When Americans were giddily drenching themselves with ice water during the “ice bucket challenge” a year ago, the cognoscenti rolled their eyes.

The aim of the ice bucket challenge was to raise money to combat A.L.S., also known as Lou Gehrig’s disease, a neurodegenerative ailment that affects some 15,000 Americans and usually leads to death within five years. But commentators scoffed: One on Time.com declared it “problematic in almost every way.” Critics sniped that the challenge wasted water and cannibalized contributions to better causes that affect more people.

The ice bucket challenge was taken as emblematic of “slacktivism,” the derisive term for cheap ways to feel good without doing anything meaningful. Critics point to Internet campaigns, the Stop Kony movement and the ice bucket challenge as merely symbolic ways for young narcissists to preen without actually achieving any change.

But now we have evidence that the ice bucket challenge may have worked.

Scientists studying A.L.S. have reported a breakthrough that could lead to therapy, not just for A.L.S. but for other ailments, too. And they say the money raised in the ice bucket challenge was crucial.

The breakthrough, published in Science, was summarized thus: “TDP-43 repression of nonconserved cryptic exons is compromised in ALS-FTD.”

Got it?

Here’s a translation: The research focused on a protein called TDP-43 that in some circumstances is linked to cell death in the brain or spinal cord of patients. The scientists found that inserting a custom-designed protein allowed cells to return to normal.

“That becomes our therapeutic strategy,” said Philip Wong, a professor at Johns Hopkins University whose lab conducted the research. He said the research team was now testing gene therapy strategies in mice to see if these can halt A.L.S. symptoms.

If it works in mice, the following step would be to seek to conduct a clinical trial in humans, he said.

The researchers are also hoping the therapy will work for a common cause of mental deterioration, frontotemporal dementia, and for inclusion body myositis, a progressive disease that leads to muscle weakness.

Jonathan Ling, a Johns Hopkins scientist who was the lead author of the Science article, said the new work might also lead to a diagnostic test (though probably not a treatment) for Alzheimer’s. Ling said the research team was also working with experts on cancer and immunology to see if other proteins might perform similar roles as TDP-43, possibly leading to far broader implications.

The ice bucket challenge went viral in 2014, partly because it was so much fun to watch videos of celebrities or friends dumping ice water on their heads. Videos of people in the challenge have been watched more than 10 billion times on Facebook . more than once per person on the planet. (I was one of the 17 million who uploaded a video of my drenching to Facebook.)

The ALS Association says the ice bucket challenge raised $115 million in six weeks, and many participants have become repeat donors. Google also reports there were more searches for “A.L.S.” in 2014 than in the entire previous decade.

The research at Johns Hopkins on TDP-43 was already underway, but Wong says ice bucket money helped accelerate the work and allowed the team to conduct some high-risk, high-reward experiments that were critical to the outcome.

It’s true that slacktivism doesn’t always work. The online campaign to “bring back our girls” . the Nigerian schoolgirls kidnapped by Boko Haram last year . raised attention, but the girls are still missing.

Likewise, Joseph Kony, the warlord, is still on the run despite the Stop Kony movement. But the United States and African countries directed more resources against Kony, and this has had a very significant effect: Killings by his group are down 90 percent since 2011.

So think of armchair activism as a gateway drug. It exposes people to causes and sometimes gets them hooked. And while it doesn’t always solve problems, it tends to build awareness of crises . a necessary but not sufficient step to getting them resolved.

In any case, armchair activism is preferable to armchair passivity.

With the ice bucket challenge, there’s little evidence of cannibalization that hurt other causes, and it seems to have been revolutionary for this one.

“Across the A.L.S. community, we are probably in our highest time of hope,” said Barbara Newhouse, president of the ALS Association.

So if you endured an ice dunking a year ago . or if you’re participating in the 2015 ice bucket challenge, now underway . there’s no need to apologize for having fun. Rather: Thank you!

Enough with the eye-rolling. Long live slacktivism!