HEARING HANDICAP IN OLDER ADULTS: A MULTI-CENTER STUDY

Objective: To determine the level of hearing handicap and its age and gender association in older adults. Study Design: Cross sectional analytical study. Place and Duration of Study: Study conducted at Ear, Nose & Throat outpatients of Yusra General Hospital, National Institute of Rehabilitation Medicine Islamabad and Cantonment General Hospital Rawalpindi, from Jul to Sep 2017. Methodology: We recruited two hundred cases of self-reported hearing difficulty, using non-probability consecutive sampling, who fulfilled inclusion criteria. After recording demographic details including history, subjects were screened by the Screening Version of Hearing Handicap Inventory for the Elderly (HHIE-S). Followed by otoscopy and pure tone audiometry. Analysis was done using SPSS-24. Results: Study revealed 133 (65.5%) males and 67 (33.5%) females with mean age of 65.45 ± 7.50 years. Out of 179 (89.5%) had significantly high level of hearing handicap with HHIE-S score >43, while 21 (10.5%) revealed mild to moderate handicap with score of 17-42. Hearing handicap was significantly associated with aging (p<0.001), while no significant gender association was noted. Hearing loss was mainly of sensory-neural type 192 (96%). Conclusion: In older adults with self-reported hearing loss, high level of hearing handicap was present in majority (89.5%) and mild to moderate in 10.5%, with significant association with aging and hearing loss was predominantly sensory- neural type.

Novel Homozygous Mutation in PDZD7 Gene in a Family with Nonsyndromic Sensorineural Hearing Loss

Hearing loss is the most common sensory neural disorder in human, and according to WHO estimation, 5.5% (466 million) people worldwide have disabling hearing loss. In this study, a Chinese family with prelingual sensorineural hearing loss was investigated. The affected individuals showed moderately-severe hearing loss at all frequencies. Using target genome enrichment and high-throughput sequencing, a homozygous mutation c.2372delC, p.S791Ffs*17 was identified in PDZD7. The deletion mutation lies in exon 15 of PDZD7 and resultes in a frame shift followed by an early stop codon. Our study expand the mutation spectrum of PDZD7 and strengthens the clinical importance of this gene in patients with moderately-severe hearing loss.

Effect of Hyperbaric Oxygenation on Blood Cytokines and Arginine Derivatives; No Evidence for Induction of Inflammation or Endothelial Injury

(1) Background: Hyperbaric oxygen therapy (HBOT) uses 100% oxygen delivered at 1.5–3 times the atmospheric pressure in a specialised chamber to achieve supraphysiological oxygen tension in blood and tissues. Besides its target, HBOT may affect inflammation, endothelial function or angiogenesis. This study analysed the effect of HBOT on blood concentrations of factors that may affect these processes in patients with necrotizing soft-tissue infections (NSTI), aseptic bone necrosis (ABN) and idiopathic sudden sensory neural hearing loss (ISSNHL). (2) Methods: Concentrations asymmetric dimethylarginine (ADMA) and other arginine derivatives were measured with liquid chromatography/mass spectrometry, whereas ELISA was used to quantitate vascular endothelial growth factor (VEGF) and cytokines (IL-1, IL-4, IL-6, IL-10, TGF-β) before and after HBOT in 80 patients (NSTI n = 21, ISSNHL n = 53, ABN n = 6). (3) Results: While some differences were noted between patient groups in ADMA and other arginine derivatives as well as in cytokine concentrations, HBOT did not affect any of these parameters. (4) Conclusions: While cytokines and arginine derivatives concentrations were modified by underlying pathology, hyperbaric oxygenation did not immediately modify it suggesting that it is neutral for inflammation and is not inducing endothelial injury.

Similarities Between Somatosensory Cortical Responses Induced via Natural Touch and Microstimulation in the Ventral Posterior Lateral Thalamus in Macaques

