Ambient Assisted Living (AAL) has become an emerging and increasingly essential area of research, given the prospects of increasing the elderly world population. The establishment of the Internet of Things (IoT) paradigm provided several advances in the field of healthcare for older adults. However, the development of AAL platforms focused on older adults is still presenting several challenges. Many of these challenges are similar to those existing for IoT architectures (i.e., interoperability) and others are derived from the healthcare domain (e.g., patients and caregivers as end-users). In this paper, we present a survey of secondary studies on AAL platforms published between 2013 to 2017. Our focus resided in investigating the state-of-the-art of the adaptive AAL platforms for older adults assistance. We have established a set of research questions with which we seek to gain an overview of AAL platforms, development patterns, and the main challenges in this domain. We describe our search protocol, the execution, the selection of the papers, and the results obtained. Among the conclusions of our overview, we can mention the absence of a reference architecture for AAL platforms and some open questions (e.g., data privacy, usability, accessibility) present in this domain