A 70-year-old man comes to the office 4 weeks after experiencing an ischemic stroke. Medical history is significant for long standing hypertension and type 2 diabetes mellitus. Vital signs are unremarkable. BMI is 24 kg/m². The patient is right-handed. Only the right side of his face is shaved. When asked to raise his left arm, the patient raises his right. When asked to fill in the numbers of a clock, he puts numbers only on the right side. Which of the following areas is most likely affected by the stroke in this patient?

Question

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Explanation: 11ec25c8_d5ae_c483_bc81_637de305b2d3_MD0003_00 After a stroke, this patient has no awareness of the left side of his world (eg, drawing numbers only on the right side of a clock) or body (eg, shaving only one side of the face), a condition called hemineglect. Profound hemineglect is usually due to a lesion impacting the nondominant parietal lobe, which is responsible for spatial organization. In the vast majority of patients, particularly right-handed patients, the right parietal lobe is the nondominant lobe. Neglect can manifest in several ways: Sensory neglect, which includes tactile, visual, and even auditory neglect. It can be assessed with extinction testing (bilateral sensory stimulus experienced only on one side). Motor-intentional neglect, which includes decreased spontaneous movement on the neglected side despite normal strength and use of the "incorrect" (ie, normal) arm when instructed to move the affected arm, as seen in this patient. Conceptual neglect, which may include a lack of awareness or concern about the deficits. In severe cases, patients may even say that half of their body does not belong to them. Drawing a clock requires both motor and sensory components, so it is a useful screening test. (Choices A and C) Lesions to the frontal cortex often lead to weakness of the contralateral body and lower face (based on the somatotopic organization of the brain) due to disruption of the primary motor cortex. Frontal cortex injury is also associated with gaze preference, social disinhibition, and deficits in attention and executive function (eg, planning, organizing, decision-making). somatotopic organization of the brain (Choice B) Left (dominant) temporal lobe lesions may impact the Wernicke area (caudal superior temporal gyrus) and result in receptive aphasia with lack of insight, leading to fluent aphasia ("word salad"). Patients can also have contralateral superior homonymous quadrantanopia; however, this impacts only the upper quadrants of vision. In addition, this would not lead to motor neglect. (Choice D) Occipital lobe damage results in cortical blindness that patients often deny, but this would not lead to motor neglect. Educational objective: Damage to the nondominant (right) parietal lobe can lead to hemineglect, which is characterized by unawareness of the left side of the world and/or body and impact sensory, motor, and conceptual functioning.

A 70-Year-Old Man Comes to the Office 4 Weeks After