Cognitive dysphasia

The term cognitive dysphasia was coined by Heidler (2006) and describes language processing disorders as a result of impaired attention , memory , perception and executive functions . Cognitive dysphasia must be distinguished from aphasia , which is caused by direct damage to the centers for language production and language understanding in the perisylvic areas of the left hemisphere - however, there are numerous overlaps, since left hemispheric brain lesions usually damage numerous other regions that are responsible for cognitive performance (e.g. B. left frontal areas for various attentional and executive functions). Patients with aphasia often suffer from cognitive dysphasia at the same time, while cognitive dysphasia can also occur without aphasia (e.g. after right-hemispherical brain damage). In patients with cognitive dysphasia, the language system as such is often intact. Rather, the cognitive tools that are required for an effective use of the tool "language" (attention, memory, perception, executive functions) are disturbed.

causes

Cognitive dysphasia can have many causes, including strokes (partial or complete blockage of blood vessels in the brain), tumors , hypoxia , alcohol abuse, traumatic brain injuries or inflammation of the brain. It is crucial that this damages areas in the brain that are responsible for attention, perception, memory and / or executive functions.

Such brain regions for attentional performance include the reticular formation in the brain stem , the thalamus and the frontal lobe . The right hemisphere is important for general alertness and the left hemisphere for specific concentration.

In addition to other regions, parts of the limbic system , which is also called the “feeling system”, are responsible for different memory functions. It includes u. a. the hippocampus and the tonsils , which play an important role in emotional assessment and in recognizing situations. In addition, the frontal lobe and the long-term memory in the left hemisphere (word memory) and in the right hemisphere (episode memory) are important for memory performance.

Executive functions are higher-order mental processes - e.g. B. Attention control, cognitive flexibility, anticipation, linguistic reasoning or planning, initiating, sequencing and controlling actions. Such functions are primarily controlled by the frontal lobe, which has connections to all other regions of the brain so that it can effectively influence behavior. Disturbances of executive functions therefore occur not only when the frontal lobe itself is damaged, but also when the connections to other (especially subcortical) areas are interrupted (e.g. between the frontal lobe and thalamus, basal ganglia or cerebellum).

Perceptual functions relevant for language processing are primarily auditory and visual perception services that are controlled by temporal, parietal and occipital regions. Lesions in these areas can cause visual and auditory-perceptual disorders such as visual or auditory agnosia.

Forms of cognitive dysphasia

On the one hand, cognitive dysphasias can be divided into cognitive dysphasias of attentional, mnestic, perceptual and / or dysexual origin with regard to the underlying cognitive dysfunction; on the other hand, they can be described in relation to the disease in which they occur, e.g. B. Cognitive dysphasia in traumatic brain injuries, after hypoxic brain damage, in the context of psychiatric diseases, etc .; In certain diseases, certain forms of cognitive dysphasias often dominate (e.g. cognitive dysphasias of mnestic origin following hypoxic brain damage or cognitive dysphasias of dysexecutive origin in affective psychoses).

Cognitive dysphasia of attentional genesis (as a result of impaired attention performance): Disturbances in the intensity of attention (wakefulness) primarily lead to a slowdown in information processing. This slows down the speed of speech processing and leads to delayed responses and a slower flow of speech. Since environmental changes can no longer be perceived in a timely manner and verbal stimuli can only be processed superficially, there are coherence breaks in the statements. Disturbances in attention selection (concentration) primarily impair the filtering out of irrelevant verbal information. In conversation situations, for example, this leads to difficulties in breaking away from a current focus and adjusting to a new focus (e.g. on a new topic or a different conversation partner). In addition, the perception of speech under noise conditions can be more difficult, so that relevant information from competing acoustic stimuli can no longer be reliably filtered out.

