Assessing gastrointestinal symptoms and perception, quality of life, motility, and autonomic neuropathy in clinical studies.

Imprecise characterization of complaints of the upper and lower gastrointestinal (GI) tract puts patients at risks of either a delayed diagnosis or misdiagnosis and contributes to an increase in the overall direct and indirect costs of the health system. The current scenario in the case of functional GI diseases originates from at least two conditions: frequency of diseases and bothersome symptoms with an impact on the quality of life (QoL). To make a correct diagnosis is therefore almost mandatory. Once a positive diagnosis of functional involvement of the GI tract is made, the correct diagnosis assessment includes the study of symptom characteristics, entity and perception, detection of abnormal patterns of GI motor-function (gallblader and gastric emptying, oro-cecal and colonic transit, etc.), potential involvement of the autonomic nervous system (sympathetic, parasympathetic), and overall impact of such abnormalities on the QoL and psychological profiles. Results of these tests can be variable, depending on the type and intensity of the illness. In the present review, the state-of-the-art methods for correct assessment of several factors regarding the onset, perpetuation and outcome of functional GI diseases are discussed.