The Epworth Sleepiness Scale (ESS) is a validated tool used to assess daytime sleepiness in patients receiving brain radiotherapy. This study evaluated the occurrence of somnolence syndrome in 23 patients with primary or metastatic brain tumors undergoing cranial radiotherapy. The ESS was administered at baseline and weekly during and for 6 weeks after treatment. The results showed that 60.86% of patients experienced increased daytime sleepiness, with 3 patients having ESS scores above 16. The study highlights the effectiveness of the ESS in detecting and quantifying somnolence, although it does not account for other symptoms of the syndrome. The ESS is a simple, widely used questionnaire that can help grade the severity of somnolence. However, it should be combined with other tools like the visual analog scale for a more comprehensive assessment. The study is the second to use the ESS for post-radiation somnolence evaluation. The findings align with existing literature, indicating that somnolence is a common early-delayed side effect of brain radiotherapy. The study's limitations include a small sample size and the absence of sleep latency monitoring. Future research should explore the use of the ESS in conjunction with other scales for better diagnosis. The study concludes that the ESS is an effective tool for assessing somnolence, but it should be used alongside other assessments to ensure a complete understanding of the syndrome.The Epworth Sleepiness Scale (ESS) is a validated tool used to assess daytime sleepiness in patients receiving brain radiotherapy. This study evaluated the occurrence of somnolence syndrome in 23 patients with primary or metastatic brain tumors undergoing cranial radiotherapy. The ESS was administered at baseline and weekly during and for 6 weeks after treatment. The results showed that 60.86% of patients experienced increased daytime sleepiness, with 3 patients having ESS scores above 16. The study highlights the effectiveness of the ESS in detecting and quantifying somnolence, although it does not account for other symptoms of the syndrome. The ESS is a simple, widely used questionnaire that can help grade the severity of somnolence. However, it should be combined with other tools like the visual analog scale for a more comprehensive assessment. The study is the second to use the ESS for post-radiation somnolence evaluation. The findings align with existing literature, indicating that somnolence is a common early-delayed side effect of brain radiotherapy. The study's limitations include a small sample size and the absence of sleep latency monitoring. Future research should explore the use of the ESS in conjunction with other scales for better diagnosis. The study concludes that the ESS is an effective tool for assessing somnolence, but it should be used alongside other assessments to ensure a complete understanding of the syndrome.