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Biomedical subjects

W J Kelly

Publications and source records attributed to W J Kelly.

At least 37 records · Page 2Linked to original sources
PubMed1991

Unilateral hearing loss in children.

Recent reports suggest that early onset, severe unilateral sensorineural hearing loss (USNHL) in children may be associated with significant deficits in auditory and psycholinguistic skills and school performance. This report reviews a consecutive series of 324 children and adolescents (202 males, 122 females) with documented USNHL evaluated at the Boys Town National Research Hospital. The left ear was affected in 168 (52%) and the right ear in 156 (48%). Based on speech frequency threshold averages (i.e., 500, 1000, and 2000 Hz), the losses were classified by severity as follows: borderline, 43 (13%); mild, 51 (16%); moderate, 40 (12%); severe, 19 (6%); profound, 31 (10%), and anacusic, 50 (15%). The remaining 90 children (28%) had high frequency losses (i.e., above 2000 Hz). The mean and median age of diagnosis were 8.78 years and 7.75 years. Temporal bone imaging studies, auditory brainstem responses (ABRs), and vestibular evaluations were performed on selected cases. Etiology was uncertain in 34.8% of cases, while hereditary factors (12.6%), head trauma (10.8%), and perinatal risk factors (10.7%) were the most commonly identified etiologies. Thirty-one percent of the children had scholastic or behavioral problems in school. A concerted effort aimed at early identification and intervention in cases of USNHL is warranted.

Adolescent↗
PubMed1990

Atopy in subjects with asthma followed to the age of 28 years.

The relationship between markers of asthma and atopy was examined in 323 subjects at the age of 28 years who have been followed since the age of 7 years. Hay fever was common in all groups with severe asthma, increasing from 25% of the control group to 67% of the group with the most severe asthma, class V. Eczema was uncommon at this age in all groups. IgE levels, peripheral blood eosinophil counts, and skin reactions were significantly (p less than 0.05) higher in class V than in the control group. Increasing age was associated with a progressive fall in eosinophil counts and an increase in skin reactivity to common allergens. No change in IgE levels was observed from 21 to 28 years. A general relationship between bronchial hyperreactivity and atopic markers was found. However, only the occurrence of hay fever was significantly related to reactivity when account was taken of severity of asthma. The results indicate that the relationship between asthma and atopy observed at earlier reviews continues into adult life and that bronchial hyperreactivity and atopy are not directly linked.

Adolescent↗
PubMed1990

Speech perception in low-pass filtered noise for normal and hearing-impaired listeners.

Two experiments were conducted concerning speech perception in noise. In Experiment 1, a comparison was made between adaptive and fixed-level procedures to estimate the S/N ratio at which 50% correct performance occurred for nonsense syllables for normal-hearing listeners. The two methods yield similar S/N ratio estimates, but the consonant confusions found with the fixed-level method could not be predicted accurately from the adaptive procedure. In Experiment 2, the adaptive procedure was used to estimate the S/N ratio for a 50% performance level in low-pass filtered noise with a range of cutoff frequencies. Data were obtained from 5 normal-hearing listeners at two speech levels (50 and 75 dB SPL) and 4 hearing-impaired listeners at one speech level (75 dB SPL). The hearing-impaired listeners required a better S/N ratio than the normal listeners at either presentation level for all except the widest bandwidth, where their S/N ratios began to converge with the normal values. In addition, the S/N ratios for the hearing-impaired listeners plateaued at relatively narrow bandwidths (0.75 to 2.5 kHz) compared to the normal-hearing group (3.0 to 5.0 kHz). That is, the addition of high-frequency components to the noise did not alter performance. These findings suggest that the hearing-impaired listeners may have relied upon either low-frequency cues or prosodic cues in the perception of these test items.

Adaptation, Physiological↗
PubMed1990

Severe versus profound sensorineural hearing loss in children: implications for cochlear implantation.

The advent of cochlear implants for children has stimulated interest in the specific sensory deficits and communicative capabilities of children with severe or profound bilateral sensorineural hearing loss. Appropriate management of these children and their families requires an appreciation of the multifaceted developmental and educational challenges confronting deaf children, even after cochlear implantation. Evaluation results from 200 children with bilateral sensorineural deafness (63 severe/137 profound, anacusic, and fragmentary) reveal significant differences between these two subpopulations. Within the profoundly impaired group, important differences were also noted in the children's ability to benefit from conventional amplification, depending on residual hearing at or above 1000 Hz. Strategies for assessing auditory function and aided benefit in severely and profoundly hearing-impaired children must involve a pediatric test battery, serial evaluations, and parental cooperation/support. When selecting candidates for cochlear implantation, it is inappropriate to categorize severely hearing-impaired children with those children having profound sensorineural losses. Even profoundly impaired populations are not homogeneous, and rehabilitation potential with conventional amplification must be determined on an individual basis, over time.

