Abstract

Mild cognitive impairment (MCI) is a term applied to people who have memory problems that do not impact on daily function. It is assumed that earlier identification of neurodegenerative disease will lead to earlier treatment which may be more effective and which could modify the trajectory of decline. Because of shortcomings in disease identification and modification, MCI has previously been (inaccurately) viewed as a categorical entity. Instead, this chapter examines MCI as part of the clinical spectrum of neurodegenerative disease. We explore how the concept of MCI has evolved over time, where the historical roots of the condition lie, and elaborate on the challenges surrounding the status of MCI in current clinical practice. We argue that the condition needs to be formulated more accurately, incorporating genetic background, individual risk factors over the whole life-course, and, crucially, longitudinal assessment.