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Biomedical subjects

R W Keith

Publications and source records attributed to R W Keith.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of cochlear function in a patient with "far-advanced" otosclerosis.

A patient with "far-advanced" otosclerosis with a profound bilateral hearing loss was evaluated for cochlear reserve using transtympanic electrocochleography (ECoG) and promontory stimulation. Results indicated that both ECoG and promontory responses were present, indicating that cochlear function was present bilaterally. A stapedectomy resulted in closure of the air-bone gap. Postoperative hearing yielded excellent aided responses compared to no measurable preoperative hearing aid benefit. This case serves to demonstrate the value of evaluating cochlear function using these electrophysiologic techniques.

Aged↗
PubMed1991

Effects of methylphenidate on the auditory processing abilities of children with attention deficit-hyperactivity disorder.

Stimulant medications are widely used as part of the treatment for children with attention deficit-hyperactivity disorder (ADHD). The current study investigated the effects of methylphenidate on auditory vigilance, auditory processing abilities, and receptive language abilities of children with ADHD. Twenty subjects (17 males and 3 females) ranged in age from 7 to 13 years. Each subject had been diagnosed as having ADHD and had been prescribed methylphenidate for the control of hyperactivity. The test battery included the Auditory Continuous Performance Test (ACPT), SCAN (a screening test for auditory processing disorders in children), and the Token Test for Children. Results indicated that there was significant improvement in the children's performance on all measures when on methylphenidate. Implications of these findings are discussed.

Adolescent↗
PubMed1991

Prediction of bithermal caloric response from monothermal stimulation.

The use of either cold or warm caloric stimulation alone as a screening tool for unilateral weakness has been suggested as a means of both shortening testing time and reducing patient discomfort. The validity of the monothermal caloric test must be well established before it can be routinely used in clinical situations. The purpose of this investigation was to re-evaluate the monothermal caloric test by examining the correlations between unilateral weakness derived from bithermal caloric stimulation compared to monothermal caloric results using either warm or cool stimulation alone. A retrospective analysis of 200 patients indicated significant correlations between bithermal and monothermal unilateral weakness for patients with unilateral weakness of less than 15% and greater than 30% for both warm and cool water stimulation. For patients with 15% to 30% unilateral weakness, the bithermal and monothermal calorics were significantly correlated for only the cool condition. When predicting normal or greater than 20% unilateral weakness, either of the monothermal calorics have greater than 85% efficiency, with specificity greater than 94% and sensitivity greater than 64%. However, the false-negative rate is 29% for warm and 36% for cool calorics. The high rate of false-negative findings indicates that screening tests have no place in a diagnostic battery, especially in view of the implications for missing significant pathology.

Adolescent↗
PubMed1991

Central auditory function.

Central auditory disorders in children and adults have become more widely recognized in patients seen by otolaryngologists and audiologists. This article briefly defines those clinical entities, discusses the historic background of testing, and describes current and future test approaches to assessment of central auditory disorders.

Audiometry, Evoked Response↗
PubMed1990

A comparison of the SSW and language test results.

The purpose of this paper is to determine the relationship between the SSW and a battery of auditory-language tests in a group of children suspected of auditory processing problems. Thirty-one children between the ages of 6.2 and 10.4 were referred by their classroom teachers. All children were administered a pure tone and an acoustic immittance battery, the SSW test, selected subtests of the Clinical Evaluation of Language Functions, the Goldman-Fristoe-Woodcock Auditory Skills Battery, an elicited language sample, and the Observational Profile of Classroom Communication. No significant correlations were found between the SSW right competing and left competing conditions and the auditory-language test battery. The findings suggest that these two test approaches measure different aspects of auditory processing abilities in children, and both are required to adequately describe auditory processing abilities at all levels.

Attention↗
PubMed1990

Somatosensory cortical evoked potentials: a review of 100 cases of intraoperative spinal surgery monitoring.

A review of our experience with evoked potential monitoring of over 100 spinal procedures is summarized here. Typical results of somatosensory cortical evoked potential (SCEP) testing found that latency of responses increased slightly and amplitude decreased substantially from preanesthesia to predistraction with no further changes. SCEP results are effected by many factors, but when they are understood and recognized, evoked potential monitoring can play a significant role in recognizing potential problems and preventing postoperative neurological problems in patients undergoing spinal surgery.

Adolescent↗
PubMed1989

Comparison of SCAN results with other auditory and language measures in a clinical population.

