Search Results (46)

Developmental dyslexia (DD) often involves difficulties in phonological processing of speech. Objectives: While underlying neural changes have been identified in terms of stimulus- and task-related responses within specific brain regions and their neural connectivity, there is still limited understanding of how these changes affect the overall organization of brain networks. Methods: This study used EEG and functional network analysis, focusing on small-world propensity across various frequency bands (from δ to γ), to explore the global brain organization during the auditory discrimination of words and pseudowords in children with DD. Results: The main finding revealed a systemic inefficiency in the functional network of individuals with DD, which did not achieve the optimal small-world propensity. This inefficiency arises from a fundamental trade-off between localized specialization and global communication. During word listening, the δ-/γ1-networks (related to impaired syllabic and phonemic processing of words) and the θ-/β-networks (related to pseudoword listening) in the DD group showed lower local clustering and connectivity compared to the control group, resulting in reduced functional segregation. In particular, the θ-/β-networks for words in the DD group exhibited a less optimal balance between specialized local processing and effective global communication. Centralized midline hubs, such as the postcentral gyrus (PstCG) and inferior frontal gyrus (IFG), which are crucial for global coordination, attention, and executive control, were either absent or inconsistent in individuals with DD. Consequently, the DD network adopted a constrained, motor-compensatory, and left-lateralized strategy. This led to the redirection of information flow and processing effort toward the left PstCG/IFG loop, interpreted as a compensatory effort to counteract automatic processing failures. Additionally, the γ1-network, which is involved in phonetic feature binding, lacked engagement from posterior sensory hubs, forcing this critical process into a slow and effortful motor loop. The γ2-network exhibited unusual activation of right-hemisphere posterior areas during word processing, while it employed a simpler, less mature routing strategy for pseudoword listening, which further diminished global communication. Conclusions: This functionality highlights the core phonological and temporal processing deficits characteristic of dyslexia. Full article

Background: Language mapping is a critical component of epilepsy surgery, as postoperative language deficits can significantly impact patients’ quality of life. Electrical stimulation mapping has emerged as a valuable tool for identifying eloquent areas of the brain and minimising post-surgical language deficits. However, recent studies have shown that language deficits can occur despite language mapping, potentially due to variability in stimulation techniques and language task selection. The validity of specific linguistic tasks for mapping different cortical regions remain inadequately characterised. Objective: To systematically evaluate the validity of linguistic tasks used during electrical cortical stimulation (ECS) for language mapping in epilepsy surgery, analyse task-specific responses across cortical regions, and assess current evidence supporting optimal task selection for different brain areas. Methods: Following PRISMA [2020] guidelines, a systematic literature search was conducted in PubMed and Scopus covering articles published from January 2013 to November 2025. Studies on language testing with electrical cortical stimulation in epilepsy surgery cases were screened. Two reviewers independently screened 956 articles, with 45 meeting the inclusion criteria. Data extraction included language tasks, stimulation modalities (ECS, SEEG, ECoG, DECS), cortical regions and language error types. Results: Heterogeneity in language testing techniques across various centres was identified. Visual naming deficits were primarily associated with stimulation of the posterior and basal temporal regions, fusiform gyrus, and parahippocampal gyrus. Auditory naming elicited impairments in the posterior superior and middle temporal gyri, angular gyrus, and fusiform gyrus. Spontaneous speech errors varied, with phonemic dysphasic errors linked to the inferior frontal and supramarginal gyri, and semantic errors arising from superior temporal and perisylvian parietal regions. Conclusions: Task-specific language mapping reveals distinct cortical specialisations, with systematic patterns emerging across studies. However, marked variability in testing protocols and inadequate standardisation limit reproducibility and cross-centre comparisons. Overall, refining and standardising the language task implementation process could lead to improved outcomes, ultimately minimising resection-related language impairment. Future research should validate task–region associations through prospective multicentre studies with long-term outcome assessment. Full article

