Relational learning in children with deafness and cochlear implants

This four-experiment series sought to evaluate the potential of children with neurosensory deafness and cochlear implants to exhibit auditory-visual and visual-visual stimulus equivalence relations within a matching-to-sample format. Twelve children who became deaf prior to acquiring language (prelingual) and four who became deaf afterwards (postlingual) were studied. All children learned auditory-visual conditional discriminations and nearly all showed emergent equivalence relations. Naming tests, conducted with a subset of the: children, showed no consistent relationship to the equivalence-test outcomes.. This study makes several contributions: to the literature on stimulus equivalence. First; it demonstrates that both pre- and postlingually deaf children-can: acquire auditory-visual equivalence-relations after cochlear implantation, thus demonstrating symbolic functioning. Second, it directs attention to a population that may be especially interesting for researchers seeking to analyze the relationship. between speaker and listener repertoires. Third, it demonstrates the feasibility of conducting experimental studies of stimulus control processes within the limitations of a hospital, which these children must visit routinely for the maintenance of their cochlear implants.

Auditory Neuropathy/Auditory Dyssynchrony in children with Cochlear Implants

The electrical stimulation generated by the Cochlear Implant (CI) may improve the neural synchrony and hence contribute to the development of auditory skills in patients with Auditory Neuropathy / Auditory Dyssynchrony (AN/AD). Aim: Prospective cohort cross-sectional study to evaluate the auditory performance and the characteristics of the electrically evoked compound action potential (ECAP) in 18 children with AN/AD and cochlear implants. Material and methods: The auditory perception was evaluated by sound field thresholds and speech perception tests. To evaluate ECAP`s characteristics, the threshold and amplitude of neural response were evaluated at 80Hz and 35Hz. Results: No significant statistical difference was found concerning the development of auditory skills. The ECAP`s characteristics differences at 80 and 35Hz stimulation rate were also not statistically significant. Conclusion: The CI was seen as an efficient resource to develop auditory skills in 94% of the AN/AD patients studied. The auditory perception benefits and the possibility to measure ECAP showed that the electrical stimulation could compensate for the neural dyssynchrony caused by the AN/AD. However, a unique clinical procedure cannot be proposed at this point. Therefore, a careful and complete evaluation of each AN/AD patient before recommending a Cochlear Implant is advised. Clinical Trials: NCT01023932

Telehealth in audiology: The need and potential to reach underserved communities

Permanent hearing loss is a leading global health care burden, with 1 in 10 people affected to a mild or greater degree. A shortage of trained healthcare professionals and associated infrastructure and resource limitations mean that hearing health services are unavailable to the majority of the world population. Utilizing information and communication technology in hearing health care, or tele-audiology, combined with automation offer unique opportunities for improved clinical care, widespread access to services, and more cost-effective and sustainable hearing health care. Tele-audiology demonstrates significant potential in areas such as education and training of hearing health care professionals, paraprofessionals, parents, and adults with hearing disorders; screening for auditory disorders; diagnosis of hearing loss; and intervention services. Global connectivity is rapidly growing with increasingly widespread distribution into underserved communities where audiological services may be facilitated through telehealth models. Although many questions related to aspects such as quality control, licensure, jurisdictional responsibility, certification and reimbursement still need to be addressed; no alternative strategy can currently offer the same potential reach for impacting the global burden of hearing loss in the near and foreseeable future.

The impact of stress and anxiety on the pressure pain threshold of myofascial pain patients

