Writing fluency in patients with low-grade glioma before and after surgery

Abstract

Background: Low-grade glioma (LGG) is a type of brain tumour often situated in or near areas involved in language, sensory or motor functions. Depending on localization and tumour characteristics, language or cognitive impairments due to tumour growth and/or surgical resection are obvious risks. One task that may be at risk is writing, both because it requires intact language and memory function and because it is a very complex and cognitively demanding task. The most commonly reported language deficit in LGG patients is oral lexical-retrieval difficulties, and poor lexical retrieval would be expected to affect writing fluency. Aims: To explore whether writing fluency is affected in LGG patients before and after surgery and whether it is related to performance on tasks of oral lexical retrieval. Methods & Procedures: Twenty consecutive patients with presumed LGG wrote a narrative and performed a copy task before undergoing surgery and at 3-month follow-up using keystroke-logging software. The same tasks were performed by a reference group (N = 31). The patients were also tested using the Boston Naming Test (BNT) and word-fluency tests before and after surgery. Writing fluency was compared between the patients and the reference group, and between the patients before and after surgery. Relationships between performance on tests of oral lexical retrieval and writing fluency were investigated both before and after surgery. Outcome & Results: Different aspects of writing fluency were affected in the LGG patients both before and after surgery. However, when controlling for the effect of typing speed, the LGG group differed significantly from the reference group only in the proportion of pauses within words. After surgery, a significant decline was seen in production rate and typing speed in the narrative task, and a significant increase was seen in pauses before words. Strong positive relationships were found between oral lexical retrieval and writing fluency both before and after surgery. Conclusions & Implications: Although aspects of writing fluency were affected both before and after surgery, the results indicate that typing speed is an important factor behind the pre-surgery differences. However, the decline in overall productivity and the increase in pauses before words after surgery could be related to a lexical deficit. This is supported by the finding that oral lexical-retrieval scores were strongly correlated with writing fluency. However, further exploration is needed to identify the language and cognitive abilities affecting writing processes in LGG patients.