The Influence of Noise Exposure at Different Loudness Levels on EEG Index and Types of Attention.

Bachground: Noise is one of the most important harmful factors in the environment. There are limited studies on the effect of noise loudness on brain signals and attention. The main objective of this study was to investigate the relationship between exposure to different loudness levels with brain index, types of attention, and subjective evaluation. Methods: Four noises with different loudness levels were generated. Sixty-four male students participated in this study. Each subject performed the integrated visual and auditory continuous performance test (IVA-2) test before and during exposure to noise loudness signals while their electroencephalography was recorded. Finally, the alpha-to-gamma ratio (AGR), five types of attention, and the subjective evaluation results were examined. Results: During exposure to loudness levels, the AGR and types of attention decreased while the NASA-Tax Load Index (NASA-TLX) scores increased. The noise exposure at lower loudness levels (65 and 75 phon) leads to greater attention dysfunction than at higher loudness. The AGR was significantly changed during exposure to 65 and 75 phon and audio stimuli. This significant change was observed in exposure at all loudness levels except 85 phon and visual stimuli. The divided and sustained attention changed significantly during exposure to all loudness levels and visual stimuli. The AGR had a significant inverse correlation with the total score of NASA-TLX during noise exposure. Conclusions: These results can lead to the design of methods to control the psychological effects of noise at specific frequencies (250 and 4000 Hz) and can prevent non-auditory damage to human cognitive performance in industrial and urban environments.

Visual, Vestibular, and Proprioceptive Dependency of the Control of Posture in Chronic Neck Pain Patients.

Sensory reweighting of postural control was compared in participants with and without neck pain. Center of pressure variables of 60 volunteers, the same in each group, were calculated under four standing conditions: (a) eyes open, neutral head posture; (b) foam interface, eyes open; (c) cervical extension, eyes open; and (d) cervical extension, eyes closed. All center of pressure variables except anterior posterior range/velocity increased significantly in Condition 2 compared with Conditions 1 and 3 (p < .001) and in Condition 4 compared with Conditions 1 and 3. The mediolateral range/velocity and path length in both groups, anterior posterior range in patients, and center of pressure area in the control group were significantly different between Conditions 2 and 4 (p < .001). No overweighting was observed on the vestibular or visual afferents in patients. Compensatory strategies seem to lie within the proprioceptive system.

Development and feasibility of a soft pneumatic-robotic glove to assist impaired hand function in quadriplegia patients: A pilot study.

One of the common disorders in people with quadriplegia is having a weak grip strength that can affect activities of daily living (ADL). This study presents the design of a soft robotic glove via pneumatic actuators and feasibility according to a range of motion (ROM) of proximal interphalangeal (PIP) joint and user friendly. The soft robotic glove includes a neoprene cockup, two pumps, a controller that adjusts the pressure of the pumps, two-direction parts, and two silicone tubes placed on an index and middle fingers. A total of seven subjects (2healthy, 5quadriplegia patients) participated in this project. Performance of the device was verified through assessment in healthy participants first and then spinal cord injury (SCI) participants. The device evaluated the range of motion (ROM) of a proximal interphalangeal (PIP) joint. Then, subjects completed a satisfaction questionnaire. Results showed the ROM of the PIP joint (p value = 0.042) increased by using the robotic glove. The average score of the satisfaction questionnaire was 4.24 which was beyond the desirable threshold. In conclusion, the glove obtained ROM requirements to the grip usual objects and underlined the potential for assisting SCI participants in ADLs. Providing motion in all fingers should be investigated and developed in the future.

Attentional Demands of Postural Control in Chronic Ankle Instability, Copers and Healthy Controls: A Controlled Cross-sectional Study.

BACKGROUND: It has been shown that cognitive loading affects postural control in different populations. However, there is limited and conflicting information about dual task challenges on postural control in chronic ankle instability (CAI). RESEARCH QUESTION: Does cognitive task performance change standing postural control in individuals with CAI, copers and healthy subjects? METHODS: A descriptive, analytic, and controlled cross-sectional study was conducted on 75 individuals. They were assigned into three matched groups, including CAI, copers, and healthy controls. Postural control variables were collected during single leg standing on a force plate with and without vision and cognition. Parameters of center of pressure (COP), including mean COP area, range, sway index and velocity, were measured. Additionally, cognitive task performance by auditory stroop was assessed by calculating the reaction time and error ratio. Mixed model ANOVAs were used to determine the effects of group and testing conditions. RESULTS: The CAI group demonstrated greater COP sway parameters compared to other groups under all testing conditions. The main significant effect of vision was observed for all COP parameters with greater COP sway during eyes closed compared to eyes open (P < 0.05). The main effect of a cognitive task was significant with reduced COP sway while performing the secondary cognitive compared to a single task in all three groups (P < 0.05). The cognitive task results revealed significantly longer reaction times in the CAI group compared to copers and healthy individuals (p < 0.05). SIGNIFICANCE: Considering postural control deficits in CAI, especially in eye-closed condition and effects of cognitive loading, may guide us to improve postural control in those with CAI with neurocognitive training. Furthermore, no difference between coper and healthy groups may imply a successful compensatory postural control mechanism in copers.

