From MN Bench Book - Trial Procedures & Practices for Judges
The trial judge is responsible for monitoring all activities that occur in the court room that may affect the outcome of the trial. Attorneys are focused, by necessity, on the what is happening with the witness. While the trial judge focuses on the interrogation of the witness, he or she must also monitor the activities that are occuring at counsel table, in the jury box and in the spectator section.
It is impossbile for the judge to monitor all of these areas of the courtroom by him or herself. Judges can and should use the courtroom staff, the court clerk, the court reporter and the bailiff or courtroom attendant to monitor what is going on in the courtroom. Judges should specifically empower their staff to do so and bring any inappropriate or unusual behavior they observe to the judge's attention. An example would be a clerk observing a juror falling asleep.