Immunity through early development of coral larvae.

As a determinant of survival, immunity is likely to be significant in enabling coral larvae to disperse and successfully recruit, however, whether reef-building coral larvae have immune defenses is unknown. We investigated the potential presence and variation in immunity in the lecithotrophic larvae of Acropora tenuis through larval development. Enzymes indicative of tyrosinase and laccase-type melanin-synthesis were quantified, and the concentration of three coral fluorescent proteins was measured over six developmental stages; egg, embryo, motile planula, planula post-exposure to crustose coralline algae (CCA; settlement cue), settled, settled post-exposure to Symbiodinium (endosymbiont). Both types of melanin-synthesis pathways and the three fluorescent proteins were present in A. tenuis throughout development. Laccase-type activity and red fluorescence increased following exposure of planula to CCA, whereas tyrosinase-type activity and cyan fluorescence increased following settlement. No change was detected in the measured parameters following exposure to Symbiodinium. This study is the first to document coral larval immune responses and suggests the melanin-synthesis pathways have disparate roles-the laccase-type potentially non-immunological and the tyrosinase-type in cytotoxic defense. Our results indicate that corals have the potential to resist infection from the earliest life history phase.

Towards an integrated network of coral immune mechanisms.

Reef-building corals form bio-diverse marine ecosystems of high societal and economic value, but are in significant decline globally due, in part, to rapid climatic changes. As immunity is a predictor of coral disease and thermal stress susceptibility, a comprehensive understanding of this new field will likely provide a mechanistic explanation for ecological-scale trends in reef declines. Recently, several strides within coral immunology document defence mechanisms that are consistent with those of both invertebrates and vertebrates, and which span the recognition, signalling and effector response phases of innate immunity. However, many of these studies remain discrete and unincorporated into the wider fields of invertebrate immunology or coral biology. To encourage the rapid development of coral immunology, we comprehensively synthesize the current understanding of the field in the context of general invertebrate immunology, and highlight fundamental gaps in our knowledge. We propose a framework for future research that we hope will stimulate directional studies in this emerging field and lead to the elucidation of an integrated network of coral immune mechanisms. Once established, we are optimistic that coral immunology can be effectively applied to pertinent ecological questions, improve current prediction tools and aid conservation efforts.

Enzyme activity demonstrates multiple pathways of innate immunity in Indo-Pacific anthozoans.

Coral reefs are threatened by increasing levels of coral disease and the functional loss of obligate algal symbionts (bleaching). Levels of immunity relate directly to susceptibility to these threats; however, our understanding of fundamental aspects of coral immunology is lacking. We show that three melanin-synthesis pathway components (mono-phenoloxidase, ortho-diphenoloxidase (tyrosinase-type pathway) and para-diphenoloxidase (laccase-type pathway)) are present in both their active (phenoloxidase, PO) and inactive (prophenoloxidase, PPO) forms across a diverse range of 22 species of healthy Indo-Pacific anthozoans. We also demonstrate transglutaminase activity of the coagulation cascade for, to our knowledge, the first time in a coral. Melanin-synthesis enzyme activities varied among taxa, although they were generally lowest in the coral family Acroporidae and highest in the Poritidae and Oculinidae. Inactive tyrosinase-type activity (PPO) and active laccase-type activity (PO) correlate with taxonomic patterns in disease resistance, whereas the converse pattern in activity levels correlates with bleaching resistance. Overall, we demonstrate the presence of several melanin-synthesis pathways in Indo-Pacific corals, co-regulation among some pathway components, and highlight their potential roles in coral health.

A comparative study of phenoloxidase activity in diseased and bleached colonies of the coral Acropora millepora.

