On the Data Sheets I found the "Full-Scale Range" (+- 1V) and the "Clipping Level" (+- 1.3V), but nothing about the input common mode voltage (with +-5V power supplies).
I have the same question.
The sister-part AD835 has a common-mode specified from -2.5V to +3V.
Can we assume that it's the same on the AD834?