This study was conducted to compare results of SCAN: A Screening Test for Auditory Processing Disorders with other central auditory and language tests. The SCAN, Staggered Spondee Word test (SSW), Competing Sentence test, Peabody Picture Vocabulary Test (PPVT), and the Clinical Evaluation of Language Fundamentals-Revised (CELF-R) were administered to 155 children between the ages of 6 and 15 years. All subjects were referred for possible auditory or language processing disorders. Results showed significant correlations between the SCAN, SSW, and Competing Sentence test results except for Filtered Word and Auditory Figure Ground subtests of SCAN that were not significantly correlated with the Competing Sentence Test. Significant correlations also existed between SCAN and the PPVT, but there were no significant correlations between SCAN and the CELF-R subtests. Patterns of responses according to histories of Attention Deficit Disorders were also found.

Adolescent↗
PubMed1989

Neuroaudiologic abnormalities in patients with type 1 neurofibromatosis.

Although the protean manifestations of neurofibromatosis have been studied for many years, much is yet to be learned about this disease in young children. Specifically, little is known about the prevalence and significance of early neurotologic abnormalities in this population. Our review of the recent literature, however, failed to identify any publication on the use of ABR and acoustic reflex testing in the pediatric neurofibromatosis population. This study reports on a standardized differential diagnostic battery conducted on 44 children diagnosed as having neurofibromatosis. Results of the neuroaudiologic battery indicated that 32% of the children had significant abnormalities on ABR and acoustic reflex dynamic tests. This is a substantially higher prevalence of abnormalities than reported by another group at a recent NIH concensus meeting on neurofibromatosis. Discussion of the implications of these findings regarding evaluation protocols, as well as management for this select patient population, will follow.

Acoustic Impedance Tests↗
PubMed1979

Effect of middle-ear dysfunction and disease on hearing and language in high-risks infants.

The effect of middle-ear dysfunction and disease on hearing and language development at one year of age was evaluated for 143 high-risk infants. These infants were categorized as normal or abnormal based on otologic history, otoscopic examinations, and on tympanometric examinations. Language was significantly related to gestational age, being delayed by approximately the amount of prematurity. Language scores were therefore adjusted for gestational age. Speech-detection threshold was not related to gestational age, and was used as the measure of hearing. Hearing levels were negatively correlated with adjusted language quotients. Infants with abnormal otologic histories reported were not different from infants with normal histories in either hearing or language development. Infants with bilateral otoscopic abnormalities had significantly higher speech-detection thresholds, but did not differ in language development from those with bilaterally normal otoscopy. Infants who were abnormal bilaterally by tympanometric examination had significantly higher speech-detection thresholds as well as significantly delayed language development. A significant effect on both hearing and language was found among those infants bilaterally abnormal by tympanometry for whom evidence of middle-ear disease was not visualized by otoscopic examination. Implications of these findings are discussed.

Hearing Disorders↗
PubMed1979

The effects of chronic middle ear effusion on speech and language development -- a descriptive study.

In this study, the speech and language skills of children with histories of chronic middle ear effusion were analyzed. Forty-seven children between the ages of one year eleven months and five years five months were given a battery of speech and language tests in the course of a diagnostic evaluation. All the children had been referred to speech pathology by a physician because of a suspected communication disorder. All subjects had histories of three or more episodes of middle era effusion, with the first episode occurring prior to 18 months of age. All medical records were checked and in-depth case histories were obtained in order to rule out other possible complicating factors that might have contributed to a speech and language delay. The results of this study revealed essentially age-appropriate receptive language skills in this group of children. Expressive language and articulatory skills were significantly below chronological age level expectation, indicating the possible serious effects of chronic middle ear effusion on speech and language development.

Child, Preschool↗
PubMed1979

Hypermobility of the incudostapedial joint: a clinical entity.

During exploratory tympanotomy for conductive deafness, the surgeon is occasionally perplexed to find no apparent cause for the air-bone gap. This unexplained deafness has been called "inner ear conductive hearing less" because of the apparent absence of pathology in the middle ear. The incudostapedial joint was studied in 68 vertically sectioned temporal bones and the anatomy is presented. Varying amounts of laxity is observed in the normal joint capsule at the time of surgery. A theory is suggested in which an elongated capsule allows incus motion without energy transmission to the stapes. It is proposed that hypermobility of the incudostapedial joint may exist and explain conductive hearing loss of undetermined etiology.

Audiometry↗
PubMed1978

Stapedial reflex in neonates.

