US STOCKS-Wall St suffers worst day in 4 years, S&P confirms correction
* Chinese market falls 8 percent
* At one point, Dow down more than 1,000 points
* Apple mostly recovers after falling as much as 13 pct
* Indexes close down: S&P 3.94 pct, Nasdaq 3.82 pct, Dow 3.58 pct (Updates to market close, adds comment)
By Noel Randewich
Aug 24 (Reuters) - Investors rattled about China sent U.S. stock indices almost 4-percent lower on Monday in an unusually volatile session that confirmed the S&P 500 was formally in a correction, even after a dramatic rebound by Apple.
The Dow Jones industrial average briefly slumped more than 1,000 points, its most dramatic intraday trading range ever.
Monday's drop followed an 8.5 percent slump in Chinese markets, which sparked a selloff in global stocks along with oil and other commodities.
Wall Street had stayed in s narrow range for much of 2015, but volatility jumped this month as investors became increasingly concerned about a potential stumble in China's economy and after Beijing surprisingly devalued its currency. Continuación...