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In recent years, advances in structural health monitoring (SHM) of composite materials have been observed, driven by the adoption of intelligent diagnostic techniques. Vibration signals, which embed valuable structural health information, have been increasingly utilized in SHM. However, the high dimensionality of this data has necessitated significant computational resources and has made the differentiation between health states more complex. Highlighting the need for effective feature extraction and dimensionality reduction (DR), a study is conducted. In this research, advanced DR techniques, i.e., principal component analysis (PCA), locally linear embedding (LLE), t‐distributed stochastic neighbors embedding (t‐SNE), and uniform manifold approximation and projection (UMAP), are applied to an experimental dataset from a wind turbine blade under various health and environmental conditions (controlled‐environment vibration signals). The extracted features are then processed for the classification phase, and it is found that UMAP provides the best performance, albeit with a slightly increased computational demand. The findings from this research offer invaluable insights for researchers and engineers, assisting in the selection of the most appropriate DR method for SHM, and weighing up accuracy against computational time. [ABSTRACT FROM AUTHOR]

Ultrasonic guided waves (UGWs) based structural health monitoring (SHM) systems are widely used in several engineering fields for real‐time damage detection, since they are particularly sensitive to material local changes, induced, i.e., by a damage. This paper aims to investigate on the use of SHM systems in additively manufactured laminate. Specifically, a flat panel made of XSTRAND GF30‐PA6 material, fabricated by Ultimaker S5 fused filament fabrication (FFF) based 3D printer, is used as a case study. Signals recorded by a piezoelectrics (PZTs) array are analyzed to highlight the dispersive behavior of symmetric, S0, mode along different measurement paths in the excitation frequency range of 100–300 kHz. [ABSTRACT FROM AUTHOR]

Background and Aim: Experiencing dizziness/vertigo is often an indication of dysfunction in the vestibular system. Recent findings show a connection between peripheral vestibular dysfunction and cognitive impairments. The Neuropsychological Vertigo Inventory (NVI) can assess physical, emotional, and cognitive issues in individuals with dizziness/vertigo. The aim of this research was to translate, cultural adaptation and evaluation of the reliability and validity of NVI to Persian. Methods: In this descriptive-analytical study, the NVI scale was translated and adapted to the Iranian cultural context following the international quality of life assessment protocol for translation and equivalence. After obtaining face validity, the scale was administered to 140 patients with peripheral vestibular system dysfunction and 70 control group (age between 25 and 80 years). After one week, 50 participants were asked to complete the questionnaire again. Eventually, reliability was evaluated with both methods of internal consistency and test-retest reproducibility. Results: Out of the 28 items in the NVI scale, 3 items were modified to better align with the cultural conditions of Iranians. The impact scores for most items in this scale were found to be higher than 1.5. The Cronbach's alpha coefficient values for the overall scale (0.90) and test-retest reliability with intra-class correlation coefficient for the overall scale (0.91) were confirmed. Conclusion: The Persian version of NVI scale demonstrates excellent validity and reliability, and it exhibits a high level of content alignment with the original version. Therefore, it can be a useful tool to better understand the physical, emotional and cognitive disturbances in patients with vertigo/dizziness. [ABSTRACT FROM AUTHOR]

Ultrasonic guided waves (UGW) are widely used in structural health monitoring (SHM) systems due to the sensitivity of their propagation mechanisms to local material changes, i.e., those induced by damage. Post-processing of the signals gathered by piezoelectric sensors, typically used for both the excitation and the sensing of UGW, is a fundamental step to extract all the peculiar features that can be related to both damage location and severity. This research probes the efficacy of machine learning (ML) models in discerning damage location (R-Classification) and size (S-Classification). Seven supervised ML classifiers were examined: Ensemble-Subspace K-Nearest Neighbors (KNN), Ensemble-Bagged Trees, KNN-Fine, Ensemble-Boosted Trees, Support Vector Machine (SVM), Linear Discriminant, and SVM-Quadratic. The experimental dataset comprised measurements from varied reversible damage configurations on a composite panel, represented by wooden cuboids of single and three different sizes. Signal noise was minimized by performing a low-pass filter, and sequence forward selection-aided feature selection. The optimized ensemble classifier proved to be the most precise for R-Classification (95.83% accuracy), while Ensemble-Subspace KNN excelled in S-Classification (98.1% accuracy). This method offers accurate, efficient damage diagnosis and classification in composite structures, promising potential applications in aerospace, automotive, and civil engineering sectors. [ABSTRACT FROM AUTHOR]

