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.
The Speaker is the most powerful member of the House of Representatives, and arguably, the most influential single legislator in both houses. Always a member of the majority party, the speaker's influence depends partly on strength of personality and respect of colleagues, but also on several important powers.