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Biomedical subjects

S C Levine

Publications and source records attributed to S C Levine.

At least 19 recordsLinked to original sources
PubMed2001

Effects of the Clarion Electrode Positioning System on auditory thresholds and comfortable loudness levels in pediatric patients with cochlear implants.

OBJECTIVE: To evaluate the effects of using the Electrode Positioning System on psychophysical auditory thresholds, most comfortable loudness levels, and electric auditory brainstem response (EABR) thresholds in children with the Clarion version 1.2 cochlear implant. DESIGN: Retrospective analysis. SETTING: Academic tertiary care center. PATIENTS AND METHODS: Clinical records of a series of 25 children who received the Clarion version 1.2 cochlear implant at the University of Minnesota, Minneapolis, between January 1997 and August 1999 were examined. Measures evaluated were psychophysical thresholds (T-levels) and most comfortable loudness levels (M-levels) obtained at the 3-month posthookup audiologic evaluation and EABR thresholds obtained during implant surgery. Relevant threshold measures were available for 24 patients, 11 of whom had received the Clarion spiral electrode and electrode positioner (EP group) and 13 of whom had received the spiral electrode without positioner (non-EP group). The 3 measures (T-levels, M-levels, and EABR thresholds) were compared across groups. In addition, EABR thresholds were compared with T-levels and M-levels within groups. RESULTS: Mean T-levels and M-levels were significantly lower for the EP group than for the non-EP group, and interpatient variability for these measures was considerably smaller in the EP group. Electric auditory brainstem response thresholds were not significantly different for EP vs non-EP patients; however, EABR data were available for only a few non-EP patients. CONCLUSIONS: Use of the electrode positioner results in lower T-levels and M-levels in children with the Clarion version 1.2 cochlear implant, consistent with results of previous studies in adults, and reduces across-patient variability for these measures. It is unclear from the present data whether use of the electrode positioner systematically reduces intraoperative EABR thresholds.

Auditory Threshold↗
PubMed2001

Securing cochlear implants to the skull: two alternate methods.

In view of the various problems encountered with the traditional methods of securing cochlear implants--including dural tear and suture dissolution following infection--we devised two alternate methods of performing this procedure. We use a titanium mesh or a Gore-Tex patch secured with two 4-mm screws to fix the receiver to the skull. No patient who has undergone either of these procedures at our institution has experienced any of the complications that are associated with the older silk, nylon, and Dacron sutures. Moreover, our two alternate methods are less technically difficult and can be performed in a shorter period of time.

Cochlear Implantation↗
PubMed2000

What do infants know about continuous quantity?

We investigated infants' sensitivity to amount of continuous quantity and to change in amount of continuous quantity. Using a habituation procedure, Experiment 1 examined whether 6-month-old infants can distinguish between different amounts of liquid in a container. Infants looked significantly longer at a novel quantity than at the familiar quantity. Using a violation-of-expectation paradigm, Experiment 2 examined whether 9-month-old infants expect a change in amount when liquid is added to a hidden container which is already one-fourth full of liquid. Infants looked significantly longer at the impossible event than at the possible event. These findings indicate that infants are sensitive to amount, calling into question claims that infants have a quantitative mechanism which is exclusive to number.

Cognition↗
PubMed2000

Carotid stenting and "extarterectomy" in the management of head and neck cancer involving the internal carotid artery: technical case report.

OBJECTIVE AND IMPORTANCE: Head and neck cancer that invades the internal carotid artery (ICA) represents a significant management challenge. We describe a novel technique that allows for aggressive tumor removal without disrupting blood flow through the affected ICA. CLINICAL PRESENTATION: A 62-year-old man was referred to our institution for management of a neck malignancy involving the ICA. Cerebral angiography suggested that there was good collateral flow from the opposite hemisphere, but the patient reported visual loss in the ipsilateral eye during balloon test occlusion of the ICA. INTERVENTION: A self-expanding stent was deployed in the ICA; it spanned the entire length of the artery involved by tumor. One month later, the patient underwent tumor resection. During surgery, a long ICA arteriotomy was performed directly down to the mesh of the stent. A neoendothelium had formed within the stent, which prevented arterial bleeding. The carotid wall was dissected from the stent without difficulty and removed en bloc with the surrounding tumor. The exposed stent was wrapped circumferentially with a synthetic patch material. The patient tolerated the procedure well, and postoperative angiography demonstrated normal filling of the ICA. CONCLUSION: We describe a novel approach to a patient with head and neck cancer involving the cervical ICA. Preliminary stenting, which allows time for endothelialization before surgery, may permit aggressive tumor resection without interrupting flow through the ICA. This technique obviates the need for complicated carotid reconstruction procedures and avoids the risk of delayed ischemia from carotid sacrifice.

