同频音掩蔽试验及其在法医学鉴定中应用的研究

目的应用同频音掩蔽试验观察不同个体最小对侧掩蔽级(MCML)与主观纯音听阈之间的关系,进而通过MCML判定被试者主观真实听阈。方法30例受试者(60耳)分别进行纯音测听,首先测出双耳的纯音听阈,然后应用同频音掩蔽试验测试各个频率的MCML。结果当被掩蔽耳的声强处于阈值时,掩蔽耳的MCML与主观纯音听阈差值在0～30dBHL之间,其中差值在10dBHL以内的占82.4%,在15dBHL以内的占97.1%;当被掩蔽耳的声强处于阈上10dBHL时,掩蔽耳的MCML与主观听阈间差值在0～35dBHL之间,其中差值在25dBHL以内的占90.5%,在30dBHL以内的占98.1%。结论利用同频音掩蔽试验可以准确地判定各个频率被掩蔽耳的真实主观听阈。特别是对于语音范围内听力状况的法医学评定更具有特殊的意义。

The application of the same frequency tone masking test in forensic identification

Objective To investigate the relationship between minimum contralateral masking level(MCML) and pure tone threshold of the masking ears by the same frequency tone masking test. Methods The pure tone thresholds of 30 subjects(60 ears) were measured by pure tone audiometry and MCML was obtained by means of the same frequency tone masking test. Results When the stimulus was at the threshold of masked ears,the differences between MCML and pure tone threshold of masking ears were among 0-30 dBHL. 82.4 percent of results showed the differences not higher than 10 dBHL, 97.1 percent of results showed the differences not higher than 15 dBHL.When the stimulus was at 10 dBHL above the threshold of masked ears,the differences between MCML and pure tone threshold of masking ears were among 0-35 dBHL. 90.5 percent of results showed the differences not higher than 25 dBHL,98.1 percent of results showed the differences not higher than 30dBHL. Conclusion The real thresholds can be deduced correctly by the same frequency tone masking test.