The promoter for former WBC light heavyweight champion Adonis Stevenson says the boxer remains unconscious and has not improved since doctors sedated him and placed him on a ventilator after a December 1 knockout loss.

Promoter Yvon Michel said Thursday "doctors do not venture an opinion on what lies ahead" for the 41-year-old fighter.

Stevenson is in intensive care at Quebec City's Hopital de l'Enfant-Jesusstill and "needs mechanical assistance to breathe"

Stevenson's condition deteriorated after he was helped to the dressing room following a mandatory defense of the WBC title against Oleksandr Gvozdyk of Ukraine at the Videotron Centre.

After a close fight in the first half, Stevenson began to fade as the bout played out in the later rounds. After staging a finally rally in the tenth, when he managed to hurt Gvozdyk, the challenger then unleashed an assault of hard punches in the eleventh that sent Stevenson down hard. The contest was quickly waved off.

Stevenson went back to the dressing room, but he began to feel dizzy and unwell.

He was taken to hospital by ambulance. And then admitted with a traumatic brain injury that required immediate neurosurgery.

Intensive care specialist Dr Alexis Turgeon said on December 5 most patients suffered lasting effects from such injuries.

The hospital has not provided an official update on Stevenson's condition since.