Assessment methods and prevalence of cognitive dysfunction in patients with low-grade glioma: A systematic review.

OBJECTIVE To systematically review the literature for studies on cognitive functioning in patients with low-grade glioma to evaluate assessment methods and prevalence of cognitive dysfunction. DATA SOURCES A search was made in PubMed, Embase, and PsycINFO for articles published between January 2002 and June 2012 using cognition, memory, attention, executive functioning, and low-grade glioma as search terms. STUDY SELECTION Two reviewers independently performed the study selection and data extraction. Inclusion criteria were: studies including at least 10 adult patients, with suspected or confirmed low-grade glioma and cognitive functioning as outcome measure. DATA EXTRACTION A standard data extraction form was used, with items regarding study quality, patient characteristics, type of measurement instruments, cognitive domain, definition of cognitive dysfunction, and reported prevalence. DATA SYNTHESIS Of the 312 articles screened on title/abstract, 69 were screened on full-text and, finally, 17 were included. A total of 46 different measurement instruments were found for the assessment of cognitive functioning; 5 of these were used 5 or more times. There was variability in the definition of cognitive dysfunction. The reported prevalence of cognitive dysfunction ranged from 19% to 83%. CONCLUSION Many patients with low-grade glioma experience cognitive dysfunction. However, there is no consensus on how to assess cognitive functioning in these patients.