Adolescent↗
PubMed1990

Auditory brainstem response results as predictors of behavioral auditory thresholds in severe and profound hearing impairment.

Pediatric cochlear implantation is restricted to patients with stable, bilateral profound sensorineural hearing losses who derive no benefit from conventional amplification. Obtaining reliable audiologic thresholds in a young child with sudden or early-onset hearing loss can be challenging. This study examines the accuracy with which auditory brainstem response evaluation can predict unaided and aided behavioral thresholds in a child with severe-to-profound hearing loss. Reliable behavioral thresholds were obtained on 119 children who had no measurable click-evoked auditory brainstem responses at instrumentation limits of 100 dB HLn. These data show that an absent auditory brainstem response at 100 dB HLn does not necessarily indicate the absence of measurable unaided hearing for test frequencies ranging from 250 Hz to 4000 Hz. Average aided thresholds of better than 60 dB were present in 43% of the children for 500, 1000, and 2000 Hz and in 53% for 500 and 1000 Hz. Therefore, the absence of a click-evoked auditory brainstem response at 100 dB HLn in a young child is not prima facie evidence of the child's cochlear implant candidacy.

Audiometry, Evoked Response↗
PubMed1989

High-frequency audiometry: test reliability and procedural considerations.

This study compared the reliability of a recently developed high-frequency audiometer (HFA) [Stevens et al., J. Acoust. Soc. Am. 81, 470-484 (1987)] with a less complicated system that uses supraaural earphones (Koss system). The new approach permits calibration on an individual basis, making it possible to express thresholds at high frequencies in dB SPL. Data obtained from 50 normal-hearing subjects, ranging in age from 10-60 years, were used to evaluate the effects on reliability of threshold variance, earpiece/earphone fitting variance, and the variance associated with the HFA calibration process. Without earpiece/earphone replacement, the reliability of thresholds for the two systems is similar. With replacement, the HFA showed poorer reliability than the Koss system above 11 kHz, largely due to errors in estimating the calibration function. HFA reliability is greater for subjects with valid calibration functions over the entire frequency range. When average correction factors are applied to the Koss data in an effort to convert threshold estimates to dB SPL, individual transfer functions are not represented accurately. Thus the benefit of being able to express thresholds at high frequencies in dB SPL must be weighed against the additional source of variability introduced by the HFA calibration process.

Adolescent↗
PubMed1988

Childhood asthma and adult lung function.

An age-matched group of 247 subjects who had had asthma as children and 39 control subjects were studied with lung function and bronchial reactivity testing at the age of 28 years. Lung function of those who had ceased wheezing was essentially normal, but lung function was increasingly abnormal in those who continued to wheeze. Those with frequent wheezing at 28 demonstrated a greater decline in their respiratory function since the age of 7 years than the other groups. Methacholine provocation testing was performed in 91% of the group and was associated with frequency of wheezing and evidence of small airways obstruction. No association was found between reactivity and loss of ventilatory capacity since 21 years of age.

Adult↗
PubMed1987

Childhood asthma in adult life: a further study at 28 years of age.

A group of 323 subjects who had wheezed in childhood and 48 control subjects of the same age were studied prospectively from 7 to 28 years of age. A classification system based on wheezing frequency was found to correlate well with clinical and spirometric features of airway obstruction. The amount of wheezing in early adolescence seemed to be a guide for severity in later life with 73% of those with few symptoms at 14 continuing to have little or no asthma at 28 years. Similarly 68% of those with frequent wheezing at 14 still suffered from recurrent asthma at 28 years. Most subjects with frequent wheezing at 21 continued to have comparable asthma at 28 years. Of those with infrequent wheezing at 21, 44% had worsened at 28 years. Women fared better than men between 21 and 28 with 19% having worse symptoms compared with 28% of men. Treatment at all ages was generally inadequate. The number of smokers among those with asthma was of concern.

Adult↗
PubMed1987

Isolation and characterization of a strictly anaerobic, cellulolytic spore former: Clostridium chartatabidum sp. nov.

Cellulolytic, strictly anaerobic spore-forming bacteria were isolated from chloroform treated rumen contents. They were different from previously described cellulolytic rumen clostridia in several characteristics. They formed subterminal rod-shaped spores approximately 0.7 micron by 3.5 micron. In broth cultures the growth rate was maximal at 39 degrees C and after log growth extensive autolysis occurred. Fermentation products consisted of acetate, butyrate, hydrogen and ethanol. The GC content was 31%.