Background and Objectives: Post-stroke aphasia (PSA) severely limits communication and quality of life. This case study explores the impact of an integrated Neurologic Music Therapy (NMT) approach, combining Melodic Intonation Therapy (MIT) and Therapeutic Singing (TS), on language recovery and brain reorganization in a 59-year-old woman with non-fluent motor aphasia following an ischemic stroke. Methods: Over 8 weeks, the patient underwent 24 sessions of MIT alongside standard speech therapy. Language abilities were assessed using the Western Aphasia Battery-Revised, while fMRI scans captured neurophysiological changes pre- and post-intervention. Results: The results showed significant language improvements: spontaneous speech increased by 68.9%, auditory comprehension by 30.8%, and naming by 83.3%. The Aphasia Quotient rose from 39.3 to 61.4, marking a shift from severe to moderate aphasia. Neuroimaging revealed heightened activation in both hemispheres, especially in the superior frontal and parietal regions, supplementary motor area, and superior temporal gyrus. Increased engagement of the limbic system, particularly the paracingulate gyrus, pointed to emotional involvement and widespread cortical reorganization. Conclusions: These findings highlight the effectiveness of integrating MIT and TS with emotionally meaningful music, supporting language recovery and neural plasticity in PSA. Full article

Vascular dementia (VaD) is a heterogeneous group of brain disorders caused by cerebrovascular pathologies and the second most common cause of dementia, accounting for over 20% of cases and posing an important global health concern. VaD can be caused by cerebral infarction or injury in critical brain regions, including the speech area of the dominant hemisphere or arcuate fasciculus of the dominant hemisphere, leading to notable cognitive impairment. Although the exact causes of dementia remain multifactorial and complex, oxidative stress (reactive oxygen species), neuroinflammation (TNFα, IL-6, and IL-1β), and inflammasomes are considered central mechanisms in its pathology. These conditions contribute to neuronal damage, synaptic dysfunction, and cognitive decline. Thus, antioxidants and anti-inflammatory agents have emerged as potential therapeutic targets in dementia. Recent studies emphasize that cerebrovascular disease plays a dual role: first, as a primary cause of cognitive impairment and then as a contributor to the manifestation of dementia driven by other factors, such as Alzheimer’s disease and other neurodegenerative conditions. This comprehensive review of VaD focuses on molecular mechanisms and their consequences. We provided up-to-date knowledge about epidemiology, pathophysiological mechanisms, and current therapeutic approaches for VaD. Full article

Background/Objectives: Cerebral Palsy (CP) is a non-progressive clinical condition characterized by secondary issues, including speech impairments. Our study aims to evaluate the volumes of brain areas related to speech in patients diagnosed with CP between the ages of 0–17. Methods: this study includes the images of 84 children: 42 in the control group who applied to the hospital between the specified dates and were reported as healthy by MRI from the patient records, and 42 patients with CP. Results: in the CP group, white and gray matter, cerebrum, cerebellum, thalamus, lobus frontalis, lobus temporalis, lobus parietalis, lobus insularis, gyrus cinguli, and nuclei basales volumes were observed to decrease statistically significantly compared to the control group (p ˂ 0.001). Conclusions: we found a significant decrease in the volumes of speech-related brain areas in CP patients, indicating that CP can significantly impact the brain’s speech-related regions. Full article

Objectives: The effects of brain tumors located in the supplementary motor area (SMA) have so far been described mainly in the context of motor and speech disorders. There are few studies that have considered other cognitive domains, so this study aimed to fill this gap by focusing on examining attention and working memory in a population of patients with gliomas in the SMA region. Methods: This study included 50 patients diagnosed with gliomas located in the SMA who have not yet had any treatment and 57 demographically matched healthy individuals. A set of neuropsychological tests was conducted to assess attention and working memory: Digit Span from WAIS-R, Visual Elevator from TEA, Verbal Fluency Test (switching condition), and Color Trails Test (CTT). Results: The analyses showed that patients scored lower in most of the evaluated tests and indicators, namely in Digit Span-forward (t = −2.05; p = 0.022), Digit Span-backward (t = −2.63; p = 0.005), CTT-2 (t = 4.24; p = 0.001), CTT-interference (t = 2.31; p = 0.012), Visual Elevator-time (t = 1.83; p = 0.035), Visual Elevator-accuracy (t = −2.42, p = 0.010), and Verbal Fluency-switching (t = −3.41; p = 0.001). A significant relationship was also demonstrated between the grade of tumor malignancy and the results achieved in some of the neuropsychological tests. The lateralization of the tumor, the size of the lesion, and the presence of epilepsy did not prove to be particularly significant. Conclusions: Due to the significant decline in cognitive performance in terms of attention and working memory, we believe that every patient with a tumor in the SMA should undergo a detailed neuropsychological examination, which will profile their functioning and help tailor the best possible psychological care. Full article