Despite some proposed roles for the diagnostic impact of the cervical vestibular evoked myogenic potential test in the patients with Meniere's disease, the role of this test as an objective instrument in following up the patients with Meniere's disease who underwent. Intratympanic steroid injection is not cleared. In a prospective study, thirty-one adult patients with definite one-sided Meniere's disease with vertigo as main complaint refractory to medical treatments for three months, were selected. Patients underwent three times of intratympanic dexamethasone injection with one-week intervals. We performed cervical vestibular evoked myogenic potential test at first and four weeks after the last injection for all participants. We followed the patients for one year. The study results were analyzed with the chi-square test. Cervical vestibular evoked myogenic potential test could not be recorded in 26 patients (83.9%), and the test results were abnormal in the remaining 5 patients. The results were abnormal in the healthy ear of 32.3% of the patients. Despite the clinical improvement of the symptoms after intratympanic injection, the test results were not changed. Cervical vestibular evoked myogenic potential test could not be recorded in the majority of the patients with Meniere's disease; while it is usually recorded in normal ears. On the other hand, results of the cervical vestibular evoked myogenic potential test do not change during the early phase after treatment and could not be a good option for follow up and evaluating the response in this situation. © 2018 Tehran University of Medical Sciences. All rights reserved. [ABSTRACT FROM AUTHOR]

Introduction: Meniere's disease (MD) is a disease of the inner ear that presents itself with repeated episodes of vertigo (96.2%), tinnitus (91.1%), and sensorineural hearing loss (87.7 %). In this article we sought to assess the effects of intratympanic (IT) injections of dexamethasone on definite cases of MD using electrocochleography (ECOG). Materials and Methods: In this hospital-based case series in 36 patients, we measured audiometric values and ECOG in all patients before, 1 month and 6 months after 4-mg/mL IT injections of dexamethasone. Results: Four patients (11%) had improved hearing following the intervention. No difference in pure tone audiometry (PTA) was observed following IT injections (P=0.492), while speech discrimination score (SDS) was significantly improved (P=0.008). There was a significant improvement in vertigo 1 month after IT injections (P<0.001), although this effect did not last for 6 months. No significant change in ECOG was observed between before and after treatment (P=0.052). Conclusion: IT dexamethasone injections can improve vertigo in definite cases of MD, although it seems that the effect is only temporary. [ABSTRACT FROM AUTHOR]

Meniere's disease is the disorder of inner ear characterized by vertigo, tinnitus and sensorineural hearing loss. The vestibular evoked myogenic potential (VEMP) test could be useful in the analysis of saccular function, and diagnosis of Meniere's disease. In this study, we've analyzed the saccular function, using VEMP test in different groups of Meniere's disease. Patients were categorized as possible, probable or definite Meniere's disease groups according to the guideline of American Academy of Otolaryngology-Head and Neck Surgery. The exclusion criteria were neuromuscular system diseases, diseases of central nervous system, inner ear disorders, conductive hearing loss, a history of ototoxic drug consumption, being a drug abuser and a positive history of inner ear surgery or manipulations. The VEMP test is the recording of positive and negative waves from sternocleidomastoid muscle that is made by an auditory click to the ear. From the total of 100 patients, the waves of VEMP test was seen in 59 patients which 19 patients had abnormal amplitude, and latency and 40 patients were with normally recorded waves. There was a significant relationship between the severity of hearing loss and a VEMP test without any recorded waves. Most of the cases with 'no wave recorded' VEMP test, were patients with severe hearing loss. However, there wasn't any relation between the pattern of hearing loss and 'no wave recorded' VEMP test. VEMP test could be a valuable diagnostic clue especially in patients with definite Meniere's disease. [ABSTRACT FROM AUTHOR]

