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Updated: May 30, 2026
Quantifying Cognitive Decrements Caused by Cranial Radiotherapy
Published on: October 18, 2011
Somnolence syndrome in patients receiving radical radiotherapy for primary brain tumours: a prospective study
Cerri Powell1, Douglas Guerrero, Susan Sardell
1Neuro-Oncology Unit, The Royal Marsden NHS Foundation Trust, London and Sutton, UK.
Background And Purpose:
To characterise the incidence, pattern and severity of post cranial radiotherapy somnolence and to identify factors predictive of frequency and severity.
Materials And Methods:
Seventy consecutive patients receiving radical cranial irradiation were prospectively assessed for somnolence at baseline, during and up to 10weeks following radiotherapy using five variables scored on a visual analogue scale (VAS) and the Littman scale. Fatigue was measured using the FACT-G score and quality of life using the EORTC QLQC30+3 with the brain tumour module questionnaire.
Results:
Ninety percent of patients experienced ⩾grade 1 somnolence (Littman score) and this correlated with VAS scores (r=0.456, p<0.001). The score increased from 3 to 12weeks (p<0.001) with a peak at the end of treatment and improvement 6weeks later. None of the patient, disease or treatment characteristics analysed were predictive for the development or the severity of somnolence.
Conclusions:
The majority of patients experience some degree of somnolence following radical radiotherapy for primary brain tumour and this follows a clear pattern during and after treatment. While there are no clear predictors of severity, the pattern described allows for provision of information for patients and carers to minimise the distress the syndrome may cause.
