Case Report: Intraductal Papillary Mucinous Neoplasms of the Biliary Tract

The present case report describes intraductal papillary mucinous neoplasms of the biliary tract (IPMN-BT), a rare neoplasm of the biliary tract that is described as the biliary counterpart of intraductal papillary mucinous neoplasms of the pancreas (IPMN-P). The importance of appropriate diagnosis and awareness of the clinical manifestations is highlighted. IPMN-BT has a more favorable prognosis and is easier to resect than other forms of intrahepatic cholangiocarcinomas; therefore, early and accurate diagnosis is required for planning of the best treatment strategies for this neoplasm.

Effects of acclimatization and deprivation on non-speech auditory abilities

This article reviews the evidence for acclimatization and deprivation with respect to non-speech auditory abilities. Although this subject has not been studied extensively, clear evidence exists for acclimatization and/or deprivation effects on intensity discrimination, binaural masking level difference, and auditory localization and lateralization. There is also some argument for such effects with regard to changes in tolerance for intense sounds or preferred levels of amplification. However, the main evidence for these effects, changes in loudness discomfort levels with repeated testing, may reasonably be explained as procedural or task-related effects rather than changes in auditory abilities. On the other hand, the successful use of tinnitus maskers to treat hyperacusis suggests that particularly low tolerance levels may be improved by exposure to certain types of auditory stimulation. Overall, this retrospective review of changes in non-speech auditory abilities, associated with the presence or absence of listening experience, indicates that acclimatization or deprivation effects may have influenced the results of some of the experiments reviewed. This suggests that experiments designed to study acclimatization or deprivation are timely and useful. In addition, acclimatization and deprivation are potential variables that should be considered, and preferably controlled, within experiments on auditory abilities. Clinically, the review adds weight to the argument for considering acclimatization and/or deprivation in hearing aid fitting and evaluation.

Continuous tissue pH monitoring in the term fetus

Since Saling's work in 1961, many investigators have attempted to perfect methods to detect fetal acidosis during labor. A system for continuous tissue pH monitoring of the fetus is evaluated in this study of 59 patients. There was poor correlation of tissue pH values and capillary scalp pH values in 19 cases (r = 0.487), and no significant correlation of tissue pH values to the outcome measurements of Apgar scores and cord gas levels. The benefits realized were those of monitoring the trend of tissue pH over time. We believe that a continuous pH monitoring system offers several advantages over intermittent fetal scalp sampling. Further refinement of the technology employed may offer such a system in the future.

Optical method for measurement of ear canal length

A noninvasive optical method using an operating microscope was developed to measure the length of an ear canal under both open and occluded conditions. The method is based on the optical measurement of the distance between a reference point at the eardrum and a second point on the lateral aspect of an earmold-occluded ear canal. To estimate the occluded canal length, the length of the earmold is then subtracted from results of the previous measurement. The method was also used to determine the open ear canal length (the lateral reference point was the ear canal entrance), and averaged results agreed closely with previously reported data.

Cerebellar-pontine angle tumors. Results of quantitative vestibulo-ocular testing

A new quantitative vestibulo-ocular test battery was evaluated in 12 patients with surgically confirmed cerebellar-pontine angle tumors. The battery consisted of precise vestibular and visual stimuli and digital computer analyses of responses. Eleven of 12 patients, including all patients with acoustic neurolemmomas, had significant vestibular deficits on the tumor side (P less than .01). Contrary to previous reports, rotatory tests (impulse and sinusoidal acceleration) reliably identified the side and magnitude of vestibular deficit. Eight of nine patients with surgically confirmed brain stem compression had significantly impaired smooth pursuit (P less than .05). Optokinetic nystagmus was impaired in five of nine patients with brain stem compression (P less than .05). By combining the results of the entire test battery with standard clinical evaluation, a good prediction of tumor size, location, and type was possible.

The variability of occluded and unoccluded bone-conduction thresholds

A series of three experiments of similar basic design was performed on individuals with normal hearing to compare the variability associated with occluded and unoccluded bone-conduction thresholds.

Estimates of threshold were obtained at each test frequency for air conduction, unoccluded bone conduction, and occluded bone conduction stimuli. Eleven young adults participated in Experiment I. Their ears were occluded by TDH-39 earphones encased in MX41/AR cushions. In Experiment II 11 young adults were tested with a Grason-Stadler 001 circumaural cushion replacing the MX41/AR cushion. Two types of occluders were compared in Experiment III, using nine subjects with previous experience in Bekesy tracing.

The variability of the occluded bone-conduction thresholds was either similar or less than that observed during the unoccluded measurements. The variability of the occlusion effect itself was comparable or less than the variability of the unoccluded or occluded bone-conduction thresholds. The source of the variability stemmed largely from differences between individuals rather than from test-retest variability. Although the variability of the occluded thresholds was reduced slightly when the circumaural cushion was used as compared to the supra-aural cushion, the results of the final experiment did not completely support the earlier finding.

Binaural and monaural speech intelligibility in reverberation

Forty-eight subjects with normal hearing were tested to determine binaural and monaural near- and far-ear speech discrimination in various reverberant conditions. One half of the group listened to the recorded PB words in quiet, while the other half received the words with a competing message. Binaural superiority was maintained throughout the study, except in the anechoic-quiet condition. Interaural time differences make a significant contribution to speech intelligibility; and the monaural far ear supplies valuable aid to binaural listening.