Digital multi-filter auditory prosthesis: study of its efficiency in function of number of filters and their programming

A new method to determine a rate constant and total reaction product using data of reaction product kinetics is proposed. The method is based on the solution of the system of irrational equations (for special case), which describes such processes. This method was used to determine the reaction rate constant of interaction of some monoclonal antibodies with the antigens immobilized on immunological plates.     

Intensity coding of auditory stimuli: an fMRI study

The effect of stimulus intensity (sound pressure level, SPL) of auditory stimuli on the BOLD response in the auditory cortex was investigated in 14 young and healthy subjects, with no hearing abnormalities, using echo-planar, functional magnetic resonance imaging (fMRI) during a verbal and a non-verbal auditory discrimination task. The stimuli were presented block-wise at three different intensities: 95, 85 and 75 dB (SPL). All subjects showed fMRI signal increases in superior temporal gyrus (STG) covering primary and secondary auditory cortex. Most importantly, the spatial extent of the fMRI response in STG increased with increasing stimulus intensity. It is hypothesized that spreading of excitation is associated with the encoding of increasing stimulus intensity levels. In addition, we found bifrontal activation supposedly evoked by the auditory-articulary loop of working memory. The results presented here should assist in the design of optimal activation strategies for studying the auditory cortex with fMRI paradigms and may help in understanding intensity coding of auditory stimuli.     

Hearing handicap--an addition to audiometric hearing loss. Results of an exploratory study of auditory communication disorders in the elderly

Hearing problems in elderly patients cannot be evaluated completely with conventional audiological tests in most cases. Two hundred and one subjects aged 60 years or more complaining of hearing problems were studied. The following tests were employed: pure-tone audiometry, the "Basler Satztest" (a German version of the SPIN-test assessing speech perception in noise), and a German version of a "Hearing Handicap Inventory for the Elderly" (HHIE). These latter versions were developed in our institution. An auditory handicap was found in one-third of subjects with mild hearing losses (PTA < 30 dB; n = 135) and in two-thirds of subjects with greater hearing losses (PTA > and = 30 dB; n = 65). The relatively weak correlations of the pure-tone audiogram (r = 0.49) or speech audiometry (r = 0.41) with HHIE indicate that more than 50% of the variance of the hearing handicap was due to non-audiologic factors. For this reason, we recommend that the handicap questionnaire be added to the audiometric evaluation.     

Hearing in passerine and psittacine birds: A comparative study of absolute and masked auditory thresholds.

Operant conditioning and a psychophysical tracking procedure were used to measure auditory thresholds for pure tones in quiet and in noise for seven species of small birds—the budgerigar, canary, cockatiel, European starling, song sparrow, swamp sparrow, and the zebra finch. Audibility curves are roughly similar among the seven birds, with the maximum sensitivity between 2 and 5 kHz and poorer sensivitity outside this narrow region. Critical ratios (signal-to-noise ratio at masked threshold) were calculated from pure-tone thresholds in noise. Except for the budgerigar, the critical ratio functions of all birds increase at the rate of 3 dB/octave. This pattern is typical of that observed in most vertebrates. Critical ratios in the budgerigar, on the other hand, decrease gradually from 0.5 kHz to 2.8 kHz and increase dramatically above 2.8 kHz. The present research demonstrates that the critical ratio function for the budgerigar is not only different from other vertebrates but also different from other birds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual behaviours of neurologically impaired children with cerebral visual impairment: an ethological study

BACKGROUND/AIMS: Visual functions of neurologically impaired children with permanent cerebral visual impairment (CVI) can be difficult to determine. This study investigated the behavioural profile of CVI children by means of ethological observations in order to gain a better understanding of their visual functions. METHODS: Video registrations of nine subjects who were unable to undergo more orthodox methods of visual function testing were observed and analysed by an ethologist. RESULTS: A series of behaviours (direct signs) and supportive or confirming behavioural elements (indirect signs) indicating some visual perception in the children were found. CONCLUSION: Detailed ethological observations of visual behaviour were shown to be useful for analysing visual functions of children with permanent CVI.     

