TORONTO — NHL commissioner Gary Bettman has brushed aside the latest swipes from U.S. Senator Richard Blumenthal over the league's stance on concussions.

Bettman responded Wednesday to attacks earlier this week from Blumenthal, who said that the NHL, and Bettman in particular, were on the wrong side of history regarding the link between concussions and long-term brain damage.

"Obviously the senator has his opinions and we have ours," Bettman said in an interview.

While suggesting that he wouldn't get into a "public debate about this," Bettman said he believes "medical and scientific decisions should be made by scientists and physicians."

That was the essence of his 23-page response to questions from Blumenthal regarding the NHL's stance on concussions and CTE. Bettman suggested that based on the "consensus" of medical experts, no definitive link had been made between the two.

He denied any suggestion that the NHL was "dismissiveness of the evidence" on Wednesday.

"If you've read the letter you could hardly suggest that a 23-page, single-spaced letter is dismissive," Bettman said.

The senator rebuked that earlier response, stating Monday that common sense as well as mounting scientific evidence demonstrate "clear links" between brain trauma and brain disease later in life, including CTE.

He called on the NHL to fund research studying the issue, describing it as imperative that the NHL take the lead on this issue.

Blumenthal first reached out to Bettman a day before the NHL draft, requesting clarification over the NHL's stance on the link between head trauma and CTE. That request came after emails between league officials were made public in an ongoing class-action lawsuit the NHL is facing over its' handling of concussions.

Some of those emails exposed internal concerns on the subject.

One email sent from Bettman to then-league disciplinarian Brendan Shanahan in December 2011 asked: "Any more concussions?"

"Not so far," Shanahan responded.

"Night is young!" Bettman said, replying from his iPhone.

Blumenthal cited the emails, including those among league officials which raised questions about the future of fighting in hockey.

He asked Bettman nine questions, wondering how head trauma in hockey differed from football, what changes the NHL could make to protect the long-term health of players, and whether the NHL had considered eliminating fighting, among other queries related to the matter.

Up for re-election in Connecticut this November, Blumenthal was inquiring as the ranking member of the Senate subcommittee on consumer protection, product safety, insurance and data security, which he said had jurisdiction over sports.

In his response, Bettman included expansive detail on why the science was not yet definitive, why hockey was different from football, while also explaining the NHL and NHL Players' Association's various education and testing programs. The NHL, Bettman noted, was the first professional sports league with a "Concussion Program", which mandated neuropsychological testing.

The program was established in 1997.

"Thus, while we agree that the ongoing research is very important, it is particularly unfair to criticize the NHL when we have followed the medical consensus of experts examining the science," Bettman wrote.

"If that consensus changes, so, too, will my answers."

Speaking Wednesday after a World Cup-related announcement in Toronto's Distillery District, Bettman disputed the notion that Blumenthal's attacks were striking a chord in the public sphere.

"It hasn't gained any traction," he said. "In fact, we haven't heard from very many people about it all."