Background: Blast exposure is a potential hazard in modern military operations and training, especially for some military occupations. Helmets, peripheral armor, hearing protection, and eye protection worn by military personnel provide some acute protection from blast effects but may not fully protect personnel against cumulative effects of repeated blast overpressure waves experienced over a career. The current study aimed to characterize the long-term outcomes of repeated exposure to primary blast overpressure in experienced career operators with an emphasis on the assessment of hearing and vestibular outcomes. Methods: Participants included experienced "breachers" (military and law enforcement explosives professionals who gain entry into structures through controlled detonation of charges) and similarly aged and experienced "non-breachers" (non-breaching military and law enforcement personnel). Responses to a clinical interview and performance on audiological and vestibular testing were compared. Results: Hearing loss, ringing in the ears, irritability, and sensitivity to light or noise were more common among breachers than non-breachers. Breachers reported more combat exposure than non-breachers, and subsequently, memory loss and difficulty concentrating were associated with both breaching and combat exposure. Vestibular and ocular motor outcomes were not different between breachers and non-breachers. Conclusion: Hearing-related, irritability, and sensitivity outcomes are associated with a career in breaching. Future studies examining long-term effects of blast exposure should take measures to control for combat exposure.

BACKGROUND Unilateral centrifugation (UC) is a test of utricular function that involves the eccentric displacement of a patient while undergoing high velocity rotation. These off-center placements permit evaluation of utricles as only one organ is subjected to linear stimulation. Currently, several different protocols are used for translation times between positions (e.g., Clarke et al, 1996; Wuyts et al, 2003). PURPOSE This study examined the effects of different translation times between eccentric and centric positions during UC on an individual's perceived subjective visual vertical (SVV). RESEARCH DESIGN A prospective repeated measures design was used in this study. STUDY SAMPLE Forty-three young adults with no history or complaints of vestibular or neurological disorders participated in this study. DATA COLLECTION All testing was performed on a Neuro Kinetics Inc. (Pittsburgh, PA) Neuro-Otologic Test Center (NOTC) rotational chair at the Bloomsburg University of Pennsylvania Vestibular Clinic. Each participant completed six SVV trials in the static condition (sSVV) as a baseline of function. In addition, each participant completed UC trials using a rotational velocity of 300°/sec with 4 cm eccentric lateral displacements that were maintained for 60 sec per position. Translations of 5, 10, 15, 20, 25, and 30 sec were randomized. The maximum velocity was maintained for 90 sec prior to the eccentric placement. Multiple estimations of dynamic subjective visual vertical (dSVV) were performed for each position. RESULTS dSVV data yielded several trends. At 5 sec translations, dSVV values had greater variability and required longer for participant responses to stabilize. Regardless of UC translation time, initial trial values were often quite different from the remaining trials. Shorter UC translation times were associated with more eccentric dSVV values outside of the clinical norms. While not statistically significant, more variance was associated with the shortest UC translation times, while 15 and 25 sec translation data demonstrated the best correlations and lowest variances. DISCUSSION Findings suggest that incorporating sSVV data to normalize dSVV data should be considered to reduce the influence of the underlying baseline static otolithic function on the UC results. The presence of a clear tendency for shorter UC translation times to be associated with larger numbers of clinically abnormal findings may indicate that very short UC translation times may not be ideal for clinical applications. This is supported by our finding that longer UC translation times elicited more consistent SVV results and less response variability. While some of these findings were not statistically significant, the results do suggest that clinical UC testing may benefit from optimization of translation time as well as inclusion of sSVV in response interpretation.

The purpose of this study was to design an automated mental alerting task that could be utilized when performing vestibular testing on a broad range of patient populations, including certain difficult-to-test populations, such as the hard-of-hearing. A device was developed that utilized vibrotactile stimuli output to two vibrators placed on the subject's left leg, and responded to activation of two momentary pushbuttons controlled by the subjects. Fourteen normal-hearing subjects without history or symptoms of vestibular involvement participated. Each participant underwent three mental-alerting conditions, defined as no task, verbal task, or vibrotactile task. Each condition involved four irrigations of the ear canals, two with warm water and two with cool water. The resultant nystagmus was recorded and analyzed using four measures to compare the effect of the mental alerting task condition. No significant difference was found between verbal and vibrotactile alerting both of which provided better responses than the no alerting task (F=8.443; df=2,13; p=0.001). Between-subjects analysis showed that the number of gaps, which are undesirable periods of absent nystagmus during test recordings, was smallest for the verbal and vibrotactile tasks, and largest for the no task condition. Overall, the results showed that the vibrotactile tasking device (VTD) is an effective alternative means of providing mental alerting during vestibular testing, specifically that of caloric examination.

