Functional mapping of glomus tumors reveals underlying embryology.

A functional map of cranial nerves was created by the multidimensional scaling (MDS) of adults' symptoms from glomus tumors. Differences between cranial-nerve deficits in eight different subsets of glomus tumors were input to MDS. MDS determines coordinates of points (representing cranial nerves) such that distances between points are related as closely as possible to differences in the observed symptoms. For example, two nerves that are equally likely to be affected by a glomus tumor would be put close together in the calculated map, even though they may be physically distant. The result resembles a stage in the developing nervous system. This correlation provides mathematical confirmation that adults' glomus tumors are related to early embryology. This in turn suggests that functional maps can provide a useful way for computers to depict underlying patterns in medical data.