baseline MDS-UPDRS III score was 40 ±9.5 for Group A and 42 ±9.4 for Group B. In Group A, there were significant reductions in motor scores to 29 ±8.3 (27%) at 40 minutes and 30 ±9.4 (25%) at 90 minutes. In Group B, motor scores improved to 34 ±11.0 (19%) at 40 minutes and 33 ±6.7 (21%) at 90 minutes. Improvements in motor scores exceeded the MCID and 55% of subjects improved from a moderate to mild motor score (MDS-UPDRS III score of ≤33). Improvements were observed in all sub-categories including tremor (23%), axial (34%), bradykinesia (35%), and rigidity (8%). There were no adverse events.

Conclusion: IAMZ stimulation improved motor scores beyond 90 minutes. In Group A, motor scores improved by >25% following 40 minutes of IAMZ stimulation. Improvements were observed in all the cardinal motor features of Parkinson’s disease. Transcutaneous stimulation of the IAMZ is safe and clinically effective.

References: 1. Cakmak YO, Ozsoy B, Ertan S, Cakmak OO, Kiziltan G, Yapici-Eser H, et al. Intrinsic Auricular Muscle Zone Stimulation Improves Walking Parameters of Parkinson’s Patients Faster Than Levodopa in the Motion Capture Analysis: A Pilot Study. Frontiers in Neurology. 2020;11.
2. Liugan M, Zhang M, Cakmak YO. Neuroprosthetics for Auricular Muscles: Neural Networks and Clinical Aspects. Frontiers in Neurology. 2018;8.
3. Fernandez HH, Macklin EA, Hauser RA, Chou KL, Cakmak YO, Ozsoy B, et al. Intrinsic auricular muscle zone stimulation for Parkinson disease EARSTIM-PD Phase II multi-center pilot study results. Parkinsonism & Related Disorders. 2023;Online ahead of print.
4. Cakmak YO, Apaydin H, Kiziltan G, Gündüz A, Ozsoy B, Olcer S, et al. Rapid Alleviation of Parkinson’s Disease Symptoms via Electrostimulation of Intrinsic Auricular Muscle Zones. Frontiers in Human Neuroscience. 2017;11.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/intrinsic-auricular-muscle-zone-stimulation-for-moderate-to-severe-parkinsons-disease/