Activation of human auditory cortex in retrieval experiments: an fMRI study

The medical profession in America would benefit from including aromatherapy with massage in its care of elderly and hospice patients. The appropriate use of these modalities will enhance the quality of patient care and will compliment conventional treatment regimens. Currently, the medical profession in America treats the pathophysiological diseases of patients, but falls short in treating their emotional needs. Aromatherapy and massage can be used to fill this gap, as well as to improve the patient's response to traditional treatment routines. While there is an abundance of literature extolling the use of essential oils, the articles reflect subjective, individual findings and don't account for the multitude of influencing environmental factors which would include such things as the patient's degree of pain, personality of the person administering care and that of the patient, or even the temperature of the room itself. Further research needs to be made so that scientific, qualitative measurements can be proven and documented.     

The gradient of spatial auditory attention in free field: an event-related potential study

Young adult subjects attended selectively to brief noise bursts delivered in free field via a horizontal array of seven loudspeakers spaced apart by 9 degrees of angle. Frequent "standard" stimuli (90%) and infrequent "target/deviant" stimuli (10%) of increased bandwidth were delivered at a fast rate in a random sequence equiprobably from each speaker. In separate runs, the subjects' task was to selectively attend to the leftmost, center, or rightmost speaker and to press a button to the infrequent "target" stimuli occurring at the designated spatial location. Behavioral detection rates and concurrently recorded event-related potentials (ERPs) indicated that auditory attention was deployed as a finely tuned gradient around the attended sound source, thus providing support for gradient models of auditory spatial attention. Furthermore, the ERP data suggested that the spatial focusing of attention was achieved in two distinct stages, with an early more broadly tuned filtering of inputs occurring over the first 80-200 msec after stimulus onset, followed by a more narrowly focused selection of attended-location deviants that began at around 250 msec and closely resembled the behavioral gradient of target detections.     

Anterior temporal white matter lesions in myotonic dystrophy with intellectual impairment: an MRI and neuropathological study

We studied 12 patients with myotonic dystrophy using MRI and the Mini-mental state examination (MMSE), to see it specific MRI findings were associated with intellectual impairment. We also compared them with the neuropathological findings in an autopsy case of MD with intellectual impairment. Mild intellectual impairment was found in 8 of the 12 patients. On T2-weighted and proton density-weighted images, high-intensity areas were seen in cerebral white matter in 10 of the 12 patients. In seven of these, anterior temporal white-matter lesions (ATWML) were found; all seven had mild intellectual impairment (MMSE 22-26), whereas none of the four patients with normal mentation had ATWML. In only one of the eight patients with intellectual impairment were white-matter lesions not found. Pathological findings were severe loss and disordered arrangement of myelin sheaths and axons in addition to heterotopic neurons within anterior temporal white matter. Bilateral ATWML might be a factor for intellectual impairment in MD. The retrospective pathological study raised the possibility that the ATWML are compatible with focal dysplasia of white matter.     

Development and differentiation of the anuran auditory brainstem during metamorphosis: an acetylcholinesterase histochemical study

The time course of cell differentiation and the presence of histochemically defined areas in brainstem auditory nuclei were examined in developing bullfrogs, Rana catesbeiana, using cresyl violet staining and acetylcholinesterase (AChE) histochemistry. In the medulla, the dorsolateral nucleus (DLN) can be seen as a distinct structure in its adult location only at Gosner stage 40 and beyond. The majority of cells in the DLN are not fully differentiated until late metamorphic climax (stages 45-46) and early postmetamorphosis. The more ventral vestibular nucleus differentiates earlier (stage 37) than the DLN. Adult-like organization of auditory nuclei in the torus semicircularis (TS) of the midbrain cannot be reliably discerned until metamorphic climax stages. Cellular masses in the brainstem reveal AChE from the earliest stage examined (stage 27) but the intensity of staining differs among cell groups. Staining intensity in the DLN is at a peak in recently metamorphosed froglets. The time course of cell differentiation in the DLN precedes slightly or is coincident with the increased, transient presence of AChE. Staining of the superior olive stabilizes at a moderate level in early postmetamorphic stages. Ventral regions of the principal nucleus in the TS stain more intensely than dorsal regions beginning at stage 40. This dorsal-ventral gradient in staining persists in adult stages. There is a transient decline in staining of the laminar nucleus in metamorphic climax stages. Staining intensity in the magnocellular nucleus peaks during stages 40-46 and in early postmetamorphic froglets and then declines in adults, paralleling the pattern seen in the DLN. These data suggest that metamorphic climax and early froglet periods are an important developmental window for major differentiation and maturational events in the auditory brainstem.     

