Aphasia: central speech disorder
Dysarthria: Peripheral speech disorder
Aphasias
• It is a language dysfunction that occurs with brain damage.
• As a rule, the left hemisphere undertakes the speech function.
• In 40% of left-handers only, the right hemisphere is the dominant hemisphere.
• Right hemisphere parietal lobe lesions
1. The patient does not recognize a half or part of his body.
2. The patient is not aware of the neurological deficit. He denies his illness.
3. Left hemiplegia
This picture is called neglect syndrome.
• The most common cause is thrombotic-embolic occlusion of the left middle cerebral artery or left carotid interna.
• Broca's area is area 44 and is in the inferior posterior frontal lobe. It is close to the motor cortex.
• Wernicke's area is area 22 and is located in the superior lateral posterior of the temporal lobe. It is close to vision centers.
• The arcuate fascicle connects these two areas.
Classical aphasia syndromes
Broca's (motor) aphasia:
Comprehension is quite good, while self-expression (motor component of speech) is impaired.
Wernicke (sensory) aphasia:
It is a type of aphasia in which the patient's understanding is severely impaired. There is fluent but nonsensical speech, a condition called Verbal paraphasia is seen. For example, when he wants to say "give me the pen", he may say "where is the school".
Conduction type (conduction) aphasia:
It occurs in lesions of the arcuate fascicle connecting Wernicke and Broca's area.
Comprehension and speaking are normal. However, repetition and reading aloud are typically impaired.
Anomic aphasia:
It is the type of aphasia in which the naming is broken. Patients cannot use names. It occurs mostly in parietotemporal region tumors.
Global (total) aphasia:
It is seen in lesions involving Broca, Wernicke and arcuate fascicles. Speech, comprehension and repetition are impaired. It is seen in middle cerebral artery occlusions. In this case, the perisylvian region is affected. It is always accompanied by right hemiplegia.
Transcortical aphasia:
Its main feature is that only the repetition feature is preserved.
Subcortical aphasia:
It is seen in thalamic and basal ganglia involvement. It is atypical aphasia type that does not fit into classical aphasia syndromes.
|
aphasias |
|||
|
Aphasia
Type |
SPEECH |
UNDERSTANDING |
REPEAT |
|
Broca |
not
fluent |
Protected |
degraded |
|
Wernicke |
Fluent,
but pointless |
degraded |
degraded |
|
Transmission |
Fluent |
Protected |
degraded |
|
Transcortical
motor |
not
fluent |
Good |
Protected |
|
Transcortical
sensory |
Fluent |
Degraded
(like Wernicke) |
Protected |
|
Anomic
(Amnestic) |
Isolated
word finding difficulty |
Normal |
Normal |
|
Global |
not
fluent |
degraded |
no |
Alexia-agraphia
• The inability of a conscious person to read the text is called alexi.
• While the lesion is in the visual cortex in agraffitiless alexia, the lesion is in the parietal lobe in agraphia seen in agraphia.
Acalculia
• Ability to calculate is impaired. It is usually seen in dominant parietal lobe lesions.
Agnosia
• The inability of a person to recognize something learned through that sense without a sensory disorder is called agnosia.
• Patients may not be able to evaluate what they see, hear and touch.
visual agnosia
• The patient cannot recognize and evaluate what he sees, it is seen in occipital lobe lesions.
Hearing agnosia
• The patient cannot evaluate what he hears. It is seen in temporal lobe lesions.
tactile agnosia
• It is a disorder of evaluation by the parietal lobe of the sense of touch
Astereognosia
It is the state of not being able to recognize the object (shape, size) placed in the hand while the eyes are closed.
Apraxia
• It is the inability to perform purposeful and planned movements without motor, coordination and sensory defects.
• Not being able to comb one's hair and buttoning a button is an example of apraxia.