Stanislav Lem on the philosophy of language: recovery from fragments of phrases

This article examines some of S. Lem’s statements about his philosophical and worldview positions regarding the mysterious nature of language and the linguistic sign, the connection between language, mind and reality. The main goal of the paper is to understand what texts on the philosophy of language the Polish thinker read and what attitude he has formed towards them. Lem is the follower of an analytical intellectual culture that focuses on the naturalistic worldview and the consequences of the “linguistic turn” in Western philosophy. For Lem, language is not only an interesting philosophical object, but also a complex precise instrument of his own creative thinking. In this regard, the philosophy of language for a writer cannot be based only on logical-linguistic atomistic methodology. Lem seeks (and finds) in his contemporary interdisciplinary methods ways to combine realistic and anti-realist positions. Many concepts, such as “the effect of semantic transparency”, “polymorphic language model”, “variation model” are quite correlated with modern theories of language and require additional philosophical comments.

P.201 Disruption of the Frontal Aslant Tract is Associated with Transient Aphasia and not Agraphia: A Neurosurgical Case Report

Background: The frontal aslant tract (FAT) is a recently discovered white-matter tract connecting the medial superior frontal gyrus to the inferior frontal gyrus. There is increasing evidence for its importance in speech initiation and production. Despite this, there remains limited evidence demonstrating clinical outcomes when lesioning this tract. Methods: Medical records for the case were reviewed. Imaging was exported and tractography was performed using 3D Slicer. Results: A 58-year-old female presented with a focal seizure and imaging demonstrating a left frontal extra-axial lesion. She underwent a left frontal craniotomy for tumour debulking and biopsy. The final pathology was consistent with a diffuse large B-cell lymphoma. Postoperatively, she presented with expressive aphasia without agraphia. She was able to write out answers to questions she could not verbalize. We used tractography to provide evidence of postoperative disruption to her left FAT. At a 6-week clinical follow-up, her language deficits were clinically resolved. Conclusions: To our knowledge, this is the first reported case of aphasia without agraphia seen with disruption of the left FAT. Further elucidating clinical outcomes of disrupting the dominant FAT will aid in improved patient counselling, prognostication and neurosurgical planning. Further research is required to investigate the mechanisms underlying language recovery and handwriting.

Bilingual aphasia as the initial presentation of a hemorrhagic stroke: Case report

With a great number of bilingual individuals in the world, there is a growing need for understanding and studying language. In cases of bilingual aphasia, patterns of language recovery can vary. Case report: The present case refers to a male patient, 52 years old, right-handed, born in Arkansas-United States of America and resident for 20 years in the city of Santos, São Paulo. The patient is bilingual fluent in English and Portuguese and had a sudden language disorder associated with a right-sided strength and sensitivity deficit; Imaging exams showed a left lenticular nucleus hemorrhagic stroke. In the language assessment, he presented an important impairment of fluency, compression and repetition in the Portuguese language and relative preservation, with slight dysfunction in fluency in the English language. Symptomatic treatment was instituted with partial improvement of the symptoms. Keywords: bilingual aphasia; hemorrhagic stroke.

Effects of tDCS on Language Recovery in Post-Stroke Aphasia: A Pilot Study Investigating Clinical Parameters and White Matter Change with Diffusion Imaging

Objectives: In this pilot study we investigated the effects of transcranial direct current stimulation (tDCS) on language recovery in the subacute stage of post-stroke aphasia using clinical parameters and diffusion imaging with constrained spherical deconvolution-based tractography. Methods: The study included 21 patients with subacute post-stroke aphasia. Patients were randomly classified into two groups with a ratio of 2:1 to receive real tDCS or sham tDCS as placebo control. Patients received 10 sessions (5/week) bi-hemispheric tDCS treatments over the left affected Broca’s area (anodal electrode) and over the right unaffected Broca’s area (cathodal stimulation). Aphasia score was assessed clinically using the language section of the Hemispheric Stroke Scale (HSS) before and after treatment sessions. Diffusion imaging and tractography were performed for seven patients of the real group, both before and after the 10th session. Dissection of language-related white matter tracts was achieved, and diffusion measures were extracted. A paired Student’s t-test was used to compare the clinical recovery and diffusion measures of the dissected tracts both pre- and post- treatment. The partial correlation between changes in diffusion measures and the language improvements was calculated. Results: At baseline assessment, there were no significant differences between groups in demographic and clinical HSS language score. No significant clinical recovery in HSS was evident in the sham group. However, significant improvements in the different components of HSS were only observed in patients receiving real tDCS. Associated significant increase in the fractional anisotropy of the right uncinate fasciculus and a significant reduction in the mean diffusivity of the right frontal aslant tract were reported. A significant positive correlation was found between the changes in the right uncinate fasciculus and fluency improvement. Conclusions: Aphasia recovery after bi-hemispheric transcranial direct current stimulation was associated with contralesional right-sided white matter changes at the subacute stage. These changes probably reflect neuroplasticity that could contribute to the recovery. Both the right uncinate fasciculus and right frontal aslant tract seem to be involved in aphasia recovery.