The purpose of this study was to evaluate the influence of stress and anxiety on the pressure pain threshold (PPT) of masticatory muscles and on the subjective pain report. Forty-five women, students, with mean age of 19.75 years, were divided into two groups: group 1:29 presenting with masticatory myofascial pain (MFP), according to the Research Diagnostic Criteria for Temporomandibular Disorders and group 2: 16 asymptomatic controls. An electronic algometer registered the pain thresholds on four different occasions throughout the academic year. To measure levels of stress, anxiety and pain, the Beck Anxiety Inventory, Lipp Stress Symptoms Inventory and Visual Analog Scale (VAS) were used. Three-way anova and Tukey`s tests were used to verify differences in PPT between groups, times and sites. Levels of anxiety and VAS were compared using Mann-Whitney test, while Friedman`s test was used for the within-groups comparison at different times (T1 to T4). The chi-squared and Cochran tests were performed to compare groups for the proportion of subjects with stress (alpha = 0.05). Differences in PPT recordings between time (P = 0.001) and sites (P < 0.001) were detected. Higher levels of anxiety and lower PPT figures were detected at T2 (academic examination) (P = 0.001). There was no difference between groups for anxiety and stress at any time (P > 0.05). The MFP group also has shown significant increase of VAS at the time of academic examination (P < 0.001). External stressors such as academic examinations have a potential impact on masticatory muscle tenderness, regardless of the presence of a previous condition such as masticatory myofascial pain.

Osteoinductivity potential of rhBMP-2 associated with two carriers in different dosages

The objective of this study was to evaluate bone formation after application of different doses of recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with monoolein or poloxamer gels, in critical bone defects of rats. Forty-five Wistar rats were divided into nine treatment groups with five animals each: I: application of 1 A mu g rhBMP-2 + monoolein; II: 3 A mu g rhBMP-2 + monoolein; III: 7 A mu g rhBMP-2 + monoolein; IV: 1 A mu g rhBMP-2 + poloxamer; V: 3 A mu g rhBMP-2 + poloxamer; VI: 7 A mu g rhBMP-2 + poloxamer; VII: monoolein only; VIII: poloxamer only; and IX: critical bone defect only. A critical-sized defect of 6 mm diameter was produced in the left parietal bone and it was filled with gels of the above mentioned treatments. After 2 weeks, the calvarial bones were removed for histological processing. Bone formation in the groups that received poloxamer gel and rhBMP-2 was not significantly different from the control group (IX). Groups receiving monoolein and rhBMP-2 (1 and 3 A mu g) and those that received only the carriers (VII and VIII) had less bone formation in relation to the control. The association of rhBMP-2 to both poloxamer and monoolein did not exhibit any significant differentiation in bone formation in comparison with the control group.

Potential effect of sodium bicarbonate-containing dentifrice in controlling enamel erosion in situ

Purpose: To assess, by a crossover 2 x 2 in situ study, the speculated protective role of a sodium bicarbonate-containing toothpaste in controlling erosive lesions. Methods: Bovine enamel slabs were sterilized, and submitted to baseline Knoop microhardness measurements. After a 3-day lead-in period, 14 volunteers wore palatal acrylic appliances containing six enamel slabs (three on each side), for 4 consecutive days. On the first day, appliances with contained specimens were placed in the oral cavity to allow salivary pellicle formation. On the subsequent days, half of the enamel slabs were immersed extraorally in a lemonade-like soft drink for 90 seconds, twice daily. On both of these occasions, the appliance was dipped in toothpaste slurry of either a sodium bicarbonate-containing toothpaste or a regular counterpart for 60 seconds. Following a 3-day washout period, a new set of enamel slabs were mounted and the volunteers started the second period using the alternate dentifrice. Results: ANOVA (alpha = 0.05) showed no statistically significant difference between enamel treated with regular and sodium bicarbonate-based dentifrices, regardless of whether specimens were eroded or not (P=0.8430). Acid-challenged specimens revealed lower microhardness values than uneroded samples. (Am J Dent 2008;21:300-302).

Study on the potential inhibition of root dentine wear adjacent to fluoride-containing restorations

The purpose of this in vitro study was to determine whether the vicinity of root dentine that had been restored with fluoride-releasing materials was at reduced risk for erosive/abrasive wear compared to root dentine restored with a non-fluoride-containing material. According to a randomized complete block design, standardized cavities prepared on the surface of 150 bovine root dentine slabs were restored with glass-ionomer cement, resin-modified glass ionomer, polyacid-modified resin composite, fluoride-containing or conventional composite. Specimens were coated with two layers of an acid-resistant nail varnish exposing half of the dentine surface and half of the restoration. Subsequently, specimens were either eroded in an acidic drink or left uneroded, then exposed to artificial saliva and abraded in a toothbrushing machine. Wear depth in the vicinity of restorations was quantified by a stylus profilometer, based on the nonabraded areas surrounding the erosion/abrasion region. Two-way ANOVA did not demonstrate significant interaction between restoratives and eroded-uneroded dentine (p = 0.5549) nor significant difference among restorative materials (p = 0.8639). Tukey`s test ascertained that the wear depth was higher for eroded than for uneroded groups. Fluoride-releasing materials seemed to negligibly inhibit wear in the vicinity of restored root dentine subjected to erosive/abrasive challenges.

