TUCSON, Arizona (Reuters) - Congressional staffer Ron Barber was standing in a receiving line next to Representative Gabrielle Giffords at her first outreach event of the year when the gunman opened fire at point-blank range.

Moments later he was lying in a pool of his own blood on the sidewalk when Giffords and fellow aide Gabe Zimmerman fell beside him outside the Tucson area grocery store.

"I saw the congresswoman being shot, I saw myself being shot, I saw Gabe die in front of me," recalls Barber, 66, Giffords's district director who was shot in the face and thigh.

"They are memories that will never go away," added the aide, who has since been diagnosed with post traumaticstress disorder, or PTSD.

Sunday marks a year since a gunman fired a semi-automatic pistol into a crowd gathered at Giffords's "Congress on Your Corner" event last January 8, killing six people and wounding 13 others.

As Tucson prepares to mark the somber anniversary, survivors like Barber are at various stages of recovery from the physical and emotional wounds of the deadly spree that ripped apart scores of lives, rocked this close-knit southwest city and shocked America.

"I've struggled with the emotions," said military veteran Bill Badger, 75, who was hailed as a hero for his role in ending the spree by grabbing accused triggermanJared Loughner and slamming him to the ground before he could reload.

"It changed my life," he said.

Giffords plans to attend the candlelit vigil in Tucson on Sunday with her husband, retired astronautMark Kelly, although it remains unclear if she will seek to resume her political career and run for re-election in November.

Loughner was found mentally incompetent to stand trial at a hearing in May and is being treated at a federal prison hospital in Missouri.


Hours after the shooting, Barber underwent emergency surgery at the University of Arizona Medical Center to repair damage from a bullet that struck his cheek and fractured his jaw, and from another that hit near his groin.

In the following months, as Giffords underwent intensive rehab for a head wound at a hospital in Houston, Texas, Barber recovered sufficiently to return to work in July, where he was welcomed by colleagues with balloons and a carrot cake.

"I just love being here. They are wonderful people," Barber said in an interview at Giffords's Tucson district office, where he works half time.

"But being here was a daily reminder that Gabe wasn't here, because he and I would huddle six or seven times a day on issues," he said.

Zimmerman, 30 and a Tucson native, had worked for Giffords since her first congressional campaign in 2006. Colleagues remembered him as a gentle, thoughtful person.

Barber now walks with a cane and deals with the lingering symptoms of PTSD, which include flashbacks, nightmares and panic attacks.

Speaking out about the events also helps him deal with the trauma, and, he hopes, create a greater understanding about PTSD, which also affects other survivors.

Badger, who received a glancing bullet wound to his scalp, was patched up with medical glue after the shooting and promptly discharged from the hospital.