Roger M. Ellingson

Comparison of manual and computer-automated procedures for tinnitus pitch-matching.

Clinical assessment of tinnitus usually includes pitch-matching between the tinnitus and a pure tone. Although such testing is performed routinely, response reliability has not been demonstrated yet. The present study continues a series of studies designed to develop automated methodology for quantifying tinnitus perceptual characteristics. Three methods for tinnitus pitch-matching were performed in a group of 42 subjects. Two methods were computer-automated (Binary and Subject-Guided) and the third method was a traditional manual technique. Each method provided excellent response reliability for about half of the subjects. The most reliable subjects, however, differed widely between the different methods. Each subject provided a total of 14 pitch matches using the three different methods. Analyses based on each subjects total of 14 pitch matches revealed the range of pitch matches for each subject. About half of the subjects selected pitch matches over a range of 2 1/3 octaves. Results of this study suggest that specifying the range of tinnitus pitch matches rather than attempting to identify a single pitch match may be more appropriate.

Assessing Sleep Architecture in Dementia Caregivers at Home Using an Ambulatory Polysomnographic System

Findings from previous research assessing sleep quality in caregivers are inconsistent due to differences in sleep assessment methods. This study evaluated sleep in dementia caregivers using a comprehensive sleep assessment utilizing an ambulatory polysomnography (PSG) device. A total of 20 caregivers and 20 noncaregivers rated their perceived sleep quality, stress, and depressive symptoms; provided samples of cortisol and inflammatory biomarkers; and completed an objective sleep assessment using a portable PSG device. Caregivers reported greater perceived stress than noncaregivers. Next, the groups had different sleep architecture: caregivers spent less proportion of their sleep in restorative sleep stages compared to noncaregivers. Further, levels of C-reactive protein and awakening salivary cortisol were greater in caregivers than in noncaregivers, and these measures were related to sleep quality. Our findings indicate that sleep disruption is a significant concomitant of caregiving and may affect caregiver’s health. Sleep quality of caregivers might be a useful target for a clinical intervention.

Heart rate variability analysis of effect of nicotine using periodograms

Heart rate variability (HRV) is frequently used to measure autonomic nervous system (ANS) activity. However, little is known about the mechanism underlying pharmacologically induced changes in HRV. Previous research has shown that nicotine exposure stimulates the ANS, mediating a wide spectrum of physiological and behavioral effects, including altered respiratory sinus arrhythmia and enhanced arousal and attention. Using Lomb-Welch periodograms, the effect of nicotine on the ANS in 14 nicotine-naive human subjects are studied. Results showed an increase in the low frequency (LF) to high frequency (HF) ratio with little change in mean heart rate. Results suggest that nicotine affects both sympathetic and parasympathetic reactivities and that the LF/HF best characterizes early ANS activated nicotine changes in HRV. The Lomb-Welch periodogram of the HRV is also compared to the conventional interpolated Welch periodogram. The attenuation of the high frequency components due to interpolation of the non-uniform R-R intervals is found to be a function of the power of the high frequency components, increasing with increasing power. Thus analyses using Welch periodograms that make use of the high frequency components may yield erroneous results.

Feasibility and performance evaluation of generating and recording visual evoked potentials using ambulatory Bluetooth based system

Report contains the design overview and key performance measurements demonstrating the feasibility of generating and recording ambulatory visual stimulus evoked potentials using the previously reported custom Complementary and Alternative Medicine physiologic data collection and monitoring system, CAMAS. The methods used to generate visual stimuli on a PDA device and the design of an optical coupling device to convert the display to an electrical waveform which is recorded by the CAMAS base unit are presented. The optical sensor signal, synchronized to the visual stimulus emulates the brains synchronized EEG signal input to CAMAS normally reviewed for the evoked potential response. Most importantly, the PDA also sends a marker message over the wireless Bluetooth connection to the CAMAS base unit synchronized to the visual stimulus which is the critical averaging reference component to obtain VEP results. Results show the variance in the latency of the wireless marker messaging link is consistent enough to support the generation and recording of visual evoked potentials. The averaged sensor waveforms at multiple CPU speeds are presented and demonstrate suitability of the Bluetooth interface for portable ambulatory visual evoked potential implementation on our CAMAS platform.

Second generation complementary and alternative medicine physiologic data collection and monitoring research platform

Progress on our second generation portable system specifically designed to collect 24 hour ambulatory physiologic data from human subjects is reported. The upgraded system has more sensor flexibility and better performance and is smaller, lighter, and simpler to use than our previous version. The new system continues to support a wide variety of sensors found useful for complementary and alternative medicine (CAM) research and has been designed using a modular approach for future expansion of capabilities. The system has improved data storage and supports popular physiologic data formats. Support for wireless control and real-time data monitoring has been added which demonstrates capabilities to be used for physiologic feedback control. The system was designed specifically to support the needs of investigators studying CAM mind-body interventions but could be used for a variety of research needs.