In scleractinian (hard) corals, immune responses involving phenoloxidase (PO) activity are known to play a role in coral wound healing, but there have been no studies investigating their roles in mitigating either disease or bleaching in an Indo-Pacific coral. PO activity induces the release of reactive oxygen species leading to a cytotoxic cellular environment, which enhances resistance against pathogens, but is also likely to compound oxidative stress induced during bleaching. Antioxidants such as melanin, whose synthesis is activated by PO activity, and peroxidase are potentially important for mitigating the effects of oxidative stress. Therefore, PO activity was investigated in healthy and diseased colonies of Acropora millepora. PO activity levels were compared among tissues bordering white syndrome lesions (WS) and at two locations (mid and outer) at increasing distances from lesions. Equivalent locations were sampled for PO activity on visibly healthy colonies. Additionally, PO and peroxidase activity were compared between severely bleached and healthy colonies of A. millepora. Overall, PO activity of diseased colonies was significantly lower than that of healthy colonies, but with relatively higher activity at the WS lesion border. Severely bleached colonies had significantly lower PO activity than healthy colonies, and peroxidase was also lower, but not significantly. Lower PO activity in unhealthy colonies supports earlier suggestions that lower immune activity leads to increased susceptibility to disease and bleaching. Additionally, low enzyme activity levels may indicate a depletion of colony resources. Increased PO activity at lesion borders in diseased colonies confirms the relative up-regulation of a key coral immune defense in response to WS in A. millepora.

Adaptation to loudness and environmental stimuli in three newly fitted hearing aid users.

Hearing aid fitting strategies can be categorized according to whether a loudness normalization or a loudness equalization rationale is employed. Regardless of the underlying rationale, the amount of patient participation in determining the initial hearing aid settings will vary when an audiologist-driven (AD) versus a patient-driven protocol is employed. When an AD protocol is used, few changes are made during the initial fitting session based on user feedback. It is assumed that the patient will adapt to the loudness and/or sound quality provided by the hearing aids if not immediately acceptable. The following three case reports document varying degrees of adaptation to hearing aid settings derived using an AD approach. Clinical implications will be discussed.

Effect of interstimulus interval on subjective categorical loudness judgements.

The Independent Hearing Aid Fitting Forum uses the visual input/output locator algorithm and the Contour Test of Loudness Perception to achieve the goal of restoring normal loudness perception with amplification. This method presupposes that subjective categorical loudness judgments are valid and reliable when using the procedure outlined by the test developers. There is no indication in the instructions of the Contour Test of a specific duration for interstimulus interval (ISI). The effect of ISI on loudness perception is important to establish because of potential time-error effects. Time-error refers to the extent to which the judged magnitude of a second stimulus varies with the time interval by which it follows the first stimulus. Past research has indicated that judgments of a second stimulus are shifted in the direction of the intensity of the preceding stimulus and that this effect intensifies with shorter ISIs. The current experiment was designed to examine whether a change in ISI produced a change in the loudness rating of the subsequent stimulus for subjective categorical loudness judgment testing. A trend toward lower, median dB values for ratings 2 to 5 at 500 Hz in a group of subjects with normal hearing was noted when 1-sec intervals were used in comparison with longer ISIs. No trends for the effect of ISI were noted at 3000 Hz. The findings provide ISI recommendations for loudness judgment test administration.

Attitudes toward nurse practitioners: influence of gender, age, ethnicity, education and income.

Survey research was undertaken to measure relationships between gender, age, ethnicity, education, income level, and an individual's attitude toward using a nurse practitioner (NP) for health care. Pender's Health Promotion Model provided the theoretical basis for the research initiative and instrument design. Following initial pilot work, 238 individuals were surveyed. While no significant differences on the basis of gender and race were found, high school graduates demonstrated significantly more positive attitudes toward NPs than non-high school graduates, and older subjects and those with lower incomes were less positively inclined to use NP services. These findings have implications for the marketing of NP services, NP education, and public education, and should be used as a basis for additional research in this area.

Accuracy of hearing aid use time as reported by experienced hearing aid wearers.

OBJECTIVE: The purpose of this study was to investigate the relationship between the amount of time that a person reports wearing his or her hearing aid and the actual time that the hearing aid is worn. Although use time data are used in the analysis and interpretation of investigations concerned with auditory perceptual learning and with user satisfaction, the accuracy of self-reported use time has not been fully investigated. DESIGN: The experimental and control group were fit with a hearing aid that has the capability of storing use time data for later analysis. The experimental group was told that the self-reported use time would be verified with a computer analysis of the hearing aid that provides the actual use time. The control group was not informed of the use time validation procedure. The agreement between self-reported and actual use time was compared statistically between groups (knowledge of validation versus no knowledge of validation). RESULTS: The experimental group provided accurate self-reported use time whereas the control group showed a significant difference between actual use time and self-reported use time. CONCLUSIONS: The results may assist in the interpretation of results of previous investigations that have depended on self-reported use time and in the design of future investigations. For the clinician, the results indicate that relying on a patient's self-reported hearing aid use time for documentation of satisfaction or signal processing preference may be misleading.