Carotid Artery, Internal↗
PubMed1999

A review of type 3 tympanoplasty.

With the introduction of newer technologies, the advent of antibiotics, and improved surgical methods; the past 25 years have seen a great revolution, refinement, and improvement of tympanoplastic procedures. Furthermore, the methods of classification have been modified. The introduction of ossicular reconstruction with biocompatible implants greatly enhanced the success of type 3 tympanoplasty. This article reviews the classification, indications, surgical techniques, biomechanical properties, and expected hearing results of type 3 tympanoplasty.

Child↗
PubMed1999

Prospective study of tympanic membrane retraction, hearing loss, and multifrequency tympanometry.

Tympanic membrane retraction is a significant sequela of OME and has been linked clinically to atelectasis, ossicular erosion, and cholesteatoma. We investigated important factors for prediction of tympanic membrane retraction in a prospective study of 112 children. After 4 to 6 years of follow-up, 12% of ears had pars tensa retraction without atrophy, and 28% had various degrees of retraction with atrophy. Mild pars flaccida retraction was present in 23%, and severe pars flaccida retraction was present in 12%. Retraction severity was related to hearing level and multifrequency tympanometry. Three factors were significantly related to retraction severity: type of tube, male sex, and percent of visits in the second year with abnormal tympanograms. This study shows that type of tube was the most important factor in long-term outcome after tympanostomy tube treatment of OME.

Acoustic Impedance Tests↗
PubMed1999

Early fraction calculation ability.

Three- to 7-year-olds' ability to calculate with whole-number, fraction, and mixed-number amounts was tested using a nonverbal task in which an amount was displayed and then hidden (J. Huttenlocher, N. C. Jordan, & S. C. Levine, 1994). Next, an amount was added to or subtracted from the hidden amount. The child's task was to determine the hidden amount that resulted from the transformation. Although fraction problems were more difficult than whole-number problems, competence on all problem types emerged in the early childhood period. Furthermore, there were striking parallels between the development of whole-number and fraction calculation. This is inconsistent with the hypothesis that early representations of quantity promote learning about whole numbers but interfere with learning about fractions (e.g., R. Gelman, 1991; K. Wynn, 1995, 1997).

Age Factors↗
PubMed1999

Early sex differences in spatial skill.

This study investigated sex differences in young children's spatial skill. The authors developed a spatial transformation task, which showed a substantial male advantage by age 4 years 6 months. The size of this advantage was no more robust for rotation items than for translation items. This finding contrasts with studies of older children and adults, which report that sex differences are largest on mental rotation tasks. Comparable performance of boys and girls on a vocabulary task indicated that the male advantage on the spatial task was not attributable to an overall intellectual advantage of boys in the sample.

Adult↗
PubMed1999

Safety and clinical performance of acoustic reflex tests.

OBJECTIVE: Safety and effectiveness of acoustic reflex tests are important issues because these tests are widely applied to screen for retrocochlear pathology. Previous studies have reported moderately high sensitivity and specificity for detection of acoustic neuroma. However, there have been reports of possible iatrogenic hearing loss resulting from acoustic reflex threshold (ART) and decay (ARD) tests. This study assessed safety and clinical performance of ART tests for detection of acoustic neuroma. DESIGN: We report a case in which ARD testing resulted in a significant bilateral permanent threshold shift. This case was the impetus for us to investigate the clinical utility of ART and ARD tests. We analyzed sensitivity and specificity of ART, as well as asymmetry in pure-tone thresholds (PTT) for detection of acoustic neuroma in 56 tumor and 108 non-tumor ears. RESULTS AND CONCLUSIONS: Sensitivity and specificity were higher for PTT asymmetry than for ART. Ipsilateral ART at 1000 Hz had poor sensitivity and specificity for detection of acoustic neuroma, and involves some potential risk to residual hearing for presentation levels higher than 115 dB SPL. Approximately half of the acoustic neuroma group had ipsilateral ARTs that would require administration of ARD tests at levels exceeding 115 dB SPL. Therefore, we conclude that PTT asymmetry is a more effective test for detection of acoustic neuroma, and involves no risk to residual hearing. Future studies of contralateral reflex threshold and ARD in combination with PTT asymmetry are recommended.