24 Hour Ambulatory Research System Supporting Multiple Physiologic Sensors

The design and development of a 24-hour ambulatory physiological data collection system is reported. The system was designed specifically to support the needs of investigators studying mind-body interventions but could be used for a variety of research needs. The system is novel in that it supports a wide variety of physiologic sensors with a relatively high sample rate, full data storage, and standalone run-time of greater than 24 hours. Experience with data acquisition and methods for post-acquisition data analysis are also discussed

Planning, design, and installation experience with subterranean installation of a fully-anechoic acoustical testing chamber including preliminary performance figures

One of the purposes of a fully-anechoic chamber is to provide a very quiet, near-echo-free environment simulating free-field acoustical conditions. From design specification to completion, installation of a fully-anechoic chamber can be an enormous undertaking as compared to installation of conventional sound-attenuated acoustical test rooms, which generally are smaller in physical size and have less stringent sound attenuation requirements. The authors had the opportunity to oversee the planning, design, and installation of a fully-anechoic chamber designed to support near-full-frequency, human-hearing range acoustical experiments at the VA National Center for Rehabilitative Auditory Research (NCRAR), located in Portland, OR, USA. Design and installation of the NCRAR chamber to support entry at laboratory floor level was complicated by the job site location, a subterranean area beneath a structure that accommodates clinical and research offices on the upper floors, and serves as a parking garage on the l...

Mobile software Apps support personalized-SRO and serial monitoring with results indicating early detection of hearing loss

This paper presents an overview of key software applications implemented for our mobile, full-frequency-range, auditory testing system which is designed to detect changes in hearing sensitivity due to treatment with ototoxic medications. The system can be used efficiently in remote locations such as hospital wards, out-patient clinics, and industrial settings, as well as in patient homes to monitor for hearing change and also to perform general audiometric hearing threshold testing at frequencies out to 20kHz. We believe the system is the worlds first instrument specifically designed to support the Sensitive Range for Ototoxicity (SRO), a shortened serial hearing monitoring protocol which has been shown sensitive and reliable in detecting early hearing change. The primary focus of this paper is to present a functional overview of the main mobile software application designed to support the SRO hearing monitoring protocol. Serial monitoring information for an actual patient is used to illustrate how the main software application is used to monitor and detect hearing change. Analysis of the patients SRO monitoring data demonstrates the systems efficacy in detecting hearing threshold change. Overviews of two other support applications, one used for system calibration in the acoustics laboratory, and one used for acoustic performance verification in the field are also included.

Instrumentation System Upgrade Supports Mobile Personalized Healthcare Delivery

Clinicians and patients need mobile tools to detect ototoxic change early and prevent hearing loss. We report on the development of an upgrade of our existing desktop-based clinical-audiological instrumentation into a mobile instrument platform which efficiently supports personalized ototoxicity monitoring on the hospital wards as well as clinic by a trained clinician. Our new wireless-enabled system also serves as the instrumentation platform for the next phase of our work which is remote healthcare delivery with patient-guided at-home ototoxicity monitoring using an evidence-based individualized SRO protocol

A cognitive stressor for event-related potential studies: the Portland arithmetic stress task

Abstract In this experiment, we developed and evaluated the Portland Arithmetic Stress Task (PAST) as a cognitive stressor to evaluate acute and sustained stress reactivity for event-related potential (ERP) studies. The PAST is a titrated arithmetic task adapted from the Montreal Imaging Stress Task (MIST), with added experimental control over presentation parameters, improved and synchronized acoustic feedback and generation of timing markers needed for physiological analyzes of real-time brain activity. Thirty-one older adults (M = 60 years) completed the PAST. EEG was recorded to assess feedback-related negativity (FRN) and the magnitude of the stress response through autonomic nervous system activity and salivary cortisol. Physiological measures other than EEG included heart rate, respiration rate, heart rate variability, blood pressure and salivary cortisol. These measures were collected at several time points throughout the task. Feedback-related negativity evoked-potential responses were elicited and they significantly differed depending on whether positive or negative feedback was received. The PAST also increased systolic blood pressure, heart rate variability and respiration rates compared to a control condition attentional task. These preliminary results suggest that the PAST is an effective cognitive stressor. Successful measurement of the feedback-related negativity suggests that the PAST is conducive to EEG and time-sensitive ERP experiments. Moreover, the physiological findings support the PAST as a potent method for inducing stress in older adult participants. Further research is needed to confirm these results, but the PAST shows promise as a tool for cognitive stress induction for time-locked event-related potential experiments.