Brain injury is a broad concept that may develop as a result of head trauma or surgical interventions, vascular injuries (such as subarachnoid hemorrhage or stroke), metabolic or toxic causes, cerebral anoxia, inflammation, or infection. A meta-analysis conducted between 1990 and 2016 reported an annual incidence of 43.6 million cases of brain injury worldwide. According to data published by the Turkish Statistical Institute in the same year, 24.3% of deaths in Türkiye were attributed to cerebrovascular events. Although advances in emergency medical services and palliative care have increased survival rates, a substantial proportion of survivors experience significant physical, cognitive, emotional, behavioral, and social disabilities. Consequently, these individuals often require supervision, support, and care from caregivers for the remainder of their lives. Caregivers in this population are typically family members who receive no financial compensation and are primarily responsible for providing social, mental, and physical care.

Studies examining caregivers have identified numerous physical, psychological, emotional, social, and economic challenges associated with caregiving. Research indicates that prolonged caregiving is associated with increased levels of anxiety, depression, deterioration in physical health, social isolation, burnout, and related conditions.

Mental health nurses, who play a critical role as healthcare professionals, adopt a holistic approach by evaluating individuals together with their families and caregivers throughout the care process. In this context, they implement various interventions that support treatment and rehabilitation. It is essential that these interventions also encompass caregivers and are grounded in evidence-based and collaborative practices.

According to Pektekin (2013), within the framework of the Tidal Model developed by psychiatric nursing theorists Phil Barker and Poppy Buchanan-Barker, emphasis is placed on individuals' lived experiences and the meanings they attribute to these experiences. This perspective, with its strong focus on individuality, is considered to facilitate a comprehensive evaluation of the person in all dimensions.

In light of this information, the aim of this study is to examine the effect of a Tidal Model-based nursing approach on the levels of anxiety, depression, and burnout among caregivers of individuals diagnosed with traumatic brain injury.

Aim of the Study (Primary and Secondary Objectives): Brain injury is a broad condition that may result from head trauma or surgical interventions, vascular injuries (such as subarachnoid hemorrhage or stroke), metabolic or toxic causes, cerebral anoxia, inflammation, or infection (Turner-Stokes, 2015). Meta-analyses conducted between 1990 and 2016 have estimated an annual incidence of 43.6 million new cases of brain injury worldwide (GBD, 2016).

Among the causes of traumatic brain injury (TBI), motor vehicle accidents rank first, accounting for approximately 50% of cases (Thurman et al., 1999), followed by falls, which constitute 20-30% of cases (Karpuz, 2019). The risk of TBI is highest among individuals aged 15-24 years, decreases in middle adulthood, and rises again after the age of 70 (Thurman et al., 1999). According to the Turkish Statistical Institute (2019), 24.3% of deaths in Türkiye are attributed to cerebrovascular diseases.

Head injuries are life-threatening conditions that can lead to long-term disability and require prolonged treatment and care, ranking fourth among the leading causes of death. Although advances in emergency care and palliative services have increased survival rates, many survivors experience significant physical, cognitive, emotional, behavioral, and social disabilities. As a result, these individuals often require continuous supervision, support, and care for the remainder of their lives.

Caregivers of individuals with TBI are typically unpaid individuals-most often family members-who are primarily responsible for providing physical, psychological, and social care (Çetinkaya & Dönmez, 2023). Caregiving is defined as all activities performed attentively and respectfully to help individuals meet their basic needs, maintain and develop their abilities, and live with minimal suffering while sustaining a functional life (Engster, 2005).

Research has demonstrated that caregivers experience numerous physical, psychological, emotional, social, and economic challenges (Karahan & İslam, 2013). Long-term caregiving has been associated with increased anxiety, depression, deterioration in physical health, social isolation, and burnout (Sarı, 2007; Dökmen, 2012).

Within healthcare systems, nurses play a crucial role as frontline professionals who maintain continuous contact with patients and caregivers. Structuring care within theoretical frameworks and models is essential for ensuring a systematic and holistic approach (Dökmen, 2012). Mental health nurses, in particular, implement evidence-based, collaborative, recovery-oriented, and holistic interventions that support both patients and caregivers throughout treatment and rehabilitation processes (Barker, 2001a).

The importance of focusing on individuals' strengths in improving mental health has been emphasized (Xie, 2013). Similarly, the Tidal Model developed by Phil Barker and Poppy Buchanan-Barker highlights individuals' lived experiences and the meanings they attribute to these experiences (Pektekin, 2013; Barker & Buchanan-Barker, 2005). This model's emphasis on individuality enables comprehensive evaluation of individuals in all dimensions.

