Combined Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) of the Cerebellum and the Dorsolateral Prefrontal Cortex (DLPFC) on Cognitive Functions in Older Adults with Mild Cognitive Impairment (MCI)

To evaluate the effects of repetitive transcranial magnetic stimulation of the cerebellum, the dorsolateral prefrontal cortex, and their combined stimulation on cognitive functions in older adults with mild cognitive impairment.

Single blind, randomized, sham controlled, parallel group clinical trial with four groups and 24 participants. Block randomization with concealed allocation will be used. This is a non drug clinical trial.

The study will be conducted in the research laboratories of the Cognitive Neuroscience Center at the University of Tabriz and neurotherapy clinics equipped with transcranial magnetic stimulation devices in Tabriz, Iran. Eligible participants will receive 10 intervention sessions according to their assigned group. Participants will be blinded to treatment allocation. Cognitive assessments will be performed before and after completion of the intervention.

Older adults aged 60 to 80 years with mild cognitive impairment and a Montreal Cognitive Assessment score of 19 to 25. Exclusion criteria include dementia, epilepsy or seizure history, contraindications to transcranial magnetic stimulation, major psychiatric disorders, severe neurological diseases, or medications that increase seizure risk.

Four groups: sham stimulation; cerebellar repetitive transcranial magnetic stimulation; dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation; combined cerebellar and dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation.

Episodic memory; visuospatial working memory; executive function.

Participants who meet the eligibility criteria and provide written informed consent will be randomly allocated to one of four parallel groups, including Sham stimulation, Cerebellar rTMS, DLPFC rTMS, and Combined Cerebellar plus DLPFC rTMS, with an allocation ratio of 1:1:1:1. Block randomization will be performed using a computer-generated random sequence prepared by an independent researcher. Allocation concealment will be maintained using sequentially numbered, opaque, sealed envelopes. After completion of the baseline assessment, the intervention operator will open the corresponding envelope and administer the assigned intervention. The participants will remain blinded to group allocation, while the intervention operator will be aware of the assigned group.

Participants who meet the eligibility criteria and provide written informed consent will be randomly allocated to one of four parallel groups, including Sham stimulation, Cerebellar rTMS, DLPFC rTMS, and Combined Cerebellar plus DLPFC rTMS, with an allocation ratio of 1:1:1:1. Block randomization will be performed using a computer-generated random sequence prepared by an independent researcher. Allocation concealment will be maintained using sequentially numbered, opaque, sealed envelopes. After completion of the baseline assessment, the intervention operator will open the corresponding envelope and administer the assigned intervention. The participants will remain blinded to group allocation, while the intervention operator will be aware of the assigned group.

Deidentified individual participant data, the data dictionary, study protocol, statistical analysis plan, and a blank copy of the informed consent form will be available for sharing. The shared dataset may include demographic variables, group allocation, intervention parameters, and cognitive outcome scores measured before and after the intervention. All information that could identify participants will be removed before data sharing.

Data and supporting documents will be available from 12 months after publication of the main study results and will remain available for 5 years.

Researchers affiliated with recognized universities, research institutions, or scientific centers may request access after submitting a specific research proposal that is scientifically and ethically acceptable.

The data may be used for scientific analyses related to mild cognitive impairment, transcranial magnetic stimulation, reanalysis of study findings, systematic reviews, and meta-analyses. Access will require approval of the research proposal, a commitment to confidentiality, agreement not to attempt participant identification, and completion of a data use agreement. Commercial use or transfer of the data to third parties without written permission will not be allowed.

Requests should be submitted by email to the responsible researcher, Masoud Ghaffarvand Mokari, University of Tabriz, Tabriz, Iran. Applicants should provide their personal and institutional details, the purpose of the request, the proposed analysis plan, and relevant ethics approval documents.

Requests must be submitted in writing and include the research objective, analysis plan, institutional affiliation of the researchers, and relevant ethics approval. The request will be reviewed by the responsible researcher and the study supervisor. A decision will be communicated within 30 days. Following approval and completion of a data use agreement, the files will be transferred through a secure electronic method.