Lost sensations, such as touch, could be restored by microstimulation (MiSt) along the sensory neural substrate. Such neuroprosthetic sensory information can be used as feedback from an invasive brain-machine interface (BMI) to control a robotic arm/hand, such that tactile and proprioceptive feedback from the sensorized robotic arm/hand is directly given to the BMI user. Microstimulation in the human somatosensory thalamus (Vc) has been shown to produce somatosensory perceptions. However, until recently, systematic methods for using thalamic stimulation to evoke naturalistic touch perceptions were lacking. We have recently presented rigorous methods for determining a mapping between ventral posterior lateral thalamus (VPL) MiSt, and neural responses in the somatosensory cortex (S1), in a rodent model (Choi et al., 2016; Choi and Francis, 2018). Our technique minimizes the difference between S1 neural responses induced by natural sensory stimuli and those generated via VPL MiSt. Our goal is to develop systems that know what MiSt will produce a given neural response and possibly a more natural "sensation." To date, our optimization has been conducted in the rodent model and simulations. Here we present data from simple non-optimized thalamic MiSt during peri-operative experiments, where we MiSt in the VPL of macaques with a somatosensory system more like humans. We implanted arrays of microelectrodes across the hand area of the macaque S1 cortex as well as in the VPL thalamus. Multi and single-unit recordings were used to compare cortical responses to natural touch and thalamic MiSt in the anesthetized state. Post stimulus time histograms were highly correlated between the VPL MiSt and natural touch modalities, adding support to the use of VPL MiSt towards producing a somatosensory neuroprosthesis in humans.

Efficient Inference of Sensitivity to Electrical Stimulation from Intrinsic Electrical Properties of Primate Retinal Ganglion Cells

High-fidelity sensory neural implants must be calibrated to precisely activate specific cells via extracellular stimulation. However, collecting and analyzing the required electrical stimulation data may be difficult in the clinic. A potential solution is to infer stimulation sensitivity from intrinsic electrical properties. Here, this inference was tested using large-scale high-density stimulation and recording from macaque retinal ganglion cells ex vivo. Electrodes recording larger spikes exhibited lower activation thresholds, with distinct trends for somas and axons, and consistent trends across cells and retinas. Thresholds for somatic electrodes increased with distance from the axon initial segment. Responses were inversely related to thresholds, and exhibited a steeper dependence on injected current for axonal than somatic electrodes. Dendritic electrodes were largely ineffective for eliciting spikes. Biophysical simulations qualitatively reproduced these findings. Inference of stimulation sensitivity was employed in simulated visual reconstruction, revealing that the approach could improve the function of future high-fidelity retinal implants.

Hierarchical Timescales in the Neocortex: Mathematical Mechanism and Biological Insights

A cardinal feature of the neocortex is the progressive increase of the spatial receptive fields along the cortical hierarchy. Recently, theoretical and experimental findings have shown that the temporal response windows also gradually enlarge, so that early sensory neural circuits operate on short-time scales whereas higher association areas are capable of integrating information over a long period of time. While an increased receptive field is accounted for by spatial summation of inputs from neurons in an upstream area, the emergence of timescale hierarchy cannot be readily explained, especially given the dense inter-areal cortical connectivity known in modern connectome. To uncover the required neurobiological properties, we carried out a rigorous analysis of an anatomically-based large-scale cortex model of macaque monkeys. Using a perturbation method, we show that the segregation of disparate timescales is defined in terms of the localization of eigenvectors of the connectivity matrix, which depends on three circuit properties: (1) a macroscopic gradient of synaptic excitation, (2) distinct electrophysiological properties between excitatory and inhibitory neuronal populations, and (3) a detailed balance between long-range excitatory inputs and local inhibitory inputs for each area-to-area pathway. Our work thus provides a quantitative understanding of the mechanism underlying the emergence of timescale hierarchy in large-scale primate cortical networks.

An Approach for Stabilizing Abnormal Neural Activity in ADHD Using Chaotic Resonance

Reduced integrity of neural pathways from frontal to sensory cortices has been suggested as a potential neurobiological basis of attention-deficit hyperactivity disorder. Neurofeedback has been widely applied to enhance reduced neural pathways in attention-deficit hyperactivity disorder by repeated training on a daily temporal scale. Clinical and model-based studies have demonstrated that fluctuations in neural activity underpin sustained attention deficits in attention-deficit hyperactivity disorder. These aberrant neural fluctuations may be caused by the chaos–chaos intermittency state in frontal-sensory neural systems. Therefore, shifting the neural state from an aberrant chaos–chaos intermittency state to a normal stable state with an optimal external sensory stimulus, termed chaotic resonance, may be applied in neurofeedback for attention-deficit hyperactivity disorder. In this study, we applied a neurofeedback method based on chaotic resonance induced by “reduced region of orbit” feedback signals in the Baghdadi model for attention-deficit hyperactivity disorder. We evaluated the stabilizing effect of reduced region of orbit feedback and its robustness against noise from errors in estimation of neural activity. The effect of chaotic resonance successfully shifted the abnormal chaos-chaos intermittency of neural activity to the intended stable activity. Additionally, evaluation of the influence of noise due to measurement errors revealed that the efficiency of chaotic resonance induced by reduced region of orbit feedback signals was maintained over a range of certain noise strengths. In conclusion, applying chaotic resonance induced by reduced region of orbit feedback signals to neurofeedback methods may provide a promising treatment option for attention-deficit hyperactivity disorder.

