Slide Slam D11
Chronic aphasias after left-hemisphere resective surgery
Greig de Zubicaray1, Kylie Wall1, Sonia Brownsett2, Gail Robinson2, David Copland2, Kate Drummond3, Sarah Olson4, Lindy Jeffree4, Katie McMahon1,5; 1Queensland University of Technology, 2University of Queensland, 3Melbourne Health, 4Queensland Health, 5Herston Imaging Research Facility
Surgical resection of primary left-hemisphere brain tumours is associated with an increased risk of aphasia. The overwhelming majority of post-surgical investigations have documented language performance in the acute phase (i.e., within 1 month). However, relatively little is known about post-surgical aphasia in the chronic phase (> 6 months). With modern treatment approaches combining surgery and adjuvant therapies for brain tumours, survival rates have increased. Hence, it is imperative to document the incidence of chronic post-surgical aphasia and characterise the neuroanatomical mechanism(s) responsible for poor outcomes. Using voxel-based lesion symptom mapping, we investigated whether chronic post-surgical language impairments are related to the location of surgical resection, residual tumour characteristics (e.g., progressive infiltration, oedema) or both. Forty patients who underwent surgical resection of a primary left-hemisphere brain tumour participated in the present study. Language performance was assessed with the Comprehensive Aphasia Test (CAT) between 6 and 24 months post-surgery. Thirty-one patients (77%) scored below the cut-off for aphasia on one or more subtests, with most showing deficits on verb naming, picture description, spoken and written comprehension subtests. After controlling for age, sex, education, tumour grade, chronicity and lesion volume, verb naming and spoken comprehension deficits were significantly associated with lesions comprising both the resection site and residual tumour characteristics. These lesions were predominantly in white matter tracts underlying the anterior temporal and temporoparietal regions, respectively. Spoken comprehension deficits were also significantly associated with residual tumour characteristics in the temporoparietal white matter outside of the resected areas. Lesion symptom mapping based exclusively on the resected tissue did not reveal significant associations with any post-surgical language deficits. These results indicate chronic post-surgical aphasias are common, occurring in the majority of patients in the present cohort. In addition, the nature of the aphasia reflects a combination of resection and progressive tumour infiltration of language-related white matter tracts, implicating disconnection as the critical mechanism. This information may prove useful for predicting language outcomes and planning appropriate language therapies following surgery.