A 65-year-old man is brought to the emergency department due to an acute change in mental status. The patient was having dinner with his family when he suddenly had difficulty using his fork and appeared confused. Other medical conditions include type 2 diabetes mellitus, hyperlipidemia, and hypertension. The patient is a high school calculus teacher and has a 40-pack-year smoking history. Blood pressure is 180/98 mm Hg and pulse is 98/min and regular. On physical examination, the patient is well oriented, answers questions appropriately, and has no motor, sensory, or visual deficits. He is unable to add simple numbers such as 17 plus 9; he is also unable to recognize or distinguish his fingers. Which of the following brain areas is most likely affected in this patient?

Question

A 65-year-old man is brought to the emergency department due to an acute change in mental status.  The patient was having dinner with his family when he suddenly had difficulty using his fork and appeared confused.  Other medical conditions include type 2 diabetes mellitus, hyperlipidemia, and hypertension.  The patient is a high school calculus teacher and has a 40-pack-year smoking history.  Blood pressure is 180/98 mm Hg and pulse is 98/min and regular.  On physical examination, the patient is well oriented, answers questions appropriately, and has no motor, sensory, or visual deficits.  He is unable to add simple numbers such as 17 plus 9; he is also unable to recognize or distinguish his fingers.  Which of the following brain areas is most likely affected in this patient?

Quizplus · Accepted Answer

11ec160b_35b7_01e6_9249_993f79787cb1_MD0001_00 This patient has had a stroke but has no motor, sensory, or visual deficits. However, he has trouble eating, solving simple mathematical problems (despite being a calculus teacher), and identifying his fingers, which are all tasks requiring multisensory integration (eg, visual-spatial, tactile, proprioceptive). The parietal association cortex is the brain region responsible for processing this information, and facilitates comprehension (eg, understanding words & symbols) and problem solving (eg, numerical calculation, spatial orientation). This patient's particular pattern of deficits is suggestive of injury involving the angular gyrus of the left (dominant) parietal lobe. Damage to this region classically results in Gerstmann syndrome, which is characterized by the following signs: Although Gerstmann syndrome may occur as an isolated syndrome, lesions to the angular gyrus may also be associated with alexia (inability to read) and aphasia (impaired speech), also tasks that require multisensory integration. (Choice A) This area just anterior to the central sulcus is the precentral gyrus (primary motor cortex). Lesions to this area would result in contralateral weakness according to the somatotopic organization of the brain. (Choice B) This area posterior to the central sulcus is the postcentral gyrus (parietal somatosensory cortex). A lesion here would cause sensation loss in the contralateral body. (Choice C) This location in the caudal part of the inferior frontal gyrus of the dominant hemisphere is Broca area. A stroke in this area leads to an expressive aphasia. Although patients with expressive aphasia may have difficulty writing, speech would also be impacted (usually characterized by nonfluent speech). (Choice E) A lesion to the visual cortex, located in the occipital lobe, can lead to cortical blindness or visual impairment. Educational objective: Because the parietal association cortex integrates multisensory information, damage can lead to difficulties in comprehension and problem-solving in the absence of motor or sensory deficits. Specific injury to the angular gyrus classically results in Gerstmann syndrome (agraphia, acalculia, finger agnosia, and left-right disorientation). __________ References: Gerstmann's syndrome in acute stroke patients. (http://www.ncbi.nlm.nih.gov/pubmed/23378691) A proposed reinterpretation of Gerstmann's syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/25377466)

A 65-Year-Old Man Is Brought to the Emergency Department Due