Measurement of Nonmotor Symptoms in Clinical Practice.

Nonmotor symptoms constitute a prominent part of Parkinson's disease manifestations. They are present since the first phases of the disease, increase their number and severity with disease progression, and importantly impact on patients' health and quality of life, caregivers' burden, and social resources. Research on Parkinson's disease has traditionally focused on the motor aspects of the disease, but an increasing interest in the nonmotor manifestations has risen in the past decade. The availability of assessment instruments for detecting and measuring these symptoms has allowed understanding of their importance and course over time, as well as estimation of therapeutic effects on them. In this chapter, a review of the basic characteristics of nonmotor symptom assessments used in clinical practice and research are presented.