Cochlear implantation constitutes a successful therapy of inner ear deafness, with the majority of patients showing good outcomes. There is, however, still some unexplained variability in outcomes with a number of cochlear-implant (CI) users, showing major limitations in speech comprehension. The current study used a multimodal diagnostic approach combining single-photon emission computed tomography (SPECT) and electroencephalography (EEG) to examine the mechanisms underlying speech processing in postlingually deafened CI users ( = 21). In one session, the participants performed a speech discrimination task, during which a 96-channel EEG was recorded and the perfusions marker Tc-HMPAO was injected intravenously. The SPECT scan was acquired 1.5 h after injection to measure the cortical activity during the speech task. The second session included a SPECT scan after injection without stimulation at rest. Analysis of EEG and SPECT data showed N400 and P600 event-related potentials (ERPs) particularly evoked by semantic violations in the sentences, and enhanced perfusion in a temporo-frontal network during task compared to rest, involving the auditory cortex bilaterally and Broca's area. Moreover, higher performance in testing for word recognition and verbal intelligence strongly correlated to the activation in this network during the speech task. However, comparing CI users with lower and higher speech intelligibility [median split with cutoff + 7.6 dB signal-to-noise ratio (SNR) in the Göttinger sentence test] revealed for CI users with higher performance additional activations of parietal and occipital regions and for those with lower performance stronger activation of superior frontal areas. Furthermore, SPECT activity was tightly coupled with EEG and cognitive abilities, as indicated by correlations between (1) cortical activation and the amplitudes in EEG, N400 (temporal and occipital areas)/P600 (parietal and occipital areas) and (2) between cortical activation in left-sided temporal and bilateral occipital/parietal areas and working memory capacity. These results suggest the recruitment of a temporo-frontal network in CI users during speech processing and a close connection between ERP effects and cortical activation in CI users. The observed differences in speech-evoked cortical activation patterns for CI users with higher and lower speech intelligibility suggest distinct processing strategies during speech rehabilitation with CI.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7431776 | PMC |
http://dx.doi.org/10.3389/fnins.2020.00787 | DOI Listing |
Cureus
November 2024
Department of Surgery - Center for Anatomical Science and Education, Saint Louis University School of Medicine, St. Louis, USA.
Polymicrogyria (PMG) is the most common malformation of cortical development (MCD) and presents as an irregularly patterned cortical surface with numerous small gyri and shallow sulci leading to various neurological deficits including developmental delays, intellectual disability, epilepsy, and language and motor issues. The presentation of PMG varies and is often found in conjunction with other congenital anomalies. Histologically, PMG features an abnormal cortical structure and dyslamination, resulting in its classification as a defect of neuronal migration and organization.
View Article and Find Full Text PDFCureus
November 2024
Orthopaedics, Virginia Commonwealth University School of Medicine, Richmond, USA.
Distal femoral anterior cortical perforation is a rare complication of intramedullary nailing for proximal femur fractures. Awareness and intraoperative preventive measures are key to minimizing the risk of this complication. We report a case of a patient who experienced an anterior cortical breach of the distal femur during routine antegrade nailing for an intertrochanteric fracture, which was attributed to a sclerotic lesion in the distal femur.
View Article and Find Full Text PDFFront Hum Neurosci
December 2024
Department of Psychology and Institute of Neuroscience, University of Nevada, Reno, NV, United States.
The neural underpinnings of working memory (WM) have been of continuous scientific interest for decades. As the understanding of WM progresses and new theories, such as the distributed view of WM, develop, the need to advance the methods used to study WM also arises. This perspective discusses how building from the state-of-the-art in the field of transcranial magnetic stimulation (TMS), and utilising cortico-cortical TMS, may pave the way for testing some of the predictions proposed by the distributed WM view.
View Article and Find Full Text PDFSleep Adv
December 2024
Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan.
Study Objectives: Astrocytes change their intracellular calcium (Ca) concentration during sleep/wakefulness states in mice. Furthermore, the Ca dynamics in astrocytes vary depending on the brain region. However, it remains unclear whether alterations in astrocyte activity can affect sleep-wake states and cortical oscillations in a brain region-dependent manner.
View Article and Find Full Text PDFCereb Cortex
December 2024
State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875, China.
Neural oscillations are fundamental for brain function and govern various cognitive processes. Recent functional magnetic resonance imaging advances offer the opportunity to study frequency-specific properties of blood-oxygen-level-dependent oscillations at multiple frequency bands. However, most have focused on spontaneous brain activity in the resting state, leaving a gap in direct evidence regarding the specific activations of cognitive tasks across different frequency bands.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!