Speech disorders encompass a complex interplay of neuroanatomical, genetic, and environmental factors affecting individuals’ communication ability. This review synthesizes current insights into the neuroanatomy, genetic underpinnings, and environmental influences contributing to speech disorders. Neuroanatomical structures, such as Broca’s area, Wernicke’s area, the arcuate fasciculus, and basal ganglia, along with their connectivity, play critical roles in speech production, comprehension, and motor coordination. Advances in the understanding of intricate brain networks involved in language offer insights into typical speech development and the pathophysiology of speech disorders. Genetic studies have identified key genes involved in neural migration and synaptic connectivity, further elucidating the role of genetic mutations in speech disorders, such as stuttering and speech sound disorders. Beyond the biological mechanisms, this review explores the profound impact of psychological factors, including anxiety, depression, and neurodevelopmental conditions, on individuals with speech disorders. Psychosocial comorbidities often exacerbate speech disorders, complicating diagnosis and treatment and underscoring the need for a holistic approach to managing these conditions. Future directions point toward leveraging genetic testing, digital technologies, and personalized therapies, alongside addressing the psychosocial dimensions, to improve outcomes for individuals with speech disorders. This comprehensive overview aims to inform future research and therapeutic advancements, particularly in treating fluency disorders like stuttering. Full article

Objectives: Our aim was to evaluate the possible long-term cerebral deposition of amyloid-β in patients with PD treated with subthalamic nucleus deep brain stimulation (STN-DBS) and its possible influence on axial and cognitive variables. Methods: Consecutive PD patients treated with bilateral STN-DBS with a long-term follow-up were included. The amyloid-β deposition was evaluated postoperatively through an 18F-flutemetamol positron emission tomography (PET) study. Axial symptoms were assessed using a standardized clinical–instrumental approach. The speech was assessed by perceptual and acoustic analysis, while gait was assessed by means of the instrumented Timed Up and Go test (iTUG). Motor severity was evaluated by applying the UPDRS part III score and subscores, while cognitive functions were assessed through a complete neuropsychological assessment. Different stimulation and drug conditions were assessed: on-stimulation/off-medication, off-stimulation/off-medication, and on-stimulation/on-medication conditions (single- and dual-task). Results: In total, 19 PD patients (male: 11; age: 63.52 years; on-stimulation/on-medication UPDRS-III: 17.05) with a five-year postoperative follow-up were included. The amyloid-β deposition was found in 21% of patients (4/19) with a prevalent involvement of prefrontal, limbic, and parietal areas. Compared with patients without amyloid-β deposition, PD patients with positive 18F-flutemetamol in the PET study showed a higher preoperative UPDRS-I (p = 0.037) score. Conclusions: Our results suggest that in the long term, after STN-DBS, a significant percentage of PD patients may present brain amyloid-β deposition. However, larger samples are needed to evaluate the possible role of amyloid-β deposition in the development of axial and cognitive alterations after surgery. Full article

