Search Results (731)

Learning disabilities are traditionally conceptualized as domain-specific disorders arising from deficits in reading, attention, or numerical processing. Although these approaches have substantially advanced understanding of dyslexia, attention-deficit/hyperactivity disorder (ADHD), and dyscalculia, they do not fully explain the marked heterogeneity, developmental variability, frequent comorbidity, or changing learning trajectories observed across children. This conceptual review proposes a developmental timing framework in which learning disabilities emerge, in many cases, from maturational asynchrony among interacting neural, cognitive, linguistic, sensorimotor, and executive systems rather than from isolated deficits within a single domain. Drawing on evidence from developmental neuroscience, cognitive psychology, neuroeducation, developmental systems theory, and learning sciences, we synthesize research on the developmental coordination of language, executive function, attention, motor control, working memory, symbolic learning, and numerical cognition across childhood. Within this framework, dyslexia, ADHD-related learning difficulties, dyscalculia, and mixed learning profiles are interpreted as distinct developmental expressions of differing patterns of cross-system asynchrony interacting with the increasing cognitive demands of formal education. We distinguish maturational asynchrony from related concepts, including developmental variability, developmental cascades, and multiple-deficit models, and propose measurable indicators through which the framework may be empirically evaluated. The framework further generates testable predictions concerning longitudinal developmental trajectories, educational transitions, developmental fit, and timing-sensitive intervention. Rather than replacing established cognitive accounts of learning disabilities, the developmental timing framework provides an integrative developmental architecture within which existing theories can be understood while offering a basis for future longitudinal and intervention research. This perspective highlights the importance of aligning educational expectations and instructional practices with children’s evolving neurodevelopmental readiness rather than chronological age alone. Full article

Background/Objectives: The primary objective of the present study was to assess motor competence and identify motor difficulties among Greek adolescents using the Movement Assessment Battery for Children—2nd Edition (MABC-2). The secondary aim was to evaluate associations and differences across gender, school grade (age), BMI, hand dominance, extracurricular organized PA participation, and school type in relation to motor competence. Methods: The MABC-2 was utilized primarily as an exploratory screening instrument to identify potential motor difficulties within the sampled adolescent cohort (N = 742; M_age = 13.98 yrs.), rather than as a definitive clinical diagnostic tool for Developmental Coordination Disorder. Results: This study identified a low prevalence of motor difficulties among the sampled adolescents (1.5% definite, 3.6% at risk). Preliminary trends suggested a 1.5:1 boy-to-girl motor difficulty ratio. Within exploratory analyses, “at-risk” boys scored lower in balance and manual dexterity, while girls showed potential challenges in ball skills. Tentative subgroup analyses indicated that physical activity participants within these cohorts scored higher in balance and ball skills, though small sample sizes warrant caution. Other demographic or school environmental factors—specifically academic grades, body mass index, handedness, and school types—showed no clear associations with motor competence. Conclusions: This study identified a low prevalence of motor difficulties among Greek adolescents, with preliminary trends suggesting that structured extracurricular activity may support motor development. The findings indicate potential gender variations in specific motor domains and highlight the need for longitudinal research to confirm these observations. Full article

Intuitive response and multi-objective control are well-known features of Finite Control Set Predictive Torque Control (FCSPTC). However, its implementation difficulty is a result of limitations such as high computations, strong model parameter dependency in control, and time-consuming tuning efforts for weighting factors in a cost function. Particularly, when FCSPTC is applied to a Multi-Level Inverter (MLI)-supplied motor drive, computation complexity is predominant. The proposed research work in this paper offers a new FCSPTC to dual two-level VSIs supplied for an Open Winding Permanent Magnet Synchronous Motor (OWPMSM) drive. The contributions of the proposed FCSPTC for the OWPMSM drive are the following. (i) Simplicity: There are fewer operational steps in control and limited evaluations with five prediction voltage vectors (VVs) out of 19, and a flux weighting-factor-less design is used by adopting a voltage cost function. (ii) Robustness: There is less parameter dependency in control through the involvement of stator resistance only. (iii) Switching frequency reduction: The application of an optimal switching state from the redundant switching states of optimal VVs is used to generate fewer switching state transitions, where the process is independent from the switching frequency weighting factor. According to theoretical and experimental findings, it is evident that the proposed FCSPTC technique operates effectively without the weighting factor and provides the above-stated features, resulting in an optimal response in flux, torque and current, switching frequency reduction, and low-complexity operation. The proficiency of the proposed FCSPTC technique is experimentally verified by comparing it with existing control schemes. Full article