Reduction in caregiver-identified problem behaviors in patients with Alzheimer disease post-hearing-aid fitting.

Studies and clinical procedures related to patients with Alzheimer disease (AD) largely have ignored the hearing ability of either the patient or caregiver. Yet the majority of treatment and investigation depends on or presupposes communication ability. Further, caregiver complaints often center around communication-based issues. Hearing deficits may be the most frequently unrecognized condition in patients with AD because patients either communicate adequately in quiet or the impairment is masked by other behavioral symptoms of AD. The current investigation identified individuals with AD with perceived and measured hearing impairment, provided amplification management, and evaluated the impact of treatment on caregiver-identified problem behaviors believed to be related to hearing status. Specifically, treatment compliance (hearing-aid use) and treatment efficacy (reduction in perceived hearing handicap and problem behaviors) were measured in the current investigation. A multiple-baseline design across individuals with multiple dependent variables was used to evaluate the reduction of problem behaviors post-hearing-aid treatment. Eight participants were included and 1 to 4 problem behaviors were significantly reduced for each patient after hearing-aid treatment. All participants were able to complete the necessary evaluation for hearing-aid fitting and wore their hearing aids between 5 and 15 hours per day by the end of the study. This investigation employed novel methodology in the areas of on-site hearing evaluation and hearing-aid selection, advanced hearing-aid technology, and primary data recording of caregiver-identified problem behaviors by caregivers.

Managing hearing loss in a patient with Alzheimer disease.

This case study reports the management of hearing loss in a patient with Alzheimer disease (AD) living at home with a spouse care giver. The report highlights the interaction between symptoms associated with AD and hearing loss and the lack of data regarding remediation of hearing loss in this population. Specifically, the case illustrates the modifications in evaluation and verification of the hearing aid fitting that may be advisable when working with patients with AD. The data for this patient illustrate some novel measurement techniques that may assist the professional in documenting the impact of treatment in this population.

Quantification of the ecobehavioral impact of a soundfield loudspeaker system in elementary classrooms.

Although it is widely accepted that an increased signal-to-noise ratio (SNR) is preferable for young classroom learners, there is a paucity of data that illustrate the direct effect of enhanced audibility on children with normal hearing, and schools continue to accept less-than-ideal classroom listening environments for their students. Eight students in kindergarten, first, or second grade were observed in acoustically similar classrooms while the application of soundfield amplification was experimentally controlled. Observations of appropriate and inappropriate student behavior before, during, and after soundfield treatment were recorded by trained observers. A significant decrease in inappropriate behaviors came immediately after turning on the soundfield amplification. When the soundfield system was turned off, all of the students revealed a significant increase in inappropriate behaviors. All eight students revealed an increase in appropriate task management immediately following the use of soundfield amplification. When the soundfield treatment was removed, the effect achieved during treatment was maintained for all 8 students.

Reliability of the Contour Test in a population of adults with hearing loss.

With the increasing popularity of hearing aids with wide dynamic range compression, where the goal may be to restore normal perception of loudness, there has been renewed interest in obtaining individual loudness judgments in a clinically feasible, reliable manner as part of the hearing aid evaluation. The purpose of the current investigation was to evaluate the test-retest reliability of the Contour Test of Loudness Perception. Twenty-seven adults with hearing loss participated in the experiment. They produced loudness judgments on two separate occasions. Results as assessed by the intraclass correlation statistic revealed that the Contour Test has adequate consistency and absolute agreement across frequency and loudness categories over two test sessions separated in time. Results are discussed in relation to previous reliability findings from other loudness judgment methods and other subject populations.

The functionally and physiologically plastic adult auditory system.

The potential for functional and underlying physiological change in the adult auditory system is examined through review and evaluation of several sets of literature including auditory deprivation and recovery, auditory learning after hearing aid fitting, auditory abilities of normal listeners exposed to masking noise, and neural plasticity in the sensory and motor systems of animals. This tutorial review is meant for the reader who may be interested in auditory learning and who would like to have a summary and evaluation of the various findings to date. The focus of the review is the effect that various findings of auditory learning may have on hearing aid fitting and selection.

