Symptoms of significant brain atrophy include progressive cognitive impairment involving multiple cognitive functions, otherwise known as dementia, seizures and aphasia, which is the disruption in the understanding or production of language or both.
The Senate majority leader has somewhat less official power than the Speaker of the House. This is because the vice president is technically the Senate's presiding officer, a ceremonial position that calls chiefly for casting a vote in the event of a tie.
However, the majority leader exercises influence in important areas not open to the House Speaker. Only the Senate can approve treaties with foreign governments, and the Senate alone has the authority to confirm presidential nominations to the cabinet and federal courts.