WASHINGTON — Americans increased their spending in April at the fastest pace in four months, bolstered by a solid gain in incomes. The strong results underscored expectations that the economy is poised to rebound after a lackluster start to the year.

Consumer spending rose 0.4% in April after a 0.3% rise in March, the Commerce Department said Monday. It was the best showing since December. Incomes also rose 0.4%, double the 0.2% March increase.

Consumer spending, which accounts for 70% of economic activity, grew at the slowest pace in seven years in the first quarter. That was a key reason the economy, as measured by the gross domestic product, expanded by just 1.2% at the start of the year. Economists are hopeful GDP growth will rebound to around 3% in the current April-June quarter.

A key inflation gauge preferred by the Federal Reserve edged up a slight 0.2% in April, leaving prices rising just…