Development and preliminary evaluation of a new anatomically based prosthetic alignment method for below-knee prosthesis.

The objectives of current study were to a) assess similarities and relationships between anatomical landmark-based angles and distances of lower limbs in unilateral transtibial amputees and b) develop and evaluate a new anatomically based static prosthetic alignment method. First substudy assessed the anthropometrical differences and relationships between the lower limbs in the photographs taken from amputees. Data were analyzed via paired t-test and regression analysis. Results show no significant differences in frontal and transverse planes. In the sagittal plane, the anthropometric parameters of the amputated limb were significantly correlated to the corresponding variables of the sound limb. The results served as bases for the development of a new prosthetic alignment method. The method was evaluated on a single-subject study. Prosthetic alignment carried out by an experienced prosthetist was compared with such alignment adjusted by an inexperienced prosthetist but with the use of the developed method. In sagittal and frontal planes, the socket angle was tuned with respect to the shin angle, and the position of the prosthetic foot was tuned in relation to the pelvic landmarks. Further study is needed to assess the proposed method on a larger sample of amputees and prosthetists.

Effects of noise on mental performance and annoyance considering task difficulty level and tone components of noise.

Rotating components in mechanical systems produce tonal noises and the presence of these tones effect the quality and comfort of occupants leading to annoyance and a decrease in mental performance. The ISO 1996-2 and ANSI S1.13 standards have described metrics to quantify the effects of prominent tones, but more research on how noise attributes effect annoyance and performance, especially in different levels of task difficulty are necessary. This paper investigates relations between noise metrics, annoyance responses and mental performance under different task difficulty levels while exposed to background noise with tonal components. In this study, sixty participants were evaluated on subjective perceived annoyance and varying workloads while exposed to 18 noise signals with three different prominence tones at three frequency tones and two background noise levels while doing three different levels of n-back tasks in a controlled test chamber. Performance parameters were measured by recording the reaction time, the correct rate, and the number of misses. The results indicate an increasing trend for number of misses and reaction times at higher task difficulty levels, but a decrease for correct rate. The study results showed a significant difference for subjective responses except for annoyance and loudness under different levels of task difficulty. The participants were more annoyed with higher background noise levels, lower tone frequencies and increasing tone levels especially under increasing task difficulty. Loudness metrics highly correlate with other noise metrics. Three models for the prediction of perceived annoyance are presented based on the most strongly correlated noise metrics using neural network models. Each of the three models had different input parameters and different network structures. The accuracy and MSE of all three neural network models show it to be appropriate for predicting perceived annoyance. The results show the effect of tonal noise on annoyance and mental performance especially in different levels of task difficulty. The results also suggest that neural network models have high accuracy and efficiency, and can be used to predict noise annoyance. Model 1 is preferred in certain aspects, such as lower input parameters, making it more user-friendly. The best neural network model included both loudness metrics and tonality metrics. It seems that combined metrics have the least importance and are unnecessary in the proposed neural network model.

Correction to: Effects of noise on mental performance and annoyance considering task difficulty level and tone components of noise.

[This corrects the article DOI: 10.1007/s40201-019-00353-2.].

Gender-Related Differences in Reliability of Thorax, Lumbar, and Pelvis Kinematics During Gait in Patients With Non-specific Chronic Low Back Pain.

OBJECTIVE: To evaluate test-retest reliability of trunk kinematics relative to the pelvis during gait in two groups (males and females) of patients with non-specific chronic low back pain (NCLBP) using three-dimensional motion capture system. METHODS: A convenience sample of 40 NCLBP participants (20 males and 20 females) was evaluated in two sessions. Participants were asked to walk with self-selected speed and kinematics of thorax and lumbar spine were captured using a 6-infrared-cameras motion-analyzer system. Peak amplitude of displacement and its measurement errors and minimal detectable change (MDC) were then calculated. RESULTS: Intraclass correlation coefficients (ICCs) were relatively constant but small for certain variables (lower lumbar peak flexion in female: inter-session ICC=0.51 and intra-session ICC=0.68; peak extension in male: inter-session ICC=0.67 and intra-session ICC=0.66). The measurement error remained constant and standard error of measurement (SEM) difference was large between males (generally ≤4.8°) and females (generally ≤5.3°). Standard deviation (SD) was higher in females. In most segments, females exhibited higher MDCs except for lower lumbar sagittal movements. CONCLUSION: Although ICCs were sufficiently reliable and constant in both genders during gait, there was difference in SEM due to difference in SD between genders caused by different gait disturbance in chronic low back pain. Due to the increasing tendency of measurement error in other areas of men and women, attention is needed when measuring lumbar motion using the method described in this study.

