Tongue Postures and Tongue Centers: A Study of Acoustic-Articulatory Correspondences Across Different Head Angles

Recent research on body and head positions has shown that postural changes may induce varying degrees of changes on acoustic speech signals and articulatory gestures. While the preservation of formant profiles across different postures is suitably accounted for by the two-tube model and perturbation theory, it remains unclear whether it is resulted from the accommodation of tongue postures. Specifically, whether the tongue accommodates the changes in head angle to maintain the target acoustics is yet to be determined. The present study examines vowel acoustics and their correspondence with the articulatory maneuvers of the tongue, including both tongue postures and movements of the tongue center, across different head angles. The results show that vowel acoustics, including pitch and formants, are largely unaffected by upward or downward tilting of the head. These preserved acoustics may be attributed to the lingual gestures that compensate for the effects of gravity. Our results also reveal that the tongue postures in response to head movements appear to be vowel-dependent, and the tongue center may serve as an underlying drive that covariates with the head angle changes. These results imply a close relationship between vowel acoustics and tongue postures as well as a target-oriented strategy for different head angles.

Virtual Reality Simulator for Training on Surgery Ergonomics Skills

This work focuses on ergonomics skills based on Virtual Reality (VR) training simulator for spine surgery. The proposed system used the Head Mounted Display (HMD) device for monitoring and data collection. The aim of the project was to provide a training approach for residents that would enable them to acquire the proper ergonomic skills needed while performing spine surgery. A VR training simulator has been designed and implemented to measure two ergonomic skills required that need to be maintained during any surgery. The two components were neck’s angle and table’s height. The experiments showed that the users are usually focused on their work and tend to pay less attention to their body’s position and movements. This can result in a wrong ergonomics setup, which leads to musculoskeletal pain. Thus, the users (residents) need to be trained to have good ergonomics positions. The proposed system measured this using a specific metric that collected head positions, angles, elbow height, and other parameters. The designed model was a VR simulator for neurosurgical education in particular; however, it might be good for some other similar surgeries. The study concluded that incorporating simulations into residents’ training and simulated surgeries can strengthen the surgeons’ skills and outcomes. As a result, both residents and expert surgeons can benefit from the use of the developed model.

KEEPING IN TOUCH WITH OUR HIDDEN SIDE

Previous studies have shown that the sensory modality used to identify the position of proprioceptive targets hidden from sight, but frequently viewed, influences the type of the body representation employed for reaching them with the finger. The question then arises as to whether this observation also applies to proprioceptive targets which are hidden from sight, and rarely, if ever, viewed. We used an established technique for pinpointing the type of body representation used for the spatial encoding of targets which consisted of assessing the effect of peripheral gaze fixation on the pointing accuracy. More precisely, an exteroceptive, visually dependent, body representation is thought to be used if gaze deviation induces a deviation of the pointing movement. Three light-emitting diodes (LEDs) were positioned at the participants' eye level at -25 deg, 0 deg and +25 deg with respect to the cyclopean eye. Without moving the head, the participant fixated the lit LED before the experimenter indicated one of the three target head positions: topmost point of the head (vertex) and two other points located at the front and back of the head. These targets were either verbal-cued or tactile-cued. The goal of the subjects (n=27) was to reach the target with their index finger. We analysed the accuracy of the movements directed to the topmost point of the head, which is a well-defined, yet out of view anatomical point. Based on the possibility of the brain to create visual representations of the body areas that remain out of view, we hypothesized that the position of the vertex is encoded using an exteroceptive body representation, both when verbally or tactile-cued. Results revealed that the pointing errors were biased in the opposite direction of gaze fixation for both verbal-cued and tactile-cued targets, suggesting the use of a vision-dependent exteroceptive body representation. The enhancement of the visual body representations by sensorimotor processes was suggested by the greater pointing accuracy when the vertex was identified by tactile stimulation compared to verbal instruction. Moreover, we found in a control condition that participants were more accurate in indicating the position of their own vertex than the vertex of other people. This result supports the idea that sensorimotor experiences increase the spatial resolution of the exteroceptive body representation. Together, our results suggest that the position of rarely viewed body parts are spatially encoded by an exteroceptive body representation and that non-visual sensorimotor processes are involved in the constructing of this representation.

