A Comparison of Variability among Measurements of Subjective Tinnitus and Objective Stimuli

8 patients with subjective tinnitus were trained in pitch-matching, loudness-matching, and simultaneous-masking tasks using narrow-band noise and/or pure-tone stimuli. Extensive pitch-matching, loudness-matching and masking measurements were then obtained for their tinnitus, after which the same measurements were obtained for objective stimuli which approximated the frequency and intensity of the tinnitus. Variability for pitch and loudness matching to tinnitus was extremely large relative to the same measurements for objective stimuli. This was particularly true for pitch-matching where even the most consistent patients showed variability for matches to their tinnitus which was an order of magnitude greater than for matches to objective stimuli in the same frequency region. No evidence of frequency-specific masking of tinnitus was seen in any of the patients although such evidence was obtained for the masking of objective stimuli. The results suggest that the large variability in matches to tinnitus, and the lack of normal frequency-specific masking of tinnitus in these patients may reflect interactions at levels higher than the end-organ rather than a degradation in peripheral auditory function.     

多层CT螺距与z轴空间分辨率的关系探讨

目的：采用客观方法测定多层CT在不同螺距扫描时的z轴空间分辨率,分析多层CT的螺距对z轴空间分辨率的影响。方法：应用螺旋CT层敏感度曲线测试模体分别测试GE Light Speed 16层、Somatom Cardiac 16层和Soma-tom Sensation 64层三种CT的z轴空间分辨率。采用腹部模式,0.1mm重建间隔重建图像。GE Light Speed 16层CT扫描参数：准直宽度0.625mm×16,重建层厚0.625mm,螺距分别为0.562、0.938、1.375、1.75。Somatom Cardiac 16层CT扫描参数：准直宽度0.75mm×16,重建层厚0.75mm,螺距分别为0.5、0.75、1.0、1.25、1.5。Somatom Sensation 64层CT扫描参数：准直宽度0.6mm×32,重建层厚0.6mm,螺距分别为0.5、0.75、1.0、1.25、1.5。测定出各机型不同螺距的调制传递函数（MTF）,在各条MTF曲线上测试出相对信号强度2%的空间分辨率。结果：在各MTF曲线上测试的相对信号强度2%的空间分辨率,GE Light Speed 16层CT在螺距为0.562、0.938、1.375、1.75时的测定值分别是14.3、11.4、11.41、1.1 LP/cm,Somatom Cardiac 16层CT在螺距为0.5、0.75、1.0、1.25、1.5时的测定值分别是10.6、11.3、9.5、9.7、9.5 LP/cm,Somatom Sensation 64层CT在螺距为0.5、0.75、1.0、1.25、1.5时的测定值分别是15.5、15.6、15.5、15.61、5.5 LP/cm。结论：多层CT的z轴空间分辨率受螺距的影响比较小,且与采用的锥形角校正重建算法有关。对于16层CT,如欲获得最大的z轴空间分辨率,需选择最佳螺距。     

Risk of depression enhances auditory Pitch discrimination in the brain as indexed by the mismatch negativity

Objective

Depression is a state of aversion to activity and low mood that affects behaviour, thoughts, feelings and sense of well-being. Moreover, the individual depression trait is associated with altered auditory cortex activation and appraisal of the affective content of sounds.

Neural network application in Japanese sign language: distinction of similar Yubimoji gestures

In a previous paper, the authors built a neural network model to recognize Japanese sign language syllabary or yubimoji. One of the problems encountered in that study was the accurate digital representation and distinction of similar yubimoji gestures, i.e. gestures with the same finger flexure positions but with different hand/finger orientations. This study focuses on these yubimoji gestures. Using data from a glove interface with bend sensors and accelerometers, a neural network was built, trained and tested. The network performed well and good results were obtained.     

Chest CT in patients with shortness of breath: Comparing high pitch CT and conventional CT on respiratory artefacts and dose

IntroductionTo investigate chest respiratory artefact reduction using High Pitch Dual Source Computed Tomography (HPCT) compared to conventional CT (CCT) in symptomatic patients with shortness of breath.MethodsForty patients were prospectively examined on a second-generation Dual Source scanner. They were randomly divided into two groups: twenty patients underwent an experimental HPCT protocol and twenty control cases CCT protocol. Respiratory artefacts were evaluated using an ordinal score (0, 1 and 2) assigned by two readers with five and thirty years of experience. A qualitative assessment was performed using two categorical groups, group 1 = acceptable and group 2 = unacceptable. Dose Length Product (DLP) was compared.ResultsThe two groups showed a statistical difference in artefacts reduction (p < 0.0001). HPCT demonstrated no artefacts in 82% of cases, while CCT showed no artefacts in 39% of cases. DLP showed no statistical differences (p = 0.6) with mean = 266.9 for HPCT and mean = 282.65 for CCT. HPCT provides high table speed in the z-direction allowing a high temporal resolution, which reduces respiratory artefacts during free-breathing acquisition. Despite the use of two x-ray tubes, the HPCT did not increase the dose to the patient but provided the highest images quality.ConclusionsIn the emergency setting, HPCTs have been critical for achieving good image quality in uncooperative patients.Implications for practiceAcute respiratory failure is a common emergency department presentation, and the choice of high-speed acquisition CT may increase image quality.     

