Inner speech in post-stroke aphasia : a behavioural and imaging study

Patients with aphasia often complain that there is a poor correlation between the words they think (inner speech) and the words they say (overt speech). Previous studies show that there are some cases in which inner speech is preserved while overt speech is impaired, and vice versa. However, these studies have various methodological and theoretical drawbacks. In cognitive models of language processing, inner speech is described as either dependent on both speech production and speech comprehension, or on the speech production system alone. Lastly, imaging studies show that inner speech is correlated with activation in various language areas. However, these studies are sparse and many have methodological caveats. Moreover, studies looking at inner speech in stroke patients are rare. This study examined inner speech in post-stroke aphasia using three different methodological approaches. Using cognitive behavioural methods, inner speech was characterised in healthy participants and stroke patients with aphasia. Using imaging, the brain structures which support inner speech were investigated. Two different methods were employed in this instance: Voxel based Lesion Symptom Mapping (VLSM) and Voxel Based Morphometry (VBM). Lastly, functional magnetic resonance imaging (fMRI) was used to study the dynamics of functional activations supporting inner speech production. The study showed that inner speech can remain intact while there is a marked deficit in overt speech. Structural studies suggested an involvement of the dorsal language route in inner speech processing, together with systems supporting motor feedback and executive functions. Functional imaging showed that inner speech processing in stroke is correlated with compensatory peri-lesional and contra-lesional activations. Activations outside the language network might reflect increase in effort or attention, or the use of feed forward and feedback mechanisms to support inner speech production. These results have implications for diagnosis, prognosis and therapy of certain patients with post-stroke aphasia

Dominant hemisphere functional networks compensate for structural connectivity loss to preserve phonological retrieval with aging.

INTRODUCTION: Loss of hemispheric asymmetry during cognitive tasks has been previously demonstrated in the literature. In the context of language, increased right hemisphere activation is observed with aging. Whether this relates to compensation to preserve cognitive function or dedifferentiation implying loss of hemispheric specificity without functional consequence, remains unclear. METHODS: With a multifaceted approach, integrating structural and functional imaging data during a word retrieval task, in a group of younger and older adults with equivalent cognitive performance, we aimed to establish whether interactions between hemispheres or reorganization of dominant hemisphere networks preserve function. We examined functional and structural connectivity on data from our previously published functional activation study. Functional connectivity was measured using psychophysiological interactions analysis from the left inferior frontal gyrus (LIFG) and the left insula (LINS), based on published literature, and the right inferior frontal gyrus (RIFG) based on our previous study. RESULTS: Although RIFG showed increased activation, its connectivity decreased with age. Meanwhile, LIFG and LINS connected more bilaterally in the older adults. White matter integrity, measured by fractional anisotropy (FA) from diffusion tensor imaging, decreased significantly in the older group. Importantly, LINS functional connectivity to LIFG correlated inversely with FA. CONCLUSIONS: We demonstrate that left hemispheric language areas show higher functional connectivity in older adults with intact behavioral performance, and thus, may have a role in preserving function. The inverse correlation of functional and structural connectivity with age is in keeping with emerging literature and merits further investigation with tractography studies and in other cognitive domains

Does stroke location predict walk speed response to gait rehabilitation?

Objectives Recovery of independent ambulation after stroke is a major goal. However, which rehabilitation regimen best benefits each individual is unknown and decisions are currently made on a subjective basis. Predictors of response to specific therapies would guide the type of therapy most appropriate for each patient. Although lesion topography is a strong predictor of upper limb response, walking involves more distributed functions. Earlier studies that assessed the cortico-spinal tract (CST) were negative, suggesting other structures may be important. Experimental Design: The relationship between lesion topography and response of walking speed to standard rehabilitation was assessed in 50 adult-onset patients using both volumetric measurement of CST lesion load and voxel-based lesion–symptom mapping (VLSM) to assess non-CST structures. Two functional mobility scales, the functional ambulation category (FAC) and the modified rivermead mobility index (MRMI) were also administered. Performance measures were obtained both at entry into the study (3–42 days post-stroke) and at the end of a 6-week course of therapy. Baseline score, age, time since stroke onset and white matter hyperintensities score were included as nuisance covariates in regression models. Principal Observations: CST damage independently predicted response to therapy for FAC and MRMI, but not for walk speed. However, using VLSM the latter was predicted by damage to the putamen, insula, external capsule and neighbouring white matter. Conclusions Walk speed response to rehabilitation was affected by damage involving the putamen and neighbouring structures but not the CST, while the latter had modest but significant impact on everyday functions of general mobility and gait

