With survival rates above 70 percent for pediatric medulloblastoma patients, there are now treatment options that offer hope for resumed childhoods and normal learning experiences into adolescence. However, one of the unfortunate side effects of both the tumor and the treatment is a risk of cognitive deficits. These deficits typically are not a loss of skills but rather a struggle to gain new skills at the same rate as their healthy peers in areas of attention, working memory and processing speed. As a result, careful monitoring of cognitive changes is now standard practice for those children with brain tumors, including medulloblastoma, the most common form of malignant tumor located in the brain’s posterior fossa.
Traditional neuropsychological tests have established a gold standard for researchers to assess change. However, computerized assessments, like the Cogstate battery, offer advantages such as improved administration across examiners and settings, increased precision and reliability in measuring response time, repeatability due to alternate forms, reduced testing time and flexibility in terms of the testing environment.
While Cogstate tests have been validated across a wide range of diseases, including pediatric cancers, a recent study, published in the Journal of Neuro-Oncology, was designed specifically “to assess the sensitivity of Cogstate in detecting therapy-related changes in children undergoing medulloblastoma treatment. Secondary goals sought to further establish the validity of the Cogstate tasks by investigating clinical predictors of performance and correlations with established neuropsychological measures.”
In this study, a group of patients diagnosed with medulloblastoma, aged 3 to 22, completed the Cogstate battery of tasks at baseline (post-surgery and before radiation or chemotherapy) and again three months later (six weeks after completion of any adjuvant therapy). The battery consisted of five tasks: Detection (Psychomotor Function), Identification (Attention), One-Back (Working Memory), and the Groton Maze Learning Task (Executive Function). Two versions were used with age-appropriate stimuli sets, one for children age 5 to 9 and another for children age 10 and up. Results were also divided among three sub-groups of radiation treatment level (low dose, standard dose and high dose).
At baseline, prior to radiation treatment, results showed compliance with expected age performance. After radiation, Cogstate results showed a decline in reaction time by the participants on the Identification and One Back tasks, especially in younger patients and those that had a higher dose of radiation treatment.
In addition, the Cogstate reaction time tasks showed small to moderate correlations with traditional neuropsychological tests.
“This study provides evidence for the use of the Cogstate battery in pediatric oncology studies seeking to measure safety profiles and maturational trajectories among children undergoing radiation therapy for medulloblastoma,” said Dr. Adrian Schembri, Science Director at Cogstate. “Whilst performance was comparable to a normal healthy pediatric population at baseline, findings suggest sensitivity to decline following radiation therapy. Of note, higher doses of radiation and younger age were associated with more pronounced decline, which is consistent with previous literature that these patient subsets may be at greater risk of cognitive effects whilst undergoing radiation therapy.”