Biomedical subjects
Publications and source records attributed to S C Levine.
Thirty-four ears have been explored to rule out perilymph fistulas resulting from ear trauma. Eight ears (24%) were identified with a fistula, often persisting months (average 7.5 months) after the precipitating injury. Repair of fistulas, even if done relatively late, markedly reduces vestibular symptoms and may improve low and middle frequency sensorineural hearing. Complications from negative explorations are rare.
We examined the possible uses of the "rotary door" sternohyoid myocutaneous flap (RDF) in laryngotracheal reconstruction. This well-vascularized myocutaneous flap, when rotated axially, can replace or widen the anterolateral walls of the airway. It provides a large epithelial surface, together with bulky structural support. The flap is readily available within the immediate surgical field and can replace large defects in the airway, from the level of the glottis to the cervical trachea. After extensive structural and soft-tissue loss of the larynx and trachea were produced to simulate commonly encountered traumatic and postsurgical stenotic conditions, the RDF was employed in 23 dogs in a single-stage laryngotracheal reconstruction. A stable, widely patent airway was achieved. The dogs were followed up for periods varying from three to six months. No complications or secondary stenoses were encountered. Photographic, radiologic, and endoscopic examinations demonstrated the viability and usefulness of this newly described flap. Long-term tracheostomy was used so that intraluminal stents and cannulas could be avoided. Histopathologic studies confirmed the integration of the RDF into the framework of the larynx and trachea. Application of this technique in cases of tumors, trauma, and stenosis of the airway is suggested.
Perceptual asymmetries for processing chimeric faces were investigated in dextral subjects, ranging in age from 5 years to elderly adults. The task involved deciding which member of a pair of face chimeras presented in free vision looks happier, the one with the smile to the left or its mirror image with the smile to the right (Levy, Heller, Banich, & Burton, 1983a, Brain and Cognition, 2, 404-419). A leftward bias was found for all age groups. However, kindergarteners' mean asymmetry score was lower than that of all other groups combined, most likely due to noise in their data. The direction in which subjects drew circles with their left and right hands was also observed as an index of interhemispheric communication. All groups showed a bias toward drawing the circles in concordant directions except the kindergarteners. The relation between subjects' performance on the circle drawing and facebook tasks is discussed.
The dog is an animal widely used in experiments, and tracheostomy is frequently necessary when laryngeal experiments are carried out. Unfortunately, dogs generally do not tolerate tracheostomy well because the inserted cannula easily becomes displaced or blocked. This article presents a new surgical technique aimed at providing a long-term, dependable, and safe airway. It is based on previously established, clinically tested principles to avoid local tracheal complications. No essential tissue is removed or irreparably damaged and the procedure is reversible. Flexibility in management of the resultant stoma is possible, allowing either maintenance of maximal patency or gradual closure. Twenty-one animals were studied for 3- and 6-month periods, and there was no morbidity because of airway obstruction. This technique can reduce loss of valuable experimental animals caused by airway complications. It may also have application in human beings.
This article presents a new technique for creation of a model that can be used to study the aerodynamics of the nasal airway. The model is employed to determine parameters used to calculate nasal resistance and modified to compare various types of nasal obstruction. It quantitatively compares the importance of septal deviation, turbinate size, and nasopharyngeal port size to airflow. A new parameter of nasal resistance is introduced.
Contemporary otomicrosurgical techniques have made total removal of acoustic tumor with preservation of the seventh and sometimes the eighth cranial nerves possible. The four approaches currently used in acoustic tumor surgery are the middle cranial fossa, the translabyrinthine, the suboccipital, and the combined translabyrinthine-suboccipital. This review examines the surgical results in the removal of more than 600 acoustic tumors and outlines a rationale for the choice of approach. Tumor size on computed tomographic scan and auditory reserve establish the parameters used in planning the surgical procedure. The translabyrinthine exposure is used most frequently followed by the combined translabyrinthine-suboccipital. The middle fossa and suboccipital approaches are used when preservation of hearing is attempted. Total removal of tumor was accomplished in more than 99% of patients with a mortality rate of less than 1%. Anatomic preservation of the facial nerve, which is directly related to tumor size, was achieved in more than 80% of patients. Preservation of hearing is unlikely when the tumor is larger than 2 cm; anatomic preservation of the cochlear nerve was successful in 73% of hearing preservation procedures.
