Date: 201907
Local time of day: 0001-0600
Location: ZAU.ARTCC, IL
Light: Daylight
Aircraft: PA-34-200 Seneca I
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Cruise
Airspace: Class E ZAU
ATC / advisory: Center ZAU
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Confusion; Physiological - Other; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Other / Unknown; Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; General Physical Injury / Incapacitation
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Aircraft X was direct for the arrival in to ZZZ. This route put the aircraft in a direct conflict with many westbound departures; so I turned the aircraft to a 080 heading to provide lateral separation. Aircraft X was level at 17;000' which was fine with me until I got it north of the westbound departure track. When the aircraft was in the vicinity of the Hinkley airport the pilot requested lower. I asked what altitude and he requested 12;000 (maybe 11;000?). There was some insistence in his tone so I coordinated with West Departures at C90 to get him lower. The controller I spoke to questioned the APREQ; but I made it clear that I thought that the pilot really did need lower. They approved 15;000' on the current heading and gave me a freq. I then shipped the aircraft to C90 and I observed the aircraft descend to 14;000'.C90 then called me back on the land line asking what was up with giving them someone low flying through their airspace. They also said that the pilot told them that he did not want lower. I made it very clear that yes; the pilot did request lower and even stated that he would like 12;000'; maybe 11;000' and that I would not have called them about it if the pilot didn't ask. A different C90 controller called me back later and asked if I would work the aircraft at 14;000' northbound and I said I gladly would. Aircraft X checked back in on my frequency and again requested lower. I asked the pilot to 'say again request' and he said he wanted lower. I then questioned the pilot saying that he requested lower but then said he didn't want lower with TRACON and now he's requesting lower again. Then pilot then very firmly stated that he never requested lower. So then I confirmed that he wanted to stay at 14;000' and the pilot said that he wanted lower; 10;000.' I then immediately called C90 and said something isn't right with this pilot and that we need to get him lower. They said they'd call me back. They did quickly and said to send him direct ZZZ and descend to 7;000' which I did. The aircraft was then shipped to C90 with no incident.No recommendations; it was just a very strange event that I thought needed to be noted.




Synopsis: ZAU Center Controller reported an aircraft repeatedly requested lower altitudes than said they didn't request lower altitudes so the Controller descended the aircraft suspecting the pilot was suffering some sort of illness.