Adult↗
PubMed1999

Physiologic identification of eighth nerve subdivisions: direct recordings with bipolar and monopolar electrodes.

The purpose of this study was to determine stimulation and recording parameters that maximize differences in evoked responses recorded between the cochlear nerve and the surrounding tissues. Click-evoked potentials were obtained using monopolar and bipolar recording electrodes placed directly on the exposed eighth nerve of anesthetized cats. Responses were compared as stimulus intensity, electrode location, and bipolar electrode orientation and interelectrode spacing were systematically varied. Wave amplitudes increased monotonically with intensity for both monopolar and bipolar configurations, but bipolar configurations exhibited greater selectivity in differentiating cochlear from vestibular subdivisions. The optimal stimulus intensity was 70 to 80 dB peak sound pressure level (pSPL). Monopolar recordings were often confounded by activity originating at remote sites, typically the cochlear nucleus and (for recording sites on the vestibular nerve) the cochlear nerve. Bipolar response amplitudes increased with interelectrode spacing and were largest when electrodes were oriented parallel to the long axis of the nerve. Extrapolation of empirical data indicated that amplitudes of bipolar responses would be maximal at an electrode separation of 7.5 mm. Cochlear nerve conduction velocity, calculated from wave latencies at each of the two monopolar electrodes, was 11.6 +/- 1.6 m/sec.

Animals↗
PubMed1998

Relationships between otitis media sequelae and age.

OBJECTIVES: To explore relationships between age and sequelae in two groups of children treated with tympanostomy tubes for chronic otitis media with effusion (OME). STUDY DESIGN: Cross-sectional study of sequelae among children, adolescents, and adults at 4 years and 9 to 23 years after tympanostomy tube treatment. METHODS: Group I was examined with otomicroscopy, tympanometry, and audiometry two to four times a year as part of a prospective study, and they were evaluated 4 years after initial tube treatment for this study. Group II received tubes while participating in a chronic OME study, but participants were not followed prospectively after treatment. Nine to 23 years after tube treatment, they were examined with otomicroscopy, tympanometry, and hearing screening. RESULTS: Among the 5- to 28- year-old subjects, cholesteatoma (< or = 1%) and perforation (< or = 2%) were rare. In Group I, tympanosclerosis increased with age (P < .01), and OME (flat tympanograms) decreased with age in Group II (P < .01). The older cohort was more likely to have severe retractions (18% vs. 4%, P = .02), hearing loss (21% vs. 10%, P < .01), and severe atrophy (24% vs. 0%, P < .01) than the younger cohort, but they were less likely to have flat tympanograms (2% vs. 12%, P < .01). CONCLUSIONS: Although OME became less prevalent with age, important sequelae (severe atrophy, severe tympanic membrane retraction, hearing loss, cholesteatoma, and chronic perforation) may develop in children with chronic OME as they become adolescents and young adults. Long-term prospective studies are important in defining the progression of sequelae in these children.

Adolescent↗
PubMed1998

Management of otitis media using Agency for Health Care Policy and Research guidelines. The Agency for Health Care Policy and Research.

Increased costs of managing otitis media and its complications may result from delays in diagnosis and treatment. The Agency for Health Care Policy and Research developed guidelines to assist in the management of chronic otitis media with effusion. We examined the medical care adherence to Agency for Health Care Policy and Research guidelines in 59 consecutive patients referred because of chronic otitis media with effusion and recurrent acute otitis media. Patient history and examination data were collected prospectively. In the group with chronic otitis media with effusion, the rate of adherence to Agency for Health Care Policy and Research guidelines was 0%; in those with recurrent acute otitis media, adherence was 5%. Delayed referral occurred in 34% of patients; 25% of patients were referred early. The average duration of effusion in patients with chronic otitis media with effusion was 5.2 months; the duration of recurrent acute otitis media immediately before referral was 9.3 months. Eighteen patients (47%) in the chronic otitis media with effusion group had a history of recurrent chronic otitis media with effusion spanning an average of 22.7 months. On referral, hearing loss was discovered in 92% of all patients, and in 69% the tympanogram was flat. The complication and sequelae rate was 49.1%, and speech delay was the most frequent at 16.9%. We conclude that in our study patients there is a significant referral delay, long history of chronic otitis media with effusion in patients before referral, high rate of hearing loss, and high complication rate. Continued efforts should be directed toward improving education of all clinicians so that diagnostic tools and timely otolaryngologic referral are better used.

Acoustic Impedance Tests↗
PubMed1997

Menstrual cycle phase and mood effects on perceptual asymmetry.

