A 45-year-old man presents with progressive clumsiness, stat…

A 45-year-old man presents with progressive clumsiness, stating he often drops objects and recently has had difficulty performing tasks requiring fine motor coordination, such as hammering a nail. He also reports that his speech has become slurred, and his legs occasionally feel weak. He denies visual or cognitive changes. A chronic degenerative disease of the central nervous system involving predominantly motor neurons is suspected. Which of the following is the most likely diagnosis?

A 40-year-old administrative assistant presents with daily h…

A 40-year-old administrative assistant presents with daily headaches that she describes as a dull, pressure-like pain around the forehead and occipital area. The pain is bilateral, non-pulsatile, and is not associated with nausea, vomiting, photophobia, or aura. She notes that the headaches often begin in the afternoon and are worse during periods of stress. Over-the-counter analgesics provide some relief. What is the most likely patient’s diagnosis?

A 29-year-old woman presents with intermittent visual distur…

A 29-year-old woman presents with intermittent visual disturbances, right arm weakness, and numbness in the left leg. MRI of the brain and spinal cord reveals multiple demyelinating lesions in both supratentorial and spinal regions. Which of the following best explains the asymmetric and varied presentation of her symptoms?