The purpose of this study is to better understand how physical characteristics, walking patterns, and a blood-based brain health marker differ between older adults with dementia and healthy older adults.

Dementia is often associated with changes in physical health and movement, but these changes are not fully understood. This study asks whether people with dementia show differences in body composition, walking ability, and levels of brain-derived neurotrophic factor (BDNF), a protein involved in brain function, compared with individuals without dementia.

To answer this question, participants will complete a single assessment session that includes basic physical measurements, an assessment of walking while moving at a comfortable pace, and a small blood sample collection. The information collected will be used to compare the two groups and explore possible relationships between physical function, walking patterns, and BDNF levels.

This observational, cross-sectional comparative study is designed to characterize differences in physical measurements, gait parameters, and circulating brain-derived neurotrophic factor (BDNF) levels between individuals with dementia and cognitively healthy older adults.

All data will be collected during a single study visit using standardized procedures. Physical and physiological measurements will be obtained following established protocols to ensure consistency across participants. Gait data will be captured using two-dimensional video-based motion capture and analyzed using validated software to extract spatiotemporal gait parameters. Calibration procedures will be performed prior to data collection to ensure measurement accuracy.

Venous blood samples will be collected by trained personnel and processed according to laboratory standard operating procedures to obtain plasma and serum. Samples will be stored and analyzed under controlled conditions using standardized assays for the quantification of BDNF.

Data quality will be ensured through predefined data entry procedures, range and consistency checks, and verification of source data against original measurement records. All collected data will be anonymized and stored in a secure database accessible only to authorized study personnel. Any missing or incomplete data will be documented, and analyses will be conducted using appropriate statistical methods to account for missing values.

The sample size is determined based on feasibility and prior literature involving similar observational comparisons. Statistical analyses will focus on descriptive and inferential comparisons between study groups, using appropriate parametric or non-parametric methods depending on data distribution. Multivariable analyses may be performed to account for relevant covariates. Statistical significance will be assessed using a predefined alpha level.

No study interventions will be administered, and participants will not undergo longitudinal follow-up.

Inclusion Criteria:

• Older adults aged 50 years and above
• Able to ambulate independently without the use of walking aids
• Must be able to understand instructions, communicate effectively
• Free from any acute or unstable medical conditions at the time of assessment.

Healthy older adults group:

-No history or symptoms of cognitive impairments and have normal cognitive screening results.

Mild Cognitive Impairment (MCI) group:

-Must fulfill established diagnostic criteria for MCI, showing measurable cognitive decline without significant functional impairment and without a diagnosis of dementia.

Exclusion Criteria:

• Present with any diagnosed neurological disorder such as stroke or Parkinson's disease
• History of psychiatric illness, including major depressive disorder.
• Individuals with uncontrolled cardiovascular, metabolic, or endocrine conditions
• Have significant visual, auditory, or musculoskeletal impairments that may influence gait performance
• Currently taking medications known to affect cognitive or motor function
• Unable to provide written informed consent

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