Several studies have reported shifts in perceptual asymmetry during the menstrual cycle, but the potential confounding effect of mood changes has been largely ignored. In this study, 24 female subjects completed four visual laterality tasks and a mood questionnaire at three phases of the cycle. Results indicate no overall effect of cycle phase on any of the asymmetry or mood scores. However, results revealed significant associations between affect and perceptual asymmetry on a face perception task. Implications for mood effects on perceptual asymmetry and future research on cycle-related shifts in asymmetry are discussed.

Adolescent↗
PubMed1997

Numerical abstraction in infants: another look.

This article examines an important finding from the literature on infant numerical competence. The finding, reported by P. Starkey, E. S. Spelke, and R. Gelman (1990), was that infants looked longer toward a visual display that was equal in number to an auditory set. In Experiment 1, when the procedures described by P. Starkey et al. were followed and duration was held constant across auditory sequences that varied in number, infants looked longer toward the display that was not numerically equivalent to the auditory set. In Experiment 2, when the rate and duration of the auditory sequences were varied randomly within infants, no significant preference for either the equivalent or nonequivalent visual display was shown. These results raise questions about P. Starkey et al.'s claims that infants can represent the numerosity of sets in different modalities and then perform one-one correspondence computations over them.

Attention↗
PubMed1996

Retrospective study of postcraniotomy headaches in suboccipital approach: diagnosis and management.

PURPOSE: The suboccipital approach used for cerebellopontine angle tumors, microvascular decompression, vestibular nerve section, and other procedures has been associated with significant postoperative headache. This study was undertaken to evaluate retrospectively the incidence and management of headaches in these patients. METHODS: Operation logs from 1988 through 1993 were reviewed to identify patients who underwent lateral suboccipital craniotomy or craniectomy. The nature of the operation, preoperative and postoperative complaints of headache, treatment for postoperative headache, and the use of primary cranioplasty were recorded from the medical records. RESULTS: Fifty-six suboccipital approaches were performed by the senior authors between 1988 and 1990. Seven patients had debilitating postoperative headaches. None responded to conservative management, and all underwent secondary cranioplasty. All seven patients showed significant improvement in their pain, with four of seven requiring no other treatment (follow-up from 15 to 38 months). Fifty patients underwent cranioplasty at the time of their initial operation, from 1991 to 1993. No case of debilitating headache was identified post-operatively in these patients. CONCLUSIONS: Cranioplasty at the time of lateral craniectomy appears to reduce the incidence of debilitating postoperative headache.

Adult↗
PubMed1996

Do preschool children recognize auditory-visual numerical correspondences?

The present study investigated the ability of 3- and 4-year-old children to perform tasks which require matching sets of sounds to numerically equivalent visual displays. We found that 3-year-olds performed at chance on the auditory-visual matching task, while 4-year-olds performed significantly above chance. There is evidence that mastery of the linguistic counting system is related to success on this task. These findings are unexpected given previous research reporting that 6-8-month-olds can detect the numerical equivalence between a set of sounds and items in a visual display.

Age Factors↗
PubMed1995

Calculation abilities in young children with different patterns of cognitive functioning.

This study examined the arithmetic calculation abilities of kindergarten and first-grade children with different patterns of cognitive functioning: children with low language but adequate spatial abilities (Low Language; n = 33, male = 42%); children with low spatial but adequate language abilities (Low Spatial; n = 21, male = 42%); children with general delays (Delayed; n = 21, male = 48%); and children with no language or spatial impairments (Nonimpaired; n = 33, male = 48%). Each child was given a series of addition and subtraction calculations presented as nonverbal problems, story problems, and number-fact problems. Story problems and number-fact problems require mastery of conventional verbal symbols, whereas nonverbal problems do not. The findings show that nonverbal, story, and number-fact problem formats are differentially sensitive to variation in cognitive ability. The Low Language group performed significantly worse than the Nonimpaired group on story problems but not on nonverbal problems or number-fact problems. The Delayed group performed significantly worse than the Nonimpaired group on nonverbal problems as well as on story problems but not on number-fact problems. The Low Spatial group did not differ significantly from the Nonimpaired group on any of the three problem types, although the overall performance of these children was weaker. When we adjusted for finger use on number-fact problems, the Nonimpaired group outperformed both the Low Language and the Delayed groups but not the Low Spatial group. Thus, the finding that the Low Language and Delayed groups perform as well as the Nonimpaired group on number-fact problems is attributable to their greater finger use.

Child↗