Barth syndrome (BTHS) is a rare, X-linked genetic disorder caused by mutations in the enzyme TAFAZZIN (TAZ), resulting in insufficient cardiolipin (CL) remodeling and mitochondrial dysfunction. While BTHS respiratory distress and breathing difficulties are commonly reported, the precise role of intrinsic respiratory tissue vulnerabilities has only recently begun to be appreciated. Historically, BTHS respiratory distress is frequently attributed to secondary consequences like cardiomyopathy or generalized skeletal myopathy, leaving the intrinsic vulnerability of vital respiratory muscles poorly understood. Using a patient-tailored point mutant knock-in mouse model (Taz^PM) harboring a stable but enzymatically deficient Taz^D75H protein, we investigated the autonomous physiological and metabolic responses in the diaphragm and lungs. Contrary to the paradigm that respiratory muscles are unaffected, Taz^PM diaphragms exhibit structurally abnormal mitochondria and undergo a survival-critical, bifurcated compensatory remodeling response to prevent fatal respiratory failure under severe bioenergetic stress. The Taz^PM adaptive mechanism is orchestrated by chronic activation of the mitochondrial Integrated Stress Response (ISR) via the Gcn2/eIF2α signaling pathway. This stress pathway halts global translation to conserve cellular ATP at the expense of reduced NAD+ levels, while selectively upregulating defensive mitokines and metabolic sirtuins and structural muscle remodeling. Furthermore, the Taz^PM diaphragm transitions into a highly specialized, slow-twitch motor system that is expected to reduce the energy cost per contraction. Concurrently, despite Taz^PM lungs exhibiting structurally abnormal mitochondria, they resist generalized mitochondrial collapse despite ADP reduction, executing tissue-specific metabolic reprogramming and localized biochemical adaptations to sustain respiratory homeostasis. Full article

Individuals with post-stroke hemiplegia may experience difficulty performing independent nail care because conventional nail clippers require bilateral hand function, grip strength, and fine motor control. Despite its relevance to personal hygiene and independence, nail care remains underexplored in rehabilitation engineering. The aim of this study was to design and develop a user-centered electric nail clipper for individuals with post-stroke hemiplegia and evaluate the preliminary functional suitability of the finalized prototype under supervised conditions. A sequential mixed-methods, user-centered device-development study was conducted following ISO 9241-210 principles. Phase I involved 10 healthy volunteers who participated in semi-structured interviews and controlled prototype testing to identify preliminary operational, ergonomic, and safety considerations. Stroke-specific functional requirements were additionally informed by the clinical context, relevant literature, and subsequent evaluation in the intended user population. These inputs were translated into engineering requirements and four iterative prototype configurations, which were independently evaluated by a five-member multidisciplinary expert panel. In Phase II, the finalized prototype underwent supervised participant-based evaluation in 20 individuals with post-stroke hemiplegia. These participants constituted the same cohort previously reported in a randomized controlled trial; previously published comparative clinical outcomes were not analyzed as new findings in the present study. Five principal functional considerations informed prototype development: one-handed stabilization, reduced operating effort, controlled nail reduction, operational safety, and practical device handling and debris management. The finalized design incorporated a stabilized triangular tabletop structure, silicone suction base, motor-driven rotary filing mechanism, adjustable operating speed, removable buffing head, debris-collection compartment, LED illumination, and rechargeable power. Prototype 4 received the highest overall expert rating (mean = 4.43, SD = 0.48) and was selected for participant-based evaluation. Under short-term supervised conditions, participants with post-stroke hemiplegia were able to perform one-handed nail care using the finalized prototype, with no device-related adverse events or malfunctions observed. The study demonstrates a structured user-centered pathway for translating functional and contextual requirements into an assistive nail-care device for individuals with post-stroke hemiplegia. The finalized prototype showed preliminary functional suitability during short-term supervised use; however, these findings do not establish comparative clinical effectiveness, long-term safety, or performance during unsupervised use. Larger, longitudinal, and home-based studies incorporating objective performance measures and validated user-reported instruments are warranted. Full article