Survey form and methods for second CASC survey of academic research computing and data center usage

Full analysis paper is in the ACM PEARC'21 Proceedings: ACM ISBN 978-1-4503-8292-2/21/07. https://doi.org/10.1145/3437359.3465589Availability of cloud-based resource delivery modes is transforming many areas of computing. Many academic institutions that support research computing facilities are considering and changing their mix of on-premise and remote facilities (including in particular use of commercial cloud facilities). A working group of the Coalition for Academic Scientific Computation (an educational nonprofit 501(c)(3) organization) has conducted an annual survey of higher education institutions now for two years running, with intentions of continuing. This survey asks a number of questions of academic institutions regarding their investments in research and data-oriented computing facilities, the extent of those facilities, and institutional activities. This technical report includes the full text of the survey instrument itself and describes the methods and survey population.http://deepblue.lib.umich.edu/bitstream/2027.42/167731/1/CASC 2021 Survey Methods and Form.pdfDescription of CASC 2021 Survey Methods and Form.pdf : Survey form and methods to accompany the full publication in the ACM PEARC'21 Proceedings, ACM ISBN 978-1-4503-8292-2/21/07. https://doi.org/10.1145/3437359.3465589SEL

Volume reduction of caudate nucleus is associated with movement coordination deficits in patients with hippocampal atrophy due to perinatal hypoxia-ischaemia

Acute sentinel hypoxia-ischaemia in neonates can target the hippocampus, mammillary bodies, thalamus, and the basal ganglia. Our previous work with paediatric patients with a history of hypoxia-ischaemia has revealed hippocampal and diencephalic damage that impacts cognitive memory. However, the structural and functional status of other brain regions vulnerable to hypoxia-ischaemia, such as the basal ganglia, has not been investigated in these patients. Furthermore, it is not known whether there are any behavioural sequelae of such damage, especially in patients with no diagnosis of neurological disorder. Based on the established role of the basal ganglia and the thalamus in movement coordination, we studied manual motor function in 20 participants exposed to neonatal hypoxia-ischaemia, and a group of 17 healthy controls of comparable age. The patients’ handwriting speed and accuracy was within the normal range (Detailed Assessment of Speed of Handwriting), and their movement adaptation learning (Rotary Pursuit task) was comparable to the control group’s performance. However, as a group, patients showed an impairment in the Grooved Pegboard task and a trend for impairment in speed of movement while performing the Rotary Pursuit task, suggesting that some patients have subtle deficits in fine, complex hand movements. Voxel-based morphometry and volumetry showed bilateral reduction in grey matter volume of the thalamus and caudate nucleus. Reduced volumes in the caudate nucleus correlated across patients with performance on the Grooved Pegboard task. In summary, the fine movement coordination deficit affecting the hand and the wrist in patients exposed to early hypoxic-ischaemic brain injury may be related to reduced volumes of the caudate nucleus, and consistent with anecdotal parental reports of clumsiness and coordination difficulties in this cohort

Regulation of vascular endothelial growth factor-A and its soluble receptor sFlt-1 by luteinizing hormone in vivo: implication for ovarian follicle angiogenesis

Objective: To determine in vivo whether LH supplementation during the late follicular phase induces ovarian follicle angiogenesis in humans, as reflected by vascular endothelial growth factor (VEGF)-A, its soluble receptor sFlt-1, and placental growth factor (PlGF) expression. Design: Randomized, double-blind, placebo-controlled study. Setting: Academic tertiary care medical center. Patient(s): Twenty infertile, healthy women (aged 18-39 years) undergoing IVF. Intervention(s): Administration of recombinant FSH after down-regulation and equal randomization of subjects to receive recombinant LH 75 IU/day or placebo when two or more follicles reached a mean diameter of 14 mm

Enhanced left superior parietal activation during successful speech production in patients with left dorsal striatal damage and error-prone neurotypical participants