A large invasive chondroblastoma on the temporomandibular joint and external auditory canal: a case report and literature review

Background Chondroblastomas, which account for approximately 1% of all bone tumors, typically occur in long bones, such as the femur, humerus, and tibia. However, in extremely rare cases, they may also occur in the craniofacial region where the tumor is often found in the squamous portion of the temporomandibular joint (TMJ) and in the temporal bone. Case presentation This case report describes a large chondroblastoma (diameter, approximately 37 mm) that occurred in the TMJ. The tumor was sufficiently aggressive to destroy the TMJ, mandibular condyle neck, external auditory canal (EAC), mandibular fossa of the temporal bone, and facial nerve. The tumor was completely excised using a pre-auricular approach. The EAC and surgical defect were successfully reconstructed using a temporoparietal fascia flap (TPFF) and an inguinal free fat graft. There was no local tumor recurrence at the 18-month follow-up visits. However, the patient developed sensory neural hearing loss, and his eyebrow paralysis worsened, eventually requiring plastic surgery. Conclusion Large, invasive chondroblastomas of the TMJ can be completely removed through a pre-auricular approach, and the resulting surgical defect can be reconstructed using TPFF and free fat grafts. However, preoperative evaluation of the facial nerve and auditory function is necessary. Therefore, a multidisciplinary approach is essential.

Hearing Loss in Treacher-Collins Syndrome

Treacher Collins Syndrome is a craniofacial disorder that has dominant autosomal disorder in facial development, found 1 in every 50,000 births. The common manifestations can be mandibulofacial disorder, microtia, atresia of the ear canal, and hearing loss. This syndrome is also accompanied by malformations of the ossicular chain of bone in the middle ear, which can lead to conductive hearing loss up to 50% of cases and sensory neural hearing loss. The aim of this report was to present one case of Treacher-Collins Syndrome at the Audiology - Vestibular clinic Dr. Hasan Sadikin General Hospital Bandung. The main complaint of the patient is micrognathia and microtia with hearing loss in both ears. The right ear is smaller than the left ear, and supported to 2nd grade of Microtia. The patient had performed reconstruction ear surgery in the right ear, and had improvement from audiological examination after the 2nd stage of reconstruction. There was TCOF 1 gene mutation involved from this case. Conclusion: Treacher Collins syndrome is a rare inherited disorder, but the diagnose can be easily enforced. Early intervention with hearing rehabilitation, audio-verbal rehabilitation, and reconstruction ear surgery must be carried out for a better quality of life. Keyword : Treacher collins syndrome, micrognathia, microtia, hearing loss

A universal probabilistic spike count model reveals ongoing modulation of neural variability

Neural responses are variable: even under identical experimental conditions, single neuron and population responses typically differ from trial to trial and across time. Recent work has demonstrated that this variability has predictable structure, can be modulated by sensory input and behaviour, and bears critical signatures of the underlying network dynamics and computations. However, current methods for characterising neural variability are primarily geared towards sensory coding in the laboratory: they require trials with repeatable experimental stimuli and behavioural covariates. In addition, they make strong assumptions about the parametric form of variability, rely on assumption-free but data-inefficient histogram-based approaches, or are altogether ill-suited for capturing variability modulation by covariates. Here we present a universal probabilistic spike count model that eliminates these shortcomings. Our method builds on sparse Gaussian processes and can model arbitrary spike count distributions (SCDs) with flexible dependence on observed as well as latent covariates, using scalable variational inference to jointly infer the covariate-to-SCD mappings and latent trajectories in a data efficient way. Without requiring repeatable trials, it can flexibly capture covariate-dependent joint SCDs, and provide interpretable latent causes underlying the statistical dependencies between neurons. We apply the model to recordings from a canonical non-sensory neural population: head direction cells in the mouse. We find that variability in these cells defies a simple parametric relationship with mean spike count as assumed in standard models, its modulation by external covariates can be comparably strong to that of the mean firing rate, and slow low-dimensional latent factors explain away neural correlations. Our approach paves the way to understanding the mechanisms and computations underlying neural variability under naturalistic conditions, beyond the realm of sensory coding with repeatable stimuli.