Investigating Language and Domain-General Processing in Neurotypicals and Individuals With Aphasia — A Functional Near-Infrared Spectroscopy Pilot Study

Brain reorganization patterns associated with language recovery after stroke have long been debated. Studying mechanisms of spontaneous and treatment-induced language recovery in post-stroke aphasia requires a network-based approach given the potential for recruitment of perilesional left hemisphere language regions, homologous right hemisphere language regions, and/or spared bilateral domain-general regions. Recent hardware, software, and methodological advances in functional near-infrared spectroscopy (fNIRS) make it well-suited to examine this question. fNIRS is cost-effective with minimal contraindications, making it a robust option to monitor treatment-related brain activation changes over time. Establishing clear activation patterns in neurotypical adults during language and domain-general cognitive processes via fNIRS is an important first step. Some fNIRS studies have investigated key language processes in healthy adults, yet findings are challenging to interpret in the context of methodological limitations. This pilot study used fNIRS to capture brain activation during language and domain-general processing in neurotypicals and individuals with aphasia. These findings will serve as a reference when interpreting treatment-related changes in brain activation patterns in post-stroke aphasia in the future. Twenty-four young healthy controls, seventeen older healthy controls, and six individuals with left hemisphere stroke-induced aphasia completed two language tasks (i.e., semantic feature, picture naming) and one domain-general cognitive task (i.e., arithmetic) twice during fNIRS. The probe covered bilateral frontal, parietal, and temporal lobes and included short-separation detectors for scalp signal nuisance regression. Younger and older healthy controls activated core language regions during semantic feature processing (e.g., left inferior frontal gyrus pars opercularis) and lexical retrieval (e.g., left inferior frontal gyrus pars triangularis) and domain-general regions (e.g., bilateral middle frontal gyri) during hard versus easy arithmetic as expected. Consistent with theories of post-stroke language recovery, individuals with aphasia activated areas outside the traditional networks: left superior frontal gyrus and left supramarginal gyrus during semantic feature judgment; left superior frontal gyrus and right precentral gyrus during picture naming; and left inferior frontal gyrus pars opercularis during arithmetic processing. The preliminary findings in the stroke group highlight the utility of using fNIRS to study language and domain-general processing in aphasia.

Genetic and neurophysiological biomarkers of neuroplasticity inform post-stroke language recovery

Background: There is high variability in poststroke aphasia severity, and predicting language recovery remains imprecise. Standard prognostic measures do not include neurophysiological indicators or genetic biomarkers of neuroplasticity, which may be critical sources of variability. Objective: To evaluate whether a common polymorphism (Val66Met) in the gene for brain derived neurotrophic factor (BDNF; a gene related to neuroplasticity) contributes to variability in poststroke language recovery, and to assess whether BDNF polymorphism interacts with neurophysiological indicators of neuroplasticity (cortical excitability and stimulation induced plasticity in response to continuous theta burst stimulation [cTBS]) to improve estimates of aphasia severity. Methods: Saliva samples and motor evoked potentials (MEPs) were collected from participants with chronic aphasia subsequent to a left hemisphere ischemic stroke. MEPs were collected prior to cTBS (index for cortical excitability) and 10 minutes following cTBS (index for stimulation induced neuroplasticity) to the left primary motor cortex. Analyses assessed the extent to which BDNF polymorphism interacted with cortical excitability and stimulation induced neuroplasticity to predict aphasia severity beyond established predictors. Results: Val66Val carriers showed less aphasia severity than Met allele carriers, after controlling for lesion volume and time poststroke. Furthermore, Val66Val carriers showed expected responses of strong effects of age on aphasia severity, and positive associations between both cortical excitability and stimulation induced neuroplasticity and severity. In contrast, Met allele carriers showed weaker effects of age and unexpected negative associations between cortical excitability, stimulation induced neuroplasticity and aphasia severity. Conclusions: Neurophysiological indicators and genetic biomarkers of neuroplasticity improved ability to predict poststroke aphasia severity. Furthermore, BDNF polymorphism interacted with cortical excitability and stimulation-induced neuroplasticity to predict aphasia recovery. These findings provide novel insights into mechanisms of variability in stroke recovery and may improve aphasia prognostics.