The respondent must be present at all hearings unless the respondent waives the right to be present either orally or in writing. A respondent's refusal to attend a hearing is presumed to be a waiver of the right to be present at the hearing. The judge must be notified if the respondent has been medicated within twenty-four hours of the beginning of the hearing or an adjourned session of the hearing, and of the probable effects of the medication.