Variants of benign paroxysmal positional vertigo in relation to head position during sleep

BACKGROUND: Patients with posterior- and lateral-(canal)-benign paroxysmal positional vertigo (BPPV)-canalolithiasis sleep in the affected-ear-down head position. Posterior-BPPV-canalolithiasis typically affects the right than left ear; sleeping in the right-ear-down head position may be causal. OBJECTIVE: To investigate the relationship between habitual head position during sleep and the onset of BPPV variants. METHODS: Among 1,170 cases of BPPV variants with unknown etiology, the affected ears, habitual head positions during sleep based on interviews, and relationships among them were investigated. RESULTS: Posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-geotropic affected the right ear significantly more often. Significantly more patients with posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-apogeotropic habitually slept in the right-ear-down head position. Patients with posterior- and lateral-BPPV-canalolithiasis and light cupula were more likely to sleep habitually in the affected-ear-down position than in the healthy-ear-down head position; no relationship was observed in patients with posterior- and lateral-BPPV-cupulolithiasis. In patients with posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-geotropic, the proportion of right-affected ears in those sleeping habitually in the right-ear-down head position was significantly greater than that for the left-affected ear. CONCLUSIONS: A habitual affected-ear-down head position during sleep may contribute to BPPV-canalolithiasis and light cupula onset, but not BPPV-cupulolithiasis onset. However, habitual sleeping in the right-ear-down head position cannot explain the predominance of right-affected ears.

Therapy-Resistant Atypical Downbeat Nystagmus with Vertigo Confined to Specific Head-Hanging Positions: Mapping to the Gravity Vector on a Multi-Axis Turntable

Downbeat nystagmus (DBN) observed in head-hanging positions, may be of central or peripheral origin. Central DBN in head-hanging positions is mostly due to a disorder of the vestibulo-cerebellum, whereas peripheral DBN is usually attributed to canalolithiasis of an anterior semicircular canal. Here, we describe an atypical case of a patient who, after head trauma, experienced severe and stereotypic vertigo attacks after being placed in various head-hanging positions. Vertigo lasted 10–15 s and was always associated with a robust DBN. The provocation of transient vertigo and DBN, which both showed no decrease upon repetition of maneuvers, depended on the yaw orientation relative to the trunk and the angle of backward pitch. On a motorized, multi-axis turntable, we identified the two-dimensional Helmholtz coordinates of head positions at which vertigo and DBN occurred (<i>y</i>-axis: horizontal, space-fixed; <i>z</i>-axis: vertical, and head-fixed; <i>x</i>-axis: torsional, head-fixed, and unchanged). This two-dimensional area of DBN-associated head positions did not change when whole-body rotations took different paths (e.g., by forwarding pitch) or were executed with different velocities. Moreover, the intensity of DBN was also independent of whole-body rotation paths and velocities. So far, therapeutic approaches with repeated liberation maneuvers and cranial vibrations were not successful. We speculate that vertigo and DBN in this patient are due to macular damage, possibly an unstable otolithic membrane that, in specific orientations relative to gravity, slips into a position causing paroxysmal stimulation or inhibition of macular hair cells.

Degenerative Cervical Spondylosis: A Cause of Vertigo?

