URGENCH, Uzbekistan — Muhammad Bekjanov, often called the world’s longest-imprisoned journalist, did 18 years of hard time in some of Uzbekistan’s most notorious prisons, with nicknames like “Goodbye to Youth.” He was a writer with never much hope for a happy ending to his own story.

“I was accused of insulting President Karimov,” he said, referring to Islam A. Karimov, the thin-skinned and iron-fisted former president of Uzbekistan, a strategically important country north of Afghanistan. In prison, Mr. Bekjanov lost his hearing in one ear and contracted tuberculosis.

And yet, despite his years of suffering and deprivations, Mr. Bekjanov has become an improbable spokesman for a political and economic overhaul underway in Uzbekistan that began after Mr. Karimov’s death last year, a movement sometimes called the Uzbek Spring.

The thaw, which started to take shape quietly this year, has already loosened police controls on the population and is testing the limits of gradual political change in a region more noted for its revolutions, such as those that deposed authoritarian leaders in Georgia, Ukraine and Kyrgyzstan.