A protocol for clinical trial study of the effect of core stabilization exercises on spine kinematics during gait with and without load in patients with non-specific chronic low back pain.

Background: Non-specific chronic low back pain (NCLBP) is a major public health and global socioeconomic burden with a variety of symptoms such as gait abnormality. Trunk stiffness and deep trunk muscles dysfunction known as guarding mechanism in gait are factors leading to abnormal movement pattern of the spine. Anterior load carriage task during gait is also challenged the trunk stability and its movement pattern. It will be therefore of interest to examine the effect of a Core Stabilization Training Program (CSTP) on the trunk and pelvis kinematics including variability and peak displacement during gait with and without load in NCLBP patients. Methods: Patients with NCLBP will participate in a program containing 16 sessions of CSTP and perceived pain, disability and kinematic will be evaluated with 100 mm visual analog scale (VAS), Oswestry Disability Index (ODI) and motion analyzing system respectively before and after the intervention. Participants will be asked to walk with self-selected comfortable speed for 3 times without load and 3 times with caring a load with hands. Discussions: We will quantify the effectiveness of CSTP on the kinematic of trunk, lumbar and pelvis during gait. Comparing the kinematic pattern and movement variability using CVo and CVp can contribute to better understand the motor control strategy and movement pattern of the spine during an anterior load carriage task between patients with NCLBP and healthy. Trial registration: IRCT number: IRCT2016080829264N1; pre-result.

Nonlinear feature extraction for objective classification of complex auditory brainstem responses to diotic perceptually critical consonant-vowel syllables.

OBJECTIVE: To examine if nonlinear feature extraction method yields appropriate results in complex brainstem response classification of three different consonant vowels diotically presented in normal Persian speaking adults. METHODS: Speech-evoked auditory brainstem responses were obtained in 27 normal hearing young adults by using G.tec EEG recording system. 170ms synthetic consonant-vowel stimuli /ba/, /da/, /ga/ were presented binaurally and the recurrence quantification analysis was performed on the responses. The recurrence time of second type was proposed as a suitable feature. ANOVA was also used for testing the significance of extracted feature. Post-comparison statistical method was used for showing which means are significantly different from each other. RESULTS: Dimension embedding and state space reconstruction were helpful for visualizing nonlinearity in auditory system. The proposed feature was successful in the objective classification of responses in window time 20.1-35.3ms, which belonged to formant transition period of stimuli. Also the p value behavior of recurrence time of second type feature as a discriminant feature was close to the nature of the response that includes transient and sustained parts. On the other hand, the /ba/ and /ga/ classification period was wider than the others. CONCLUSION: The extracted feature shown in this paper is helpful for the objective of distinguishing individuals with auditory processing disorders in the structurally similar voices. On the other hand, differing nonlinear feature is meaningful in a special region of response, equal to formant transition period, and this feature is related to the state space changes of brainstem response. It can be assumed that more information is within this region of signal and it is a sign of processing role of brainstem. The state changes of system are dependent on input stimuli, so the existence of top down feedback from cortex to brainstem forces the system to act differently.

Gender disparity in subcortical encoding of binaurally presented speech stimuli: an auditory evoked potentials study.

OBJECTIVES: To investigate the influence of gender on subcortical representation of speech acoustic parameters where simultaneously presented to both ears. METHODS: Two-channel speech-evoked auditory brainstem responses were obtained in 25 female and 23 male normal hearing young adults by using binaural presentation of the 40 ms synthetic consonant-vowel/da/, and the encoding of the fast and slow elements of speech stimuli at subcortical level were compared in the temporal and spectral domains between the sexes using independent sample, two tailed t-test. RESULTS: Highly detectable responses were established in both groups. Analysis in the time domain revealed earlier and larger Fast-onset-responses in females but there was no gender related difference in sustained segment and offset of the response. Interpeak intervals between Frequency Following Response peaks were also invariant to sex. Based on shorter onset responses in females, composite onset measures were also sex dependent. Analysis in the spectral domain showed more robust and better representation of fundamental frequency as well as the first formant and high frequency components of first formant in females than in males. CONCLUSIONS: Anatomical, biological and biochemical distinctions between females and males could alter the neural encoding of the acoustic cues of speech stimuli at subcortical level. Females have an advantage in binaural processing of the slow and fast elements of speech. This could be a physiological evidence for better identification of speaker and emotional tone of voice, as well as better perceiving the phonetic information of speech in women.