Background and Aim: Cervical vestibular-evoked myogenic potential (cVEMP) is one of the diagnostic tests used in assessing vestibular function. Two aims of this study were to investigate implications of cervical vestibular evoked myogenic potential in children with spastic cerebral palsy (7-12 years), and to compare vestibular function in these children and normal children. Methods: In this cross-sectional study, myogenic potential was recorded in 31 children with spastic cerebral palsy (8 girls, 23 boys,7-12 years of age, with mean age of 8.77 years old and standard deviation of 1.52 years) and 31 normal children (13 girls, 18 boys with mean age of 8.77 years and standard deviation of 1.52 years). Cervical vestibular evoked myogenic potential was recorded with 500 Hz tone burst. The recorded parameters included p13 and n23 latency, p13-n23 pick to pick amplitude, and threshold. Results: Myogenic Potential was recorded in 31 normal children. They had bilateral responses. In children with cerebral palsy, 21 children showed bilateral responses, 3 children had only right-sided responses, 8 children had only left-sided responses, and two children did not show any responses. The statistical significant differences were shown between the two groups in n23, p13-n23 pick to pick amplitude, and threshold (p<0.05). Conclusion: These findings showed that cervical vestibular evoked myogenic potential can be used in children with cerebral palsy. There were significant differences in myogenic potential parameters between the two groups. More studies are needed to investigate the causes of these differences. [ABSTRACT FROM AUTHOR]

Background and Aim: Vestibular evoked myogenic potentials and acoustically evoked short latency negative response are two non-cochlear responses with probably saccular origin. The present study was conducted to determine the percentage of presence and the relation between these two responses in children with hearing loss. Methods: Thirty children with profound congenital sensorineural hearing loss were studied. Vestibular evoked myogenic potentials ellicitedby tone burst stimuli and acoustically evoked short latency negative response ellicited by click stimuli were recorded. Both responses were recorded at air conduction threshold level monaurally via an internal receiver. Results: Vestibular evoked myogenic potentials in 53.3% of children and acoustically evoked short latency negative response in 40.0% of cases were recorded. There was a significant correlation between the percentage of recording these two responses (p=0.005). Gender and the stimulated ear had no effect on the results. Conclusion: In almost half of these disabled children, both vestibular evoked myogenic potentials and acoustically evoked short latency negative response were recorded. This finding may both indicate that hearing loss has no effect on the function of otolith organs in some children and vestibular deficits probably exist along with hearing impairment in others. This finding reiterates the importance of evaluation of vestibular system as part of standard auditory evaluations. [ABSTRACT FROM AUTHOR]

Background and Aim: Research conducted since the early 1900s has consistently identified differences between deaf and hearing children on performance of a wide variety of motor tasks, most notably balance. Our study was performed to test static and dynamic balance skills in congenital severe to profound hearing impaired children in comparison with normal age-matched children. Methods: This cross-sectional study was conducted on 30 severe to profound hearing impaired and 40 normal children with age 6 to 10 years old. Bruininks-Oseretsky test of motor proficiency 2, balance subset with 9 parts was used for evaluation of balance skills. Results: Hearing-impaired children showed 16.7 to 100% fail results in 7 parts of the balance subset. In normal children fail result was revealed just in 3 parts of the balance subset from 2.5 to 57.5%, and differences between two groups were significant (p<0.0001). There was a significant difference between two groups in two static balance skills of standing on one leg on a line and standing on one leg on a balance beam with eyes closed (p<0.0001). Conclusion: It seems that development of static balance skills are longer than dynamic ones. Because severe to profound hearing-impaired children showed more weakness than normal children in both static and dynamic balance abilities, functional tests of balance proficiency can help to identify balance disorders in these children. [ABSTRACT FROM AUTHOR]

