Neurocognitive Effects of Radiotherapy

Abstract : This report describes continued work on the award Neurocognitive Effects of Radiotherapy , which examines the neurocognitive and imaging impact of proton therapy for patients will low grade glioma and base of skull meningioma. A total of 59 subjects (patients and control) have been enrolled, 12 of whom have enrolled in the past year. All subjects have completed a 4-5 hour neurocognitive testing assessment at baseline by Dr. Carol Armstrong. In addition, all subjects have completed a 1 hour standard MRI as well as additional testing including diffuse tensor imaging (DTI), perfusion and diffusion. The majority of patients have completed baseline and at least two additional time-points in regards to both neurocognitive testing and MRI. Eight patients have completed neurocognitive and imaging evaluation at all planned timeponts, and preliminary data analysis is provided in this report. Local control and overall survival remain 100% in both testing cohorts. Although data are preliminary, neurocognitive results suggest that, on measures of verbal retrieval from longterm memory (retrieval after interface and retrieval after time), patients treated with proton therapy show post-treatment decline, but a stronger recovery and larger memory capacity compared to those treated with photons. Implicit cognition was tested via cerebellar tests, and results were compared for 20 patients and 20 controls. Control patients appeared to perform better than patients after proton therapy on specific cerebellar tests, including Timing Functions Test and Serial Response Test, although the performance of the two groups on the Audiovisual Attentional Shift Test did not differ. These tests have not been used previously within the proton radiation population, and appear to be promising tools for elucidating differences in implicit cognition in this and future studies. Imaging analysis has been carried out independently from neurocognitive analysis.