Study Design: Prospective observational study. Objectives: Studying the effect of degenerative cervical spondylosis(CS) on blood flow velocity of vertebral artery (VA) during cervical spine rotation in different head positions and its association with vertigo. Introduction: Vertigo is one of the most common complaints seen in an out-patient clinic. Its association with CS remains an enigma for a treating physician. This study planned to systematically analyze the association between vertigo and CS by evaluating VA blood flow dynamics in different head positions. Methods: 100 patients with ages ranging from 20-80 years were recruited. First group of 50 patients with CS with vertigo were compared with second study group of 50 patients having CS without vertigo. Cervical radiographs were used to evaluate CS using cervical degenerative index (CDI). Color doppler was used to measure VA blood flow with head in neutral position and 60° lateral rotation with 30° extension. Same procedure was repeated on opposite side. Measurements performed included peak systolic blood flow velocity(PSV) and end diastolic blood flow velocity (EDV). Results: Among patients with CS, patients having vertigo showed significantly more evident degenerative changes (CDI ≥25) ( P=<0.001). High grade CS patients (CDI ≥25) with vertigo had statistically significant lower blood flow parameters with head rotation in the left and right VAs as compared to CS patients without vertigo. Conclusion: This study highlights important pathophysiological mechanism of vertigo observed in patients of CS. The magnitude of reduction in VA blood flow was significantly higher in patients with advanced CS presenting as vertigo.

The Use of Synthetic Data to Facilitate Eye Segmentation Using Deeplabv3+

The human eye contains valuable information about an individual’s identity and health. Therefore, segmenting the eye into distinct regions is an essential step towards gathering this useful information precisely. The main challenges in segmenting the human eye include low light conditions, reflections on the eye, variations in the eyelid, and head positions that make an eye image hard to segment. For this reason, there is a need for deep neural networks, which are preferred due to their success in segmentation problems. However, deep neural networks need a large amount of manually annotated data to be trained. Manual annotation is a labor-intensive task, and to tackle this problem, we used data augmentation methods to improve synthetic data. In this paper, we detail the exploration of the scenario, which, with limited data, whether performance can be enhanced using similar context data with image augmentation methods. Our training and test set consists of 3D synthetic eye images generated from the UnityEyes application and manually annotated real-life eye images, respectively. We examined the effect of using synthetic eye images with the Deeplabv3+ network in different conditions using image augmentation methods on the synthetic data. According to our experiments, the network trained with processed synthetic images beside real-life images produced better mIoU results than the network, which only trained with real-life images in the Base dataset. We also observed mIoU increase in the test set we created from MICHE II competition images.

Effects of head positions on awake fiberoptic bronchoscope oral intubation: a randomized controlled trial

Background There are many factors affecting the success rate of awake orotracheal intubation via fiberoptic bronchoscope. We performed this study was to investigate the effects of head positions on awake Fiberoptic bronchoscope oral intubation. Methods Seventy-five adult patients, received general anaesthesia were included in this study. After written informed consent, these patients were undergoing awake orotracheal intubation via fiberoptic-bronchoscope and according to the head position, the patients were randomized allocated to neutral position group (NP group), sniffing position group (SP group) or extension position group (EP group). After sedation the patients were intubated by an experienced anesthesiologist. The time to view the vocal cords, the percentage of glottic opening scores (POGO), the time to insert the tracheal tube into trachea and the visual analog scale (VAS) scores for ease experienced of passing the tracheal tube through glottis, the hemodynamic changes and the adverse events after surgery were recorded. Results The time to view the vocal cords was significantly shorter and the POGO scores was significantly higher in the EP group compared with the other two groups (P < 0.05); The SpO2 in the EP group was higher than NP group at before intubation and higher than SP group and NP group at immediate after intubation (P < 0.05); The time to insert the tracheal tube into trachea, the VAS scores for passing the tracheal tube through glottis, the coughing scores had no significant differences among groups (P > 0.05). There were also no significant differences regard to the incidence of postoperative complications, mean arterial pressure and heart rate among the groups (P > 0.05). Conclusions The head at extension position had a best view of glottic opening than neutral position or sniffing position during awake Fiberoptic bronchoscope oral intubation, so extension position was recommended as the starting head position for awake Fiberoptic bronchoscope oral intubation. Trial registration Clinical Trials.gov. no. NCT02792855. Registered at https://register.clinicaltrials.gov on 23 september 2017.