USMLE Forum Archives - USMLE Step 3 - Localise this lesion ?
Localise this lesion ?
harry206 - 05-04-09 16:31
A 72-year-old Caucasian female is brought to the emergency room because of a sudden onset of confusion and clumsiness. Her daughter tells you that she was watching television when the symptoms started. She has a past history of hypertension and atrial fibrillation. On physical examination, there is no evidence of any focal weakness of her extremities. Her speech is clear, and she is able to repeat the sentences after you. She is able to engage in an intelligent conversation, and provide her own past medical history. When you ask her to copy a picture of a matchstick, she is unable to do it. Which of the lobes of the brain is most likely affected in this patient?
harry206 - 05-04-09 16:31
A 72-year-old Caucasian female is brought to the emergency room because of a sudden onset of confusion and clumsiness. Her daughter tells you that she was watching television when the symptoms started. She has a past history of hypertension and atrial fibrillation. On physical examination, there is no evidence of any focal weakness of her extremities. Her speech is clear, and she is able to repeat the sentences after you. She is able to engage in an intelligent conversation, and provide her own past medical history. When you ask her to copy a picture of a matchstick, she is unable to do it. Which of the lobes of the brain is most likely affected in this patient?
The correct answer and explanation will be available after you answer.
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#1
Re: Localise this lesion ? InSitu - 05-04-09 16:36 My answer is: a.
Its the Parietal lobe for sure, but is it dominant or non? The dominant lobe is particularly important for perception, interpretation of sensory information, and the formation of the idea of a complex meaningful motor responses to the stimuli (whereas the frontal lobes are important for the execution of the act.). Particularly, the supramarginal gyrus and the angular gyrus of the dominant inferior lobe are concerned with language, mathematical operations, and body image. The non-dominant lobe is especially important for visual-spatial functions.
#6
Re: Localise this lesion ? ammara - 05-05-09 01:20 My answer is: a.
following r the features of leison of nondominant parietal lobe..
deniel of illness,difficulty outlining objects and neglect of opposite side of body..i wonder y neglect is not mentioned thats making it confusing???
#7
Re: Localise this lesion ?
harry206 - 05-06-09 03:47 EXPLANATION:
Almost 90% of left-handed patients and 60% of right-handed patients have a left hemispheric dominance for speech and language functions. The patient in the above scenario appears to be suffering from construction apraxia. This is seen with the involvement of parietal lobes, and is much more pronounced with lesions of the right parietal hemisphere (nondominant parietal lobe). Patients have marked difficulty in copying simple line drawings. They may also experience difficulty in wearing clothes, and appear to struggle while attempting to get into a coat or pants. This is known as dressing apraxia, which is seen with bilateral or right-sided (nondominant) parietal lobe lesions. Confusion is also seen in patients with lesions of the nondominant parietal lobe.
#25
Re: Localise this lesion ? babbu5508 - 07-07-10 13:51 My answer is: a.
when asked to copy a picture of a matchstick, she is unable to do it...in the absence of other significant findings ...right parietal lobe
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