Background and Aim: Vestibular evoked myogenic potential in response to click or short tone burst stimuli have been used as a clinical test for distinguish saccule and inferior vestibular nerve diseases. Different studies show that cochlear implant could have inverse effects on vestibular structures. We aimed to investigate vestibular evoked myogenic potential in unilateral cochlear implanted individuals in compare to normal individuals. Methods: Thirty-three unilateral cochlear implanted patients (mean age 19.96 years) and 30 normal hearing individuals (mean age 24-27 years) as control group were enrolled in this cross- sectional study. Absolute latencies and amplitudes of myogenic potential responses were measured and compared in both groups. Results: Myogenic potential recorded in both ears of all controls were normal. No response could be recorded in 16 patients (48.48%) from both ears. In three patients, responses were recorded in both ears though the amplitude of waves was reduced in implanted ear. Unilateral response could be recorded in 14 patients only in their non-implanted ear. Conclusion: Vestibular evoked myogenic potential test is a useful tool for assessing saccular function in cochlear implant patients. Damages of osseous spiral lamina and basilar membrane after cochlear implantation could result in dysfunctions of vestibular organs specially saccule. It seems that saccule could be easily damaged after cochlear implantation. This would cause absence or reduced amplitudes in myogenic potential. [ABSTRACT FROM AUTHOR]

Background and Aim: Vestibular evoked myogenic potential (VEMPs) is one of the clinical tools to evaluate vestibular function. The VEMPs can be recorded from sternocleidomastoid muscle by auditory stimulation with various sound stimuli and are thought to have saccular origin. The aim of this study was to compare the VEMP responses evoked by short (500 Hz) tone burst (STB) with those evoked by click stimuli in healthy young individuals. Materials and Methods: Thirty healthy volunteers (15 males, 15 females) with ages of 18 to 30 years were enrolled in this study. Subjects were instructed to sit on a chair and rotate their head to the opposite side of the recording muscle. The VEMPs was recorded using 500 Hz STB and then click sound stimuli to each ear. The p13 and n23 latencies, p13-n23 peak-to-peak amplitude and VEMPs thresholds were obtained for further analysis. Results: The VEMP responses were present in all subjects for STB and ware not recorded in one subject for click. The latencies of p13 and n23 of STB-VEMP were significantly longer, and the p13- n23 amplitudes were significantly greater for STB-VEMP (p<0.05), and thresholds were higher for clicks (p < 0.05). No significant difference was obtained between both ears and genders. (p > 0.05). Conclusion: The VEMP responses were significantly different between the stimuli of STB and click, and the norms of different stimuli should be established for clinical interpretations. According to these data, we recommend STB stimuli in comparison with clicks for clinical diagnosis. [ABSTRACT FROM AUTHOR]

Background: The purpose of this investigation is to determine auditory neuropathy in the students with severe to profound hearing losses in Ahwaz. Materials and Methods: In this cross-sectional study, 212 children of 7-11 year old with severe to profound hearing loss performed ordinary audiometric evaluations as well as ABR and OAE. The patients with normal DPOAE who had no record of acoustic reflex having normal ABR, were considered as the patients with auditory neuropathy. Results: The neuropathic complication found in 14 children was appeared in 8 ones as one-sided (57.14%) and in 6 ones (42.86%) as two-sided. 68% of the patients as diagnosed had a very low Speech Discrimination Score (SDS). Conclusion: we must be very vigilant in auditory neuropathy diagnosis for the purpose to be successful in appropriate treatment of severe to profound hearing losses. [ABSTRACT FROM AUTHOR]

Introduction: Meniere's disease (MD) is a disease of the inner ear that presents itself with repeated episodes of vertigo (96.2%), tinnitus (91.1%), and sensorineural hearing loss (87.7 %). In this article we sought to assess the effects of intratympanic (IT) injections of dexamethasone on definite cases of MD using electrocochleography (ECOG)., Materials and Methods: In this hospital-based case series in 36 patients, we measured audiometric values and ECOG in all patients before, 1 month and 6 months after 4-mg/mL IT injections of dexamethasone., Results: Four patients (11%) had improved hearing following the intervention. No difference in pure tone audiometry (PTA) was observed following IT injections (P=0.492), while speech discrimination score (SDS) was significantly improved (P=0.008). There was a significant improvement in vertigo 1 month after IT injections (P<0.001), although this effect did not last for 6 months. No significant change in ECOG was observed between before and after treatment (P=0.052)., Conclusion: IT dexamethasone injections can improve vertigo in definite cases of MD, although it seems that the effect is only temporary.