Objective To study the characteristics of auditory brainstem responses with different forward - masking intervals in newborns with normal hearing ,and to find out the most efficient interval .Methods Auditory evoked brainstem responses were recorded from 30 newborns(60 ears) ,with forward - masking intervals of 4 ms ,8 ms ,16 ms ,32 ms ,and unmasked as control .The ABR data were statistically analyzed with SPSS 13 .0 .Results With forward - masking intervals ,all waves Ⅰ ,Ⅲ ,Ⅴ latencies and Ⅰ - Ⅴ ,Ⅰ - Ⅲ ,Ⅲ - Ⅴ interpeak latencies were significantly (P< 0 .01) prolonged compared with those of in the unmasked ,except wave Ⅲ and Ⅰ - Ⅲ interpeak latencies with 4 ms forward - masking intervals .The waves from 8 ms interval were the most prolonged .Conclusion Forward masking increases human newborn ABR latencies and interpeak latencies .The interval time influenced the effect ,and 8 ms interval is the most efficient .

We observed the structure and form of adult annulus fibrosus of lumbar intervertebral disc at the fibrous layer level. The annulus fibrosus of lumbar interverbral disc was delaminated by using microsurgical technique. 8 testing points were taken in each layer and the angles between their fibers going and horizontal plane were measured. The results showed that the fiber going angle at each measurement point continually increased with the increase of fibrous layer from outside to inside along the radial direction in horizontal plane. The least fiber going angle was 25 degrees - 30 degrees. The fiber going angle at the same layer gradually increased from front to back. The fiber going angle was 70 degrees - 90 degrees at the middle of the back of annulus fibrosus of lumbar interverbral disc. The fiber going was consistent with the posterior longitudinal ligament going. Through the normalized equation and normalized line, the fiber going angle at any point in any layer could be obtained conveniently. We also observed that the annuli fibrosus were interlaced in the front, left and right of annulus fibrosus of lumbar intervertebral disc. And there were more interlaced areas in local sides of lumbar intervertebral disc, but there was no interlaced areas between layers near the middle of posterior annulus fibrosus. So we came to the conclusion: Annulus fibrosus of lumbar intervertebral disc has a special micro-structure in adaptation with its function.
Adult ; Compressive Strength ; Fibrillar Collagens ; physiology ; Humans ; Intervertebral Disc ; anatomy & histology ; physiology ; Lumbar Vertebrae ; anatomy & histology ; Male ; Middle Aged