Cognitive dysphasia of mnestic origin (as a result of impaired memory performance): There is a constitutive interaction between memory and language processing processes, since without a functioning memory system it is not possible to generate linguistic structures. Long-term memory (semantic and episodic knowledge), procedural memory systems (syntactic processing) as well as verbal working and short-term memory processes are important. For its part, language processing is a prerequisite for many memory functions (for example encoding processes), so that in the case of language system disorders (aphasia) it can be difficult to acquire new knowledge. Cognitive dysphasia of mnestic origin can affect long-term memory, for example. Severe old memory disorders primarily lead to an impoverishment of linguistic expression, since it is usually only the memory of certain episodes that makes a linguistic utterance come alive. In addition, there can be confabulations, i. H. wrong expression content without conscious intent to deceive ("At the weekend I was eating ice cream on Mars."). If, on the other hand, the storage function of the memory is impaired (new memory disorder), in extreme cases what was said in the conversation will be forgotten after a short time. The consequences are language comprehension problems, which are mostly embedded in general disturbances in orientation to place, time and situation.

Cognitive dysphasia of dyexecutive genesis (as a result of impaired executive functions): Speech processing disorders as a result of impaired executive processes affect the planning, starting, stopping and controlling of speech acts. Disturbances of the drive and the initiation can lead to the affected person not being able to start his speech production in the first place (inhibition). A lack of control can mean that a started speech production can no longer be stopped (disinhibition). Often associations cannot be inhibited, so that it is difficult for the person concerned to limit himself to the essentials and he talks a lot and often incoherently and tangentially (past the topic). Disrupted control processes mean that mistakes (wrong word selection, telling of irrelevant details, etc.) cannot be noticed and accordingly cannot be corrected.

Cognitive dysphasias of perceptual origin (as a result of impaired perceptual functions): A common cause of cognitive dysphasias of perceptual origin are material-specific or generalized apperceptive and / or associative agnosias, in which either the phase of recognition is impaired (apperceptive) or the connection to meaning fails (associative ). In the case of visual agnosias, for example, the patients can no longer recognize objects or faces (and accordingly cannot name them correctly); in the case of auditory agnosias they can no longer recognize / understand meaningful environmental noises (dog barking, mobile phone ringing) or spoken language.

Diagnostics of cognitive dysphasia

Numerous standardized neuropsychological test procedures are available for recording disturbed attentional, mnestic, perceptual and executive functions.

Therapy of cognitive dysphasia

The treatment of cognitive dysphasia should primarily be carried out by neuropsychologists who specialize in training impaired attention, memory, perceptual and executive functions. However, since there are hardly any resident neuropsychologists, such services must and can also be trained within the scope of speech therapy with the help of special cognitively-oriented speech therapy. The aim is either a disorder-specific treatment or a skill-preserving treatment of those cognitive functions that most impair the patient's speech processing in everyday life. Priority is generally given to generating a sufficient level of activity through training executive functions, selective attention, attention focusing and mental adaptability, since brain areas relevant to language processing can only be specifically activated with sufficient attention functions.

literature

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R. Drechsler: Speech disorders after head trauma. Discourse analytical investigations from a text-linguistic and neuropsychological point of view. Gunter Narr, Tübingen 1997.
M.-D. Heidler: Cognitive Dysphasia. Differential diagnosis of aphasic and non-aphasic central language disorders and therapeutic consequences. Peter Lang, Frankfurt am Main a. a. 2006.
M.-D. Heidler: attention and language processing. In: "Language - Voice - Hearing" 2008, 32, pp. 74–85.
M.-D. Heidler: Cognitive Dysphasias - Recognize and Treat. memo, Stuttgart 2020.
M.-D. Heidler: " Cognitive dysphasia - new wine in old bottles? " In: "Aphasia and related areas " 2017, 1, pp. 3–9.
M.-D. Heidler, & P. Eling: "Puzzling confabulations - an overview of classifications and theories ." In: " Zeitschrift für Neuropsychologie " 2015, 26, pp. 257–270.
B. Schneider: Cognitive dysphasia and anxiety: linguistic studies in patients with epilepsy and anxiety disorders. (on-line)
LS Turkstra, C. Coelho, M. Ylvisaker: Use of standardized tests for individuals with cognitive-communication disorders. In: " Seminars in Speech and Language" 2005, 26, pp. 215-222.