Pathology of the Peripheral Nervous System

Abstract

While pathology of the peripheral nervous system (PNS) is not usually considered to be within the province of the neuropsychologist, such pathology may complicate, or confuse, an attempt to evaluate a dysfunction of the central nervous system (CNS). Many PNS disorders, or neuropathies, often go unrecognized since they produce symptoms similar to other functional and organic disorders that the neuropsychologist frequently encounters. In addition, the types of processes that result in CNS dysfunction also are capable of affecting the PNS, including trauma (e.g., compression or entrapment injuries), toxins, infectious diseases, malnutrition, alcoholism, and genetic disorders. Not being aware of some of the more common disorders involving the PNS can lead to misdiagnosis and inappropriate treatment for the patient thought to have a CNS disorder. As with any medical disorder, precise evaluation and treatment of neuropathies should be done by a practitioner competent to do so. However, a familiarity with the general features of peripheral neuropathies is essential for the neuropsychologist to identify the presence of these disorders, distinguish between peripheral and central symptoms and signs, and at the same time, recognize potential limitations imposed by a peripheral disorder on procedures used to assess CNS functions. The intent of this chapter is to provide information that can help neuropsychologists address these issues.