Epworth Sleepiness Scale- a novel tool to assess somnolence syndrome in patients receiving radiotherapy to the brain

Abstract

Purpose: Radiation to brain causes early, early-delayed, and delayed side effects. There is paucity of literature regarding early-delayed effects like somnolence syndrome. Existing studies use general symptom assessment and visual analog scales. Epworth Sleepiness Scale (ESS) is a time tested tool to assess daytime sleepiness in various conditions. In this study, the ESS has been used to determine the occurrence of somnolence in patients receiving cranial radiotherapy for primary and metastatic brain tumors. Thus the ESS has been used in a novel setting in our study. The ESS is a simple to administer questionnaire and may be useful in grading the severity of somnolence. To our knowledge, this is the second study to determine post radiation somnolence using ESS.

Methods: This prospective study was conducted in 23 patients with primary and metastatic brain tumor. Patient demographics and tumor type and grade was noted. Those with Karnofsky Performance Scale (KPS) less than 70 and with pre-existing sleep disorders were excluded. Radiotherapy regimen included palliative whole brain radiation for brain metastases and conformal adjuvant radiotherapy for primary brain tumors as per standard guidelines. All subjects included were administered ESS at baseline and weekly thereafter during and for 6 weeks after radiation.

Results: All 23 patients (median age 50 years) completed the planned questionnaires until 6 weeks post radiation. Twenty (87%) patients had primary brain tumors whereas three (13%) patients had metastatic lesions in brain. Of the 23 patients, 14 patients (60.86%) had abnormal or increased daytime sleepiness; of which 3 had ESS scores greater than 16.

Conclusion: Somnolence was noted in 60.86% of the patients, which is in accordance with existing literature. Epworth sleepiness scale is an effective tool to detect and quantify somnolence, However, it does not consider other symptoms of somnolence syndrome and hence should be combined with visual analog scale to get complete information.