Multidimensional scaling procedures were used to investigate developmental changes in the ability to process previously unfamiliar faces. Eighty male subjects, aged 7, 9, 12, or adult, rated the similarity of pairs of faces. The faces were presented to subjects in either the upright or the inverted orientation. Multidimensional scaling analyses suggest that subjects of all ages use similar information in judging the similarity of faces. However, for upright faces, individual subjects under age 10 seem to use fewer features at a time. The results argue against a qualitative shift in face processing at age 10, and suggest that the improvement in face recognition ability noted at this age is due at least in part to an increased ability to consider more features simultaneously.
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Comparing visual field asymmetries for bilaterally presented words and corresponding line drawings, we found an RVF advantage for words and no visual field asymmetry for line drawings. We suggested that the RVF advantage previously obtained by Young, Bion, and Ellis (Brain and Language, 11, 54-65, 1980) for bilaterally presented line drawings may have resulted from a forced order of report procedure, noting that the RVF advantage was greater on trials on which subjects were forced to report in the nonpreferred right-to-left order. Young and Ellis (Brain and Language, 20, 166-171, 1983) attempt to discredit this claim and maintain their hypothesis that the RVF advantage for line drawings is attributable to better temporary storage of these stimuli by the left than the right hemisphere. In the present article, we present in greater detail our arguments for the effects of forced order to report on the perception of bilaterally presented stimuli and refute Young and Ellis's ibid. criticisms of this proposal.
Evidence supporting individual variations in patterns of hemispheric involvement in the recognition of visuo-spatial and verbal stimuli among dextrals is reported. In Experiment 1, subjects' asymmetry scores on a task that was nonlateralized for the group as a whole were significantly correlated with their asymmetry scores on right-hemisphere-specialized tasks, including face recognition. In Experiment 2, subjects' asymmetry scores on a task that was nonlateralized for the group as a whole were significantly correlated with their asymmetry scores on a left-hemisphere-specialized word recognition task. These results suggest that individual dextrals' asymmetry scores on lateralized tasks are a joint function of a subject's underlying hemispheric specialization for that task and stable individual variations in asymmetric hemispheric reliance.
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Words and famous faces were tachistoscopically presented in bilateral view to normal right-handed subjects. A left visual field advantage was obtained for famous faces whether naming or recognition from an array was required and a right visual field advantage was obtained for words. While the finding of a left visual field advantage for the recognition of famous faces is consistent with studies of face recognition deficits in brain-damaged patients, a right visual field advantage for the recognition of famous faces has recently been reported in normal subjects. Possible explanations for this discrepancy are discussed.
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Recent literature has suggested that total intrauterine volume (TIUV) estimation is useful fir distinguishing normal from growth-retarded fetuses. One hundred seventy-nine measurements of TIUV were obtained from the ultrasonograms taken between 21 and 40 weeks of gestation in 140 patients who delivered average birthweight babies. We constructed a mean curve for TIUV with upper and lower 2.5 and 10% tolerance limits and later evaluated the TIUV's of 16 patients with growth-retarded fetuses. Nine of these fetuses had birthweights below the fifth percentile for gestational age, and in each of these pregnancies the TIUV ultimately fell below the lower 2.5% tolerance limit.
The value of preliminary ultrasonography as a guide for amniocentesis in the early second trimester of pregnancy was prospectively evaluated. One hundred and fifty patients were alternately assigned to a control group or to an ultrasound group who underwent examination with a real-time scanner immediately prior to amniocentesis. All amniotic fluid samples were assessed as to the presence of blood by: (1) visual observation during the amniocentesis; (2) appearance of the centrifugate; and (3) microscopic analysis. Ultrasonography did not reduce the failure rate, the incidence of multiple needle insertions, or the proportion of amniotic fluid samples containing blood.
Real-time ultrasonography utilizing a hand-held linear array transducer provides a highly accurate method of identifying and evaluating the twin gestation. The rapidity of real-time scanning eliminates interpretational problems caused by fetal movements. Additionally, the versatility of transducer positioning facilitates recognition of appropriate fetal planes for assessment of viability and growth. A prospective study of 595 consecutive pregnancies yielded no misdiagnoses of the number of fetuses present and only one false positive diagnosis of fetal viability.
After 8 weeks of fetal age, real-time ultrasonography is a simple, rapid, and highly reliable technic for differentiating a viable from a dead fetus. Fetal movements are invariably detected after 8 weeks of fetal life, and a discrete, fluid-filled, intrathoracic pulsating heart can be seen after 11-12 weeks of fetal life. Absence of these findings, as observed by two independent examiners each viewing the fetus for 3 minutes with real-time sonography, provides reliable evidence of fetal demise. A prospective evaluation of 390 consecutive fetuses yielded only one false positive diagnosis of fetal viability. No living fetus was diagnosed as being dead.