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.
As their title implies, the majority leaders represent the party holding the majority of seats in the House and Senate, while the minority leaders represent the opposing party. In the event each party holds 50 seats in the Senate, the party of the Vice President of the United States is considered the majority party.