Scores of workers from MTV Networks walked off the job yesterday afternoon, filling the sidewalk outside the headquarters of its corporate parent, Viacom, to protest recent changes in benefits.

The walkout highlighted the concerns of a category of workers who are sometimes called permalancers: permanent freelancers who work like full-time employees but do not receive the same benefits.

Waving signs that read “Shame on Viacom,” the workers, most of them in their 20s, demanded that MTV Networks reverse a plan to reduce health and dental benefits for freelancers beginning Jan. 1.

In a statement, MTV Networks noted that its benefits program for full-time employees had also undergone changes, and it emphasized that the plan for freelancers was still highly competitive within the industry. Many freelancers receive no corporate benefits.