Effects of 3-Month Melatonin Treatment on Regional Cerebellar Structure and Blood Biomarkers in Alzheimer's Disease Spectrum

The goal of this clinical trial is to explore and verify the preventive effects of melatonin on the progression of Alzheimer's disease. The study aims to analyze the changes in blood biomarkers (phosphorylated tau, glial fibrillary acidic protein, neurofilament chain), various sleep-related subjective report questionnaire scores, physical performance, cognitive function scores and cerebellar volume change after three months of melatonin administration in patients with Alzheimer's-type mild cognitive impairment (MCI) accompanied by insomnia. The main questions it aims to answer are:

1. Does melatonin administration alter the levels of blood biomarkers associated with Alzheimer's disease?
2. What changes occur in sleep-related subjective report questionnaire scores and cognitive function scores following melatonin administration?
3. Does melatonin administration effect on physical performance?
4. Is there any relations between cognitive decline, phsycal performance and cerebellar volume change? We will compare the data collected before and after melatonin administration to determine its preventive effects on Alzheimer's disease progression.

Participants Will:

1. Take melatonin every day for 3 months and Complete sleep-related subjective report questionnaires, neuropsychological assessments and physical performance test
2. Visit the clinic at the initial visit and after 3 months for checkups and tests.
3. Complete sleep-related subjective report questionnaires and neuropsychological assessments and physical performance test
4. Provide blood samples for biomarker analysis.


Eligibility Criteria:
Inclusion Criteria:

* Male and female participants aged 60 to 90 years
* Individuals presenting with cognitive impairment as their chief complaint at the Department of Psychiatry, St. Vincent's Hospital
* Those capable of undergoing imaging studies, including Brain MRI and Amyloid PET CT
* Individuals able to complete cognitive function tests, such as the Alzheimer's Disease Consortium test battery, K-MMSE, CDR, and GDS
* Participants who can perform tests at the hospital's Smart Center, including the Short Physical Performance Battery and body composition analysis using direct segmental multi-frequency bioelectrical impedance analysis for sarcopenia
* Individuals on acetylcholinesterase inhibitors (ACEi) or NMDA receptor antagonists who have maintained the same dosage and regimen for more than 3 months from the screening date.
* Patients who are taking medications for cognitive function treatment other than acetylcholinesterase inhibitors and NMDA receptor antagonists (e.g., pregabalin, gabapentin, choline alfoscerate), as well as medications for chronic diseases such as antidepressants, antihypertensives, diabetes, hyperlipidemia, thyroid disorders, etc., must have maintained the same dosage and regimen for more than 1 month from the screening date.
* Individuals with sufficient language proficiency to read and understand the informed consent document and respond to survey questionnaires

Exclusion Criteria:

* Individuals with progressive mental or neurological disorders (including those with a history of psychotic disorders such as major depressive disorder, bipolar disorder, schizophrenia, schizoaffective disorder, schizophreniform disorder, or unspecified psychosis; patients currently experiencing major depressive disorder with psychotic symptoms; organic mental disorders; epilepsy or seizure disorders; patients currently suffering from eating disorders or obsessive-compulsive disorder).
* Individuals with unstable or severe medical conditions.
* Patients with severe snoring, REM sleep behavior disorder, or narcolepsy.
* Illiterate individuals.
* Individuals who, in the opinion of the investigator, are deemed unable to comply with the requirements of the study.
* Patients currently taking sleeping pills within 2 weeks of the screening point.