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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.

Background: Low-grade glioma (LGG) is a slow-growing brain tumour often situated in or near areas involved in language and/or cognitive functions. Consequently, there is a risk that patients develop language impairments due to tumour growth or surgical resection. Purposes: The main aim of this thesis was to investigate language ability in patients with LGG in relation to surgical treatment. Language ability was investigated using various sensitive methods such as a test of high-level language. To acquire norms for the test used to investigate high-level language, normative values were obtained in a methodological study (Study I). Methods: In Study I, 100 adults were assessed using a Swedish test of high-level language (BeSS) and a test of verbal working memory. Relationships between these tests and demographic variables were investigated. In Study II, the language ability of 23 newly diagnosed LGG patients was assessed and compared with that of a reference group. The patients were also asked about self-perceived changes in language. In Study III, the language ability of 32 LGG patients was assessed before surgery, early after surgery and at three-months follow-up. The patients’ language ability was compared across these assessment points and with a reference group. Finally, in Study IV, 20 LGG patients wrote a short narrative before and after surgery. The aim was to explore whether the lexical-retrieval difficulties previously seen in oral language could be seen in writing as well. Keystroke logging was used to explore writing fluency and word-level pauses. Here, too, comparisons were made between the assessment points and with a reference group. Results and conclusions: Study I showed that demographic variables had a limited impact on performance on the BeSS whereas verbal working memory influenced performance. Hence verbal working memory was found to influence performance on a test of high-level language. In Study II, the LGG group performed worse than the reference group on tests of lexical retrieval. However, the majority of the newly diagnosed patients with presumed LGG had normal or nearly normal language ability prior to surgery. Only a few patients reported a change in their language ability. In Study III, most patients with a tumour in the left hemisphere manifested language impairment shortly after surgery, but the majority of them had returned to their pre-operative level of performance three months after surgery. Language impairment in patients with a tumour in the right hemisphere was rare at all assessment points. In Study IV, LGG patients had a higher proportion of pauses within words before surgery than the reference group did. After surgery, the patients’ production rate decreased and the proportion of pauses before words increased. Measures of lexical retrieval showed moderate to strong relationships with writing fluency both before and after surgery. The higher frequency of word-level pauses could indicate a lexical deficit. Overall, lexical-retrieval deficits were the most common type of impairment found both before and after surgery in patients with presumed LGG.