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?

Question

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?

Quizplus · Accepted Answer

Explanation: Almost 90% of right-handed patients and 60% of left-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. (Choice B) Damage to the dominant parietal lobe, especially the inferior parietal lobe, presents as Gerstmann syndrome. The patients have difficulty in performing simple arithmetic tasks (acalculia), inability to name individual fingers (finger agnosia), impaired writing (agraphia) and right/left confusion (difficulty in identifying or distinguishing the right or left side of the body). (Choice C) Lesions of the nondominant temporal lobe can cause visual disorders (homonymous upper quadrantanopia) and impaired perception of complex sounds (auditory agnosia). (Choice D) Dominant temporal lobe lesions, in addition to having homonymous upper quadrantanopia, almost always involve the language functions, and lead to aphasia. Wernicke's aphasia is usually seen in patients with dominant temporal lobe lesions. It is characterized by the impairment in comprehension of spoken or written language. Patients have difficulty in expressing their thoughts in a meaningful manner. Apraxia is not seen in temporal lobe lesions. Educational Objective: Nondominant parietal lobe lesions present with constructional and dressing apraxia. Aphasia is typically seen in dominant temporal lobe lesions.

A 72-Year-Old Caucasian Female Is Brought to the Emergency Room