Performance of children with severe to profound auditory impairment in instrumentally guided reduction of nasal resonance

Twelve students at the Kentucky School for the Deaf were studied using a bioelectronic instrument to provide visual feedback of the degree of nasal resonance, thereby guiding them toward reduction of excessively nasal voice quality. The subjects were given a maximum of fourteen 20-min sessions of training. The results indicated that the feedback information was used very effectively by five subjects and somewhat effectively by four others. The remaining three subjects did not demonstrate a consistent relationship between periods of training and reduction in nasal resonance. Pre- and post-training testing using stimuli not included in the training material demonstrated significant generalization of the nasalance control gained in the training sessions.     

Perineurioma: an unusual cause of an external auditory canal polyp

BACKGROUND: Home parenteral nutrition (HPN) is used to treat intestinal failure. A minority of HPN patients are dependent on opiates and benzodiazepines to control pain and anxiety. The aim of this study was to determine what effects such drug dependence had on patient outcomes. METHODS: Ten dependent patients were prospectively compared with 10 well-matched, nondependent HPN patients for the same 12-month period. Episodes of line sepsis and other complications were documented and the cost of treatment estimated. Health status was measured using the SF36 and EuroQol instruments. RESULTS: The dependent group had significantly more episodes of central line sepsis (p = .0007) as well as other complications (p = .0002). This led to significantly longer periods of inpatient care (p = .0004) and therefore higher costs of treatment. Health status was lower in the dependent group; they reported more pain (p = .04) and less energy (p = .04). CONCLUSIONS: The complication rate and increased cost of treatment for opiate- and sedative-dependent patients receiving HPN significantly detract from the overall outcome of this therapy.     

Inferior vena caval filters: an overview of current use

MTX-induced hepatic injury and liver enzyme elevations have been demonstrated after treatment of leukemia, gestational disease and during treatment of psoriasis and rheumatoid arthritis. A 40-year-old man with a long standing history of rheumatoid arthritis was treated with MTX over a 6 month period and developed an overwhelming hepatic necrosis. He was successfully transplanted.     

Speech intelligibility following maxillectomy with and without a prosthesis: an analysis of 54 cases

BRCA1 accounts for nearly all families with multiple cases of both early onset breast and ovarian cancer and about 45% of families with breast cancer only. Although to date more than 200 distinct mutations have been described, several have been found to be recurrent in the gene. We have analyzed 87 Spanish breast/ovarian cancer families for the six most recurrent mutations in the BRCA1 gene. The analysis of the five exons where these mutations are located was made using the SSCP and sequenciation techniques. Four mutations were found in our families and only two carried one of the six mutations analyzed. In both cases the mutation identified was 185delAG. Our results suggest that these six mutations are not specially recurrent in the Spanish population and that differences in the geographical origin of the families can influence the type and proportion of mutations identified.     

Human pancreatic RNase1-human epidermal growth factor fusion: an entirely human 'immunotoxin analog' with cytotoxic properties against squamous cell carcinomas

