Central neurotoxicity of standard treatment in patients with newly-diagnosed high-grade glioma: a prospective longitudinal study.

Following tumor resection, the majority of high-grade glioma (HGG) patients are treated with a combined modality regimen of radiotherapy and temozolomide. As a result of the tumor itself or as treatment-related neurotoxic side-effects, these patients may experience cognitive deficits. Additionally, radiological abnormalities expressed as white matter hyperintensities (WMH) and cerebral atrophy (CA) can develop. In this study, these functional and morphological parameters are evaluated, and their relation is investigated. After surgery, HGG patients underwent chemo-irradiation for six weeks, followed by six cycles of temozolomide. Assessments were performed before chemo-irradiation, post-concomitantly, after the third and sixth adjuvant cycle, and 3 and 7 months after treatment. Degree of WMH and CA was scored on MRI. Patients' neuropsychological performance was compared to healthy matched controls, yielding six cognitive domain z-scores. Development or progression of pre-existing WMH and CA during follow-up was observed in 36 and 45 % of the patients (n = 39) respectively. Cognitive functioning remained stable or improved in 70 % of the patients and deteriorated in 30 % of the patients (n = 33). Of the cognitive decliners, 80 % had tumor progression within 4 months thereafter. No clear association between cognitive functioning and WMH or CA was found. Central neurotoxic effects of combined modality treatment in HGG patients expressed by radiological abnormalities are encountered in approximately 40 % of patients. However, functional impact as indexed by cognitive functioning was found to be limited. Furthermore, development or progression of pre-existing WMH and CA does not consistently result in functional impairment as measured by cognitive tests.

The influence of low-grade glioma on resting state oscillatory brain activity: a magnetoencephalography study.

PURPOSE: In the present MEG-study, power spectral analysis of oscillatory brain activity was used to compare resting state brain activity in both low-grade glioma (LGG) patients and healthy controls. We hypothesized that LGG patients show local as well as diffuse slowing of resting state brain activity compared to healthy controls and that particularly global slowing correlates with neurocognitive dysfunction. PATIENT AND METHODS: Resting state MEG recordings were obtained from 17 LGG patients and 17 age-, sex-, and education-matched healthy controls. Relative spectral power was calculated in the delta, theta, upper and lower alpha, beta, and gamma frequency band. A battery of standardized neurocognitive tests measuring 6 neurocognitive domains was administered. RESULTS: LGG patients showed a slowing of the resting state brain activity when compared to healthy controls. Decrease in relative power was mainly found in the gamma frequency band in the bilateral frontocentral MEG regions, whereas an increase in relative power was found in the theta frequency band in the left parietal region. An increase of the relative power in the theta and lower alpha band correlated with impaired executive functioning, information processing, and working memory. CONCLUSION: LGG patients are characterized by global slowing of their resting state brain activity and this slowing phenomenon correlates with the observed neurocognitive deficits.