Measurement of brainstem speech-evoked potentials (BSEPs) and thier application in hearing assessment and speech processing technology

当声音到达耳朵时，微小的电脉冲通过大脑中不同的听觉中心传播，产生听觉感觉。虽然这个过程在很大程度上仍然是个谜，但通过在头皮上贴上电极，我们可以非侵入性地记录这些听觉中心的电活动。这种信号被称为听觉诱发电位，临床医生可以用它来诊断听力问题，并确定这些问题的来源是大脑。临床医生在这项测试中最常用的声音是短暂的响亮的滴答声，其好处是它是一种简单的刺激，具有明确的诱发电位。然而，点击并不能提供足够的信息来评估听到语音的能力。因此，人们对开发记录大脑对语音的电反应或语音诱发电位的测试越来越感兴趣。例如，我们最近发现，语音诱发电位与元音音调的细微变化密切相关。事实上，这种大脑信号与语音波形非常相似，如果将其转换为声音并回放，它就会被感知为可理解的语音。这意味着它让我们能够“监听”大脑中语言的内部表示。

When sound reaches the ear, tiny electrical pulses propagate through the different auditory centres in the brain, resulting in the sensation of hearing. Although much about this process remains a mystery, by taping electrodes to the scalp we can non-invasively record the electrical activity in these auditory centres. This signal, called the Auditory-Evoked Potential, allows clinicians to diagnose hearing problems and localize their origin in the brain. The sound that clinicians most commonly use for this test is a brief loud click, which has the benefit of being a simple stimulus with a well-defined evoked potential. However, a click does not provide sufficient information to allow assessing the ability to hear speech. As a result, there is increasing interest in developing tests that record the brain's electrical response to speech, or the Speech-Evoked Potential. For example, we have recently shown that the Speech-Evoked Potential closely follows the fine variations in the pitch of a vowel. In fact, this brain signal is so similar to the speech waveform, if it is converted to a sound and played back, it is perceived as intelligible speech. This means that it allows us to "listen in" on the internal representation of speech within the brain.