Gap prepulse inhibition of acoustic startle (GPIAS) method has been used effectively for the objective assessment of tinnitus in animals. Among two types of enclosures for the GPIAS, the unconstrained type carries less risk of animal death due to the absence of binding stress in the enclosure, and lack of need for alteration to animal size variation as it grows. However, animals' voluntary movements, which have no relation to the startles evoked by acoustic stimuli, are problematic, as they cannot be excluded in the case of the unconstrained enclosure based GPIAS measurement system. In order to discount voluntary movements which are not associated with external acoustic stimuli, we propose the conditional random interstimulus interval (CR ISI) method for unconstrained enclosure based GPIAS measurement. With the proposed ISI method, the unconstrained enclosure based acoustic startle response measurement system has been implemented in this paper. As a result, the effectiveness of the proposed CR ISI method has been verified and compared with those of conventional ISI methods through animal experiments using SD-rats. The experimental results showed that abnormal startle responses and invalid GPIAS values caused by motion were prevented when our proposed CR ISI method was applied to our implemented system. It was also verified that our proposed CR ISI method is advantageous in reducing the total experimental time for acquiring normal startle responses and valid GPIAS values, compared to conventional ISI methods, since our proposed CR ISI can begin the acoustic stimulation only when the animal gets stable and motionless.
Acoustic Stimulation ; Acoustics ; Animal Experimentation ; Animals ; Integrin alpha2 ; Methods ; Prepulse Inhibition ; Reflex, Startle ; Tinnitus

PURPOSE: This study investigated the relationship between the item response time (iRT) and classic item analysis indicators obtained from computer-based test (CBT) results and deduce students' problem-solving behavior using the relationship. METHODS: We retrospectively analyzed the results of the Comprehensive Basic Medical Sciences Examination conducted for 5 years by a CBT system in Dankook University College of Medicine. iRT is defined as the time spent to answer the question. The discrimination index and the difficulty level were used to analyze the items using classical test theory (CTT). The relationship of iRT and the CTT were investigated using a correlation analysis. An analysis of variance was performed to identify the difference between iRT and difficulty level. A regression analysis was conducted to examine the effect of the difficulty index and discrimination index on iRT. RESULTS: iRT increases with increasing difficulty index, and iRT tends to decrease with increasing discrimination index. The students' effort is increased when they solve difficult items but reduced when they are confronted with items with a high discrimination. The students' test effort represented by iRT was properly maintained when the items have a 'desirable' difficulty and a 'good' discrimination. CONCLUSION: The results of our study show that an adequate degree of item difficulty and discrimination is required to increase students' motivation. It might be inferred that with the combination of CTT and iRT, we can gain insights about the quality of the examination and test behaviors of the students, which can provide us with more powerful tools to improve them.
Discrimination (Psychology) ; Humans ; Motivation ; Reaction Time ; Retrospective Studies

PURPOSE: This study investigated the relationship between the item response time (iRT) and classic item analysis indicators obtained from computer-based test (CBT) results and deduce students' problem-solving behavior using the relationship. METHODS: We retrospectively analyzed the results of the Comprehensive Basic Medical Sciences Examination conducted for 5 years by a CBT system in Dankook University College of Medicine. iRT is defined as the time spent to answer the question. The discrimination index and the difficulty level were used to analyze the items using classical test theory (CTT). The relationship of iRT and the CTT were investigated using a correlation analysis. An analysis of variance was performed to identify the difference between iRT and difficulty level. A regression analysis was conducted to examine the effect of the difficulty index and discrimination index on iRT. RESULTS: iRT increases with increasing difficulty index, and iRT tends to decrease with increasing discrimination index. The students' effort is increased when they solve difficult items but reduced when they are confronted with items with a high discrimination. The students' test effort represented by iRT was properly maintained when the items have a 'desirable' difficulty and a 'good' discrimination. CONCLUSION The results of our study show that an adequate degree of item difficulty and discrimination is required to increase students' motivation. It might be inferred that with the combination of CTT and iRT, we can gain insights about the quality of the examination and test behaviors of the students, which can provide us with more powerful tools to improve them.

Background and Objectives: The gap prepulse inhibition of the acoustic startle response has been used to screen tinnitus in an animal model. Here, we examined changes in the auditory late response under various conditions of gap prepulse inhibition. Subjects and Methods: We recruited 19 healthy adults (5 males, 14 females) and their auditory late responses were recorded after various stimuli with or without gap prepulsing. The N1 and P2 responses were selected for analysis. The gap prepulse inhibition was estimated to determine the optimal auditory late response in the gap prepulse paradigm. Results: We found that the gap per se generated a response that was very similar to the response elicited by sound stimuli. This critically affected the gap associated with the maximal inhibition of the stimulus response. Among the various gap-stimulus intervals (GSIs) between the gap and principal stimulus, the GSI of 150 ms maximally inhibited the response. However, after zero padding was used to minimize artifacts after a P2 response to a gap stimulus, the differences among the GSIs disappeared. Conclusions Overall, the data suggest that both the prepulse inhibition and the gap per se should be considered when using the gap prepulse paradigm to assess tinnitus in humans.

PURPOSE: The characteristics of hypoparathyroidism in patients with Hashimoto thyroiditis (HT) after total thyroidectomy are not well established. The aim of this study was to investigate the relationship between hypoparathyroidism and loss of parathyroid glands in patients with or without HT who underwent total thyroidectomy. METHODS: Patients who underwent total thyroidectomy were divided into two groups; with HT (n=166) and without HT (n=526). Clinicopathologic characteristics were compared between the two groups. RESULTS: The mean numbers of parathyroid glands in specimens were significantly smaller in the with HT group than in the without HT group (0.34+/-0.51 vs. 0.42+/-0.58, P=0.003). The rate of transient hypoparathyroidism was significantly higher in the with HT group than in the without HT group (51.8% vs. 34.6%, P=0.000). Serum total calcium levels in patients who experienced transient hypoparathyroidism did not differ significantly between groups (P=0.335). The incidence of transient hypoparathyroidism of patients who preserved all four parathyroid glands or sacrificed one parathyroid gland was higher in the with HT group than in the without HT group, although that of patients who sacrificed two or more parathyroid glands was similar between groups. The incidence of permanent hypoparathyroidism in the two groups did not differ (P=0.546). CONCLUSION: Patients with HT had a higher rate of transient hypoparathyroidism after total thyroidectomy, particularly patients who preserved all four or three parathyroid glands. It is likely that the blood supply to the parathyroid gland might be vulnerable in patients with HT. Therefore, even though all parathyroid glands were preserved, careful monitoring of hypoparathyroidism is necessary after total thyroidectomy in patients with HT.
Calcium ; Hashimoto Disease* ; Humans ; Hypoparathyroidism* ; Incidence ; Parathyroid Glands ; Thyroidectomy*