What explanation of each problem is most likely?

1. April always has trouble tasting foods, especially those with subtle flavors.
2. May, a rock musician, does not hear as well as she used to.
3. June has chronic shoulder pain, though the injury that initially caused it seems to have healed. (Hint: Think about the gate-control theory.)

1. April may have an impaired sense of smell, possibly due to disease, illness, or cigarette smoking.
2. Hearing impairment has many causes, but in May's case, we might suspect that prolonged exposure to loud music has damaged the hair cells of her cochlea.
3. Nerve fibers that normally close the pain "gate" may have been damaged, or a matrix of cells in the brain may be producing abnormal activity. Changes in the sensitivity of nerve cells in the central nervous system could also be involved.