This paper considers the effect of behavioral responses on stapedial reflex data of neonates. Twenty clinically normal neonates were tested to determine whether repeated acoustic stimulation would habituate the behavioral response, leaving only the stapedial reflex for observation. The results failed to show systematic decline of behavioral response over trials. Stapedial reflex testing indicates a positive response for less than 5% of stimulus presentation. The results are discussed in terms of possible explanation for the apparently low incidence of stapedial reflex in a normal neonatal population.

Acoustic Stimulation↗
PubMed1977

An evaluation of predicting hearing loss from the acoustic reflex.

Three different formulas used in predicting hearing level from acoustic reflex data have been suggested. Acoustic reflex information is also used in predicting slope of hearing loss. Seventy-four normal and hearing-impaired persons were tested, and predictions of level and slope of hearing were compared with pure tone hearing thresholds. The results indicate that the Niemeyer-Sesterhenn and Jerger unweighted formulas yield comparable results and are preferable to the Jerger weighted formula. Predictions of slope of hearing loss are equivocal.

Audiometry↗
PubMed1976

Use of low-pass noise in word-recognition testing.

This study attempted to determine whether word-recognition scores obtained in noise were more sensitive to the presence of a hearing loss than recognition scores obtained in quiet. Subjects with normal hearing, high-frequency cochlear hearing loss, and flat cochlear hearing loss were tested in quiet and in the presence of a 500-Hz low-pass noise. Two signal-to-noise conditions were employed, -4 dB and -12 dB. Words were presented at 40dB SL in one experiment and at 96 dB SPL for normal-hearing subjects in a second experiment. The results indicated that, while the word-recognition scores of groups were similar in quiet, the more negative the signal-to-noise ratio, the greater the separation of group scores, with hearing-impaired subjects having poorer recognition scores than normal-hearing subjects. When the speech and noise were presented at high SPLs, however, the normal-hearing subjects had poorer word recognition than those with flat cochlear losses. The results are interpreted as indicating greater spread of masking in normal-hearing than hearing-impaired subjects at high sound pressure levels.

Adult↗
PubMed1976

Acoustic impedance measurement in the otological assessment of multiply handicapped children.

This survey investigated the use of acoustic impedance measurement on a population of multiply handicapped children and correlated the results with otoscopy. Thirty-one children were tested with an impedance meter studying tympanometry, tympanic membrane compliance, and acoustic reflex. Otoscopic examination was also scheduled for each child. The results show that 42% of children tested had some kind of middle-ear problem, mostly unrecognized at the time of this survey. There was 100% agreement between impedance and otoscopic findings. Apparently impedance audiometry can be useful for identifying middle-ear disorders in children who cannot be tested by traditional audiometric methods.

Acoustic Impedance Tests↗
PubMed1975

Middle ear function in neonates.

This study was designed to investigate the middle ear function of neonates during the first few hours of life. Twenty normal babies, ranging in age from 2.5 to 20 hours old, were tested witn an electroacoustic impedance bridge. Measurements of the acoustic compliance of the tympanic membrane and tympanometry were obtained on both ears of each child. Results of compliance measurements indicated a median of 1,2 cu cm with a range of 0.25 to 1.65 cucm. Tympanometry results showed smooth notched-shaped tympanograms in most cases although afew M-shaped tympanograms were observed. All of the infants demonstrated normal middle ear pressures and mobile middle ear systems. The finding of normal middle ear function in these neonates suggest that mucus is not commonly present and therefore not a factor in infants' response to sound.

Compliance↗
PubMedDate not supplied

Lead exposure and the central auditory processing abilities and cognitive development of urban children: the Cincinnati Lead Study cohort at age 5 years.

This analysis examined the relationship between lead exposure as registered in whole blood (PbB) and the central auditory processing abilities and cognitive developmental status of the Cincinnati cohort (N = 259) at age 5 years. Although the effects were small, higher prenatal, neonatal, and postnatal PbB levels were associated with poorer central auditory processing abilities on the Filtered Word Subtest of the SCAN (a screening test for auditory processing disorders). Higher postnatal PbB levels were associated with poorer performance on all cognitive developmental subscales of the Kaufman Assessment Battery for Children (K-ABC). However, following adjustment for measures of the home environment and maternal intelligence, few statistically or near statistically significant associations remained. Our findings are discussed in the context of the related issues of confounding and the detection of weak associations in high risk populations.

Auditory Perceptual Disorders↗