Infantile neuroaxonal dystrophy (INAD) is a rare neurodegenerative disorder affecting 1:1,000,000 children. It results from pathogenic variants in the PLA2G6 gene located on chromosome 22q13.1. The onset of symptoms usually occurs between 6 and 18 months, causing developmental regression leading to debilitating symptoms such as muscle weakness, dementia, and loss of basic skills. Eventually, it progresses to life-threatening symptoms, including breathing difficulties, which limit the life expectancy to 5–10 years. While potential genetic therapies for treatment are being developed, they are yet to be approved for use, and management remains essentially supportive. This case report is about a nine-year-old Pakistani girl with INAD. She presented with recurrent chest infections, developmental regression, loss of speech, paralysis, hypertension, and eventually breathing difficulties. Brain magnetic resonance imaging and genetic testing confirmed the diagnosis. This case posed diagnostic challenges in view of its overlapping clinical presentation. Through this report, we aim to raise awareness about this condition among practitioners, outline the importance of genetic counseling in susceptible couples, and suggest potential areas of further research. Full article

Speech-language therapy (SLT) is the most effective technique to improve language performance in persons with aphasia. However, residual language impairments remain even after intensive SLT. Recent studies suggest that combining transcranial direct current stimulation (tDCS) with SLT may improve language performance in persons with aphasia. However, our understanding of how tDCS and SLT impact brain and behavioral relation in aphasia is poorly understood. We investigated the impact of tDCS and SLT on a behavioral measure of scripted conversation and on functional connectivity assessed with multiple methods, both resting-state functional magnetic resonance imaging (rs–fMRI) and resting-state electroencephalography (rs–EEG). An individual with aphasia received 15 sessions of 20-min cathodal tDCS to the right angular gyrus concurrent with 40 min of SLT. Performance during scripted conversation was measured three times at baseline, twice immediately post-treatment, and at 4- and 8-weeks post-treatment. rs–fMRI was measured pre-and post-3-weeks of treatment. rs–EEG was measured on treatment days 1, 5, 10, and 15. Results show that both communication performance and left hemisphere functional connectivity may improve after concurrent tDCS and SLT. Results are in line with aphasia models of language recovery that posit a beneficial role of left hemisphere perilesional areas in language recovery. Full article

Despite the improved living standards in South Korea, people with disabilities still experience health disparities. Therefore, we analyzed differences in mortality rates among people with disabilities according to income level and residential area using representative data from the National Health Insurance Service in South Korea. Descriptive statistics and Cox proportional risk models were used to identify the risk factors for mortality affecting people with disabilities stratified by income level and residential area. Those living in non-metropolitan areas and low-income households had high mortality risks, suggesting that income level and residential area were related to mortality risk. The mortality risk of those with a high-income level was 1.534 times higher in non-metropolitan areas than in Seoul metropolitan areas (95% confidence interval [CI] = 1.44–1.63). Among people with low income living in non-metropolitan areas, the crude hazard ratios of mortality risk were 1.26 (95% CI = 1.14–1.39), 1.44 (95% CI = 1.34–1.54), and 1.39 (95% CI = 1.20–1.61) for those with brain lesions, sensory impairment (visual/hearing/speech impairment), and kidney failure, respectively. No significant differences were observed between people with autism in non-metropolitan and Seoul metropolitan areas and those with low- and high-income levels. Health issues and countermeasures are crucial to reduce mortality risk among people with disabilities. Full article

Apraxia of speech is a persistent speech motor disorder that affects speech intelligibility. Studies on speech motor disorders with transcranial Direct Current Stimulation (tDCS) have been mostly directed toward examining post-stroke aphasia. Only a few tDCS studies have focused on apraxia of speech or childhood apraxia of speech (CAS), and no study has investigated individuals with CAS and Trisomy 21 (T21, Down syndrome). This N-of-1 randomized trial examined the effects of tDCS combined with a motor learning task in developmental apraxia of speech co-existing with T21 (ReBEC RBR-5435x9). The accuracy of speech sound production of nonsense words (NSWs) during Rapid Syllable Transition Training (ReST) over 10 sessions of anodal tDCS (1.5 mA, 25 cm) over Broca’s area with the cathode over the contralateral region was compared to 10 sessions of sham-tDCS and four control sessions in a 20-year-old male individual with T21 presenting moderate–severe childhood apraxia of speech (CAS). The accuracy for NSW production progressively improved (gain of 40%) under tDCS (sham-tDCS and control sessions showed < 20% gain). A decrease in speech severity from moderate–severe to mild–moderate indicated transfer effects in speech production. Speech accuracy under tDCS was correlated with Wernicke’s area activation (P3 current source density), which in turn was correlated with the activation of the left supramarginal gyrus and the Sylvian parietal–temporal junction. Repetitive bihemispheric tDCS paired with ReST may have facilitated speech sound acquisition in a young adult with T21 and CAS, possibly through activating brain regions required for phonological working memory. Full article