Variations in cone photoreceptor abundance and the visual ecology of birds

The relative abundance and topographical distribution of retinal cone photoreceptors was measured in 19 bird species to identify possible correlations between photoreceptor complement and visual ecology. In contrast to previous studies, all five types of cone photoreceptor were distinguished, using bright field and epifluorescent light microscopy, in four retinal quadrants. Land birds tended to show either posterior dorsal to anterior ventral or anterior dorsal to posterior ventral gradients in cone photoreceptor distribution, fundus coloration and oil droplet pigmentation across the retina. Marine birds tended to show dorsal to ventral gradients instead. Statistical analyses showed that the proportions of the different cone types varied significantly across the retinae of all species investigated. Cluster analysis was performed on the data to identify groups or clusters of species on the basis of their oil droplet complement. Using the absolute percentages of each oil droplet type in each quadrant for the analysis produced clusters that tended to reflect phylogenetic relatedness between species rather than similarities in their visual ecology. Repeating the analysis after subtracting the mean percentage of a given oil droplet type across the whole retina (the 'eye mean') from the percentage of that oil droplet type in each quadrant, i.e. to give a measure of the variation about the mean, resulted in clusters that reflected diet, feeding behaviour and habitat to a greater extent than phylogeny.

The relationship between leaf water potential and stem diameter in sorghum

Leaf water potential (psi (l)) represents a good indicator of the water status of plants, and continuous monitoring of it can be useful in research and field applications such as scheduling irrigation. Changes in stem diameter (Sd) were used for monitoring psi (l) of pot-grown sorghum [Sorghum bicolor (L.) Moench] plants in a glasshouse. This method requires occasional calibration of S-d values against psi (l). Predicted values of psi (l), based on a single calibration show a good correlation with measured psi (l), values over a period of 13 d before and after the calibration. The correlation can further be improved with shorter time intervals.

Veterinary drug delivery: Potential for skin penetration enhancement

A range of topical products are used in veterinary medicine. The efficacy of many of these products has been enhanced by the addition of penetration enhancers. Evolution has led to not only a highly specialized skin in animals and humans, but also one whose anatomical structure and skin permeability differ between the various species. The skin provides an excellent barrier against the ingress of environmental contaminants, toxins, and microorganisms while performing a homeostatic role to permit terrestrial life. Over the past few years, major advances have been made in the field of transdermal drug delivery. An increasing number of drugs are being added to the list of therapeutic agents that can be delivered via the skin to the systemic circulation where clinically effective concentrations are reached. The therapeutic benefits of topically applied veterinary products is achieved in spite of the inherent protective functions of the stratum corneum (SQ, one of which is to exclude foreign substances from entering the body. Much of the recent success in this field is attributable to the rapidly expanding knowledge of the SC barrier structure and function. The bilayer domains of the intercellular lipid matrices within the SC form an excellent penetration barrier, which must be breached if poorly penetrating drugs are to be administered at an appropriate rate. One generalized approach to overcoming the barrier properties of the skin for drugs and biomolecules is the incorporation of suitable vehicles or other chemical compounds into a transdermal delivery system. Indeed, the incorporation of such compounds has become more prevalent and is a growing trend in transdermal drug delivery. Substances that help promote drug diffusion through the SC and epidermis are referred to as penetration enhancers, accelerants, adjuvants, or sorption promoters. It is interesting to note that many pour-on and spot-on formulations used in veterinary medicine contain inert ingredients (e.g., alcohols, amides, ethers, glycols, and hydrocarbon oils) that will act as penetration enhancers. These substances have the potential to reduce the capacity for drug binding and interact with some components of the skin, thereby improving drug transport. However, their inclusion in veterinary products with a high-absorbed dose may result in adverse dermatological reactions (e.g., toxicological irritations) and concerns about tissue residues. These a-re important considerations when formulating a veterinary transdermal product when such compounds ate added, either intentionally or otherwise, for their penetration enhancement ability. (C) 2001 Elsevier Science B.V. All rights reserved.