Anaerobiosis↗
PubMed1986

Group conversational-skills training and social validation with mentally retarded adults.

Seven community-dwelling, mildly and moderately mentally retarded adults participated in a group social skills training program designed to improve conversational skills. A group multiple-baseline design was used. Conversational components trained were asking questions about the conversational partner, giving compliments, and appropriately disclosing information about oneself. Training sessions consisted of instructions, modeling, and behavioral rehearsal. Assessment during baseline and treatment consisted of recording conversations between subject dyads after each session. Generalization of training was assessed during baseline and treatment and at 1-month, 3-month, and 6-month follow-ups by recording conversations between subjects and novel, nonretarded persons. Behavioral ratings of the tapes indicated substantial improvements in the targeted behaviors as a function of training. Subjective social validity ratings of pretraining and posttraining generalization tapes by community volunteers reflected improvements in their social perceptions of subjects as a function of training. The results suggest that community-dwelling, mentally retarded adults can be taught to make changes in their conversational behavior that are viewed positively by others living in their communities.

Adult↗
PubMed1986

Stimulus-based limitations on the discrimination between different temporal orders of tones.

Listeners' abilities to discriminate the order of two tones, of frequency 500 Hz and 500 Hz + delta f, separated by less than 5 ms, were measured in terms of threshold durations (T) for the tones. The experiment was repeated for values of delta f between 5 and 160 Hz. The relation of the duration threshold to delta f was well-described by the reciprocity equation, delta fT = K, for K = 0.16. This reciprocity corresponds to a constant overlap of the main lobes of the power spectra for the tones of about 70%-80%. Addition of a trailing context tone severely degraded the ability to discriminate temporal order, increasing the value of the reciprocity constant to approximately K = 1.8. The primary effect of the context tones was to increase the duration required for accurate discrimination, rather than to impair actual frequency resolution. Implications of these results for speech perception are discussed.

Acoustic Stimulation↗
PubMed1985

Charcoal hemoperfusion treatment of severe theophylline toxicity.

A 38 year old man was admitted eight hours after taking ten grams of theophylline. The plasma concentration of theophylline on admission was 732 mumol/l. In view of the patient's continuing clinical deterioration, charcoal hemoperfusion was undertaken. This led to a rapid fall in plasma theophylline concentrations and improvement in clinical signs. It is suggested that charcoal hemoperfusion has a role in the severely theophylline toxic patient in whom standard conservative measures are failing. The patient's hyperglycemia, metabolic acidosis, and hypokalemia are discussed.

Adult↗
PubMed1982

Tissue dilation during multiple cast restorative techniques.

The advantages and disadvantages of three tissue dilation methods are discussed. There are distinct, identifiable advantages in selecting electrosurgery as the method, since the disadvantages to each method are essentially equal. Electrode use and type are recommended for tissue dilation for the anterior and posterior areas of the mouth. The fully rectified surgical current is suggested since it provides a clean excision of the tissue and controls hemorrhage with a thin layer of coagulum. Illustrations demonstrate electrosurgical techniques with specific electrodes for both anterior teeth and posterior teeth. The margins for full coverage preparation can be finished to the crest of the tissue and a subgingival tissue trough established to the desired depth. This provides a space to refine the preparation margins to the desired sulcular depth prior to making the elastic impression. A number of clinical examples demonstrate effective and safe electrosurgical tissue dilation. Several cases illustrate the combination of tissue recontouring along with tissue dilation. Discipline application of electrosurgery for tissue removal is safe and provides excellent results. This benefits both the patient and the dentist.

Bicuspid↗
PubMed1981

Translocatable resistance to mercuric and phenylmercuric ions in soil bacteria.

Of a sample of 42 gram-negative Hg-resistant bacteria, three (a Pseudomonas fluorescens, a Klebsiella sp. and a Citrobacter sp.) contained translocatable elements conferring resistance to Hg2+ (all three) and to Hg2+ and phenylmercuric acetate (P. fluorescens). The discovery of transposable phenylmercuric acetate resistance extends the range of known resistance "transposons" from heavy metals and antibiotics to organometallic compounds.

Bacteria↗
PubMed1979

Age differences in resolving power and decision strategies in a weight discrimination task.

Current theories of aging suggest that at least part of the decline in performance on psychophysical tasks, commonly observed in older subjects, may be the result of their becoming more cautious about sensory decisions. This conclusion has been supported by experiments in which the criterion index, beta, from signal detection theory is shown to be higher (indicating a strict criterion) for older subjects. A weight-discrimination experiments is reported which failed to replicate the earlier results; older subjects' criteria were the same or more lax than those of younger controls on that task. The possibility that extreme caution on the part of older people may be specific to certain classes of task is discussed.

Adult↗