How did some presidents in Central Asia use their powers after the disintegration of the USSR?

They became authoritarian and extended their terms.

In Central Asia, some presidents became authoritarian and extended their terms in office, limiting political dissent and opposition.

The construction of democratic institutions was not given the same attention and priority as the demands of economic transformation. The constitutions of all these countries were drafted in a hurry and most, including Russia, had a strong executive president with the widest possible powers that rendered elected parliaments relatively weak. In Central Asia, the presidents had great powers, and several of them became very authoritarian. For example, the presidents of Turkmenistan and Uzbekistan appointed themselves to power first for ten years and then extended it for another ten years. They allowed no dissent or opposition. A judicial culture and independence of the judiciary was yet to be established in most of these countries.