[music] Now we are going to talk about language impairment or even language disintegration. We are not going to discuss all language impairments that exist, because there are too many of them and they may be caused by hearing or articulatory deficits and various other reasons. What we are going to talk about today is called “central language disorders”, but professionals use the term “aphasias”. Aphasias are language disorders caused by lesions in language-specific areas of the brain that is, Broca’s and Wernicke’s areas which we have discussed earlier that are usually associated with the left cerebral hemisphere. What are the reasons for such disorders? Clinically speaking, what is their etiology? One reason may be an instantaneous damage to the brain that we in everyday use call a stroke. Another reason is brain damage caused by various injuries, like traffic accidents or, god forbid, war trauma or a domestic accident. In short, physical injuries that affect special brain areas may cause such disorders. And, finally, aphasia can be caused by tumors. There are other reasons, but these are the main ones. It is important to understand that brain lesions that we call aphasia cause the language system itself to break down. The main thing is not that the person who used to to speak loudly and lengthily has become quiet and inarticulate. This is not the point. The point is that the language system itself is impaired. In such patients encoding and decoding of the smallest acoustic units of the smallest acoustic units that we call phonemes may be impaired. The patient doesn’t have any hearing problems. It is not that sound doesn’t reach the patient, or that other people speak too quickly It is simply a malfunctioning of the cerebral mechanism mechanism that discerns these nearly indiscernible sound fragments that are crucial for speech recognition, like “bad” and “bed” for example. The retrieval of word meanings from memory lexical access, as we call it, may be impaired or mental lexicon system may be disrupted. The patient is unable to retrieve words, or even parts of words such as stems, suffixes, prefixes and inflexions. All of this may be impaired. The patient starts to add suffixes or prefixes normally used only with a certain type of words to words of a different type. In some cases, syntax, or, simply put, grammar, may be disrupted. The patient is unable to recognize the main word in the sentence, or to tell the subject from the object. The patient is unable to correctly identify verbs, noun cases, tenses and aspects of verbs Perception or even production of whole texts, of what we call “discourse”, may also be impaired. Texts are both constructed and perceived incorrectly. Aphasia was first studied, or, more precisely, first discovered a long time ago. The first and the most important discovery was made in 1861 by the French scientist Paul Broca. By the way, it was in his honor that the language area in the left hemisphere was named. This area provides speech production, not perception, but production. For example, this area is active in my brain now, because I am speaking. Lesions in this area lead to, simply put, impaired ability to speak. In English it is sometimes called “non-fluent aphasia”, which means that this type of aphasia impairs the ability to speak correctly and fluently In fact, there are many types non-fluent aphasia, which we are going to discuss later in the course. In this photograph you can see the brain of the famous patient in whom this type of aphasia was first described. This brain was preserved in formalin, and has since been studied using state-of-the-art techniques including tomography. This patient could understand others’ speech, while being unable to to speak himself. The patient’s brain was examined after he died (it is his brain that you can see in the photograph), and it was discovered that the area we now call the Broca’s area the one associated with language production, was nearly destroyed. Non-fluent aphasia may result in articulation impairments, with patients being unable to correctly produce the speech sounds that they are sure to have mastered very early in life and which are normally produced without any conscious effort. Such patients’ speech is very fragmented, and in Russian terminology this phenomenon is called “telegraphic speech.” That is, the patients don’t use any cohesive devices to link sentences together, omit all conjunctions and prepositions This way, their speech looks like telegrams that people used to send to each other in olden days when there were no cell phones, in which they omitted linking words to save space. Such patients may also demonstrate very strange and unusual grammatical errors. There is a name for this phenomenon - it is called “agrammatism” or, sometimes, “syntactic aphasia”. This means that the patient is suddenly unable to use the most straightforward grammatical constructions, ones that every child or even utterly uneducated adult can use easily. Or the patient may substitute sounds in words with other sounds. In short, the language system that provides expressive speech has collapsed. The history went on. Shortly after that first momentous discovery of the Broca’s area, another famous scientist, Carl Wernicke from Austria, described a patient with intact speech who, instead, struggled with understanding language. The patient was nearly unable to understand what was said to him, and when he did, he could not grasp the correct meaning. This phenomenon is called “fluent aphasia”, which seems to me something of an oxymoron, because, despite aphasia being a language disorder, this term implies that some aphasic patients are still fluent in speech. In sum, such patients are still able to speak, even though their speech is somewhat deficient, but they either do not understand others’ speech, or understand it inadequately. Such patients demonstrate impaired language comprehension on almost every level. They struggle with complex grammar with speech whose pace is too quick for them, even though, objectively, its pace is slow enough. They also experience difficulties understanding word meanings and inadequately perceive pseudowords, that is, specially invented words that a person with intact language system perceives as verbs or nouns, and can even use in speech as a kind of language game. In sum, such patients’ speech perception is impaired. Sadly, the disorders that I have told you about are highly prevalent. A lot of them are caused by various pathologies in the brain, by traffic accidents or trauma. In short, there are millions of aphasic patients in the world. That is why there are a lot of speech therapists, clinical practitioners that teach such patients their native language from scratch to restore their capabilities. This may take many months and sometimes years. Such disorder may prove a real tragedy for a person. That is why these disorders are studied not only by clinical practitioners or speech therapists, but also by a great number of scientists, theorists and experimenters alike, who do not work with patients directly. There is a large number of various associations, founded by both clinicians and speech therapists, with a great number of countries participating. You can find such associations in at least 30 countries. Recently, special attention has been paid to studying the so-called multilingual or polylingual language disorders. What I have described is a disorder affecting only one language. Now, imagine that such a disaster happened to a person who speaks, for example, four languages. What happened to all those languages? I have specially studied this, and it is very interesting, because one of these languages may remain completely intact, with the person speaking and understanding it as though nothing happened. Another language may disappear entirely, as if the person never spoke it. As for the third language, the person may only be able to read in it, but not speak. With the fourth language, there may be an opposite case with the person still able to speak but unable to read in it unless the text is printed in a certain font, for example, in a gothic one. Therefore, the relationships between different languages in multilingual patients are very interesting, unusual and unpredictable. That is why not only do we need a testing system that can be used with different languages, we also need one allows for two or three languages to be used simultaneously. There are special groups developing such tests. For example, you can find more details on the website whose address you can see in this slide. I would like to finish the lecture by saying that not only is this topic fascinating from a scientific point of view, it is also of immense practical significance, because every clinic in the world deals with hundreds of such patients every day. That is why our task as neurolinguists is to try and help clinicians, speech therapists, and neurotherapists using the knowledge we gather in our fundamental research. I wish you all the best.