The visual ecology of avian photoreceptors

The spectral sensitivities of avian retinal photoreceptors are examined with respect to microspectrophotometric measurements of single cells, spectrophotometric measurements of extracted or in vitro regenerated visual pigments, and molecular genetic analyses of visual pigment opsin protein sequences. Bird species from diverse orders are compared in relation to their evolution, their habitats and the multiplicity of visual tasks they must perform. Birds have five different types of visual pigment and seven different types of photo receptor-rods, double (uneven twin) cones and four types of single cone. The spectral locations of the wavelengths of maximum absorbance (lambda (max)) of the different visual pigments, and the spectral transmittance characteristics of the intraocular spectral filters (cone oil droplets) that also determine photoreceptor spectral sensitivity, vary according to both habitat and phylogenetic relatedness. The primary influence on avian retinal design appears to be the range of wavelengths available for vision, regardless of whether that range is determined by the spectral distribution of the natural illumination or the spectral transmittance of the ocular media (cornea, aqueous humour, lens, vitreous humour). Nevertheless, other variations in spectral sensitivity exist that reflect the variability and complexity of avian visual ecology. (C) 2001 Elsevier Science Ltd. All rights reserved.

Development, reliability, and concurrent validity of the modified inventory of potential reconstructive needs

Documentation of burn sequelae can be a difficult and time-consuming task. To date a reliable and systematic format for recording postburn trauma is lacking. The purpose of this research was two-fold: first, to develop a Modified Inventory of Potential Reconstructive Needs from the original Inventory of Potential Reconstructive Needs to allow methodical documentation of functional and cosmetic burn sequelae in all body surface areas of children with burns and, second, to establish interrater reliability and concurrent validity of the instrument, thus allowing its clinical application. Two raters scored the Modified Inventory of Potential Reconstructive Needs on 41 children with a range of burns types and severity. Excellent interrater reliability was demonstrated for both total (intraclass correlation coefficient = 0.996) and subsection inventory scores. Concurrent validity was also established with total scores showing strong positive correlations (0.73-0.76) with three indicators of burn severity. These findings provide initial support for the tool's clinical applicability, particularly in relation to rehabilitative planning and documentation.

The dorsomedial visual areas in New World and Old World monkeys: homology and function

The extrastriate cortex near the dorsal midline has been described as part of an 'express' pathway that provides visual input to the premotor cortex. This pathway is considered important for the integration of sensory information about the visual field periphery and the skeletomotor system, especially in relation to the control of arm movements. However, a better understanding of the functional contributions of different parts of this complex has been hampered by the lack of data on the extent and boundaries of its constituent visual areas. Recent studies in macaques have provided the first detailed view of the topographical organization of this region in Old World monkeys. Despite differences in nomenclature, a comparison of the visuotopic organization, myeloarchitecture and connections of the relevant visual areas with those previously studied in New World monkeys reveals a remarkable degree of similarity and helps to clarify the subdivision of function between different areas of the dorsomedial complex. A caudal visual area, named DM or V6, appears to be important for the detection of coherent patterns of movement across wide regions of the visual field, such as those induced during self-motion. A rostral area, named M or V6A, is more directly involved with visuomotor integration. This area receives projections both from DM/V6 and from a separate motion analysis channel, centred on the middle temporal visual area (or V5), which detects the movement of objects in extrapersonal space. These results support the suggestion, made earlier on the basis of more fragmentary evidence, that the areas rostral to the second visual area in dorsal cortex are homologous in all simian primates. Moreover, they emphasize the importance of determining the anatomical organization of the cortex as a prerequisite for elucidating the function of different cortical areas.