When charismatic Italian politician Umberto Bossi (pictured above) suffered a severe stroke in 2004, the disease changed his voice, and, strangely enough, his public image. He went from being seen as an authoritarian figure to a benevolent one. To figure out why, researchers collected sound clips of Bossi speaking before and after the stroke and analyzed various acoustic parameters. They discovered that the most prominent transformation was a narrowing of the range of frequency variation in his voice. His intonation had become very flat, probably due to asymmetrical muscle weakness caused by the stroke. When the researchers carried out more studies on the speeches of charismatic political leaders like French President François Hollande, former Italian prosecutor and current mayor of Naples Luigi de Magistris, and former president of Brazil Luiz Inácio Lula da Silva, they found that a low-frequency voice is another important indicator for dominant or even threatening speeches. The findings, reported at the 168th Meeting of the Acoustical Society of America in Indianapolis this week, bolster a 2013 study, which found that deeper voiced male CEOs tend to manage bigger firms and earn higher salaries.