Within the context of this study, the challenges experienced by caregivers of individuals with TBI can be conceptualized through the Tidal Model: the chaos and instability they experience correspond to the "tides," their interpretation of caregiving reflects the inevitability of change, and the coping strategies they develop resemble "building a boat." Based on the model's philosophy of helping individuals facing life difficulties, it is considered appropriate for use with this population.

Accordingly, the primary aim of this doctoral study is to examine the effect of a Tidal Model-based nursing intervention on the levels of anxiety, depression, and burnout among caregivers of individuals with traumatic brain injury.

Expected Benefits and Risks: This study is expected to contribute to a comprehensive evaluation of caregivers by emphasizing their lived experiences and individuality, as proposed by the Tidal Model. The use of a randomized, pretest-posttest controlled experimental design combined with mixed methods (document analysis and discourse analysis) will enable a robust, evidence-based evaluation of the intervention's effectiveness.

The study is also anticipated to improve caregivers' coping skills related to psychological challenges and provide healthcare professionals with a novel perspective on caregiver support. Strengthening caregivers' mental well-being may also positively influence patient outcomes. Furthermore, the study is expected to contribute to the academic field by supporting the use of the Tidal Model in rehabilitation nursing and holistic care practices.

No risks are anticipated in this study. Type, Scope, and Design of the Study: This study will employ a randomized, pretest-posttest controlled experimental design alongside mixed methods, including document analysis and discourse analysis.

The sample will consist of individuals who meet the inclusion criteria and voluntarily agree to participate. Sample size was determined using G*Power analysis. Based on reference values from Yıldırım et al. (2024) (Beck Anxiety Scale scores: 25.67±7.98 and 16.22±6.78), with an effect size of 1.27, power of 80%, and alpha level of 0.05, the required sample size was calculated as 18 participants (9 experimental, 9 control).

Participants (Sample Characteristics and Selection Criteria):

The study sample will consist of male and female caregivers aged 18-65 years who provide care for individuals with TBI receiving treatment at the Acute Rehabilitation Clinic of Ankara Gaziler Physical Therapy and Rehabilitation Training and Research Hospital.

Inclusion, Exclusion, and Withdrawal Criteria

Inclusion criteria:

Providing care for an individual diagnosed with TBI Aged between 18 and 65 years Providing care for at least 3 months Ability to understand and speak Turkish No communication impairments Voluntary participation

Exclusion criteria:

Under 18 or over 65 years of age Providing care for less than 3 months Illiteracy Caring for individuals without TBI diagnosis willingness to participate Incomplete completion of study forms

Withdrawal criteria:

Voluntary withdrawal from the study Incomplete data collection forms Outcome Measures and Data Collection Tools

Participants will complete:

Informed Consent Form Sociodemographic Data Form Beck Anxiety Inventory (BAI) Beck Depression Inventory (BDI) Maslach Burnout Inventory (MBI) Pretests will be conducted during the first session, and posttests will be conducted during the final session.

Intervention Procedure

The intervention group will receive eight face-to-face sessions based on the Tidal Model (twice weekly, 45 minutes each, for four weeks). The sessions will include:

Orientation Acute care phase Developmental care phase Transitional care phase Semi-structured interviews will be conducted following the intervention. The control group will receive no intervention but will complete pretest and posttest assessments at equivalent time intervals.

Statistical Analysis:

Data will be analyzed using SPSS 24.0. Normality will be assessed using Kolmogorov-Smirnov and Shapiro-Wilk tests.

Parametric tests: Independent samples t-test, paired samples t-test Non-parametric tests: Mann-Whitney U test, Wilcoxon signed-rank test Correlation: Spearman correlation analysis Reliability: Cronbach's alpha Qualitative data will be analyzed using MAXQDA. The level of statistical significance will be set at p < 0.05.

Inclusion Criteria:

Providing care for an individual diagnosed with Traumatic Brain Injury (TBI). Being between the ages of 18 and 65. Having provided care for the patient for at least 3 months. Volunteering and providing informed consent to participate in the study. Being proficient in speaking and understanding Turkish. Having no cognitive or physical impairments that would hinder effective communication.

Exclusion Criteria:

Being under the age of 18 or over the age of 65. Having provided care for less than 3 months. Being illiterate or unable to read and write. Providing care for an individual with a diagnosis other than Traumatic Brain Injury (TBI).

Unwillingness to participate in the study or refusal to provide informed consent.

Failure to fully complete the required study forms and measurement scales.

The statistical analysis will be performed by a researcher who is blinded to the group assignments to prevent bias.