This observational study aims to examine developmental status, sensory processing, and sleep quality in preschool children aged 3 to 6 years across different caregiving models. Children raised primarily by first-degree relatives, second-degree relatives, caregivers, or in daycare settings will be compared. Data will be collected using the Denver II Developmental Screening Test, the Dunn Sensory Profile, and the Tayside Children's Sleep Questionnaire. The study will also evaluate the relationships among developmental status, sensory processing, and sleep quality, and explore whether caregiving model is associated with differences in these outcomes.

This observational study is designed to investigate whether different caregiving models are associated with differences in developmental status, sensory processing, and sleep quality in preschool children. Early childhood development is influenced by both biological and environmental factors, and caregiving context is considered one of the important environmental influences shaping children's developmental outcomes. In this study, caregiving model refers to the primary care arrangement in which the child has been raised, including care by first-degree relatives, second-degree relatives, a paid caregiver, or a daycare setting.

Participants will include preschool children between 3 and 6 years of age living in Istanbul. Eligible participants must have been raised within the same caregiving model for at least the previous 6 months, and parents must provide informed consent. Children with previously diagnosed neurological, developmental, or psychiatric disorders, those currently receiving treatment for sensory, sleep, or developmental problems, or those unable to complete the assessment process will be excluded.

Data will be collected through parent-report forms and standardized assessment tools. Developmental status will be assessed using the Denver II Developmental Screening Test, sensory processing will be evaluated using the Dunn Sensory Profile, and sleep quality will be assessed using the Tayside Children's Sleep Questionnaire. Recruitment will be conducted through social media announcements, and eligible families will be invited for face-to-face assessment in the Ergotherapy Department laboratory at Fenerbahçe University.

The study plans to compare four caregiving groups and to analyze whether there are significant differences between groups in developmental status, sensory processing, and sleep quality. In addition, correlations among these three outcome domains will be examined. Statistical analyses will be conducted using SPSS, with appropriate parametric or nonparametric tests depending on data distribution. The findings are expected to contribute to a better understanding of how caregiving environments may be related to child development and functional outcomes in early childhood.

Inclusion Criteria:

• Preschool children aged 3 to 6 years
• Child has been raised within the same primary caregiving model for at least the past 6 months
• Parent or legal guardian is willing to participate voluntarily and provide informed consent
• Child and caregiver are able to understand Turkish and follow the study instructions

Exclusion Criteria:

• Previously diagnosed neurological, developmental, or psychiatric disorder (e.g., autism spectrum disorder, attention-deficit/hyperactivity disorder, developmental delay)
• Currently receiving treatment or therapy for sensory processing problems, sleep problems, or developmental difficulties
• Parent or legal guardian provides incomplete or incorrect study forms
• Child is unable to cooperate with or complete the assessment procedures

Preschool children aged 3 to 6 years living in Istanbul and raised under different caregiving models, including first-degree relatives, second-degree relatives, paid caregivers, or daycare-based care. Participants will be recruited on a voluntary basis through social media announcements, and eligible families will attend face-to-face assessment sessions at Fenerbahçe University.

Individual participant data will not be shared with other researchers because the study involves minors and includes potentially sensitive developmental and health-related information. Data will be used only for the purposes described in the approved study protocol and will be handled in accordance with applicable ethical and confidentiality requirements.