Aphasia
Aphasia is a disorder of previously formed speech activity, in which the ability to use one’s own speech and/or understand the addressed speech is partially or completely lost. The manifestations of aphasia depend on the form of speech impairment; specific speech symptoms of aphasia are speech emboli, paraphasia, perseveration, contamination, logorrhea, alexia, agraphia, acalculia, etc. Patients with aphasia need an examination of the neurological status, mental processes, and speech function. In the case of aphasia, treatment of the underlying disease and special rehabilitation training is carried out. Aphasia types
General information about Aphasia
Aphasia – decay, loss of already existing speech, caused by local organic damage to the speech areas of the brain. Unlike alalia, in which speech is not formed initially, in aphasia the possibility of verbal communication is lost after the speech function has already been formed (in children over 3 years old or in adults).
Patients with aphasia have a systemic speech disorder, that is, expressive speech (sound pronunciation, vocabulary, grammar), impressive speech (perception and understanding), inner speech, written speech (reading and writing) suffer to some extent. In addition to speech function, the sensory, motor, personal sphere, and mental processes also suffer, therefore aphasia is one of the most complex disorders, which are studied by neurology, speech therapy, and medical psychology. Aphasia types
Causes of aphasia
Aphasia is a consequence of organic damage to the cortex of the speech centers of the brain. The action of the factors leading to the onset of aphasia occurs during the period of speech already formed in the individual. The etiology of aphasic disorder affects its nature, course, and prognosis. Possible reasons:
- Strokes. Among the causes of aphasia, the largest specific weight is occupied by vascular diseases of the brain – hemorrhagic and ischemic strokes. Moreover, in patients who have had a hemorrhagic stroke, the total or mixed aphasic syndrome is more often observed; in patients with ischemic disorders of cerebral circulation – total, motor, or sensory aphasia.
- Traumatic brain injury: concussions, brain contusions.
- Inflammatory brain diseases: encephalitis, leukoencephalitis, abscess.
- Brain tumors: gliomas, glioblastomas, astrocytomas, etc.
- Chronic progressive diseases of the central nervous system: focal variants of Alzheimer’s disease and Pick’s disease ).
- Operations on the brain: removal of tumors, evacuation of intracerebral hematomas.
Risk factors of Aphasia
Risk factors that increase the likelihood of aphasia include:
- elderly age,
- family history,
- cerebral atherosclerosis,
- hypertension,
- rheumatic heart disease,
- transferred transient ischemic attacks,
- head injury.
The severity of aphasia syndrome depends on the location and extent of the lesion, the etiology of speech impairment, compensatory capabilities, the patient’s age, and premorbid background. So, with brain tumors, aphasic disorders increase gradually, and with TBI and stroke, they develop sharply. Intracerebral hemorrhage is accompanied by more severe speech impairments than thrombosis or atherosclerosis. The recovery
Symptoms of aphasia
Regardless of the mechanism, in any form of aphasia, speech impairment is observed in general. This is due to the fact that the primary loss of one or another side of the speech process inevitably entails a secondary disintegration of the entire complex functional system of speech.
1-Motor aphasias
Due to the difficulty of switching from one speech element to another, numerous permutations of sounds and syllables, perseverations, literal paraphasia’s, and contamination are observed in the speech of patients with efferent motor aphasia. Characterized by the “telegraph style” of speech, long pauses, hypophonia, violation of the rhythmic and melodic side of speech. The pronunciation of individual sounds during efferent motor aphasia is not disturbed. The disintegration of the ability for sound-letter analysis of a word is accompanied by gross violations of reading and writing (dyslexia/alexia, dysgraphia/agraphia).
Afferent motor aphasia can take two forms. In the first variant, there is articulatory apraxia or complete absence of spontaneous speech, the presence of a speech embolus. In the second variant – conductive aphasia, situational speech remains intact, however, repetition, naming, and other types of arbitrary speech are grossly violated. With afferent motor aphasia, phonemic hearing is secondarily impaired and, consequently, the understanding of spoken language, the meanings of individual words and instructions, as well as written speech.
2-Sensory aphasia
Unlike motor aphasias, with acoustic-gnostic (sensory) aphasia, the auditory perception of speech is impaired with normal physical hearing. With Wernicke‘s aphasia, the patient does not understand the speech of others and does not control his own speech flow, which is accompanied by the development of compensatory verbosity. In the first 1.5-2 months. after a brain catastrophe, the speech of patients includes a random set of sounds, syllables, and words (“speech okroshka” or jargonaphasia), therefore its meaning is unclear to those around. Then jargon-phasic gives way to verbose ( logore) with pronounced agrammatism, literal and verbal paraphasias. Since in sensory aphasia, phonemic hearing primarily suffers, a violation of writing is noted; reading remains the safest since it relies more on optical and kinesthetic control. Aphasia types
3-Acoustic-mnestic aphasia
With acoustical-mnestic aphasia, patients have difficulty retaining information perceived by the ear in their memory. At the same time, the volume of memorization is significantly reduced: the patient cannot repeat a bunch of 3-4 words after a speech therapist, does not catch the meaning of speech in complicated conditions (long-phrase, fast pace, conversation with 2-3 interlocutors). Difficulties in verbal communication in acoustic-mnestic aphasia are compensated by increased verbal activity. With optical-mnestic aphasia, there is a violation of visual memory, a weakening of the connection between the visual image of an object and a word, difficulties in naming objects. Disorder of auditory speech and visual memory entails a violation of writing, understanding of the text being read, and counting operations.