Multisensory integration is essential for the quick and accurate perception of our environment, particularly in everyday tasks like speech perception. Research has highlighted the importance of investigating bottom-up and top-down contributions to multisensory integration and how these change as a function of ageing. Specifically, perceptual factors like the temporal binding window and cognitive factors like attention and inhibition appear to be fundamental in the integration of visual and auditory information—integration that may become less efficient as we age. These factors have been linked to brain areas like the superior temporal sulcus, with neural oscillations in the alpha-band frequency also being implicated in multisensory processing. Age-related changes in multisensory integration may have significant consequences for the well-being of our increasingly ageing population, affecting their ability to communicate with others and safely move through their environment; it is crucial that the evidence surrounding this subject continues to be carefully investigated. This review will discuss research into age-related changes in the perceptual and cognitive mechanisms of multisensory integration and the impact that these changes have on speech perception and fall risk. The role of oscillatory alpha activity is of particular interest, as it may be key in the modulation of multisensory integration. Full article

Brain–Computer Interfaces (BCIs) have become increasingly popular in recent years due to their potential applications in diverse fields, ranging from the medical sector (people with motor and/or communication disabilities), cognitive training, gaming, and Augmented Reality/Virtual Reality (AR/VR), among other areas. BCI which can decode and recognize neural signals involved in speech and handwriting has the potential to greatly assist individuals with severe motor impairments in their communication and interaction needs. Innovative and cutting-edge advancements in this field have the potential to develop a highly accessible and interactive communication platform for these people. The purpose of this review paper is to analyze the existing research on handwriting and speech recognition from neural signals. So that the new researchers who are interested in this field can gain thorough knowledge in this research area. The current research on neural signal-based recognition of handwriting and speech has been categorized into two main types: invasive and non-invasive studies. We have examined the latest papers on converting speech-activity-based neural signals and handwriting-activity-based neural signals into text data. The methods of extracting data from the brain have also been discussed in this review. Additionally, this review includes a brief summary of the datasets, preprocessing techniques, and methods used in these studies, which were published between 2014 and 2022. This review aims to provide a comprehensive summary of the methodologies used in the current literature on neural signal-based recognition of handwriting and speech. In essence, this article is intended to serve as a valuable resource for future researchers who wish to investigate neural signal-based machine-learning methods in their work. Full article

Artificial intelligence has revolutionized image and speech recognition, but the neural network fitting method has limitations. Neuromorphic chips that mimic biological neurons can better simulate the brain’s information processing mechanism. As the basic computing component of the new neuromorphic network, the new neural computing unit’s design and implementation have important significance; however, complex dynamical features come with a high computational cost: approximate computing has unique advantages, in terms of optimizing the computational cost of neural networks, which can solve this problem. This paper proposes a hardware implementation of an approximate spiking neuron structure, based on a simplified piecewise linear model (SPWL), to optimize power consumption and area. The proposed structure can achieve five major neuron spiking generation patterns. The proposed design was synthesized and compared to similar designs, to evaluate its potential advantages and limitations. The results showed that the approximate spiking neuron had the lowest computational cost and the fastest computation speed. A typical spiking neural network was constructed, to test the usability of the SPWL model. The results showed that the proposed approximate spiking neuron could work normally in the spiking neural network, and achieved an accuracy of 94% on the MNIST dataset. Full article