Attention-deficit/hyperactivity disorder (ADHD) involves difficulties in sustaining attention and resisting distraction. This has motivated the development of feedback-driven environments for cognitive control training. Integrating electroencephalography (EEG) sensors into Virtual Reality (VR) serious games for cognitive therapy remains relatively underexplored and requires reliable, non-invasive brain–computer interfaces. The existing solutions use multi-channel systems that primarily suffer from requiring complex hardware, while not combining motor imagery (MI) with concentration levels. Therefore, this case study evaluates the feasibility and data quality of a lightweight, cost-effective sensor configuration for real-time control of mental state. A non-invasive, eight-channel OpenBCI Cyton board was integrated with an EEG cap using the international 10–20 placement system, alongside a Meta Quest 2 headset, to capture MI and concentration signals directly from the user’s scalp. Signal acquisition was hindered by high impedance and channel railing, which required conductive gel mitigation, while mechanical tension from the VR headset strap introduced motion artifacts and noise. Nevertheless, under stable signal conditions, the optimized eight-channel sensor setup achieved a subject-specific online classification accuracy of up to 90% using the deep learning model “EEGNet”. The findings demonstrate the technical feasibility of acquiring and classifying EEG activity using a low-cost eight-channel sensor configuration in an interactive VR-BCI Serious Gaming application, provided that skin–electrode impedance and mechanical sensor interferences are managed. The results provide a basis for future investigation of such systems in cognitive-training applications, while further studies, including clinical evaluations, are required to assess their applicability in therapeutic contexts. Full article

Pott’s disease, also known as tuberculous spondylodiscitis, accounts for 50% of all forms of skeletal tuberculosis. It is rare in children, especially in low-burden TB countries. We present a case of Pott’s disease with miliary tuberculosis in a 22-month-old child. Furthermore, we provide an exploratory literature review of pediatric cases published in PubMed and Scopus between January 2000 and August 2025, including patients aged 0 to 17 years with confirmed or clinically diagnosed tuberculous spondylodiscitis. Sixty-four cases were included. Most cases (81.3%) involved children from highly endemic countries, particularly India. Median age was 10 years, with a median diagnostic delay of 141.4 days. The most common signs and symptoms were back pain (79.6%), followed by difficulty walking (68.4%). The thoracic spine was the most affected segment (60.3%). Sixty-three received anti-TB therapy, 58% required surgical intervention, and treatment led to overall clinical recovery in 96.9% of cases. Neurological deficits were reported in 46% (paresthesia) and 68.4% (motor weakness), with permanent motor sequelae in 8.1% and persistent spinal deformity (kyphosis) in 14.5%. Our case highlights the importance of considering the suspicion of tuberculous spondylodiscitis, even in low-endemic countries, to achieve early diagnosis and appropriate therapeutic management. Early MRI combined with microbiological confirmation is essential to reduce the risk of severe complications, including neurological sequelae, progressive spinal deformities, and potentially life-threatening outcomes in growing patients. Full article

