AD9958: Communication and PWR_DWN_CTL

I have a question regarding fast recovery power-down mode and the PWR_DWN_CTL bit for the AD9958

When placing this device in power down mode using the external bit, am I still able to update the internal registers via SPI bus? And use IO Update to store these values? Or am I not able to communicate with the part until the bit is deasserted?