Validation of the adaptive scan method in the quest for time-efficient methods of testing auditory processes.

A major barrier to the clinical application of psychophysical testing of central auditory processes is the time required to obtain precise estimates of different listening abilities. In this study, we validate a novel adaptive scan (AS) method of threshold estimation that is designed to adapt on a range of values around threshold rather than on a single threshold value. This method has the advantage of providing the listener with greater familiarity with the stimulus characteristics near threshold while maintaining precise measurement and increasing time-efficiency. Additionally, we explore the time-efficiency of AS through comparison with two more conventional adaptive algorithms and the method of constant stimuli in two common psychophysical tasks: the detection of a gap in noise and the detection of a tone in noise. Seventy undergraduates without hearing complaints were tested using all four methods. The AS method provided similar threshold estimates with similar precision to those from the other adaptive methods and, thus, it is a valid adaptive method of psychophysical testing. We also provide an analysis of the AS method based on precision metrics to propose a shortened version of the algorithm that maximizes the time/precision tradeoff and can achieve similar thresholds to the adaptive methods tested in the validation. This work lays the foundation for using AS across a wide variety of psychophysical assessments and experimental situations where different levels of precision and/or time-efficiency may be required.

Cigarette smoking and duodenal ulcer healing. An endoscopic study of 197 patients.

Cigarette smoking is suspected to aggravate the symptoms and to delay the healing of gastroduodenal peptic ulceration. The healing rate of duodenal ulcer was endoscopically studied in 82 heavy smokers and compared to that of a nonsmoking control group of 92 patients. The two groups received the antiulcer treatment in a double-blind fashion with one of the following regimens: cimetidine 1 g, trimipramine 50 mg, prostaglandin E1 analogue 800 or 200 micrograms, low-dose antacid or placebo. The smokers' overall healing rate was 45.1% compared to 51.1% in the nonsmokers. The difference between the two groups was not statistically significant. This finding is not in agreement with previous reports showing an adverse effect of smoking on the healing process of duodenal ulcer.