Background/Objectives: Epidural electrical stimulation (EES) is a valuable intervention for motor recovery after spinal cord injury (SCI). However, evaluating expected outcomes can be challenging due to the difficulty of assessing residual functional connectivity and other key factors underlying the effects of EES. This case study investigates EES with two 8-contact percutaneous electrodes (Perc-EESs) as a prognostic tool and therapeutic bridge for chronic neuromodulation with EES in an individual with clinically motor-complete SCI. Methods: A 40-year-old male (AIS-B, Th5–Th6, >20 years since initial presentation followed by a complex history of progressive deterioration and two subsequent neurosurgical interventions) underwent a 7-day trial using Perc-EES, followed by chronic 5-6-5 Medtronic lead (Paddle-EES) implantation at the L2–S1 segments. Volitional motor control and EMG activity was assessed across three stages: Perc-EES at 5, 7, and 10 days post-enrollment; Paddle-EES at 13, 15, and 18 days post-enrollment; and at a 1-year follow-up (Paddle-EES (1y)). Evaluations were performed in side-lying and upright positions. Results: Without EES, no visible movements were observed. Perc-EES facilitated rhythmic EMG activity and initial voluntary movements, providing an early proof-of-concept that Perc-EES could serve as a preliminary assessment of the patient’s responsiveness to neuromodulation. Paddle-EES (1y) demonstrated a further improvement in motor coordination. Analysis using the Rudolph coefficient showed a distinct shift toward zero. This shift reflects stimulation-associated changes in EMG coordination, moving away from co-activation toward a more alternating activation pattern across side-lying and upright positions. Conclusions: This single-patient feasibility case study suggests that trial Perc-EES may have potential in determining the long-term benefits of chronic Paddle-EES in motor activation after SCI. While these conclusions remain preliminary, these findings can further serve as a potential diagnostic tool to optimize electrode placement and enhance overall recovery in motor-complete SCI patients. Full article

Purpose: Childhood apraxia of speech (CAS) is a motor speech disorder characterized by deficits in speech planning and programming. However, current diagnostic frameworks have been developed primarily from studies of English-speaking children, raising questions regarding their applicability to other languages. This study examined the common and diagnostic speech characteristics of Hebrew-speaking children with CAS as perceived by Israeli speech–language pathologists (SLPs). Method: Two hundred Israeli SLPs with experience diagnosing and/or treating children with CAS completed an online questionnaire. Participants rated 26 speech characteristics on 7-point scales reflecting their perceived frequency and diagnostic specificity in Hebrew-speaking children with CAS. Descriptive analyses included mean ratings and the percentage of clinicians endorsing each characteristic. Results: Increased difficulty with multisyllabic words (M = 6.37) and inconsistent errors (M = 6.32) received the highest frequency ratings and were endorsed by 87.0% and 84.0% of clinicians, respectively, as common characteristics of CAS. Inconsistent errors received the highest diagnostic specificity rating (M = 6.12), followed by groping movements (M = 5.73) and difficulty sequencing syllables (M = 5.48). Prosodic features, including lexical stress errors (M = 3.72) and equal stress patterns (M = 3.73), received ratings at or below the midpoint of the scale and were endorsed by fewer than 20% of clinicians as common characteristics of CAS. Breathy voice (M = 3.11) and consistent hypernasality (M = 2.79), two control characteristics not typically associated with CAS, received the lowest ratings. Conclusions: Israeli SLPs identified syllable sequencing difficulties and inconsistency as the most salient and diagnostically informative characteristics of CAS in Hebrew-speaking children. In contrast, prosodic features, particularly lexical stress errors, were perceived as less common and less central to diagnosis than suggested by English-based diagnostic frameworks. These findings suggest that the clinical manifestation of CAS may be influenced by language-specific phonological and prosodic properties and underscore the need for direct investigation of CAS characteristics in Hebrew-speaking children. Full article

This study investigated the effects of high-definition transcranial alternating current stimulation (HD-tACS) on cognitive–motor dual-task performance and upper-limb multi-joint motor control. Sixteen right-handed healthy male participants completed a double-blind, randomized crossover experiment involving active tACS and sham tACS conditions separated by a one-week washout interval. A 4 × 1 HD-tACS montage was applied over the left dorsolateral prefrontal cortex at 5 Hz for 20 min. Participants performed a synchronous cognitive–motor dual-task paradigm that combined an N-back working memory task with an upper-limb throwing task under different task difficulty levels. Task performance outcomes included accuracy, reaction time, release velocity, peak velocity, movement duration, and dual-task cost. Upper-limb motor control outcomes included elbow and wrist joint range of motion, peak angular velocity, and peak joint flexion and extension moments. Accuracy showed a significant Stimulation × Time interaction. Under active stimulation, adjusted accuracy increased by 5.4 percentage points in N1 and 10.1 percentage points in N2, whereas the corresponding changes under sham stimulation were not significant. Reaction time, release velocity, peak velocity, and movement duration showed no significant stimulation-related changes. Release-velocity DTC also showed a significant Stimulation × Time interaction across N1 and N2. Under active stimulation, the signed DTC shifted upward, indicating a smaller release-velocity decrement relative to N0. The task-specific follow-up was significant for N2 but not N1; however, the Stimulation × Time × Task interaction was not significant. Most upper-limb kinematic and kinetic outcomes showed no significant stimulation-related changes. Active HD-tACS was associated with higher accuracy and a favorable shift in release-velocity DTC, while most motor, kinematic, and kinetic outcomes were unchanged. The effects were limited to selected behavioral outcomes and did not differ significantly between N1 and N2. Full article

