Patient #1- helen, a 28-year-old woman, has noticed strange "pins and needles" feelings in her feet and hands. she has been very tired lately and she says that when she goes to the gym "she just feels weak." she says that her inability to exercise has been making her feel depressed. her vision seems to be getting worse and she's made an appointment with her ophthalmologist for later in the week. most recently, she has experienced moments of unsteadiness when she walks. she was a gymnast in high school; she has never had a problem with balance before. she has noticed that her symptoms seem to come and go. she experiences periods of fatigue and balance problems, but the majority of the time she feels just fine.