Clinical implementation of standardized neurocognitive assessment before and after radiation to the brain

Radiotherapy induced impairment of cognitive function can lead to a reduced quality of life. The aim of this study was to describe the implementation and compliance of standardized neurocognitive assessment. In addition, the first results of cognitive changes for patients receiving a radiation dose to the brain are described.

Patients that received radiation dose to the brain (neuro, head and neck and prophylactic cranial irradiation between April-2019 and Dec-2021 were included. Three neuro cognitive tests were performed a verbal learning and memory test, the Hopkins Verbal Learning Test; a verbal fluency test, the Controlled Oral Word Association Test and a speed and cognitive flexibility test, the Trail Making Test A&B. Tests were performed before the start of radiation, 6 months (6 m) and 1 year (1y) after irradiation. The Reliable Change Index (RCI) between baseline and follow-up was calculated using reference data from literature.

644 patients performed the neurocognitive tests at baseline, 346 at 6 months and 205 at 1y after RT, with compliance rates of 90.4%, 85.6%, and 75.3%, respectively. Reasons for non-compliance were: 1. Patient did not attend appointment (49%), 2. Patient was unable to perform the test due to illness (12%), 3. Patient refused the test (8 %), 4. Various causes, (31%). A semi-automated analysis was developed to evaluate the test results. In total, 26% of patients showed a significant decline in at least one of variables at 1y and 11% on at least 2 variables at 1y. However, an increase in cognitive performance was observed in 49% (≥1 variable) and 22% (≥2 variables).

Standardized neurocognitive testing within the radiotherapy clinic was successfully implemented, with a high patient compliance. A semi-automatic method to evaluate cognitive changes after treatment was defined. Data collection is ongoing, long term follow-up (up to 5 years after treatment) and dose-effect analysis will be performed.