Environmental awareness and level-dependent hearing protection devices.

OBJECTIVE: The effect of level-dependent hearing protection devices (HPDs) on subjects' ability to identify real-life environmental sounds was investigated. DESIGN: Eighteen subjects with no hunting experience attempted to identify sounds (crow, duck, turkey, deer, owl, goose, and person) recorded at various distances in the presence of the SoundScope and Sonic II level-dependent HPDs as well as in an open ear condition. Knowles Electronic's Manikin for Auditory Research was employed in making the experimental recordings. The Sonic II accomplishes level-dependent attenuation via a passive mechanism, whereas the SoundScope employs active circuitry that attenuates loud sounds while providing a small amount of high frequency amplification for soft sounds. Both devices are commercially available and are advertised for hunters/shooters. Sound identification scores (SISs) were determined for each condition. RESULTS: Mean SISs differed significantly among the three earplug conditions, collapsed over type of sound and distance, with the best SIS obtained under the open ear condition (96.43%) and the worst under the Sonic II condition (84.13%). Further analysis revealed that the listening conditions differed significantly only at the 100 yard distance. CONCLUSIONS: Auditory awareness was not maintained by either device investigated during the 100 yard condition. However, auditory awareness was maintained by both devices at a distance of 75 yards or closer. These devices may be appropriate for use in certain hunting/shooting situations depending on several factors including type of game being hunted, environment, and shooting range of the weapon. Further support also is provided for the usage of level-dependent HPDs during recreational shooting activities (i.e., at a shooting range).

Comparison of two hearing aid receiver-amplifier combinations using sound quality judgments.

Sound quality judgments were obtained on two binaural pairs of laboratory hearing aids with similar battery drain. One pair had a traditional low-current-drain "starved Class A" output stage. The other had a new (at the time) "Class D" output stage. Speech and music reproduction was rated, for seven input levels between 70 and 100 dB SPL, on an overall quality scale by juries of normal-hearing and hearing-impaired subjects. The same subjects also were asked to assign a dollar value to each condition by answering the question "What would you pay for a hearing aid that sounded like that?" Both subject groups rated the hearing aids with the Class D output stage as having superior sound quality across a variety of input levels and test materials, consistent with objective distortion measurements. On the average, each one-percentage point increase in sound quality rating corresponded to a $6.75 increase in perceived value in these experiments.

Middle ear effects secondary to nasogastric intubation.

A study was conducted of the status of the middle ear in neurologically impaired patients requiring extended nasogastric tube (NGT) feeding. Ninety percent of the study patients with NGTs demonstrated abnormal middle ear function via immittance testing; whereas, 8.5% and 0% of the clinical and normal control samples, respectively, had abnormal findings. These results support the need to conscientiously observe the middle ear status of patients requiring long-term NGT feedings. A plan for monitoring middle ear function in these patients is suggested.

Test-retest reliability of the profile of hearing aid performance.

This study was designed to replicate the test-retest reliability and critical difference components of the Profile of Hearing Aid Performance (PHAP) as established by Cox and Gilmore (1990). Subjects were 18 experienced hearing aid users ranging in age from 62 to 74 years old. The initial and retest administrations of the PHAP were conducted with no rehabilitative treatment pertaining to hearing loss or amplification provided during the intervening period. The interval between the first and second administrations of the profile was 4-5 months. The mean test-retest difference scores obtained in this investigation were small, not unlike those reported by Cox and Gilmore (1990). Critical difference (CD) values closely approximated those of the previous study except for the Background Noise subscale and the Environment C scale. A pooled estimate of each standard deviation of test-retest differences was computed using data from both investigations. This resulted in critical differences considered to be more precise than the CD values derived from either study alone. Findings strongly support the utility of the PHAP as an effective tool for generating reliable information regarding self-perceived hearing aid performance.

Variables to consider when interpreting the impact of monaural amplification.

A theoretical basis is presented for considering the current data available regarding the impact of monaural amplification over time and for the design of future prospective studies. We present a summary of essential subject parameters, amplification parameters, and test properties to be considered in this expanding area of investigation. This paper attempts to create a context in which to evaluate current findings and a framework in which to ground future investigations.