A B717 Captain reported an autothrottle malfunction on takeoff roll that included potential engine overspeed and then ground spoiler deployment. A rejected takeoff was performed; all systems reset with no faults noted; and a normal takeoff ensued.

Narrative

Power was advanced for takeoff and came up normally and stabilized at 1.40 EPR (flex 60). At 80 KTS; as I was cross-checking instruments; I felt the power levers move forward; pulling my hands and exceeding the programmed power setting. As I was trying to analyze the situation; I noticed engine indications (I believe boxed N1) illuminating red. I immediately retarded the throttles in an attempt to bring them back to the 'V's' and prevent engine overspeed or overtemp. I felt resistance in the autothrottles; so I disengaged them. It was about that time that I noticed ground-spoiler deployment; prompting an immediate rejected takeoff (RTO). Standard callouts were used for the aborted takeoff. Airspeed did not accelerate much beyond 80 KTS and moderate brake application and idle reverse thrust was all that was necessary to stop the aircraft.We cleared the runway at the first available high speed taxiway and I reassured the passengers over the PA that we were safe and no evacuation would be necessary. Maintenance Control was called and advised of our condition. Brake temps were monitored and never exceeded 120 degrees. At my request; we went through the ACARS maintenance faults to be sure there were no exceedances recorded. There were no exceedances recorded or any other cautions or warnings displayed. We could not find any reason for the uncommanded throttle movement on takeoff. After careful consideration and a re-completion of all checklists; a subsequent and uneventful takeoff was made with no further complications. Apparently; this event was caused by some type of auto-throttle anomaly; I can't be sure. The end result was auto-ground spoiler deployment; which left me no choice but to abandon the takeoff.