The four chapters in this section are concerned with the clinical
aspects of the highly specialized functions of taste and smell,
vision, hearing, and the sense of balance. These special senses
and the cranial nerves that subserve them represent the most finely
developed parts of the sensory nervous system. Dysfunction of the
eye and ear are, of course, the domain of the ophthalmologist and
otologist, but they also are of great interest to the neurologist.
Some defects in the special sensory apparatus reflect the presence
of systemic disease and others represent the initial or leading
manifestation of neurologic disease. It is from both these points
of view that they are considered here. In keeping with the general
scheme of this text, the disorders of the special senses and of
ocular movement are discussed in a particular sequence: first, certain
facts of anatomic and physiologic importance, followed by cardinal
clinical manifestations of disease, and then a consideration of
the syndromes of which these manifestations are a part.