4-Semantic aphasia
Amnestic-semantic aphasia is manifested by forgetting the names of objects (anomie); violation of understanding of complex speech turns, reflecting temporal, spatial, cause-and-effect relationships; participles and adverbs, proverbs, metaphors, catchphrases, figurative meanings, etc. Also, with semantic aphasia, acalculia is noted, the understanding of the text being read is impaired.
5-Dynamic aphasia
With dynamic aphasia, despite the correct pronunciation of individual sounds, words, and short phrases, preserved automated speech, and repetition, spontaneous narrative speech becomes impossible. Verbal activity is sharply reduced, in the speech of patients there are echolalia and perseveration. Reading, writing, and elementary counting in dynamic aphasia remain intact. Aphasia types
Classification of Aphasia
Attempts to systematize the forms of aphasia on the basis of anatomical, linguistic, psychological criteria have been repeatedly undertaken by various researchers. However, the classification of aphasia according to A.R. Luria, taking into account the localization of the lesion in the dominant hemisphere – on the one hand, and the nature of the speech disorders arising in this case – on the other. In accordance with this classification, motor (efferent and afferent), acoustic-gnostic, acoustic-mnestic, amnestic-semantic, and dynamic aphasia are distinguished.
- Efferent motor aphasia is associated with damage to the lower parts of the premotor region (Broca‘s zone). The central speech defect in Broca‘s aphasia is kinetic articulatory apraxia, which makes it impossible to switch from one articulatory position to another.
- Afferent motor aphasia develops when the lower parts of the postcentral cortex, adjacent to the Roland groove, are affected. In this case, the leading disorder is kinesthetic articulatory apraxia, that is, the difficulty in finding a separate articulatory posture necessary for pronouncing the desired sound.
- Acoustic-gnostic aphasia occurs when a pathological focus is localized in the posterior third of the superior temporal gyrus (Wernicke‘s zone). The main defect accompanying Wernicke‘s aphasia is a violation of phonemic hearing, analysis, and synthesis and, as a result, a loss of understanding of the addressed speech.
- Acoustic-mnestic aphasia is a consequence of the defeat of the middle temporal gyrus (extranuclear parts of the auditory cortex). In the case of acoustic-mnestic aphasia, due to increased inhibition of auditory traces, auditory-speech memory suffers; sometimes – visual representations of the subject.
- Semantic aphasia develops when the interparietal and posterior temporal parts of the cerebral cortex are affected. This form of aphasia is characterized by specific amnestic difficulties – forgetting the names of objects and phenomena, a violation of understanding of complex grammatical structures.
- Dynamic aphasia is pathogenetically associated with lesions of the posterior frontal regions of the brain. This leads to the inability to build an internal program of expression and its implementation in external speech, i.e., a violation of the communicative function of speech.
In the case of extensive damage to the cortex of the dominant hemisphere, involving motor and sensory speech zones, total aphasia develops – that is, a violation of the ability to speak and understand speech. Mixed aphasias are quite common: afferent-efferent, sensorimotor, etc.
Diagnostics of Aphasia
Diagnostics, rehabilitation treatment, and education of patients with aphasia are carried out by a team of specialists in neurologists, neuropsychologists, and speech therapists. If aphasia is suspected, the following is performed:
- Neurological diagnostics. To find out the immediate causes of aphasia and localization of the lesion, CT or MRI of the brain, MR angiography, ultrasound of the head and neck vessels, duplex scanning of the cerebral vessels, and lumbar puncture are performed.
- Examination of speech for aphasia. Includes diagnostics of oral speech (expressive and impressive); diagnostics of written speech (cheating, dictation, reading, and reading comprehension).
- Neuropsychological examination. A neuropsychologist working with patients with aphasia diagnoses auditory-speech memory and other model-specific forms of memory (visual, motor), praxis (oral, facial, hand, finger, somatospatial, dynamic), visual gnosis, constructive-spatial activity, intellectual processes.
Comprehensive diagnostics can differentiate aphasia from alalia (in children), dysarthria, hearing loss, mental retardation.
Correction of aphasia
Corrective action for aphasia consists of medical and speech therapy directions. Treatment of the underlying disease that caused aphasia is carried out under the supervision of a neurologist or neurosurgeon; includes drug therapy, if necessary – surgery, active rehabilitation ( exercise therapy, mechanotherapy, physiotherapy, massage ). Aphasia types
The restoration of speech function is carried out in speech therapy classes for the correction of aphasia, the structure, and content of which depends on the form of impairment and the stage of restorative learning. With all forms of aphasia, it is important to develop the patient’s mindset to restore speech, develop intact peripheral analyzers, work on all aspects of speech: expressive, impressive, reading, writing.
- with efferent motor aphasia, the main task of speech therapy classes is to restore the dynamic scheme of word pronunciation;
- with afferent motor aphasia – differentiation of kinesthetic signs of phonemes;
- with acoustic-gnostic aphasia, it is necessary to work on the restoration of phonemic hearing and understanding of speech;
- with acoustic-mnestic – overcoming defects in auditory-speech and visual memory;
- with amnestic-semantic aphasia, the main task is to overcome impressive agrammatism;
- with dynamic aphasia – overcoming defects in internal programming and speech planning, stimulating speech activity.
Corrective work for aphasia should be started from the first days or weeks after a stroke or injury, as soon as the doctor permits. An early start of restorative training prevents the fixation of pathological speech symptoms (speech embolus, paraphasias, agrammatism). Speech therapy work to restore speech in aphasia lasts 2-3 years. Aphasia types
