Perceiving and misperceiving speech: lexical and sublexical processing in the superior temporal lobes

Listeners can use prior knowledge to predict the content of noisy speech signals, enhancing perception. However, this process can also elicit misperceptions. For the first time, we employed a prime-probe paradigm and transcranial magnetic stimulation to investigate causal roles for the left and right posterior superior temporal gyri (pSTG) in the perception and misperception of degraded speech. Listeners were presented with spectrotemporally degraded probe sentences preceded by a clear prime. To produce misperceptions, we created partially mismatched pseudo-sentence probes via homophonic nonword transformations (e.g. The little girl was excited to lose her first tooth-Tha fittle girmn wam expited du roos har derst cooth). Compared to a control site (vertex), inhibitory stimulation of the left pSTG selectively disrupted priming of real but not pseudo-sentences. Conversely, inhibitory stimulation of the right pSTG enhanced priming of misperceptions with pseudo-sentences, but did not influence perception of real sentences. These results indicate qualitatively different causal roles for the left and right pSTG in perceiving degraded speech, supporting bilateral models that propose engagement of the right pSTG in sublexical processing.

Relationships between reading performance and regional spontaneous brain activity following surgical removal of primary left-hemisphere tumors: A resting-state fMRI study

Left-hemisphere intraparenchymal primary brain tumor patients are at risk of developing reading difficulties that may be stable, improve or deteriorate after surgery. Previous studies examining language organization in brain tumor patients have provided insights into neural plasticity supporting recovery. Only a single study, however, has examined the role of white matter tracts in preserving reading ability post-surgery and none have examined the functional reading network. The current study aimed to investigate the regional spontaneous brain activity associated with reading performance in a group of 36 adult patients 6-24 months following left-hemisphere tumor resection. Spontaneous brain activity was assessed using resting-state fMRI (rs-fMRI) regional homogeneity (ReHo) and fractional amplitude low frequency fluctuation (fALFF) metrics, which measure local functional connectivity and activity, respectively. ReHo in the left occipito-temporal and right superior parietal regions was negatively correlated with reading performance. fALFF in the putamen bilaterally and the left cerebellum was negatively correlated with reading performance, and positively correlated in the right superior parietal gyrus. These findings are broadly consistent with reading networks reported in healthy participants, indicating that reading ability following brain tumor surgery might not involve substantial functional re-organization.

Chronic aphasias after left-hemisphere resective surgery

Surgical resection of brain tumours is associated with an increased risk of aphasia. However, relatively little is known about outcomes in the chronic phase (i.e., >6 months). Using voxel-based lesion symptom mapping (VLSM) in 46 patients, we investigated whether chronic language impairments are related to the location of surgical resection, residual tumour characteristics (e.g., peri-resection treatment effects, progressive infiltration, oedema) or both. Approximately 72% of patients scored below the cut-off for aphasia. Action naming and spoken sentence comprehension deficits were associated with lesions in the left anterior temporal and inferior parietal lobes, respectively. Voxel-wise analyses revealed significant associations between ventral language pathways and action naming deficits. Reading impairments were also associated with increasing disconnection of cerebellar pathways. The results indicate chronic post-surgical aphasias reflect a combination of resected tissue and tumour infiltration of language-related white matter tracts, implicating progressive disconnection as the critical mechanism of impairment.

Prognostic Value of Admission-to-Discharge Change in Integral Congestion Assessment for Predicting Adverse Outcomes in Patients with Decompensated Heart Failure

This study was performed to evaluate the prognostic value of relative changes from admission to discharge (Δ%) of integrated congestion assessment to predict adverse outcomes in patients with irreversible heart failure (HF) during a one-year follow-up. The study included 122 patients (60% males, median age of 69 years) with decompensated HF. Most of the patients (92%) had a history of arterial hypertension, 53.3% had coronary heart disease, and 40.2% had type 2 diabetes mellitus. All patients underwent assessments, including NT-proBNP, lung ultrasound (LUS) B-line score, liver stiffness by transient elastography, and resistance and reactance by bioimpedance vector analysis (BIVA). The assessments were performed at admission and discharge, and a relative change from admission (delta percentage, Δ%) was calculated. Long-term clinical outcomes were assessed by a structured interview conducted 1, 3, 6, and 12 months after discharge. The cut-offs for the occurrence of the endpoint events were Δ% NT-proBNP of ≥ -25, Δ% liver stiffness of ≥ -44, Δ% B-line score on lung ultrasound of ≥ -73, Δ% BIVA resistance of ≤ 18, and Δ% BIVA reactance of ≤ 40. It was revealed that 55% of endpoint events, including 22 (18%) deaths and 33 (27%) readmissions, occurred within a median of 74 days (interquartile range: 33-147). Patients with an endpoint event had significantly worse values of all studied parameters in contrast to patients without it. There was a significant direct association between Δ% NT-proBNP and Δ% B-lines (r=0.18; P=0.04), and a highly reliable inverse association was observed between Δ% liver stiffness and Δ% BIVA reactance (r=-0.4; P<0.001). No significant associations were found between the other parameters. Univariate Cox regression analysis demonstrated the independent prognostic value of all congestion markers under study (NT-proBNP, LUS B-lines, liver stiffness, and BIVA reactance) for predicting the combined endpoint. Multivariate Cox regression analysis confirmed the independent prognostic value in predicting the risk of endpoint event for the following parameters: NT-proBNP (hazard rate [HR] 2.5, P=0.001), liver stiffness (HR 2.3, P=0.012), LUS B-line score (HR 2.2, P=0.008). However, it did not find any significant prognostic value for BIVA resistance and reactance. The relative admission-to-discharge change in the integral assessment of congestion had a prognostic value for predicting the risk of adverse outcomes (all-cause mortality and readmission rate) in patients with decompensated HF during a one-year follow-up.