Motion-direction specificity for adaptation-induced duration compression depends on temporal frequency.

Adapting to a 20 Hz oscillating grating reduces the apparent duration of a 10 Hz drifting grating displayed subsequently in the same location as the adaptor. The effect is orientation-independent as it remains once the adaptor is rotated 90° relative to the tests (Johnston, Arnold, & Nishida, 2006). However, it was shown that, for random dots moving at 3°/s, duration compression follows adaptation only when the adaptor and test drift in the same direction, and it disappears when they drift in opposite directions (Curran & Benton, 2012). Here, we explored the relationship between the relative motion direction of adaptor and test and the strength of duration compression for a wider range of speeds and for narrow-band stimuli (temporal frequencies between 3 and 18 Hz). We first measured perceived temporal frequency for the same stimuli after adaptation, and we used these estimates to match the apparent rate of the adapted and unadapted tests in the duration task. We found that, whereas at 3 Hz the effect of adaptation in the opposite direction on duration is marginal, at higher frequencies there is substantial duration compression in the opposite direction. These results indicate that there may be two contributions to apparent duration compression: a cortical contribution sensitive to orientation and motion direction at a wide range of temporal frequencies and a direction-independent subcortical contribution, which is revealed at higher frequencies. However, while direction specificity implies cortical involvement, subcortical orientation dependency and the influence of feedback to subcortical areas should not be ignored.

The Cutoff Point and Diagnostic Accuracy of the Voice Handicap Index in Cantonese-Speaking Population.

BACKGROUND: Voice Handicap Index (VHI) has been used extensively in research and clinical settings. It has been suggested to be used as a diagnostic tool in the literature. However, little is known if it could be applied as a diagnostic tool to the Cantonese-speaking population. The study aims to establish cutoff points and the diagnostic accuracy for VHI-30 and VHI-10 to discriminate between Cantonese-speaking dysphonic and nondysphonic individuals. METHODS: Data from 256 adults from Hong Kong were extracted from a database at a local institution. There were a total of 91 nondysphonic individuals and 165 dysphonic individuals. Receiver operating characteristics curve analysis was conducted to establish cutoff points for VHI-30 and VHI-10. Diagnostic accuracy statistics such as sensitivity, specificity, positive, and negative predicted values (PPV and NPV) and likelihood ratios (LRs) were also reported. RESULTS: The dysphonic group scored higher than the nondysphonic group on the mean scores of both versions of VHI. Receiver operating characteristics curve analysis revealed a moderate to strong area under curve of 0.89 in both VHI-30 and VHI-10. A cutoff point of 18.5 point was yielded for VHI-30 (Sensitivity = 86.1%, Specificity = 81.3%, PPV = 89.3%, NPV = 76.3%, LR+ = 4.60, LR- = 0.17) and a cutoff point of 7.5 point was yielded for VHI-10 (Sensitivity = 80.6%, Specificity = 87.9%, PPV = 92.4%, NPV = 71.4%, LR+ = 6.66, LR- = 0.22). CONCLUSIONS: Both the Chinese VHI-30 and VHI-10 for Cantonese speakers showed promising diagnostic accuracy. VHI can be used as adjunct to clinical diagnosis and treatment outcome measures for voice disorders in the Cantonese-speaking population.