The 76-year-old Democrat, who is serving his 13th term, said the House attending physician referred him for further evaluation following the incident.

Rep. John Larson (D-Conn.) said Tuesday that a "complex partial seizure" was what caused him to seize up during a House floor speech the previous day. Why it matters: The 76-year-old's office had initially said the incident — which quickly went viral on social media — was likely caused by an "adverse reaction to a new medication.

Rep. John Larson (D-Conn.) froze up and had difficulty speaking during a House floor speech on Monday, in what his office said was likely an “adverse reaction” to a new medication. The 76-year-old lawmaker was highlighting concerns about Social Security after the Trump administration accessed sensitive Treasury Department payment data.