Background/Objectives: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease increasingly recognized for extra-motor manifestations, including cognitive dysfunction involving frontal cortical systems. Conventional clinical assessments are primarily behavioral and may not capture subtle alterations in the neural systems that support cognitive performance. This pilot study examined whether wearable functional near-infrared spectroscopy (fNIRS) could detect task-evoked prefrontal hemodynamic differences during the King-Devick Task (KDT), a rapid oculomotor number-naming task that engages visual scanning, attention, processing speed, and verbal response production. Methods: Sixteen participants, including seven individuals with ALS and nine age-matched healthy controls (HC), completed four progressively difficult KDT conditions while prefrontal cortical activity was recorded. Results: As task difficulty increased, response times became slower across participants, while accuracy remained preserved and behavioral performance did not differ significantly between groups. Prefrontal oxygenated hemoglobin (HbO) responses increased with task difficulty across all prefrontal optodes, supporting task-evoked cortical engagement. In contrast, deoxygenated hemoglobin (HbR) responses showed a group-specific pattern in the left dorsolateral prefrontal cortex: individuals with ALS demonstrated progressively increasing HbR responses across difficulty conditions, whereas HC showed relatively stable responses, with group differences emerging at higher difficulty levels. Conclusions: These findings suggest a dissociation between preserved behavioral performance and altered prefrontal hemodynamic regulation in ALS. The observed HbR pattern may reflect differences in cortical recruitment, neurovascular coupling, oxygen extraction, vascular responsiveness, or the efficiency of cortical resource allocation during increasing cognitive-motor demands. Wearable fNIRS may therefore complement behavioral assessments by revealing task-evoked neural alterations that are not evident from performance measures alone. Full article

Background/Objectives: Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is a rare neurometabolic disorder caused by pathogenic variants in the SLC2A1 and a treatable cause of epilepsy and movement disorders. We aimed to describe clinical variability, diagnostic pathways and treatment outcomes in a paediatric case series, with a focus on ketogenic diet management. Methods: We retrospectively reviewed five paediatric patients with genetically confirmed glucose transporter type 1 deficiency syndrome followed at a tertiary center. Clinical presentation, biochemical findings, genetic results, treatment, dietary adherence and outcomes were analyzed. Results: Patients presented with development delay (4/5), movement disorders (4/5) and seizures (2/5), with symptom onset between 4 and 14 months. Diagnosis occurred between 22 and 54 months. Pathogenic SLC2A1 variants were identified in all patients, de novo in three cases. Hypoglycorrhachia was documented in two patients. All patients were treated with a classical ketogenic diet (ratio 1:1 to 3:1). Clinical improvement was observed in four patients, including better seizure control and motor function, although ketone levels were frequently suboptimal. Treatment duration ranged from two to 17 years. Long-term adherence and dietary implementation represented major challenges. Conclusions: Glucose transporter type 1 deficiency syndrome shows marked clinical heterogeneity, which may delay diagnosis. The ketogenic diet is effective in improving seizure control and neurological outcomes, although long-term adherence remains a major challenge. This case series highlights practical difficulties in diagnosis and dietary management in real-world clinical settings. Full article