Functional imaging studies of neurotypical adults report activation in the left putamen during speech production. The current study asked how stroke survivors with left putamen damage are able to produce correct spoken responses during a range of speech production tasks. Using functional magnetic resonance imaging, activation during correct speech production responses was assessed in 5 stroke patients with circumscribed left dorsal striatal lesions, 66 stroke patient controls who did not have focal left dorsal striatal lesions, and 54 neurotypical adults. As a group, patients with left dorsal striatal damage (our patients of interest) showed higher activation than neurotypical controls in the left superior parietal cortex during successful speech production. This effect was not specific to patients with left dorsal striatal lesions as we observed enhanced activation in the same region in some patient controls and also in more error-prone neurotypical participants. Our results strongly suggest that enhanced left superior parietal activation supports speech production in diverse challenging circumstances, including those caused by stroke damage. They add to a growing body of literature indicating how upregulation within undamaged parts of the neural systems already recruited by neurotypical adults contributes to recovery after stroke

Damage to Broca’s area does not contribute to long-term speech production outcome after stroke

Broca’s area in the posterior half of the left inferior frontal gyrus has long been thought to be critical for speech production. The current view is that long-term speech production outcome in patients with Broca’s area damage is best explained by the combination of damage to Broca’s area and neighbouring regions including the underlying white matter, which was also damaged in Paul Broca’s two historic cases. Here, we dissociate the effect of damage to Broca’s area from the effect of damage to surrounding areas by studying long-term speech production outcome in 134 stroke survivors with relatively circumscribed left frontal lobe lesions that spared posterior speech production areas in lateral inferior parietal and superior temporal association cortices. Collectively, these patients had varying degrees of damage to one or more of nine atlas-based grey or white matter regions: Brodmann areas 44 and 45 (together known as Broca’s area), ventral premotor cortex, primary motor cortex, insula, putamen, the anterior segment of the arcuate fasciculus, uncinate fasciculus and frontal aslant tract. Spoken picture description scores from the ComprehensiveAphasia Test were used as the outcome measure. Multiple regression analyses allowed us to tease apart the contribution of other variables influencing speech production abilities such as total lesion volume and time post-stroke. We found that, in our sample of patients with left frontal damage, long-term speech production impairments (lasting beyond 3 months post-stroke) were solely predictedby the degree of damage to white matter, directly above the insula, in the vicinity of the anterior part of the arcuate fasciculus, with no contribution from the degree of damage to Broca’s area (as confirmed with Bayesian statistics). The effect of white matter damage cannot be explained by a disconnection of Broca’s area, because speech production scores were worse after damage to the anterior arcuate fasciculus with relative sparing of Broca’s area than after damage to Broca’s area with relative sparing of the anterior arcuate fasciculus. Our findings provide evidence for three novel conclusions: (i) Broca’s area damage does not contribute to long-term speech production outcome after left frontal lobe strokes; (ii) persistent speech production impairments after damage to the anterior arcuate fasciculus cannot be explained by a disconnection of Broca’s area; and (iii) the prior association between persistent speech production impairments and Broca’s area damage can be explained by co-occurring white matter damage, above the insula, in the vicinity of the anterior part of the arcuate fasciculus

Collaborative Privacy-Preserving Analysis of Oncological Data using Multiparty Homomorphic Encryption

Real-world healthcare data sharing is instrumental in constructing broader-based and larger clinical data sets that may improve clinical decision-making research and outcomes. Stakeholders are frequently reluctant to share their data without guaranteed patient privacy, proper protection of their data sets, and control over the usage of their data. Fully homomorphic encryption (FHE) is a cryptographic capability that can address these issues by enabling computation on encrypted data without intermediate decryptions, so the analytics results are obtained without revealing the raw data. This work presents a toolset for collaborative privacy-preserving analysis of oncological data using multiparty FHE. Our toolset supports survival analysis, logistic regression training, and several common descriptive statistics. We demonstrate using oncological data sets that the toolset achieves high accuracy and practical performance, which scales well to larger data sets. As part of this work, we propose a novel cryptographic protocol for interactive bootstrapping in multiparty FHE, which is of independent interest. The toolset we develop is general-purpose and can be applied to other collaborative medical and healthcare application domains