Commuter following a Q400 landing EWR reported wake turbulence encounter.

Narrative

While on a VISUAL approach to Runway 22L in KEWR; we were told to slow back from 160 kts for Q400 ahead that was going much slower. I retarded the throttles to slow down and slowed to a speed about 10 kts above Vref which was 114 kts. Further down the approach at 1000' to 900' we encountered some type of heavy wake or some kind of disruption in the air that caused us to roll about 15 to 20 degrees to the left. At the same time my airspeed was sucked away to about 107 kts. I immediately took corrective action; rolled the wings level and added power to regain back the airspeed (pitch attitude was level the whole time). We were still at 900' when the airplane was back to a stabilized condition so we decided to land straight ahead. Notified ATC about the rough air. The airplane was never out of control. Some type of wake turbulence or weather phenomenon. This would be a good scenario to include in our training program. It was completely unexpected. Thanks to the training department for providing us with the skills to handle the situation.