Background: Developmental topographical disorientation (DTD)-like navigational difficulties can impair everyday orientation and spatial information processing. Objective: We examined whether 8-week virtual reality (VR) orienteering training improves performance on a laboratory spatial memory task in college students with operationally defined DTD-like navigational difficulties and examined task-related cortical changes. Methods: In a randomized controlled trial, 96 students were assigned to VR orienteering, VR exercise, or control groups (n = 32/group). The exercise groups trained twice weekly for 45 min for 8 weeks at moderate intensity (64–76% HRmax). Before and after the intervention, all participants completed a delayed visuospatial recognition task designed to assess spatial-memory-related processing, while functional near-infrared spectroscopy measured hemodynamic changes in prefrontal and sensorimotor cortices. The post-test session was conducted 48 h after the final scheduled session, with no immediate post-exercise assessment. Results: VR orienteering produced greater improvement in spatial-memory-task accuracy and reaction time than the other groups. After BH-FDR correction across eight ROIs, training-specific reductions in task-related activation were observed in the right primary motor cortex and left frontopolar area. Within the VR orienteering group, pre-to-post change in left orbitofrontal activation was negatively associated with change in spatial-memory-task accuracy, Pearson r(30) = −0.819, 95% CI [−0.908, −0.658], p < 0.001, R² = 0.670; the association remained significant after eight-ROI BH-FDR correction (adjusted p < 0.001). Conclusions: VR orienteering improved performance on the laboratory spatial memory task and was accompanied by reduced task-related cortical recruitment. Greater reductions in L-OFC activation were linked to greater improvements in accuracy, identifying L-OFC activation change as a neural correlate of training-related spatial-memory improvement. Full article

Handwriting is a fundamental fine motor skill in early childhood development, yet between 10% and 30% of school-age children experience significant difficulties in its acquisition. Existing automated assessment approaches predominantly classify whether the correct character was produced, rather than evaluating the morphological quality of the stroke itself—the level at which handwriting difficulties are believed to manifest. This article addresses this gap by presenting the design, implementation, and technical evaluation of an interactive social robot shaped like a capybara, developed to support Spanish-language handwriting learning in preschool children through stroke-level, rather than character-level, assessment. The system integrates a Raspberry Pi 5, a 15.6-inch touchscreen, and a stroke morphological comparison algorithm implemented with the Open Source Computer Vision Library. The evaluation engine performs preprocessing, region-of-interest masking, and pixel-level coverage analysis based on the standard recall formulation, translated into 1-to-5-star multimodal feedback. A controlled technical evaluation of 360 trials, conducted by four trained adult evaluators, yielded an overall recognition rate of 82.78% (95% CI: 78.54–86.33%) and a mean response time of 0.68 s, well below the threshold identified in the literature as critical for sustaining engagement in preschool children. Recognition was statistically equivalent across character categories (p = 0.547) but differed markedly across stroke-quality levels (p < 0.001), evidencing the formative sensitivity of the algorithm. Exploratory observations in two Peruvian preschools indicated operational stability and children’s spontaneous engagement with the system. These results position the prototype as a technically validated, replicable foundation—based on general-purpose embedded hardware—for future pedagogically oriented research on child–robot interaction in handwriting instruction. Full article

To address the difficulty of obtaining real fault data from elevator traction drive systems and the potential overestimation caused by random window splitting, this study uses two public motor-drive datasets to examine how validation protocols, signal modalities, and noise conditions affect diagnostic evaluation, rather than to claim direct validation of field performance in actual elevator systems. A PMSM inverter-drive fault diagnosis dataset is used as the main dataset to evaluate multiclass classification performance based on electrical, thermal, and derived features. A multimodal MOTOR dataset is used as an independent secondary dataset to analyze the effects of validation protocols, signal modalities, and noise disturbance on model performance. The results show that Random Forest achieves a Macro-F1 of 0.9901 under random splitting on the PMSM dataset. On the MOTOR dataset, the Macro-F1 reaches 0.9682 under random splitting but decreases to 0.5856 under strict block-split validation, indicating that random window splitting may substantially overestimate generalization performance for continuous signal data. The modality ablation results show that the vibration-only modality performs best under strict block-split validation, with a Macro-F1 of 0.6420, whereas the noise analysis indicates that this modality is sensitive to disturbance. The results show that public motor-drive data can provide a reproducible methodological test bed for studying evaluation bias and signal reliability, but they should not be interpreted as direct evidence of diagnostic performance in actual elevator systems. Full article