Subjective visual vertical assessment with mobile virtual reality system

BACKGROUND AND OBJECTIVE: The subjective visual vertical (SVV) is a measure of a subject's perceived verticality, and a sensitive test of vestibular dysfunction. Despite this, and consequent upon technical and logistical limitations, SVV has not entered mainstream clinical practice. The aim of the study was to develop a mobile virtual reality based system for SVV test, evaluate the suitability of different controllers and assess the system's usability in practical settings. MATERIALS AND METHODS: In this study, we describe a novel virtual reality based system that has been developed to test SVV using integrated software and hardware, and report normative values across healthy population. Participants wore a mobile virtual reality headset in order to observe a 3D stimulus presented across separate conditions – static, dynamic and an immersive real-world (“boat in the sea”) SVV tests. The virtual reality environment was controlled by the tester using a Bluetooth connected controllers. Participants controlled the movement of a vertical arrow using either a gesture control armband or a general-purpose gamepad, to indicate perceived verticality. We wanted to compare 2 different methods for object control in the system, determine normal values and compare them with literature data, to evaluate the developed system with the help of the system usability scale questionnaire and evaluate possible virtually induced dizziness with the help of subjective visual analog scale. RESULTS: There were no statistically significant differences in SVV values during static, dynamic and virtual reality stimulus conditions, obtained using the two different controllers and the results are compared to those previously reported in the literature using alternative methodologies. The SUS scores for the system were high, with a median of 82.5 for the Myo controller and of 95.0 for the Gamepad controller, representing a statistically significant difference between the two controllers (P < 0.01). The median of virtual reality-induced dizziness for both devices was 0.7. CONCLUSIONS: The mobile virtual reality based system for implementation of subjective visual vertical test, is accurate and applicable in the clinical environment. The gamepad-based virtual object control method was preferred by the users. The tests were well tolerated with low dizziness scores in the majority of patients

Short GSM mobile phone exposure does not alter human auditory brainstem response

<p>Abstract</p> <p>Background</p> <p>There are about 1.6 billion GSM cellular phones in use throughout the world today. Numerous papers have reported various biological effects in humans exposed to electromagnetic fields emitted by mobile phones. The aim of the present study was to advance our understanding of potential adverse effects of the GSM mobile phones on the human hearing system.</p> <p>Methods</p> <p>Auditory Brainstem Response (ABR) was recorded with three non-polarizing Ag-AgCl scalp electrodes in thirty young and healthy volunteers (age 18–26 years) with normal hearing. ABR data were collected before, and immediately after a 10 minute exposure to 900 MHz pulsed electromagnetic field (EMF) emitted by a commercial Nokia 6310 mobile phone. Fifteen subjects were exposed to genuine EMF and fifteen to sham EMF in a double blind and counterbalanced order. Possible effects of irradiation was analyzed by comparing the latency of ABR waves I, III and V before and after genuine/sham EMF exposure.</p> <p>Results</p> <p>Paired sample t-test was conducted for statistical analysis. Results revealed no significant differences in the latency of ABR waves I, III and V before and after 10 minutes of genuine/sham EMF exposure.</p> <p>Conclusion</p> <p>The present results suggest that, in our experimental conditions, a single 10 minute exposure of 900 MHz EMF emitted by a commercial mobile phone does not produce measurable immediate effects in the latency of auditory brainstem waves I, III and V.</p

Assessment of potential effects of the electromagnetic fields of mobile phones on hearing

BACKGROUND: Mobile phones have become indispensable as communication tools; however, to date there is only a limited knowledge about interaction between electromagnetic fields (EMF) emitted by mobile phones and auditory function. The aim of the study was to assess potential changes in hearing function as a consequence of exposure to low-intensity EMF's produced by mobile phones at frequencies of 900 and 1800 MHz. METHODS: The within-subject study was performed on thirty volunteers (age 18–30 years) with normal hearing to assess possible acute effect of EMF. Participants attended two sessions: genuine and sham exposure of EMF. Hearing threshold levels (HTL) on pure tone audiometry (PTA) and transient evoked otoacoustic emissions (TEOAE's) were recorded before and immediately after 10 min of genuine and/or sham exposure of mobile phone EMF. The administration of genuine or sham exposure was double blind and counterbalanced in order. RESULTS: Statistical analysis revealed no significant differences in the mean HTLs of PTA and mean shifts of TEOAE's before and after genuine and/or sham mobile phone EMF 10 min exposure. The data collected showed that average TEOAE levels (averaged across a frequency range) changed less than 2.5 dB between pre- and post-, genuine and sham exposure. The greatest individual change was 10 dB, with a decrease in level from pre- to post- real exposure. CONCLUSION: It could be concluded that a 10-min close exposure of EMFs emitted from a mobile phone had no immediate after-effect on measurements of HTL of PTA and TEOAEs in young human subjects and no measurable hearing deterioration was detected in our study

Swedish-Lithuanian telemedicine Litmed project in otolaryngology

Telemedicine is becoming a reality as a result of improvements in technology and telecommunications. The task of the otolaryngological part of the pilot international telemedicine Litmed project was devoted to the establishment of telemedicine training and demonstration facilities in cooperation between the Departments of Otolaryngology of the Kaunas University of Medicine (Lithuania) and the Lund University (Sweden). The main areas of action of the Litmed project in otolaryngology were: (1) remote rehabilitation of cochlear implant (CI) patients, and (2) phonosurgery and phoniatrics. The main results of the project were as follows: (a) establishment of telemedicine environment for remote on-line collaboration and planned off-line collaboration by use of recorded video laryngostroboscopic images, voice samples, and graphical and computed tomography (CT) data; (b) possibility to carry through telemedicine sessions for pedagogical and speech training support and for cooperative work of speech therapists from Lund and Kaunas with CI patients; (c) remote consultations and discussion of challenging laryngeal cases; and (d) establishment of a technical environment and practical routines for on-line consultations during laryngeal surgery at the Departments of Otolaryngology of Kaunas and Lund. The Litmed project served to assist medical education and research. Tele-otolaryngology helps to keep constant professional contacts with the specialists from abroad and supports an establishment of a center of reference in tele-otolaryngology in Lithuania

Potential adverse affectsof UMTS electromagnetic fields generated by mobile phones on the human inner ear: A European project (EMFNEAR)

To answer concerns as to the potential effects of electromagnetic fields (EMF) generated by third generation mobile phones on the inner ear, the European Commission funded project "EMFNEAR" assessed potential changes in auditory function induced by UMTS field both in humans and in laboratory animals. The purpose of this paper is to present the final outcomes of the project in humans. Normally hearing subjects (18-30 years old) were exposed to 20 min UMTS or sham exposure in a double-blind controlled study. Two different EMF field strengths were used: SAR of 0.069 Wkg using a commercially available phone and SAR of 1.75 Wkg using a patch antenna. Audiological assessment, involving pure tone audiometry, distortion product otoacoustic emissions, effects of contralateral acoustic stimulation on Transiently evoked otoacoustic emissions and late cognitive potentials (P300), were performed before and immediately after real or sham exposures. Results showed no effects of acute UMTS electromagnetic fields exposure on the inner auditory system of humans