Re-Entraining the Brain: Exploring and Exploiting Oscillatory Models of Speech Perception in Wernicke's Aphasia

为了理解口语，我们需要在耳朵上听到它，然后分析声音并在大脑中提取单词。这个过程被称为言语感知。只有在准确的语音感知之后，我们才能分析这些词的语法和意义。损害支持言语感知的区域的中风会导致理解口语的严重残疾。这阻止了人们与朋友和家人的联系，切断了人们的工作和休闲活动。我们的长期目标是改善这些人的治疗，让他们过上更完整和充实的生活。一个著名的言语感知理论认为，当我们听到声音时，我们的脑细胞开始与声音的节奏同步（同步），这有助于我们理解我们所听到的。这就像你在听一首歌的节奏时沿着敲。大脑活动与语音中的音节模式同步，帮助我们识别我们听到的单词。我们假设中风患者的言语感知障碍可能是由于这种同步的失败。为了验证这一点，我们将测量中风后有语言感知问题的人的大脑与语言的同步性，这种情况被称为韦尼克失语症。我们将比较没有中风的人和中风的人在大脑不同部位的能力，看看这些问题是否是韦尼克失语症特有的。我们还将比较大脑同步的程度与语言测试和日常生活中的理解障碍程度，以了解对人们的影响。令人惊讶的是，韦尼克失语症患者的言语知觉有时是准确的，即使一些言语知觉大脑结构丢失了。我们将研究大脑的哪些部分在做出反应，以及当言语感知更准确和不准确时，大脑的不同部分如何协同工作。这很重要，因为我们希望帮助大脑更经常地以最有效的方式工作。我们可以利用这些信息来尝试通过电刺激来改善语音感知。对没有中风的人的研究表明，听简单的有节奏的声音可以改变大脑与随后声音同步的方式。当大脑被施加到头皮上的非常小的电流刺激时，也会发生这种情况，这已经被证明可以帮助人们更好地听到声音和理解语言。我们假设，我们可以使用这些方法，以改善言语知觉和语言理解的人与韦尼克失语症。我们的试验数据表明，这是真的-当我们在讲话前播放有节奏的声音时，韦尼克失语症患者能够更好地听到讲话声音之间的差异。这是有希望的，因为这种能力对于理解语音至关重要。我们还将通过测量大脑活动来探索为什么有节奏的声音可以改善语音感知，看看当我们试图增强同步时，大脑是否会做出更“典型”的反应。该研究的最后一项研究将使用电流刺激来帮助大脑活动与语言同步。我们将利用我们之前的研究结果来确定大脑的哪些部分对语音的反应最有效，并刺激这些区域，然后测量人们是否能够更好地理解电刺激的口语句子。如果我们在这项研究中找到了支持这些假设的证据，我们将找到通过增强大脑同步来治疗中风后言语感知和语言理解障碍的新方法。我们还将通过观察对同步大脑活动的影响，找到新的方法来衡量我们的疗法是如何起作用的。

To understand spoken language we need to hear it at the ear and then analyse the sounds and extract the words in the brain. This process is known as speech perception. It is only after accurate speech perception that we can analyse the grammar and meaning of those words. Strokes which damage regions supporting speech perception cause a severely disabling impairment in understanding spoken language. This stops people from connecting with their friends and family and cuts people off from work and leisure activities. Our long-term goal is to improve treatments for these individuals, allowing them to lead a more complete and fulfilling life. One prominent theory of speech perception argues that when we hear sounds our brain cells start to fire in time (synchronise) with the rhythm of the sound, and this helps us to work out what we are hearing. This is not unlike tapping along to the rhythm of a song you are listening to. Brain activity synchronises with the pattern of syllables in speech and helps us to identify the words we are hearing. We hypothesise that speech perception impairments in people with strokes may arise from a failure of this synchronisation. To test this, we will measure brain synchronisation to speech in people with speech perception problems after stroke, a condition known as Wernicke's aphasia. We will compare the abilities of people without strokes and of people with strokes in different parts of their brain to see if problems are specific to Wernicke's aphasia. We will also compare the degree of brain synchronisation to the degree of comprehension impairment on language tests and in daily life to understand the impact on people. Surprisingly, speech perception is sometimes accurate in Wernicke's aphasia, even though some speech perception brain structures are lost. We will investigate which parts of the brain are responding and how different parts of the brain work together when speech perception is more accurate and when it is inaccurate. This is important because we want to help the brain to work in the most effective way more often. We can use this information to try and improve speech perception using electrical stimulation. Research in people without strokes shows that listening to simple rhythmic sounds can change the way the brain synchronises with the sounds that follow. This also happens when the brain is stimulated with a very small electrical current applied to the scalp, and this has been shown to help people hear sounds and understand speech better. We hypothesise that we can use these methods to improve speech perception and language comprehension in people with Wernicke's aphasia. Our pilot data suggests that this is true - when we played rhythmic sounds before speech, people with Wernicke's aphasia were better able to hear the difference between the speech sounds. This is promising because this ability is crucial for understanding speech. We will also explore why rhythmic sounds improve speech perception by measuring brain activity to see whether the brain responds more "typically" when we try to enhance synchronisation. The last study in the fellowship will use electrical current stimulation to help to synchronise brain activity to speech. We will use our previous results to work out which parts of the brain respond most effectively to speech and stimulate those areas, then measure whether people are better able to understand spoken sentences with electrical stimulation. If we find evidence for the hypotheses in this fellowship, we will have identified new ways to treat speech perception and language comprehension impairments after stroke, by enhancing brain synchronisation. We will also have found new ways of measuring how our therapies are working, by looking at the effects on synchronised brain activity.