The gene encoding human pancreatic ribonuclease 1 (hpRNasel) was fused with a gene encoding human epidermal growth factor (hEGF). The hybrid human protein was isolated from Escherichia coli inclusion bodies, refolded and purified to homogeneity. The fusion protein competed with 125I-hEGF for binding to hEGF receptors (EGFR) and had ribonucleolytic activities approaching those of hpRNase1. Several conformations having different enzymatic activities could be detected after reversed-phase high-performance liquid chromatographic analysis, the less hydrophobic molecules being the most active. The hybrid protein was specifically cytotoxic to A431, an EGFR overexpressing squamous carcinoma cell line, with an IC50 of approximately 10(-7) M. In contrast, recombinant hpRNase1 had an IC50 higher than 10(-4) M. A mixture of free hEGF and free hpRNasel was not more cytotoxic than hpRNasel alone and no cytotoxicity was detected in EGFR-deficient control cells. Taken together, these data suggest that this construct might be useful for targeted therapy of esophageal, lung and other squamous cell carcinomas and also breast cancers overexpressing EGFR, which correlate with a poor prognosis and cannot be cured by surgery alone. Engineering hybrid molecules with endogenous human proteins for targeted therapy may alleviate the dose-limiting immunogenicity and toxicity of conventional immunotoxins.     

New approach to aortic dissection: development of an insertable aortic prosthesis

We have developed a new aortic prosthesis with which we can replace or reinforce the aorta using a simple percutaneous technique. We have named the new prosthesis the shape-memory aortic prosthesis (SAP); it consists of a spiral-shaped nitinol stent and polyurethane tube. It can be compressed inside a 14F catheter at a low temperature and regain its original shape at above 30 degrees C. As a preliminary study, SAP sutureless grafting into the descending aorta was performed on 10 mongrel dogs. We found that when the proper diameter of SAP was applied, it functioned satisfactorily for 3 months or more. A percutaneous placement technique pertinent to the SAP also was developed and tried on 4 animals. Our procedure was applied to Stanford type B dissection models to close the entry point successfully. This newly developed SAP has potential to be applied to emergency cases of human aortic dissections.     

Loading of a unilateral temporomandibular joint prosthesis: a three-dimensional mathematical study

The load on the prosthetic side and the influence of the design on the remaining natural contralateral TMJ must be known before a unilateral temporomandibular joint (TMJ) prosthesis can be developed. The aim of the present study was to determine the maximum loading of the TMJ prosthetic side and the natural contralateral TMJ and to investigate the influence of the location of the center of rotation of the prosthesis on the maximum loading. For this purpose, a mathematical model of the mandible with a unilateral TMJ prosthesis with a fixed center of rotation (CR) was developed. The location of the CR of the TMJ prosthesis was varied from the middle of the natural mandibular condyle to 15 mm inferior to this location. Although the maximum joint reaction forces changed as a result of a unilateral TMJ prosthesis, the trend of the loading curves was similar to that of an intact mandible. A unilateral TMJ prosthesis resulted in a 50% higher loading of the prosthetic side, while the load on the natural contralateral TMJ remained within normal limits. The maximum load on the prosthetic side occurred during molar bites and could reach 100 N in the cranial direction, 30 N in the ventral direction, and 25 N in the medio-lateral direction. The location of the CR did not have a significant influence on the loading of the TMJ prosthesis and the natural contralateral TMJ.     

Prospective randomized comparative study of tracheoesophageal voice prosthesis: Blom-Singer versus Provox

OBJECTIVES: Compare the most commonly used types of tracheoesophageal voice prostheses, Blom Singer and Provox. STUDY DESIGN: Prospective study of 113 prostheses placed in 52 patients randomly selected to receive Blom-Singer and Provox. METHODS: Postoperative voice was recorded at 1 and 4 months after valve placement. Survival time of the prosthesis and four objective voice parameters were analyzed. Eight judges rated all recordings in a random order for six subjective voice parameters. Subgroup analysis for primary versus secondary placements and type of procedure was performed. In addition, patients were asked for their subjective assessment. RESULTS: Overall, Blom-Singer and Provox prostheses give very similar voice quality, lifetime, and patient satisfaction. Cleaning management is somewhat better for Provox, but there is a trend toward better overall voice quality for the Blom-Singer prosthesis. In subgroup analysis secondarily placed prostheses score somewhat better than primary placements, and patients with total laryngectomy have better voices than patients with extended laryngectomy combined with partial pharyngectomy. CONCLUSIONS: Given the equal and good results in terms of voice quality, other factors (e.g., costs, surgery-related factors, maintenance, patient preference) should be taken into account when deciding which type of tracheoesophageal voice prosthesis to use.