Faculty Bibliography

By a focus on three essential elements of language: phonology, semantics, and syntax, a time frame for critical/sensitive periods of language development is presented as a model of central auditory nervous system flexibility. Several studies support the hypothesis that the critical/sensitive period of phonology is from the 6th month of fetal life through the 12th month of infancy. Data indicate that the critical/sensitive periods for syntax run through the 4th year of life, and for semantics through the 15th or 16th year of life. The data indicate that there is a time dependent series of functions in sequence that is based on responsive adaptations made by the CNS to pyschophysical and electrophysiological stimuli.

A high jugular bulb is often discovered as an incidental finding that is asymptomatic. Conductive hearing loss in association with this anomaly may occur, but has been reported infrequently in the literature. We report five cases of high jugular bulb and associated conductive hearing loss. Mechanisms to explain the conductive hearing loss include contact of the jugular bulb with the tympanic membrane, interference with the ossicular chain, and obstruction of the round window niche. The operative findings, radiographic and audiometric data that support these mechanisms of conductive hearing loss are presented.

SPECIFIC AIM. To evaluate the take of skin grafts on conventionally prepared beds and on beds prepared by a carbon dioxide laser, with and without abrasion of the bed. SIGNIFICANCE. Graft take is dependent on hemostasis, immobility, and nutrition of the graft. Scalpel excision of the skin graft can be associated with hemostatic difficulties and laser treatment of the skin graft bed can provide hemostasis. Abrasion of the bed after laser treatment may then be a means of opening small lymphatic and blood vessels to maintain the graft. Laser treatment followed by abrasion of the bed may provide an ideal graft base before suturing of the skin graft. MATERIAL AND METHODS. Full-thickness skin grafts were taken with a scalpel at three sites on the dorsal skin of 24 guinea pigs. The three beds were prepared with pressure alone to provide hemostasis, laser vaporization followed by abrasion with gauze to produce pinpoint bleeding, and laser vaporization alone. The original skin from each of the sites was then sutured back in place. At postoperative days 1, 3, 5, 10, 21, and 35 the graft sites were assessed clinically for 'take.' Laser Doppler measurements were also made to evaluate blood flow. Histologic sections of the three sites were prepared. Immunohistochemical analysis was performed to evaluate cell proliferation and angiogenesis. RESULTS. For the animals sacrificed through day 10 the rate of take for the sites that were not lased was 100%. For the sites that were lased alone and lased and abraded the rate of take was 71% with no difference between the two techniques. The lased sites demonstrated increased inflammatory response and graft necrosis. Immunohistochemical analysis showed increased cellular proliferation and angiogenesis in the bed. DISCUSSION. Grafts take best on a scalpel-prepared bed. Laser preparation of the bed, with or without abrasion, demonstrates decreased 'take.' Therefore the carbon dioxide laser is not a recommended means to take a graft or prepare the graft bed

The gamma band response (GBR) is a predominantly exogenous, sinusoidal evoked response that occurs usually between 20 and 130 msec following stimulus onset. This response is believed to represent the synchronization of neuronal assemblies that serve auditory feature integration. The objective of the present investigation was to describe the characteristics of the scalp-recorded auditory evoked gamma band potential (aeGBP) recorded from normal young adult subjects. Results showed the aeGBP to consist of up to four oscillations and were best recorded at the frontal-central midline. The aeGBP was present 80 percent to 100 percent of the time, appeared as onset responses, and was recorded at the shortest latency over the contralateral anterior temporal scalp

Hereditary nonchromaffin paragangliomas (PGL; glomus tumors; MIM 168000) are mostly benign, slow-growing tumors of the head and neck region, inherited from carrier fathers in an autosomal dominant fashion subject to genomic imprinting. Genetic linkage analysis in two large, unrelated Dutch families assigned PGL loci to two regions of chromosome 11, at 11q23 (PGL1) and 11q13.1 (PGL2). We ascertained a total of 11 North American PGL families and confirmed maternal imprinting (inactivation). In three of six families, linkage analysis provided evidence of linkage to the PGL1 locus at 11q23. Recombinants narrowed the critical region to an approximately 4.5-Mb interval flanked by markers D11S1647 and D11S622. Partial allelic loss of strictly maternal origin was detected in 5 of 19 tumors. The greatest degree of imbalance was detected at 11q23, distal to D11S1327 and proximal to CD3D. Age at onset of symptoms was significantly different between fathers and children (Wilcoxon rank-sum test, P < .002). Affected children had an earlier age at onset of symptoms in 39 of 57 father-child pairs (chi2 = 7.74, P < .006). However, a more conservative comparison of the number of pairs in which a child had > or = 5 years earlier age at onset (n = 33) vis-a-vis that of complementary pairs (n = 24) revealed no significant difference (chi2 = 1.42, P > .2). Whether these data represent genetic anticipation or ascertainment bias can be addressed only by analysis of a larger number of father-child pairs

Primary ciliary dyskinesia refers to clinical disease attributable to congenitally abnormal or absent ciliary motility. Diagnosis typically requires electron microscopy to document aberrant axoneme ultrastructure. Electron microscopy, however, remains inaccurate and Inconvenient as a screening test for symptomatic individuals. To avoid delays in diagnosis and to ensure adequacy of the tissue sample, we recommend a tracheal biopsy with an intraoperative histologic examination of ciliary motion. This study included patients evaluated at our institution for recurrent or chronic upper respiratory conditions characterized by chronic sinusitis, chronic mucoid otitis, and chronic bronchitis. A tracheal mucosa biopsy sample was obtained from each patient and was immediately examined in the operating room using light microscopy. If the magnified image demonstrated normal ciliary motility, primary ciliary dyskinesia was excluded and electron microscopy was not ordered. In the absence of normal ciliary motility, the specimen was placed in glutaraldehyde and ultrastructural axoneme morphology was evaluated. In the last 5 years, we have evaluated ciliary motility in 20 patients. Three patients had abnormal ciliary motility identified by light microscopy, and primary ciliary dyskinesia was confirmed histologically in each patient. In the remaining 17 patients, normal ciliary motility was observed, obviating the need for electron microscopy. We advocate intraoperative microscopic study of ciliary motility as a rapid, simple, accurate, and inexpensive technique to screen patients for primary ciliary dyskinesia