This study investigates the use of the Epworth Sleepiness Scale (ESS) to assess somnolence syndrome in patients receiving cranial radiotherapy for primary and metastatic brain tumors. The ESS is a simple questionnaire that evaluates daytime sleepiness, with scores ranging from 0 to 24, where higher scores indicate greater sleepiness. The study included 23 patients, with a median age of 50 years, and found that 60.86% of them experienced increased daytime sleepiness, with 3 patients scoring above 16 on the ESS. The results are consistent with existing literature, suggesting that the ESS is an effective tool for detecting and quantifying somnolence. However, the study highlights the need to combine the ESS with other symptom assessments, such as visual analog scales, to provide a more comprehensive evaluation of somnolence syndrome. The study's limitations include a small sample size and the exclusion of patients with metastatic brain cancer, which prevented meaningful comparisons at different radiation doses. Despite these limitations, the ESS shows promise as a novel tool for assessing somnolence in patients undergoing cranial radiotherapy.This study investigates the use of the Epworth Sleepiness Scale (ESS) to assess somnolence syndrome in patients receiving cranial radiotherapy for primary and metastatic brain tumors. The ESS is a simple questionnaire that evaluates daytime sleepiness, with scores ranging from 0 to 24, where higher scores indicate greater sleepiness. The study included 23 patients, with a median age of 50 years, and found that 60.86% of them experienced increased daytime sleepiness, with 3 patients scoring above 16 on the ESS. The results are consistent with existing literature, suggesting that the ESS is an effective tool for detecting and quantifying somnolence. However, the study highlights the need to combine the ESS with other symptom assessments, such as visual analog scales, to provide a more comprehensive evaluation of somnolence syndrome. The study's limitations include a small sample size and the exclusion of patients with metastatic brain cancer, which prevented meaningful comparisons at different radiation doses. Despite these limitations, the ESS shows promise as a novel tool for assessing somnolence in patients undergoing cranial radiotherapy.