Objective: This systematic review evaluated the efficacy of transcranial magnetic stimulation (TMS) for mild cognitive impairment in idiopathic Parkinson’s disease (iPD) through review of parallel randomized controlled clinic trials.

Background: Cognitive impairments are common in iPD. However, available medications have not consistently demonstrated efficacy for patients with iPD with mild cognitive impairments [1]. TMS is a relatively new non-invasive treatment modality that is being explored for both motor and non-motor symptoms of iPD. TMS uses a magnetic coil placed over the head to induce currents that stimulate the cortex of the brain. Prior studies have assessed the use of TMS in evaluating and treating various iPD symptoms including bradykinesia and dyskinesia [2]. Although significant literature exists demonstrating the safety of TMS and possible benefit for motor symptoms, its role in treating cognitive impairment remains unclear.

Method: This systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Following identification of 62 studies, three randomized controlled studies measuring mean Montreal Cognitive Assessment (MoCA) scores pre- and post-stimulation were selected for review [3-5] (Figure 1). Data collection and synthesis was completed independently by two reviewers (SB and RR).

Results: Two [3-4] of the three studies had “some concerns” for the overall risk of bias, per the Cochrane risk of bias assessment for randomized trials, due to bias in measurement of the outcome and deviations from the intended interventions, respectively (Table 1). All three studies observed that TMS was associated with improved mean MoCA scores in the immediate post-treatment period with a 2–3-point average improvement (Table 2). Lasting effects of TMS over three to six months were shown in two of the three studies (Figure 2). Improvements were observed across protocols, which used different cortical regions of stimulation.

Conclusion: TMS is a promising non-invasive therapy that needs further validation through clinical trials prior to establishing its use as a mainstay treatment for iPD cognitive symptoms. Limitations include the lack of standardization of the treatment regimens, targets of stimulation, follow up time points, and masking protocols to minimize bias.

Figure 1

Table 1

Table 2

Figure 2

References: 1. Sun C, Armstrong MJ. Treatment of Parkinson’s Disease with Cognitive Impairment: Current Approaches and Future Directions. Behav Sci (Basel). 2021;11(4):54. Published 2021 Apr 17. doi:10.3390/bs11040054

2. Rawji V, Latorre A, Sharma N, Rothwell JC, Rocchi L. On the Use of TMS to Investigate the Pathophysiology of Neurodegenerative Diseases. Front Neurol. 2020 Nov 3;11:584664. doi: 10.3389/fneur.2020.584664. PMID: 33224098; PMCID: PMC7669623.

3. Zhuang S, Wang FY, Gu X, Wu JJ, Mao CJ, Gui H, Chen J, Liu CF. Low-Frequency Repetitive Transcranial Magnetic Stimulation over Right Dorsolateral Prefrontal Cortex in Parkinson’s Disease. Parkinsons Dis. 2020 Sep 14;2020:7295414. doi: 10.1155/2020/7295414. PMID: 33005318; PMCID: PMC7509565.

4. Khedr EM, Mohamed KO, Ali AM, Hasan AM. The effect of repetitive transcranial magnetic stimulation on cognitive impairment in Parkinson’s disease with dementia: Pilot study. Restor Neurol Neurosci. 2020;38(1):55-66. doi: 10.3233/RNN-190956. PMID: 31815705.

5. He W, Wang JC, Tsai PY. Theta Burst Magnetic Stimulation Improves Parkinson’s-Related Cognitive Impairment: A Randomised Controlled Study. Neurorehabil Neural Repair. 2021 Nov;35(11):986-995. doi: 10.1177/1545968321104131. Epub 2021 Sep 1. PMID: 34467796.

« Back to 2024 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/a-systematic-review-of-transcranial-magnetic-stimulation-clinical-trials-in-parkinsons-disease-patients-with-mild-cognitive-impairment/