Neuronal mechanisms for pitch analysis in the time domain

Summary Many units in the auditory midbrain nucleus (MLD) of the Guinea fowl are found to be tuned to amplitude modulated tones (AM). For a given response maximum the relationship of the period _m of the modulation frequency f_m and the period _c of the carrier frequency f_c may be given by an empirical equation: m · _m + n · _c = 1 · ₁, where m, n and 1 are small integers typical for a unit. ₁ is a time constant of 0.4 ms. The temporal pattern of the neuronal response support these findings. The averages of spike trains oscillate with periods multiple to ₁. These oscillations are elicited by stimulus onsets and zero crossings of f_m and may be coupled strongly to f_m depending on f_c. Variation of f_m or f_c shifts the mean delay of the phase coupled activity proportional to m · _m and n · _c, respectively. These effects may be explained with activity phase coupled to f_c which coincides at the level of the recorded units with oscillations coupled to f_m. This is expressed by the above given periodicity equation. Psychophysical results with AM-stimuli indicate that the mechanisms described and the periodicity equation are adequate for the explanation of the analysis of periodicity pitch in humans. Hence the period corresponding to pitch is defined by m · _m + n · _c = 1 · ₁, where n and 1 are integers and ₁ = 0.4 ms. Plots of _p as a function of _c reveal steps at 0.4 ms intervals indicating that the neuronal time constant is the same in both species.Supported by the DFG, SFB 45     

Brain event-related potentials to complex tones in depressed patients: Relations to perceptual asymmetry and clinical features

Brain event-related potentials (ERPs) to probe tones in a dichotic complex tone test were recorded from right-handed depressed patients (n= 44) and normal subjects (n= 19) at homologous sites over left and right hemispheres (F3, F4; C3, C4; P3, P4; O1, O2). There were no differences between groups in N1 or P2 amplitude, but patients had smaller P3 amplitude than did normal subjects. Depressed patients failed to show either the left ear advantage or behavior-related hemispheric asymmetry of P3 seen for normal subjects. Depressed patients also showed less differences in hemispheric asymmetry between same and different judgments. These findings indicate that the abnormal behavioral asymmetry for dichotic pitch discrimination in depressed patients reflects a reduction in hemispheric asymmetry and is related to relatively late stages of cognitive processing.     

Functional anatomy of pitch memory--an fMRI study with sparse temporal sampling

Auditory functional magnetic resonance imaging tasks are challenging since the MR scanner noise can interfere with the auditory stimulation. To avoid this interference a sparse temporal sampling method with a long repetition time (TR = 17 s) was used to explore the functional anatomy of pitch memory. Eighteen right-handed subjects listened to a sequence of sine-wave tones (4.6 s total duration) and were asked to make a decision (depending on a visual prompt) whether the last or second to last tone was the same or different as the first tone. An alternating button press condition served as a control. Sets of 24 axial slices were acquired with a variable delay time (between 0 and 6 s) between the end of the auditory stimulation and the MR acquisition. Individual imaging time points were combined into three clusters (0-2, 3-4, and 5-6 s after the end of the auditory stimulation) for the analysis. The analysis showed a dynamic activation pattern over time which involved the superior temporal gyrus, supramarginal gyrus, posterior dorsolateral frontal regions, superior parietal regions, and dorsolateral cerebellar regions bilaterally as well as the left inferior frontal gyrus. By regressing the performance score in the pitch memory task with task-related MR signal changes, the supramarginal gyrus (left>right) and the dorsolateral cerebellum (lobules V and VI, left>right) were significantly correlated with good task performance. The SMG and the dorsolateral cerebellum may play a critical role in short-term storage of pitch information and the continuous pitch discrimination necessary for performing this pitch memory task.     

Describing baseball pitch movement with right-hand rules

The right-hand rules show the direction of the spin-induced deflection of baseball pitches: thus, they explain the movement of the fastball, curveball, slider and screwball. The direction of deflection is described by a pair of right-hand rules commonly used in science and engineering. Our new model for the magnitude of the lateral spin-induced deflection of the ball considers the orientation of the axis of rotation of the ball relative to the direction in which the ball is moving. This paper also describes how models based on somatic metaphors might provide variability in a pitcher's repertoire.