A 55 year old woman awoke with weakness of the right arm and leg. Her husband spoke to her and she understood him but she was unable to speak in response. The doctor observed a flattened nasolabial fold on the right; on command she could only show her teeth on the right but her brows could be wrinkled symmetrically.
Her tongue deviated to the right when protruded. The upper right extremity had a spastic paralysis, the lower limb was less weak with mild hypertonia, hyperreflexia, and a positive Babinski.
Sensory and cerebellar exams were normal. She was frustrated by her difficulty in finding the right words in response to questions and her sentences were short and incomplete. Her speech was slurred making words difficult to understand.
Her spastic paralysis was more severe in the arms than the legs suggesting a cortical lesion rather than the internal capsule where the fibers are compact and more likely to be damaged together resulting in weakness of equal severity.
Right-sided paralysis of the lower face and tongue (Slurred speech) implicate corticobulbar fibers. She had trouble with the expressive aspects of language (motor aphasia) rather than comprehension.
This suggests that in the dominant left hemisphere Broca's motor speech area was affected rather than Wernicke's area or the interconnecting arcuate fasciculus. The sudden onset suggests occlusion of branches of the middle cerebral artery.
Right-sided paralysis of the lower face and tongue (Slurred speech) implicate corticobulbar fibers. She had trouble with the expressive aspects of language (motor aphasia) rather than comprehension.
This suggests that in the dominant left hemisphere Broca's motor speech area was affected rather than Wernicke's area or the interconnecting arcuate fasciculus. The sudden onset suggests occlusion of branches of the middle cerebral artery.
Extended Explanation
Slurred, poorly articulated speech (dysarthria) and a tongue which deviated to the right upon protrusion suggests that corticobulbars on the left are also involved. Right sided paralysis of the lower face indicates corticobulbar involvement on the left.
In addition to slurring of speech, which has to do with the mechanics of sound production, she had trouble with language itself (aphasia) i.e., there were problems in finding the right words to define objects and forming words into sentences.
There was no indication of problems with comprehension of language but rather its expression i.e., motor aphasia. Language functions are usually represented in the left hemisphere.
There was no indication of problems with comprehension of language but rather its expression i.e., motor aphasia. Language functions are usually represented in the left hemisphere.
In addition to paresis and paralysis of the right limbs due to the left sided lesion the patient had an apraxia of the left limbs. Apraxia is the inability to carry out a command for a motor act even though the patient understands the command and has no weakness or incoordination.
This patient was asked to scratch her left knee with her left hand, which had no signs of weakness; she made a vague gesture toward her knee, demonstrating comprehension, but didn't complete the task.
Later she used her left hand to adjust the hem on her skirt to cover her left knee. This apraxia is explained by the lesion to the motor cortices including Broca's motor speech area.
The command to scratch is first comprehended in the Wernicke's speech area in the left temporal lobe. Connections exist (arcuate fasciculus) from Wernicke's area to Broca's area and the left motor cortex.
The left arm responds to the command when the right motor cortex is activated by crossing fibers coming from the left motor cortex via the corpus callosum. In this case injury to the left motor cortex injures those crossing fibers and so the command is poorly executed.
This patient was asked to scratch her left knee with her left hand, which had no signs of weakness; she made a vague gesture toward her knee, demonstrating comprehension, but didn't complete the task.
Later she used her left hand to adjust the hem on her skirt to cover her left knee. This apraxia is explained by the lesion to the motor cortices including Broca's motor speech area.
The command to scratch is first comprehended in the Wernicke's speech area in the left temporal lobe. Connections exist (arcuate fasciculus) from Wernicke's area to Broca's area and the left motor cortex.
The left arm responds to the command when the right motor cortex is activated by crossing fibers coming from the left motor cortex via the corpus callosum. In this case injury to the left motor cortex injures those crossing fibers and so the command is poorly executed.