Cochlear implant programming necessitates accurate setting of programming levels, including maximum stimulation levels, of all active electrodes. Frequently, clinical techniques are adequate for setting these levels; however, they are sometimes insufficient (e.g., very young children). In the Nucleus 24, several methods have been suggested for estimation of comfort levels (C levels) from neural response telemetry (NRT); however, many require co-application of clinical measurements. Data was obtained from 21 adult Nucleus 24 recipients to develop reliable predictions of C levels. Multiple regression analysis was performed on NRT threshold, slope of the NRT growth function, age, length of deafness, length of cochlear implant use and electrode impedance to examine predictive ability. Only the NRT threshold and slope of the growth function measures were significant predictors yielding R2 values from 0.391 to 0.769. Results demonstrated that these measures may provide an alternative means of estimating C levels when other clinical measures are unavailable.

This study compared responses of prelingually and postlingually deafened adult Nucleus 24 cochlear implant users on two objective measures employed to predict programming levels: neural response telemetry (NRT) and electrically evoked stapedial reflexes (eSR). Thirty experienced postlingually and prelingually deafened adult implant users underwent standard behavioural judgements of maximum comfortable loudness levels (C levels) and thresholds (Ts) followed by eSR and NRT measurements. Two different programs were created based on both the subjective judgement and the objective estimates of C levels (eSR thresholds) and these were compared. Relationships between the subjective and the objective measures were statistically analysed. Maximum stimulation levels estimated by both eSR and NRT were highly correlated with C levels. Variability of NRT results was higher than for eSR results. Mean NRT thresholds for postlingually deafened patients were higher than for prelingually deafened patients. A number of prelingually deafened users could distinguish no difference between programs; however, the majority of postlingually deafened users were sensitive to the difference and many reported preference for the program with eSR-estimated C levels. Neural response telemetry thresholds and eSRTs obtained in Nucleus 24 patients are highly correlated with C levels and Ts. Results suggest that estimation of C levels and Ts using NRT or eSR requires different correction factors for prelingually versus postlingually deafened adult subjects. Copyright © 2006 John Wiley & Sons, Ltd.

Familial adenomatous polyposis (FAP) is a dominantly inherited disorder that is typically characterized by the appearance of multiple colorectal adenomas usually by the teenage years, with a risk of early colorectal cancer approaching 100%. Genetic testing can help determine which family members have the disorder and require surveillance endoscopy. Astute physicians may detect unsuspected FAP in patients with extraintestinal manifestations such as hard or soft cutaneous tumors. Colectomy will prevent cancer but is often necessary before the patient is 20 years old. Postoperative lifelong surveillance is indicated to screen for associated duodenal, thyroid, and rectal or ileal neoplasms. Attenuated FAP variants are less typical and may be confused with other types of familial colorectal neoplasia. Chemoprevention, regression, and other treatment strategies are being developed to improve the management of extracolonic neoplasms and desmoid tumors. A better understanding of the natural history of these FAP-associated phenomena will facilitate the rational selection of interventions. Management guidelines that were recently developed at Mayo Clinic Rochester to provide for uniform care and surveillance are discussed.

The effect of in vivo freezing on the liver and kidney of rats was assessed by the application of a cryoprobe to the surface of these organs. Some organs were excised immediately after freezing, others 5 min after freezing, and still others 8 min after freezing. Tissues excised immediately after freezing showed only mild vascular congestions. Tissues allowed to thaw for a period of 5 min showed an area of cell destruction equal to the area of the tip of the cryoprobe. Between the area of cell destruction and apparently normal tissue a transitional zone exists in both liver and kidney; however, this zone in the kidney is smaller than that seen in the liver. Subtle abnormalities in the characteristic of the hepatocyte cytoplasmic staining extended a distance of more than 1 cm beyond the transitional zone.