Much research has been dedicated to the effects of bilingualism on executive control (EC). For bilinguals with aphasia, the interplay with EC is complex. In this systematic review, we synthesize research on this topic and provide an overview of the current state of the field. First, we examine the evidence for EC deficits in bilingual persons with aphasia (bPWA). We then discuss the domain generality of bilingual language control impairments. Finally, we evaluate the bilingual advantage hypothesis in bPWA. We conclude that (1) EC impairments in bPWA are frequently observed, (2) experimental results on the relationship between linguistic and domain-general control are mixed, (3) bPWA with language control problems in everyday communication have domain-general EC problems, and (4) there are indications for EC advantages in bPWA. We end with directions for experimental work that could provide better insight into the intricate relationship between EC and bilingual aphasia.

Background: Glioma (brain tumour) patients can suffer from mild linguistic and non-linguistic cognitive problems when the glioma is localised in an eloquent brain area. Word-finding problems are among the most frequently reported complaints. However, mild problems are difficult to measure with standard language tests because they are generally designed for more severe aphasic patients. Aims:The aim of the present study was to investigate whether word-finding problems reported by patients with a glioma can be objectified with a standard object naming test, and a linguistic processing speed test. In addition, we examined whether wordfinding problems and linguistic processing speed are related to non-verbal cognitive abilities. Methods & Procedures: We tested glioma patients (N=36) as part of their standard pre-treatment clinical work-up. Word-finding problems were identified by a clinical linguist during the anamnesis. Linguistic processing speed was assessed with a newly designed sentence judgment test (SJT) as part of the Diagnostic Instrument for Mild Aphasia (DIMA), lexical retrieval with the Boston Naming Test (BNT), presence of aphasia with a Token Test (TT), and nonverbal processing with the Trail Making Test A and B (TMT). Test performances of glioma patients were compared to those of healthy control participants (N=35). Outcomes & Results:The results show that many glioma patients (58%) report word-finding problems; these complaints were in only half of the cases supported by deviant scores on the BNT. Moreover, the presence of reported word-finding problems did not correlate with the BNT scores. However, word-finding problems were significantly correlated with reaction times on the SJT and the TMT. Although there were no significant differences between the patient and control group on the SJT, a subgroup of patients with a glioma in the frontal lobe of the language-dominant hemisphere was ARTICLE HISTORY

BACKGROUND Low-grade glioma (LGG) patients typically suffer from mild aphasia that often cannot be detected with standard aphasia tests. The Diagnostic Instrument for Mild Aphasia (DIMA) is the first standardized test-battery to assess mild language disorders. We investigate pre- and postoperative linguistic abilities of LGG and high-grade glioma (HGG) patients with the DIMA. METHODS The DIMA consists of subtests that tap phonology (word, compound, non-word, sentence repetition), semantics (odd-picture-out), and syntax (sentence completion). Additionally, we administered the Boston Naming Test, Category- and Letter Fluency, and the Token Test. Patients were assessed before awake surgery (T1, N=98), three-months (T2, N=69), and one-year (T3, N=30) postoperatively. DIMA performance was compared to healthy controls (N=214). Group differences were examined with parametric (t-test) and nonparametric (Mann-Whitney-U, Wilcoxon) tests. RESULTS DIMA: Preoperatively, patients deviated on sentence repetition and sentence completion (p<0.05). HGG patients performed worse than LGG on word, non-word, and sentence repetition (p<0.05). There was no effect of hemispheric tumor localization. At T2, compound repetition and odd-picture-out also became impaired (p<0.05) and there was a decline compared to T1 on all repetition tasks (p<0.05). At T3, only sentence completion remained impaired (p<0.01) with a deterioration compared to T1 (p<0.01). Standard tests: At T1, patients were impaired on BNT, Category- and Letter Fluency (p<0.01). HGG patients performed worse than LGG patients on BNT and TT (p<0.01). Patients with left-hemispheric tumors performed worse on BNT and Letter Fluency compared to right-hemispheric tumors (p<0.05). At T2, TT also became impaired (p<0.05) and patients declined compared to T1 on Verbal Fluency tests (p<0.01). At T3, only BNT and Category Fluency remained impaired (p<0.05), with no significant declines compared to T1. CONCLUSION The DIMA is the first test-battery to detect peri-operative impairments at different linguistic levels (phonology, semantics, syntax) in patients with left- or right-hemispheric gliomas. It even appeared more sensitive to detect surgical effects than standard tests: all phonological DIMA subtests captured short-term decline (T1-T2), in line with earlier evidence for the value of (non-)word repetition. DIMA sentence completion detected long-term decline (T1-T3), reflecting earlier spontaneous speech analyses. As expected, Verbal Fluency was also sensitive to short-term postoperative decline. Left-hemispheric tumor localization only affected standard test performance. HGG patients had more severe impairments than LGG on DIMA repetition and standard tests (BNT and TT). We advise adding the DIMA to standard language evaluation of glioma patients, as it allows for more detailed counseling about language outcome.

IntroductionAwake craniotomy is increasingly used to resect intrinsic brain tumors while preserving language. The level of musical training might affect the speed and extend of postoperative language recovery, as increased white matter connectivity in the corpus callosum is described in musicians compared to non-musicians.MethodsIn this cohort study, we included adult patients undergoing treatment for glioma with an awake resection procedure at two neurosurgical centers and assessed language preoperatively (T1) and postoperatively at three months (T2) and one year (T3) with the Diagnostic Instrument for Mild Aphasia (DIMA), transferred to z-scores. Moreover, patients’ musicality was divided into three groups based on the Musical Expertise Criterion (MEC) and automated volumetric measures of the corpus callosum were conducted.ResultsWe enrolled forty-six patients, between June 2015 and September 2021, and divided in: group A (non-musicians, n = 19, 41.3%), group B (amateur musicians, n = 17, 36.9%) and group C (trained musicians, n = 10, 21.7%). No significant differences on postoperative language course between the three musicality groups were observed in the main analyses. However, a trend towards less deterioration of language (mean/SD z-scores) was observed within the first three months on the phonological domain (A: −0.425/0.951 vs. B: −0.00100/1.14 vs. C: 0.0289/0.566, p-value = 0.19) with a significant effect between non-musicians vs. instrumentalists (A: −0.425/0.951 vs. B + C: 0.201/0.699, p = 0.04). Moreover, a non-significant trend towards a larger volume (mean/SD cm3) of the corpus callosum was observed between the three musicality groups (A: 6.67/1.35 vs. B: 7.09/1.07 vs. C: 8.30/2.30, p = 0.13), with the largest difference of size in the anterior corpus callosum in non-musicians compared to trained musicians (A: 3.28/0.621 vs. C: 4.90/1.41, p = 0.02).ConclusionWith first study on this topic, we support that musicality contributes to language recovery after awake glioma surgery, possibly attributed to a higher white matter connectivity at the anterior part of the corpus callosum. Our conclusion should be handled with caution and interpreted as hypothesis generating only, as most of our results were not significant. Future studies with larger sample sizes are needed to confirm our hypothesis.