One of the international musicians who is performing in three Iowa cities this week has an unusual ability — she sees colors in her mind with every note played. The condition is called synaesthesia. Scotland-born Seonaid Aitken says whenever she sees a letter, number or musical note, or hears the note, she sees a corresponding color. The 25-year-old started playing violin at age eight and says the colors help her create and perform amidst a rainbow of lights. Aitken says “I thought everyone had this when I was younger. I was 16 when I found out what it was.”Aitken says every letter of the alphabet, every number and every note has a unique color. She says whenever she sees an essay in the paper or hears music, the individual letters and sounds create a symphony of color. She says synaesthesia appears only in about one in every ten-thousand people, usually females. Aitken is a member of the cast for the show “Barrage,” which is billed as weaving together music from different eras and cultures to create a musical journey of global scope. This is Aitken’s first visit to Iowa, though she fears she won’t get to see much of it, except out the window of a plane or tour bus. After two-and-a-half years on tour with “Barrage,” Aitken says she still loves the traveling, although life on the road rarely offers her the opportunity to do much sight-seeing. “Barrage” plays in Des Moines on April 15th, Sioux City on the 16th and Iowa City on the 17th.