There are primary sensory areas where the senses come to consciousness in the cortex, and adjacent to them, there are single-modality sensory association areas specific to that sense, which process the information coming in this sensory modality. For example, when we look at an apple, the image of this apple comes to consciousness in the primary visual area, Brodmann's area 17, but we do not recognize that what we see is an apple. This recognition occurs in areas 18 and 19 in the adjacent visual association cortex. Similarly, for all senses, there are primary sensory areas where this sense comes to consciousness and association areas specific to that sensory modality, where what is reflected here is known and recognized. Again, as an example, the sound produced when biting an apple and the sensation coming from our fingers when we touch the apple come to consciousness in the primary sensory areas of hearing and touch in the temporal lobe and parietal lobe cortices, respectively; However, our understanding and recognition that this sound is the sound of an apple being bitten, and that what we are touching is an apple, occurs as a result of this information reaching and being processed in the temporal and parietal single-modality association areas adjacent to the primary areas, respectively. As is known, among these association areas where the senses are processed in a single sensory modality, there are multi-modality association areas in the right and left hemispheres that receive all the senses processed in the association cortices in the sensory modality and process and integrate them at a higher level. These multimodality association areas, which include the major angular gyrus and the supramarginal gyrus, integrate processed sensations from auditory, visual, and somatosensory single-modality association cortices in both the right and left hemispheres. For example; Aphasia is a language disorder that occurs suddenly, usually as a result of a stroke or head trauma, and is caused by damage to the areas of the brain responsible for language. In most people, language areas are located in the left hemisphere of the brain. Therefore, while the language areas in the left half of the brain are damaged in aphasia, the person's right side may also be paralyzed. This disorder can affect reading and writing, as well as expressing and understanding language. Aphasia can also be accompanied by neurological speech disorders such as dysarthria or apraxia of speech.
What are the causes of aphasia? Aphasia originates from the language areas of the brain. is caused by damage to one or more of them. Most often, the cause of brain damage is a stroke. A stroke occurs when an area of the brain becomes deprived of blood. When brain cells do not receive the normal blood supply that carries oxygen and important nutrients, they die. Other causes of brain damage include severe blows to the head, brain tumors, brain infections, and other conditions that affect the brain.
Speech; It is a function with motor, cognitive and linguistic features. These features are the indispensable, cardinal features of a normal speech concept. When one of these features is missing or there is a problem with it, a normal speech function cannot be demonstrated even if the other two are healthy.
Speech is a Motor Function:
The motor feature of speech is; It is a feature related to the work of the nerves and muscles related to breathing, face and voice that play a role during speech, and the balance and coordination between them. For this reason, disruption of these properties of the mentioned nerves and muscles, either together or one by one, forms the basis of motor speech disorders. Since the strengths, deep senses, balance and coordination of the relevant muscles are revealed by different structures as a requirement of the functional structuring of the nervous system, this is the case for various reasons. Different structures are affected differently, necessitating the existence of more than one type of motor speech disorder. Apraxia of speech; It can be defined as weakness in the muscles required for speech or incompetence in articulation programs without coordination disorder. This definition is consistent with the general definition of apraxia. Apraxia of speech is a possibility that should be considered in most cases where spelling abilities are impaired as a result of cerebral events. Dysarthria(s) are motor speech disorders that occur as a result of disorders in the power, speed and coordination functions of the nerves and/or muscles related to breathing, voice and speech. Different dysarthrias are named in neurological terminology by characterizing the mechanism that is disrupted. For example, if the mechanism disorder that causes dysarthria is related to motor neurons, it is called I. motor neuron dysarthria or II. motor neuron dysarthria, referring to the involved motor neuron; if the disorder is related to the cerebellar system, cerebellar dysarthria; and if it is related to the extrapyramidal system, extrapyramidal dysarthrias (hypokinetic and hypokinetic). It can be named as kinetic dysarthrias). The characteristics of the speech disorders in these dysarthrias match the general characteristics of the findings that occur in diseases of the affected structure or system. Stuttering; It is a developmental or acquired motor speech disorder. In this disorder, there is usually a delay in pronouncing certain letters, syllables or words. Observations of stuttering sometimes give us information about the mechanisms underlying it. For example, the fact that this disorder disappears in many stuttering people while singing a song or poem, in other words, the resolution of stuttering with the contribution of right hemispheric prosody and emotion, suggests that stuttering is more related to the left hemisphere, while the fact that most stutterers solve the stiffness by resorting to trunk and head movements when they are forced indicates the role of extrapyramidal mechanisms. Sometimes involuntary facial and jaw movements accompany stuttering, which again draws attention to a phenomenon of extrapyramidal origin, dystonia.
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