Denise Gibson's voice was always distinctive. When she was younger, even strangers would comment on its lilt and melody. "People would always say, 'Your voice is like a song ,' " the Millwood woman recalls. These days, however, Gibson's song is strained. Among the first things strangers notice now, in addition to her trembling head, is her constricted voice, her distorted words, and the sheer effort it takes to speak.